6.8 SPC Forums banner

Anyone getting 3000 fps with 100 gr in a 16" Barrel?

11K views 53 replies 18 participants last post by  cajun 
#1 ·
I emailed a guy that did an article about the 6.8 SPC not so special, Nathaniel Fitch. I told him I had hand loaded a 100 gr bullet and had gotten over 3000 fps out of my 16" AR Performance with the SPC II chamber 1:11.25" twist 5R rifling. He just emailed me back and said it's too over pressured and to stop using it. I quit using it because I did not like the group as well as some of my other trials, not pressure. IIRC I had very little pressure signs but had dropped down just a bit to get a better group size. Now I can't find the info I had about the chronograph on that load.

It's a sad little article put out by The Firearm Blog (link: http://www.thefirearmblog.com/blog/2015/04/04/not-so-special-a-critical-view-of-the-6-8mm-spc/ and in the email he said he uses Silver State Armory ammo, and he told me to stop using that round as it would blow up on me.

I am pretty careful with my hand loading and usually test 1 bullet on something that looks a bit beyond recommended. Even at that I noticed no major swipes, nor flattened primers, nor excessive bulged cases. Barrels (with their unique chambers) are all as different as trees. No two are exactly the same, or else we would find the one true "Holy Grail" of hand loads, pass it along to each other and life would be good.

So inquiring minds (me) would like to know. I could swear I got that fps out of a 100 gr bullet, but without anythhing written down I might have dreamed I did.
 
See less See more
#2 ·
You can get close but it is a hot load without a doubt(Probably in the range of 62,000psi). 2997 out of an 18" with 33gr 2200 or 1200 in cooler weather. I tested in the back warehouse around 50 degrees. The load is compressed and in order to get there without pressure signs the brass must be sized about .002" under the chamber size. If you drop down to around 32gr the accuracy is very good BUT 30.5gr of either powder is as high as I will recommend after running the pressure trace on it.
 
#3 · (Edited)
Too high?

Harrison. I've used the 32.0 grain load of 1200-R for my 100 grain Nosler Accubonds and find them to be very accurate. Are you saying one should reconsider this load because it is too hot of a load? If so, what charge weight of this powder do you recommend for accuracy? I use this bullet for my hunting load.

Daniel
 
#4 ·
So inquiring minds (me) would like to know. I could swear I got that fps out of a 100 gr bullet, but without anythhing written down I might have dreamed I did.
This is telling me maybe you just aren't quite sure. I am new to the 6.8, but not handloading. In my 18" I can't get to 2900fps with the 100gr GMX, I doubt it's possible in any 16" bbl, but stranger things have happened.
 
#5 ·
Yes, absolutely that I am not sure. Most of the time I have written this data down, and can refer back. FPS has never been that important to me as small groups, good pressure signs (or lack thereof) and very functional action. It just seemed like I had done this with something like 10X or one of my other powders, and not with the normal load I use. It's been quite a while since I loaded the 100 gr and I've mostly worked around the 120 gr Hornady. BTW, I file off the tip of the loaded bullet and it allows me to load a little further out that way. Does not seem to affect accuracy one little bit... to me anyway.

Point is that even if someone can get 29xx fps from a 95 grain that should translate into a heck of a lot more performance than what the author of this story would lead us to believe.
 
#6 · (Edited)
Here's my .02
I load for Barnes 95 TTSX, Hornady 110 HPBT, and Nosler 115 HPBT, that's it, so I don't know everything. My most accurate load for the 95 is 30.0 of AA2200 netting 2825 from a 16" Stag Arms 1/11 barrel. Hornady is 28.5-28.8 AA220= 2600-2650, and 28.6 for the 115= ~2550, I use CCI 450s, SSA brass and oal is 2.285. 3K out of a 16" barrel with 100 grain pill? I'm not saying it can't or hasn't been done, but it probably shouldn't be.
 
#7 ·
AKsarben, H gave it to you straight. A 3000 fps load with a 100gr bullet in a 16” barrel is well above max pressure. I’ve gone and pushed the edges of performance because I’ve heard others make this claim. I was using top components like ARPs Superbolt. I was able to achieve just above 3000 fps in an 18” ARP with once-fired, resized brass, CCI450 primers, and AA2200 and 1200R powders. Pressure signs (swipes and primers) looked ok but I went to reload those cases, the primer pockets were so loose I had to discard cases that had more than 31 grains of powder. These loads were way over-pressure and things can break at these pressures. You are getting hot with 30.0 grains of these powders.

Daniel, How many reloads are you getting per case? Yes, 32 grains of 1200R is above max chamber pressure. But there is more to reconsider. 1200R was my favorite powder to use with 100gr bullets and most accurate until I used it for a year. I had average muzzle velocities for the exact same load vary by over 250 fps through the changing seasons. It spurred me to do some temperature sensitivity testing which found 1200R to be a temperature sensitive powder with an occasional round dropping 300 fps velocity when temps went above 90F. Be cautious.
 
#8 ·
Well, it's probably a good bet then that it was not with 100 gr bullets that I had gone over 3000 fps, but something a bit lighter.

Xman: I understand the implication of the pressure issues with the reloading and initial firing. Many of my rounds are virgin brass, Hornady, never fired or resized. I just do a quick "light" mouth widening with a special flare tool/die just to make it a bit easier to start the bullet.... not much, just a wee bit of a kiss of that special die. Using new brass in that way I might not have shown any early signs of over pressure. Possibly.

However, if this was a hot military load, and those 5.56 NATO loads are pretty warm, would it not be about the equivalent? In other words, in a world of combat where brass is not picked up, but considered spent, would that work? It would probably work quite well with the 90 gr offerings as that is still a larger pill to send down range than most of what the military has for 5.56 NATO.

Must have been a dream I had then of hitting that 3000 fps mark with 100 gr bullet. Like I posted at the very beginning, I've misplaced or never recorded well what I had gotten on the Chrony, so I was wrong in my thinking that this was a possibility.

In retrospect, the author of the article had used SSA ammo and a SPC II chamber, and insists his data is ironclad. I never doubed his data using SSA ammo, but I was sure either I or someone else in here had had success with 100 grains at or near the 3000 mark. Also, his suggestion that to get that I would have had to use a 26" barrel, is making me wonder, as I have read that you gain very little and sometimes loose velocity with too much barrel length. What he wrote back to me: "I don't know what barrel length you are getting that velocity from, but for reference 6.8 SPC should produce about 2,300 Joules of energy from a 16" barrel at safe pressure. Your figures give over 2,700 Joules of energy, which at safe pressure implies a 26" barrel or longer."
There is only so much powder you can put into that case to drive that .277 bullet down the barrel, and the key is not the barrel length but the right powder to allow push all the way down the 16 inches of that barrel. SSA makes some top quality bullets, no doubt, and I will never imply that they do not. It is just with so many different barrel configurations an chambers, no two are ever exact in how they handle pressure. Each barrel is unique, and for SSA to make a cartridge that will handle all of them, safely, they have to load to certain limitations. His using factory ammo will only give results for those loads, whereas what hand loaders have done is, or try to do, is maximize the overall performance of "their" barrel.
 
#9 · (Edited)
if this was a hot military load, and those 5.56 NATO loads are pretty warm, would it not be about the equivalent? In other words, in a world of combat where brass is not picked up, but considered spent, would that work? It would probably work quite well with the 90 gr offerings as that is still a larger pill to send down range than most of what the military has for 5.56 NATO.
Not exactly. Look at the 5.56 bolt and compare to a 6.8 bolt. The 5.56 has a lot more metal and structural strength to take those higher pressures, e.g., 5.56 above 60,000 psi and 6.8 SPC II at 58,000 psi. Then look at the Grendel 6.5 bolt and they have a 53,000 psi limit. Also, as 6.8 handloaders, we may not use the thicker primers associated with 5.56 Mil-Spec loads and typically do not crimp the primers to resist having one pop-out under the higher operating pressures.

There is only so much powder you can put into that case to drive that .277 bullet down the barrel, and the key is not the barrel length but the right powder to allow push all the way down the 16 inches of that barrel.
My 18" ARPs were averaging 60 to 100+ fps more mv than my 16" APRs. The lighter faster bullets where the ones where I was getting 100+ fps more.

If you want to approach/obtain 3000 fps from a 16" barrel, 85 to 90 grain bullets with RE7 or AA2200 will be viable options. 1200R would likely work also but I have become "gun shy" with that powder because it is very sensitive to temperature changes and I've had wild muzzle velocity variations between range sessions (temp change) and during the same range session when above 90F (300 fps drops).

Below is a Sierra 90 HP load I use in my 18". This would likely work well with a 90 Gold Dot, also. You can also push an 85 TSX toward your goal. The TSX have lower chamber pressures because of the bands and being so far from the lands (ogive ends at the front of the first band not the curve of the bullet tip). Load it as long as your mag will allow. Loading longer than mag length I've gotten 3200 fps with the 85 TSX in a 20" ARP with AA2200.

90gr Sierra HP - 2955 fps (29.5gr RE7) [BC 0.210]

Stay safe. I've broken a bolt chasing someone else's claimed "within pressure load" while trying to achieve velocity goals.
 
#10 ·
I'm not chasing down 3000 fps. Quite happy with the velocity and such from my 120 Hornady regarding groups. I thought perhaps I had read in the forum here about 3000 fps with 6.8 or I had done it some time back and can't find the info.

The author's reference to the 6.8 SPC Not So Special raised my neck hairs a bit, as I just plain feel that it (the 6.8 SPC) was well designed, thought out cartridge and in this platform way outshines any of the 5.56 NATO loads that the military uses. His article http://www.thefirearmblog.com/blog/2015/04/04/not-so-special-a-critical-view-of-the-6-8mm-spc/ has a critical evaluation of the round and he does back up what he said with data that I can't refute, but it's like saying if I cut off a flea's leg he is going to jump 1/6 less distance... until he has no legs and when instructed to jump does not, and then writing the conclusion that fleas with no legs can't hear.

I think there is a bit more to the whole of the cartridge and rifle set up that he is missing.
 
#14 ·
[Q
The author's reference to the 6.8 SPC Not So Special raised my neck hairs a bit, as I just plain feel that it (the 6.8 SPC) was well designed, thought out cartridge and in this platform way outshines any of the 5.56 NATO loads that the military uses. His article http://www.thefirearmblog.com/blog/2015/04/04/not-so-special-a-critical-view-of-the-6-8mm-spc/ has a critical evaluation of the round and he does back up what he said with data that I can't refute,
Wow, that article hurt my head. It was limited in scope (one type of bullet and one application), had too much theoretical in it, and not enough practical/real-world reality. I couldn't read it all. It looks like he used the SPC I which Remington got wrong. Also, my experience with calculators for performance like QuickLoads are so conservative as to what they 6.8 can do that they are of little value. Some of you may have seen the terminal performance testing I've done with 6.8mm bullets. I have done almost as much with .223 bullets (which I have not posted). There is a big difference in terminal performance between the .223/5.56 and the 6.8mm and their effective ranges. This testing has been limited to 300 yards with some equivalent testing out to 450 yards. Using a 24" .223/5.56, there aren't that many bullets that function base 200 yards because their energy state is so low. The 6.8mm SPC II is way ahead of the 2.23/5.56 when it comes to terminal performance over a wide range of bullets and applications.
 
#15 ·
I tried to upload a word document, but I can't get it to do so. Actually, I am not given the option to "Manage Attachements"...

I would like to upload it so it had to be opened and did not appear as the actual document...

Any thoughts?...

Thanks...BCB
 
#21 ·
Robert's Report

Yep, very familiar with that link: on my website in my signature, if you go to the "Links" page you will see that report.
http://www.taurus45acp.com/information_links/links.htm

Honestly, I think the bureacrauts at the time would have outfitted the military with a .22 semi/full auto rifle if they could have gotten away with it. And, from the miserable early failures of the M-16 with it's jamming and failures = body bags sent home, they may have been better off. Concept of lots of rounds, easy to carry, ..... did I mention lots of rounds? .223 is an excellent varmint round. Most states won't let you hunt deer with it and some, like Nebraska, it is the absolute minimum round that you can legally use. That should tell you something right there. Deer and man are not too much different in relative size.

The 6.8 SPC II IS special and I have not doubt at all about it. Proven with thousands of deer and large hogs taken and a well put together combo for the M-4 and similar AR-15
 
#23 ·
The following is from QuickLoad--it seems to think that 3000 fps with a 100 grainer might be a "challenge"...

I'm still waiting on the recipe that is giving 3000 fps with a 100 grainer. I can't get near it with a 23" barrel and an O.C.L. that wouldn't even come near to fitting in a semi-magazine...


Cartridge : 6.8 mm Rem SPC
Bullet : .277, 100, Hornady SP 2710
Useable Case Capaci: 35.110 grain H2O = 2.280 cm³
Cartridge O.A.L. L6: 2.393 inch = 60.78 mm
Barrel Length : 16.0 inch = 406.4 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Muzzle Velocity: 3000 fps or 914 m/s
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

1 loads produced a Loading Ratio below user-defined minimum of 90%. These powders have been skipped.
Powder type Filling/Loading Ratio Charge Charge Vel. Prop.Burnt P max P muzz B_Time
% Grains Gramm fps % psi psi ms
--------------------------------- -----------------------------------------------------------------
Rottweil R904 135.7 43.3 2.81 3000 83.7 84853 11062 0.669 !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 60 124.0 42.1 2.73 3000 93.2 69334 12759 0.716 !DANGEROUS LOAD-DO NOT USE!
Bofors RP19 ~approximation 130.6 41.8 2.71 3000 90.9 71380 11999 0.709 !DANGEROUS LOAD-DO NOT USE!
Hodgdon Hybrid 100V 134.3 42.0 2.72 3000 93.8 74862 11470 0.696 !DANGEROUS LOAD-DO NOT USE!
Norma URP 130.5 41.8 2.71 3000 90.9 71345 12003 0.709 !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-17 123.4 41.9 2.71 3000 92.4 69278 12515 0.716 !DANGEROUS LOAD-DO NOT USE!
Elcho 17 123.4 41.9 2.71 3000 92.4 69278 12515 0.716 !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4350 134.6 42.6 2.76 3000 87.4 80089 11271 0.683 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N550 126.9 42.0 2.72 3000 90.8 70124 12149 0.716 !DANGEROUS LOAD-DO NOT USE!
Accurate 2700 125.3 42.3 2.74 3000 88.7 88282 10594 0.668 !DANGEROUS LOAD-DO NOT USE!
IMR 4350 132.1 42.5 2.76 3000 87.6 79924 11275 0.683 !DANGEROUS LOAD-DO NOT USE!
Norma 202 117.5 37.4 2.42 3000 98.3 71736 11356 0.717 !DANGEROUS LOAD-DO NOT USE!
IMR 4007 SSC 124.3 40.8 2.64 3000 88.1 81003 11223 0.687 !DANGEROUS LOAD-DO NOT USE!
ADI AR 2206H 116.6 37.7 2.45 3000 94.3 71995 11729 0.717 !DANGEROUS LOAD-DO NOT USE!
Bofors RP7 NT ~approximation 123.7 40.4 2.62 3000 89.1 81113 11141 0.677 !DANGEROUS LOAD-DO NOT USE!
Bofors RP3 NT ~approximation 126.3 40.6 2.63 3000 90.8 80158 11103 0.681 !DANGEROUS LOAD-DO NOT USE!
Bofors RP7 128.3 40.8 2.64 3000 88.1 80902 11232 0.688 !DANGEROUS LOAD-DO NOT USE!
Rottweil R907 128.3 40.8 2.64 3000 88.1 80902 11232 0.688 !DANGEROUS LOAD-DO NOT USE!
Hodgdon H4895 116.1 37.6 2.43 3000 94.9 71068 11771 0.720 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N140 120.7 38.3 2.48 3000 98.8 74205 10963 0.705 !DANGEROUS LOAD-DO NOT USE!
SF033 fl, russ. 5,45x39 107.1 35.4 2.29 3000 100.0 71233 10416 0.726 !DANGEROUS LOAD-DO NOT USE!
IMR 8208 XBR 115.3 37.3 2.42 3000 96.2 73902 11344 0.708 !DANGEROUS LOAD-DO NOT USE!
ADI AR 2206 118.0 37.8 2.45 3000 96.0 79854 10894 0.689 !DANGEROUS LOAD-DO NOT USE!
Lovex S065 130.0 41.2 2.67 3000 90.8 77626 11413 0.699 !DANGEROUS LOAD-DO NOT USE!
Norma 201 118.6 37.6 2.43 3000 96.2 74139 11439 0.716 !DANGEROUS LOAD-DO NOT USE!
PB Clermont PCL 507 113.2 38.2 2.48 3000 95.9 72291 11546 0.713 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N530 112.3 36.5 2.37 3000 96.1 73177 11421 0.709 !DANGEROUS LOAD-DO NOT USE!
Lovex D073.5 110.4 38.3 2.48 3000 97.1 74445 11232 0.716 !DANGEROUS LOAD-DO NOT USE!
Accurate 2460 110.0 38.3 2.48 3000 97.1 74445 11232 0.716 !DANGEROUS LOAD-DO NOT USE!
Winchester 748 110.2 38.4 2.49 3000 96.3 69024 11709 0.720 !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 40 112.5 37.1 2.41 3000 95.9 76183 11233 0.703 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N133 122.3 36.2 2.35 3000 100.0 78367 10205 0.692 !DANGEROUS LOAD-DO NOT USE!
Norma 204 129.5 43.3 2.81 3000 84.4 81543 11409 0.677 !DANGEROUS LOAD-DO NOT USE!
Raufoss RA4 133.8 43.3 2.81 3000 84.4 81543 11409 0.677 !DANGEROUS LOAD-DO NOT USE!
Bofors RP4 ~approximation 133.8 43.3 2.81 3000 84.4 81543 11409 0.677 !DANGEROUS LOAD-DO NOT USE!
Lovex S060 118.6 37.3 2.42 3000 95.4 79031 10990 0.691 !DANGEROUS LOAD-DO NOT USE!
Somchem S321 111.0 38.7 2.50 3000 96.2 72528 11580 0.716 !DANGEROUS LOAD-DO NOT USE!
Hodgdon H335 105.9 37.4 2.42 3000 98.3 71655 11356 0.714 !DANGEROUS LOAD-DO NOT USE!
Rottweil R902 121.1 37.8 2.45 3000 96.3 75045 11314 0.713 !DANGEROUS LOAD-DO NOT USE!
Ramshot X-Terminator 112.3 38.8 2.51 3000 94.8 77156 11233 0.699 !DANGEROUS LOAD-DO NOT USE!
Bofors RP2 NT ~approximation 117.2 37.7 2.44 3000 95.6 77959 11026 0.693 !DANGEROUS LOAD-DO NOT USE!
Lovex D073.4 108.7 37.7 2.44 3000 97.2 75815 11053 0.708 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N160 144.8 44.9 2.91 3000 83.7 89068 10788 0.660 !DANGEROUS LOAD-DO NOT USE!
Lovex S062 122.1 38.5 2.49 3000 96.1 72971 11486 0.716 !DANGEROUS LOAD-DO NOT USE!
Accurate 2520 114.0 38.9 2.52 3000 97.4 70080 11552 0.726 !DANGEROUS LOAD-DO NOT USE!
Lovex D073.6 116.6 38.9 2.52 3000 97.4 70080 11552 0.726 !DANGEROUS LOAD-DO NOT USE!
Accurate 2200 105.3 34.6 2.24 3000 98.3 77001 10836 0.697 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N540 119.8 39.2 2.54 3000 98.2 72441 11423 0.713 !DANGEROUS LOAD-DO NOT USE!
IMR 4064 125.0 38.2 2.48 3000 94.0 75622 11296 0.700 !DANGEROUS LOAD-DO NOT USE!
Accurate 2230 109.7 38.4 2.49 3000 95.7 76895 11079 0.702 !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 9 117.3 39.2 2.54 3000 94.2 73002 11591 0.709 !DANGEROUS LOAD-DO NOT USE!
IMR 4895 118.7 38.4 2.49 3000 93.8 69200 12019 0.725 !DANGEROUS LOAD-DO NOT USE!
Hodgdon VARGET 123.7 38.7 2.51 3000 93.6 75500 11402 0.698 !DANGEROUS LOAD-DO NOT USE!
ADI AR 2208 123.3 38.7 2.51 3000 93.6 75500 11402 0.698 !DANGEROUS LOAD-DO NOT USE!
ADI AR 2219 105.7 35.3 2.29 3000 99.0 71184 11156 0.713 !DANGEROUS LOAD-DO NOT USE!
Hodgdon H322 112.4 35.3 2.29 3000 99.0 71184 11156 0.713 !DANGEROUS LOAD-DO NOT USE!
Norma 203B 120.5 39.0 2.53 3000 93.9 70385 11879 0.720 !DANGEROUS LOAD-DO NOT USE!
Raufoss RA11 120.0 38.8 2.52 3000 93.2 70824 11869 0.719 !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-15 120.0 38.8 2.52 3000 93.2 70824 11869 0.719 !DANGEROUS LOAD-DO NOT USE!
Bofors RP11 ~approximation 120.0 38.8 2.52 3000 93.2 70824 11869 0.719 !DANGEROUS LOAD-DO NOT USE!
Ramshot Wild Boar 114.0 39.4 2.55 3000 94.0 72164 11676 0.711 !DANGEROUS LOAD-DO NOT USE!
Accurate 2015 114.4 35.4 2.30 3000 100.0 74928 10573 0.714 !DANGEROUS LOAD-DO NOT USE!
Rottweil R901 117.1 36.0 2.33 3000 98.4 73756 11276 0.725 !DANGEROUS LOAD-DO NOT USE!
Ramshot TAC 114.6 40.0 2.59 3000 91.4 77498 11409 0.697 !DANGEROUS LOAD-DO NOT USE!
IMR 4320 122.2 38.9 2.52 3000 93.8 74084 11443 0.699 !DANGEROUS LOAD-DO NOT USE!
Somchem S355 125.3 39.7 2.57 3000 94.7 71947 11699 0.717 !DANGEROUS LOAD-DO NOT USE!
Alliant AR-Comp 114.4 35.8 2.32 3000 100.0 67419 10769 0.726 !DANGEROUS LOAD-DO NOT USE!
Hodgdon BL-C2 113.0 39.9 2.59 3000 95.2 69688 11876 0.721 !DANGEROUS LOAD-DO NOT USE!
Bofors RP11 TZ ~approximation 113.8 35.8 2.32 3000 100.0 67438 10769 0.726 !DANGEROUS LOAD-DO NOT USE!
Somchem S341 115.5 40.2 2.61 3000 94.2 75012 11289 0.700 !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 10 105.8 36.6 2.37 3000 98.3 71686 11362 0.717 !DANGEROUS LOAD-DO NOT USE!
IMR 3031 119.4 36.1 2.34 3000 99.1 66019 11577 0.732 !DANGEROUS LOAD-DO NOT USE!
Somchem S335 119.5 37.8 2.45 3000 99.4 78245 10640 0.701 !DANGEROUS LOAD-DO NOT USE!
PB Clermont PCL 508 (PCL223) 105.8 36.7 2.38 3000 98.3 71800 11348 0.717 !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-12 113.1 37.3 2.42 3000 99.2 74746 10881 0.704 !DANGEROUS LOAD-DO NOT USE!
ADI BM2 106.1 36.6 2.37 3000 97.5 77380 10962 0.698 !DANGEROUS LOAD-DO NOT USE!
Hodgdon CFE223 112.0 40.4 2.62 3000 93.9 69912 11926 0.715 !DANGEROUS LOAD-DO NOT USE!
Nitrochemie A/S 0300 102.7 34.1 2.21 3000 100.0 69382 10959 0.725 !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 50 119.9 40.4 2.62 3000 91.9 74840 11504 0.703 !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-10x 111.0 33.9 2.20 3000 100.0 73029 10677 0.718 !DANGEROUS LOAD-DO NOT USE!
PB Clermont PCL 516 117.4 40.5 2.62 3000 91.6 74960 11542 0.701 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N150 131.9 40.3 2.61 3000 96.6 75179 11165 0.700 !DANGEROUS LOAD-DO NOT USE!
Kazan Sunar 308W 110.9 35.1 2.27 3000 100.0 79988 10078 0.693 !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 7 115.5 40.1 2.60 3000 91.9 77024 11327 0.700 !DANGEROUS LOAD-DO NOT USE!
ReloadSwiss RS 52 120.4 40.3 2.61 3000 92.0 74544 11558 0.703 !DANGEROUS LOAD-DO NOT USE!
Hodgdon Benchmark 115.3 36.7 2.38 3000 97.3 77529 10964 0.697 !DANGEROUS LOAD-DO NOT USE!
Elcho TR140 - preliminary data 121.5 40.6 2.63 3000 92.0 75446 11443 0.701 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N130 116.0 35.1 2.27 3000 100.0 79011 10099 0.695 !DANGEROUS LOAD-DO NOT USE!
ADI AR 2210 108.0 36.1 2.34 3000 97.4 76621 11020 0.700 !DANGEROUS LOAD-DO NOT USE!
Alliant Reloder-7 106.3 33.3 2.16 3000 100.0 78430 10079 0.700 !DANGEROUS LOAD-DO NOT USE!
Hodgdon H380 121.5 40.2 2.60 3000 91.5 74022 11663 0.708 !DANGEROUS LOAD-DO NOT USE!
Norma 200 107.4 34.0 2.20 3000 100.0 74640 10458 0.722 !DANGEROUS LOAD-DO NOT USE!
Ramshot Big Game 118.7 40.9 2.65 3000 93.1 71078 11833 0.711 !DANGEROUS LOAD-DO NOT USE!
Vihtavuori N135 128.6 37.7 2.45 3000 99.7 71788 10866 0.715 !DANGEROUS LOAD-DO NOT USE!
SNPE Vectan SP 11 122.4 40.9 2.65 3000 93.1 70513 11937 0.713 !DANGEROUS LOAD-DO NOT USE!
 
#45 ·
Before anyone sees this and thinks using this info from quickload is a good idea do not try any of the info on this printout. The correct way to set up quickload is to use a maximum pressure and max fill parameter with the OAL setting on the main panel set to 2.295". That assures you do not go over pressure and do not over fill the case. It gives the correct powders that will work in the AR15. If you load longer you can change that setting on the main panel. Some of the loads below are 15gr OVER or 132% of what will fit in the case.
 
#25 ·
Well, I guess it shows that you can't get enough of any powder in the case to get 3000 fps...

Doesn't matter really. But, I would like to see the actually chronographing of the load that is getting 3000 fps--even from a 20" barrel...

Ain't doubting anyone, but I dang straight know I can't get that velocity using my Contender with a 23" barrel...

But then, I guess time and age has made me a realist...

Good-luck...BCB
 
#28 ·
These loads are ABOVE MAX

AKsarben, if you look in the bullet review thread at the 100 AB you will find some loads at those speeds. I think they are too hot for me.
Aksarben, I have pressed past max 6.8 SPC II chamber pressure in search of 3000 fps with 100gr AccuBonds with my 18" ARP. sfrank is right, the loads are hot. My estimates are - when you are going above 30.0 gr of AA2200 with SSA/Nosler brass - you are going above 58.000 psi (Hornady brass will be higher pressure). This is just my estimate using case head expansion measurements and backed up by primer pockets too loose to reload at 30.5 gr of AA2200 and above after one firing. I DO NOT recommend anyone use these loads - you can break your bolt or worse. I have the ARP Superbolt that is stronger than other 6.8 bolts - bolts that I have broken trying to press other loads to the max.

Note: I stopped using 1200R because I found it very temperature sensitive as you can see by the 20" ARP load (2.240" - longer than mag COALs) over multiple range sessions across Spring, Summer, Fall, and Winter. Above 90F, I found 1200R was unstable and would drop 300 fps (happened 4 times in about 25 loads.

These Loads are Likely Above Max 6.8 SPC II Chamber Pressure


 
#29 ·
I am not trying to push a 100 gr to 3000 fps with excessive pressure. Chances are, that the group would be horrible and that it's not necessary. An animal will not know the difference between 2700 fps or 3000 fps when shot placement is good. Accuracy is paramount. I was just curious if anyone had managed to send a 100gr bullet down range at 3000 fps. I'd rather have 3 in a clover leaf pattern touching each other at 2600 fps than 3 in a 2" group at 3000 fps any day of the week.
 
#32 · (Edited)
I am not trying to push a 100 gr to 3000 fps with excessive pressure.
I have tried lots of powders, not all but more than I should have. AA2200 has the best energy potential that I have seen for the 6.8mm. If you can't get there with AA2200, I'm doubtful there is another powder available today that will. If you want to operate at or above 3000 fps without excessive pressure, then consider getting an 6x6.8mm barrel from ARP next time he has them in stock. The 55 and 75 grain bullets should be in that domain without having to push max chamber pressure.
 
#40 · (Edited)
constrictor (sic) would indeed be considered an authority on the 6.8 but not because of his post count. He has pressure testing equipment to check his results and is one of the pioneers of this round. The one powder no one has said to have tried is the relatively new LT-30. It is reported to be a bit quicker than the LT-32, but maybe still too fluffy?
 
#46 · (Edited)
I don't believe any of the data on that print out could be used as the charges are all too much to get into a case and, if you look at the printout it emphatically states:

!DANGEROUS LOAD-DO NOT USE!

I think that is the whole point of it--it indicates that 3000 fps with a 100 grain bullet might be pretty difficult to achieve with any consideration for pressures and actual case capacities...

So, at this point, I will half-heartedly apologize for my lack of knowledge and some obvious ignorance of the 6.8 SPC cartridge...

I actually have trouble getting real close to 3000 fps with the Sierra 90 HP set out to 2.34". I am using H-322. I know there might be a better powder choice, but that load produces very good accuracy...

Let's just forget QuickLoad for now, or possibly forever on this site--there seems to be some very strong opinions on the reliability and safety of its data. I certainly never used it as a definitive source of reloading data. I have dozens of reloading manuals and I always refer to all of them and do some averages of minimum and maximum charges and work from that data. But, concerning published data, I have a couple of older Nosler manuals and I just let them on the shelf for decoration as some of the numbers in them are scary. Don't know about their new manuals...

Enjoy the 4th of July, but keep the fireworks in the sky and not near the chamber of your firearms...

Good-luck...BCB
 
#47 ·
Agree with BCB.......

I own weapons that mean something to me or my family. Don't want to destroy ANY of them.

I have reloaded for over 35 years now. I try and achieve a load that is:

1. Highest velocity with lowest pressure. This is to ensure no undue pressure on the weapon. Longevity.
2. Best Accuracy. Most accurate load. No explanation necessary.
3. Lowest max. grain count per load. Don't need to select a powder that takes more grains to achieve less.

I usually select mid-range weight bullets to help me achieve best velocity/energy combination. I've always found an accuracy curve whereby a low velocity load will yield great accuracy, as well as a hi velocity load. The slower or faster you go, things start falling apart. IMPE.

Not chasing the MAGICAL 3K in anything. No need. I like to keep my body parts intact and the weapons!
 
#48 ·
Agree with BCB.......

I own weapons that mean something to me or my family. Don't want to destroy ANY of them.

I have reloaded for over 35 years now. I try and achieve a load that is:

1. Highest velocity with lowest pressure. This is to ensure no undue pressure on the weapon. Longevity.
2. Best Accuracy. Most accurate load. No explanation necessary.
3. Lowest max. grain count per load. Don't need to select a powder that takes more grains to achieve less.

I usually select mid-range weight bullets to help me achieve best velocity/energy combination. I've always found an accuracy curve whereby a low velocity load will yield great accuracy, as well as a hi velocity load. The slower or faster you go, things start falling apart. IMPE.

Not chasing the MAGICAL 3K in anything. No need. I like to keep my body parts intact and the weapons!
Re:1-How do YOU know what pressure your loads make?
Re:3-this kind of contradicts #1. Most of the time a slow burning powder will create more velocity with less pressure. you need more slow powder to get the velocity you could get with faster burning powder.
As far as I know it's all about finding a load with accuracy we can live with. If some of us don't find the max loads and tell everyone here how does any one else know if they are close to max loads or not? As established earlier in the thread 32gr of 2200 or 1200 is very accurate(like 3/8" at 100yds accurate) with 100gr Noslers and it shows NO signs of being hot.
 
#50 ·
I have been pushing the limits of the 6.8 with 16 different powders.
Like a 130gr Berger VLD and Classic Hunter at 2600 fps from a 16in barrel among others.

Everything Constructor is saying is spot on to what I have found.
 
#53 ·
The Firearmblog article is God awful.

"
It is very curious to me that a round that was designed with an accurized designated marksman's rifle in mind also features such a short ogive and low muzzle velocity. Typically, medium/long range precision weapons platforms place a premium on both the ballistic coefficient and velocity of the projectile, seeking to obtain as laser-like a trajectory and as high a retention of energy as possible." - See more at: http://www.thefirearmblog.com/blog/...l-view-of-the-6-8mm-spc/#sthash.hCrcWopi.dpuf

This was NEVER the point of the 6.8 SPC. If that is what they wanted, they would have just looked towards the .220 swift as a replacement.

Unlike the much better Gary K. Roberts report, this blog only focused on ballistics only with no regard for actual terminal performance. Terminal performance aside,
the article was wiritten only a few months ago, yet they used 2.260" COALS and only one type of ammo. For the 5.56mm, it seems they used the the mk262, which has the very best long range performance. I would have really liked to seen the 95gr TTSX loaded at even 2.275 COAL.

Bottom line, the article was bias as all hell. It would have been nice to point out the positive attributes of the 6.8 such as: better all around tissue damage even at lower velocities; little increase to recoil (as opposed to 7.62x39); much better performance in shorter barrels; R&D cost of $5000 (laughable by today's standards); MUCH improved terminal performance vs the mk262 when implementing barriers; upgraded performance of SPC 2 while still being compatible with most mag pouches. Sadly, none of this could be shown in the cute little graphs and charts of the Firearmsblog article.

As a side note, while the Roberts article of the 6.8 spc had excellent information, their powerpoint presentation was simply awful. I would of imagined they lost most of their audience in
the first couple EXTREMELY busy slides. Shame really, since this kind of oversight can have a huge impact on policy.

 
#54 ·
H is right about quick load. I usually pick a max pressure and 108% fill as paramaters. Then let it pull a list of powders which based on burn rate will give you the best velocity. I never trust it for actual loading data. As for the 32 gr of 2200. My rifle(16" arp) maxed out at 30 with a 2.290 coal.
 
You have insufficient privileges to reply here.
Top