6.5g/6.8 ballistics

[Empty Brass]

I will goahead and ask this.

On boards we see how one is better then the other or one is short range one is long range etc. Thats all fine and dandy but here is the question.

How do these 2 calibers perform in the same barrel length. I have yet to see someone say my Grendal shoots flatter/faster then a 6.8. Yadda yadda. But I never see what barrel length they are using to get that performance.

What I'm wanting to know is how these two compare in the 16", 18" barrels.

[zoomie]

From these sources:
http://www.alexanderarms.com/grendel_ballistics.pdf
viewtopic.php?f=1&t=839 (http://www.68forums.com/viewtopic.php?f=1&t=839)

16" Barrel:
6.5G: 120gr Ballistic Tip @ 2450
6.8 SPC: 115gr SMK OTM @ 2525

~20" Barrel:
6.5G: 120gr Ballistic Tip @ 2520
6.8 SPC: 115gr SMK OTM @ 2561

There was a larger difference between the two until 6.8 users started using slower twists, different rifling, etc, and increased the 6.8 peformance.

[marinesg1012]

what is the overall length of the grendal and do they have working 25 round mags for it?

[Empty Brass]

Thanks Zoomie, Answered my ?.

[paulosantos]

Lets compare the Factory ammo from a 16" and 20" barrel. But instead of using the worst 6.8SPC bullet against the best Grendel bullet, I'll use the two best ones.

16" Barrel:


Trajectory (Basic) Output
Input Data
Manufacturer: Hornady 6.8SPC 110 gr. V-Max

Muzzle Velocity: 2550.0 ft/s 16" Barrel

Sight Height: 2.80 in LOS Angle: 0.0 deg


Temperature: 59.0 °F Pressure: 29.92 in Hg
Relative Humidity: 0.0 % Altitude: 0 ft

Calculated Table
Range Drop Drop
(yds) (in) (moa)
0 -2.8 ***
100 -0.0 -0.0
200 -3.7 -1.8
300 -15.4 -4.9
400 -36.9 -8.8
500 -70.7 -13.5
600 -119.7 -19.1
700 -187.9 -25.6
800 -279.5 -33.4
900 -399.1 -42.3
1000 -551.1 -52.6




Trajectory (Basic) Output
Input Data
Manufacturer: AA 6.5Grendel 123 gr. SMK

Muzzle Velocity: 2465.0 ft/s 16" Barrel

Sight Height: 2.80 in LOS Angle: 0.0 deg

Temperature: 59.0 °F Pressure: 29.92 in Hg
Relative Humidity: 0.0 % Altitude: 0 ft

Calculated Table
Range Drop Drop
(yds) (in) (moa)
0 -2.8 ***
100 -0.0 -0.0
200 -3.8 -1.8
300 -15.2 -4.9
400 -35.6 -8.5
500 -66.3 -12.7
600 -109.2 -17.4
700 -166.4 -22.7
800 -240.4 -28.7
900 -334.2 -35.5
1000 -450.9 -43.1



20" Barrel:


Trajectory (Basic) Output
Input Data
Manufacturer: Hornady 6.8SPC 110 gr. V-Max

Muzzle Velocity: 2700.0 ft/s 20" Barrel

Sight Height: 2.80 in LOS Angle: 0.0 deg

Temperature: 59.0 °F Pressure: 29.92 in Hg
Relative Humidity: 0.0 % Altitude: 0 ft

Calculated Table
Range Drop Drop
(yds) (in) (moa)
0 -2.8 ***
100 -0.0 -0.0
200 -3.0 -1.4
300 -13.0 -4.1
400 -31.6 -7.6
500 -61.0 -11.6
600 -103.7 -16.5
700 -163.1 -22.2
800 -243.2 -29.0
900 -348.6 -37.0
1000 -483.6 -46.2




Trajectory (Basic) Output
Input Data
Manufacturer: AA 6.5Grendel 123 gr. SMK

Muzzle Velocity: 2594.0 ft/s 19.5" Barrel

Sight Height: 2.80 in LOS Angle: 0.0 deg

Temperature: 59.0 °F Pressure: 29.92 in Hg
Relative Humidity: 0.0 % Altitude: 0 ft

Calculated Table
Range Drop Drop
(yds) (in) (moa)
0 -2.8 *** 0.0
100 -0.0 -0.0
200 -3.1 -1.5
300 -13.1 -4.2
400 -31.1 -7.4
500 -58.3 -11.1
600 -96.3 -15.3
700 -147.0 -20.0
800 -212.6 -25.4
900 -295.8 -31.4
1000 -399.5 -38.1




Out to 500 yards, they are pretty much dead even. After that, the higher BC of the Grendel bullets takes over. If Hornady ever got off of their ass, they could easily add another 100 FPS to their 6.8SPC ammo which would close the gap even more.

This is for the heavier bullets. If you compare the Speer 90 Gr. bullets, the SPC smokes the Grendel at every distance due to the higher velocity of the SPC. Basically the SPC is very similar to the 75/77 Gr. BTHP bullets for the .223.

[Clint]

So both are GTG with estimated hold over out to 400 yards ( a long shot ),
with the drop being the size of the vital zone.

Anyone shooting at ranges greater than that
had better be using their drop charts / calculators / calibrated reticles anyhow.

I'd say both are functionally the same, with similar ballistics and greater terminal effects than 5.56x45
What's not to like? :wink:

So, the decision comes down to support and the availability of parts and ammo.

[paulosantos]

So both are GTG with estimated hold over out to 400 yards ( a long shot ),
with the drop being the size of the vital zone.

Anyone shooting at ranges greater than that
had better be using their drop charts / calculators / calibrated reticles anyhow.

I'd say both are functionally the same, with similar ballistics and greater terminal effects than 5.56x45
What's not to like? :wink:

So, the decision comes down to support and the availability of parts and ammo.

If you handload and you have a good barrel, using the Hornady 110 Gr. V-Max or Hornady 110 Gr. BTHP, you can easily add another 100 FPS to those numbers and it will be almost even out to 700 Yards.

[Tim_W]

2561 for a 20" barrel and 2525 for the 16" Ha! Its more like 2650 for the 20"and 2550 -2600 for the 16" What a crappy SAAMI 1:9.5 barrel would do has no bearing as the design was never what it was suppose to be nor what was created and tested by the mil group.

We were told that the case was so that anything over 16" was a waste we even had one company state anything over that woudl result in a vel loss :lol: but low gains turned out to be only with one very special powder specifically designed to work with 16 and under barrels as that was the mandate and then again even with that seems to be larger then was orginally thought. The average gain with normal powders going from a 16 to a 20 is 120 FPS.

Just because a group of people puts up a chart or spec with a comparison that clearly favors them as proof means nothing. That is why I say put up the best you got and let the chips fall where they may. When you do that the SPC shoots flatter then the G out to 600 yards with the same length barrels. Poepl;e sem to only wantto see one fator in drop whihc is BC. Eveyone is fixated on it yet many many times velocity will trump it until you stat to geet out to eal long ranges thatlets fae ae not shot at by 99.9% of people for whatever reason. That doesn't mean you can't pick a crappy BC 6.8 bullet and put it up against a great BC 6.5 bullet and MAKE the 6.5 the winner.

Here is a example of what velocity can do compared to a high BC but slower bullet. You will se how well that light fast 90 TNT does against the well know top performers with other cartridges.

viewtopic.php?f=1&t=3589 (http://68forums.com/viewtopic.php?f=1&t=3589)

All that use to be said for the last 2-3 years when Constructor and I started showing performance gains was oh those are all way over pressure and unless you pressure test them its nothing but hot roding and you are going to blow up your gun. Well the loads are now pressure tested and guess what they are fine. In all that time and the many thousands of round even going beyond those loads not a single broken bolt. I am still using the same bolt I have and fully expect it to last the life of the barrel. Suddenly you never see those same statements from detractors anymore as it has no basis.

Then take a look at the 110 Accubond. All the shooting by Constructor and the small cc amount by me and others shows the drops to fall correctly when a .405 BC G1 factor is used. I can get 2800 FPS with it at 56K. Run those numbers thru JBM and see what you get and then compare that. The only comparison you will ever see from people that want to show the 6.8 is a short range cartridge is the 115 g SMK going 2525-2550. You will never see the AC, TNT, VMAX, TTSX

Also rememeber that the AC is really the first bullet specifically designed for the 6.8 and look at how well it does. The TNT is another that has is close but imagine as Paulo has suggested of adding a BT and then my suggestion of adding a poly tip and you have a 90-95 gr .320 3100fps laser out to 500-600 yards compared to jsut about anything out there.

We are getting vel from our 80-90 gr bullets that exceed what a .243 and 6mm Rem an get from the same weight bullets. They use 40% more powder

C put forth how he was getting good number with faster powder and oh the crys went out again. "You are crazy never can you use Rel 7" yada yada yada . Well now we have Hornady posting loads with AA1680 which is significantly faster. Norma 200 , H4198. In fact I know of one 8" barrel that is getting 2300 FPS from the 115 gr bullet using Norma 200. Hmmm

The 6.8 just keeps getting better and improving. We are starting to level off with what we can get using the best barrels specs, bullets, and current powders out there so we are waiting on the manufactures to catchup.

[BLACK LION]

wow :o

[Clint]

That 90TNT is impressive @ 3100 fps from an 18" tube.

For a point of comparison, barfcom reveals that

The 62 gr M855 round gets
2938 FPS from a 16"
and
3046 FPS from an 18"

Bottom line, the 6.8 gives you 50% more lead at nearly identical velocities.

[Tim_W]

Consider the SSA Combat 85 TSX does 3100 out of a 16" if its a SPCII 11 twist. That is with the same powder they use for the 115 SMK and everything else. If they had the abilty to use powder specific for that bullet and for guns with the right specs they woudl get another 100-150 fps out of it. In fact they already did during testing. :mrgreen: Compare that to the hottest closest weight 5.56 round which is the MK262 which is a 77 gr at 2600. 500-600 FPS faster with a almost 10 grains heavier bullet which that dif is usually worth 100 FPS so equal weight would probably have a 600-700 FPS faster round. I think people really started to see how much more powerful the 6.8 was when the 80-85 gr bullets were shown as that is within spitting of the MK262 So even at the same game the 6.8 destroys the 5.56. Consider we can throw a 66% heavier bullet at the same vel as the 5.56 and that is with a 5.56 that has a bullet and powder specifically made for the cartidge load. Imaging when the bullet and powder tech is to where its at for the 5.56. :twisted:

[marinesg1012]

So I made the right choice ;)

So what do we have to do get bullet companies to listen and make what we want like the TTSX in 85 grain and the VMAX with a BT? and getting hornandy to change their test barrels so we can get normal velocity?

who do I have to write a stern email too :D

[BLACK LION]

SSA will save us

[Empty Brass]

Thanks Tim. Thats why I asked the question is for that very very lengthy answer LOL. Thanks you guys.

All I ever see on the 6.5 is about BC. I knew the two were really close. From what all I have read and compared for myself. I prefer the 6.8. Nothing wrong with a G. But I really like the 6.8. I just wish that all the companies out there would use the same freakin chamber.

I had a buddy wanting a 6.8 after shooting mine and he said I will get a DPMS. I said please dont. They use a SPC1 chamber. I'm going to send him to this site. :mrgreen:

[Zippy]

Thanks Tim. ... that very very lengthy answer LOL. ...
Hey stop that, you'll give him a complex and we'll stop getting those answers! :mrgreen: Frankly, I love Tim's answers! :D

[marinesg1012]

THis is the response I got on another forum about the info posted here:


Sorry I missed this post, but now that I see it I think the tables are sort of interesting. You compare the 110grain 6.8 RemSPC to the 123grain 6.5 Grendel. Would it not make more sense to compare it to the 108grain 6.5 Grendel? The bullet weights would be nearly identical and the load data I have shows the velocities of those two round as starting at the same 2700fps out of a 20 inch barrel.

In that comparison this is what I have:
100 Yards:
110gr 6.8 velocity = 2422fps. Energy = 1498
108gr 6.5 velocity = 2502fps. Energy = 1501 +80fps, +3fpe

200 Yards:
110gr 6.8 velocity = 2161fps. Energy = 1192
108gr 6.5 velocity = 2312fps. Energy = 1282 +151fps, +90fpe

300 Yards:
110gr 6.8 velocity = 1916fps. Energy = 938
108gr 6.5 velocity = 2130fps. Energy = 1088 +214fps, +150fpe

400 Yards:
110gr 6.8 velocity = 1691fps. Energy = 730
108gr 6.5 velocity = 1957fps. Energy = 919 +266fps, +189fpe

500 Yards:
110gr 6.8 velocity = 1488fps. Energy = 565
108gr 6.5 velocity = 1793fps. Energy = 771 +305fps, +206fpe

[dark1]

i do not thing the 6.5 people will ever give up but i love a challenge

[marinesg1012]

are the velocities he posted not correct? am just trying to understand is all, I have a 6.8 and i see no reason for the 6.5 but i like to know for sure....

[dark1]

the 6.5 guy use 6.8 valuates from old out of date ammo fore there charts that is all

[paulosantos]

THis is the response I got on another forum about the info posted here:


Sorry I missed this post, but now that I see it I think the tables are sort of interesting. You compare the 110grain 6.8 RemSPC to the 123grain 6.5 Grendel. Would it not make more sense to compare it to the 108grain 6.5 Grendel? The bullet weights would be nearly identical and the load data I have shows the velocities of those two round as starting at the same 2700fps out of a 20 inch barrel.

In that comparison this is what I have:
100 Yards:
110gr 6.8 velocity = 2422fps. Energy = 1498
108gr 6.5 velocity = 2502fps. Energy = 1501 +80fps, +3fpe

200 Yards:
110gr 6.8 velocity = 2161fps. Energy = 1192
108gr 6.5 velocity = 2312fps. Energy = 1282 +151fps, +90fpe

300 Yards:
110gr 6.8 velocity = 1916fps. Energy = 938
108gr 6.5 velocity = 2130fps. Energy = 1088 +214fps, +150fpe

400 Yards:
110gr 6.8 velocity = 1691fps. Energy = 730
108gr 6.5 velocity = 1957fps. Energy = 919 +266fps, +189fpe

500 Yards:
110gr 6.8 velocity = 1488fps. Energy = 565
108gr 6.5 velocity = 1793fps. Energy = 771 +305fps, +206fpe


What 110 Gr. bullet did they use for the comparison? It definitely wasn't the 110 Gr. V-Max. If they did use the V-Max, the velocity at 500 yards would have been 1616 FPS, not 1488 FPS. I'm pretty sure they use the 110 Gr. Pro-Hunter, which has a ****ty BC. So they used a 108 Gr bullet which has a phenominal BC and the worse 110 Gr. bullet for the SPC. What a surprise.

[Zippy]

What 110 Gr. bullet did they use for the comparison? It definitely wasn't the 110 Gr. V-Max. If they did use the V-Max, the velocity at 500 yards would have been 1616 FPS, not 1488 FPS. I'm pretty sure they use the 110 Gr. Pro-Hunter, which has a ****ty BC. So they used a 108 Gr bullet which has a phenominal BC and the worse 110 Gr. bullet for the SPC. What a surprise.
Hey, at least they're consistent! :lol: Wouldn't the Accubond have been even better though?

[paulosantos]

What 110 Gr. bullet did they use for the comparison? It definitely wasn't the 110 Gr. V-Max. If they did use the V-Max, the velocity at 500 yards would have been 1616 FPS, not 1488 FPS. I'm pretty sure they use the 110 Gr. Pro-Hunter, which has a ****ty BC. So they used a 108 Gr bullet which has a phenominal BC and the worse 110 Gr. bullet for the SPC. What a surprise.
Hey, at least they're consistent! :lol:

:lol: :lol: :lol: :lol:

[Tim_W]

Yep if there was a 6.8 120 gr semi wad cutter you can betcha that would be up against the .600 120 gr Lapua or some **** with the SPC out of a 8" barrel and the other a 28" titled The "fill in the blank" beats the 6.8 SPC in every way. :lol: DOn;t worry there would surely be a bunch of cool graphs to pound it home and 10 years later they would still be used.

[DDriller]

I vote for taking a hack saw and cutting off the tip of a 150gr bullet :lol: Wad cutter is way to pecise.

[Wardog]

From what I have read, for long range competition use, the Grendel was a better selection. With more development maybe it can adapt to hunting/sniping mode. The 6.8 SPC drops off in energy fairly dramatically after 400 yards but still higher then the 5.56 NATO. Going back to other threads, 6.8spc is a good choice to replace M4 but neither the Grendel or 6.8 SPC as currently configured (with any barrel or load) can compare with 7.62 (or many other hunting calibres) unless weight is a factor.

If we were to do a market survey 6.8 spc would fit into 90% or more users (under 400 yards) maybe just a guess. Hopefully we get some more data this summer on all of the proposed calibres. But I am finding this a fascinating discussion.

[rcrandall]

The 6.8 wasn't invented to replace the 7.62 Nato but the 5.56 instead. They wanted a sytem that only needed the barrel and bolt replaced (initially they wanted the mags to be the same but this was not realistic as the 6.8 round is thicker and requires a different mag body and follower) in the M4, and a round that improved the lethality of the M4 from 0 to 500 yards. Mission accomplished. The 7.62 is superior in power, BC, downrange energy, etc, but at a cost of weight, bulkier and heavier rifles, ammo, and mags, and more muzzle blast. The M80 ball round for the 7.62 still doesn't perform as well as it should, DocGKR has an excellent piece on it somewhere here on the forums. Of course, even if the M80 doesn't frag it is still big enough to cause concern to the guy that was just shot :shock: I have a Socom 16 M1A 7.62 and an LRB M14 on order so I am still a believer in the 7.62mm. Much of this would be moot if the U.S. grew a set and told the UN and NATO to pound sand and started using expanding and fragmenting rounds like the Speer Trophy Bonded Bear Claw and Hornady Vmax and Amax.

[Wardog]

I just bought a copy of Barretts 2009 Annual and it has a nice review and discussion of the 6.8 Rec 7 and the 6.8 SPC, both strengths and weaknesses. I hope 6.8 is adopted as a standard NATO round but I dont think 7.62 will go away. In same issue Barrett has an article on the 98; .338 Lupua bolt action for those that need 1900 yard capability.