[Aspp]

Got the 120's up to 2950, node was at 2890 for .4".

You have to explain that trick to me. What rig, what's the load, temp and elevation?

I was under the impression that 2800 fps was not attainable even with a 24" barrel with the 120s...

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[jwtharpe]

You have to explain that trick to me. What rig, what's the load, temp and elevation?

I was under the impression that 2800 fps was not attainable even with a 24" barrel with the 120s...

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36.8gr CFE223
Hornady case
BR-4 primer
OAL 2.35
temp 90
barrel Bison 22"

1-2930-AV-2933
2-2943-es-13
3-2930-sd-5
4-2936

also shot five factory 115 fusions before and after the ladder first string averaged 2623 from clean bore, second string averaged 2613 after shooting the 49 round ladder.

edit: elevation is around 250' humidity around 85 percent

 

[Aspp]

Huh, well aint that somptin???

Does it sound like rice krispys when your pushing that bullet in? I would have to think your at 110%+ compression to get 36.8grs in a case.

 

[Ezbagr6.8]

You have to remember that JWTharpe is loading long-2.35 therefore his info is somewhat different that what a person would get when loading to 2.28-2.295.

 

[Aspp]

You have to remember that JWTharpe is loading long-2.35 therefore his info is somewhat different that what a person would get when loading to 2.28-2.295.

Oh I understand that, but he is getting 36+grs in a case that has 36grs of water capacity. Yes, powder will be a bit denser, but you still have to allow for the bullet, which is why water capacity it *usually* considered absolute max charge for your lightest bullet, not mid-range for one of the heavier bullets.
Its just supprising me that the gun functions and there are no issues craming that much powder in that case.

See here for a capacity compairison: http://68forums.com/forums/showthread.php?38411-Case-Capacity-Experiment

 

[jwtharpe]

Huh, well aint that somptin???

Does it sound like rice krispys when your pushing that bullet in? I would have to think your at 110%+ compression to get 36.8grs in a case.[/QUOTE
A 1.686" hornady case will hold 37.2 - 37.4 grains poured slowly down a 6" drop tube, I was going to stop at 37 but I couldn't get from the block to the press without spilling it, 35 is at the neck/shoulder junction, I was instructed not to use magnum primers with this, something about secondary pressure spike and ripping lugs off of bolt, breaking carrier, I started at 32gr. and went up, didn't see pressure til around 36.0, then it was very mild flattening of primer, and slight cratering at 36.6, old M1 guy helped me with working it up, he uses it for his 155 palma rounds.
I will start another thread if you guys want the data and stop hijacking XMANs thread.

Sorry Xman

 

[Xman]

Barnes 110gr TSX

After seeing how poorly the tipped Barnes 110gr TTSX expanded when shot from the 6.8, it was time to conduct terminal performance tests with the Barnes 110gr TSX. Thank WiscTJK for contributing the TSX bullets for this test. I had always been fearful of limited expansion and over penetration with the 110gr TSX which is why I had not considered using this bullet in the 6.8 even though I am a proponent of monolithic bullets from experience with the .270 Win. The tipped 110gr TTSX shot at 100 yards in the prior ballistic tip comparison test is shown for comparison ( http://68forums.com/forums/showthre.../showthread.php?33178-6-8-SPC-Bullet-Performance&p=455176&viewfull=1#post455176 ). Also included is a 110gr TSX shot from a .270 Win to see how the bullet performed at higher velocities where the tipped 110gr TTSX does perform well. Muzzle velocities for the rounds used in this test were,

From .270 Win
110gr Barnes TSX - 3375 fps (60.0gr IMR4350) [BC 0.323]

From 6.8 SPC II
110gr Barnes TTSX - 2600 fps (??.?gr AA2200) [BC 0.377]
110gr Barnes TSX - 2740 fps (28.6gr AA2200) [BC 0.323] 18" ARP 1:11 barrel

Caution - these loads worked in my rifles but this is no guarantee that they will work safely in yours.
Go to the First Page for Quick Links to all the bullets tested.

 

[Xman]

Observations

Observations
110gr Barnes TSX - I actually started testing the 110gr TSX at 300 yards and was pleasantly surprise to hear the "shwack" on gallon jug and see it jump away from the bullet trap. I was all smiles by the time I completed the test series.

At 300 yards, the bullet expanded to 0.445" while traveling at 1965 fps which is the same expansion as the 85gr TSX had at 200 yards traveling 2210 fps, 245 fps faster. This expansion is 0.060" less than the 95gr TTSX and the same as the 110gr AccuBond at this 300-yard range. The 110gr TSX bullet penetrated the 1500 page phonebook and 2 magazines, good penetration for 300 yards and about the same as the 95gr TTSX and better than the 110gr AccuBond that penetrated through an additional 4 magazines.

At 200 yards, the 110gr TSX expanded to 0.548" which is greater than any other copper bullet tested at this distance in the 6.8. The only bullets to beat this amount of expansion are the Federal Fusion MSR/Gold Dot bullets which do not retain their weight as well as the TSX. Penetration was 1300 pages into the phonebook which is excellent.

At 100 yards, the bullet was pulled from the back of the phonebook (1500 pages) and was fully expanded to 0.585" and the pedals had peeled back to the bottom of its expansion cavity. This is more expansion than the 85gr E-Tip with its tip removed which had the most expansion to date for a copper bullet shot from a 6.8. Note that the bullet shot from the .270 Win peeled back well past the expansion cavity but the bullet still retained 100% of its weight.

Conclusions. Unlike the tipped 110gr TTSX, the Barnes 110gr TSX is designed for and performs effectively in the 6.8. If you want a bullet that expands well and can penetrate through bone, like on a shoulder shot, this is an excellent bullet for the job. IMO, it may be the best bullet out there for a 6.8 to take on large Northern deer, big boars, elk, and caribou.

Here is a link to a 110 TSX recovered from a buck.

http://68forums.com/forums/showthre...ms/showthread.php?43464-Barnes-110-TSX-penetrates-31-inches-in-south-Texas-buck

 

[WiscTJK]

Excellent data like usual xman. I appreciate the time and effort you have put into this research. I always figured the 95 gr ttsx, which was designed to open at lower velocities for the 6.8, was the bullet of choice. Your work tells a little different story. Thanks.

Todd

 

[Xman]

Thanks, Todd. The eye opener for me was how well the 110gr TSX expanded, even at velocities below 2100 fps which is the advertised min opening velocity for TSX bullets. The 85gr TSX, 85gr E-Tip, and 95gr TTSX are all excellent bullets and also have their advantages. I need to compile a section that shows all the copper/monolithic bullets together.

 

[jwtharpe]

I was quite surprised with your results on the 110 tsx, I had written it off when the 95's came out, now I think I will revisit it, based on your findings. As always excellent report Xman!
How long is it compared to the 95TTSX?, wondering how much powder will fit under it

 

[Xman]

Copper Bullet Comparison

Here is a collective picture of the monolithic, copper bullets that have been tested in the 6.8 to date. Note that both 85gr TSX and the 300-yard 95gr TTSX bullets were repeat shots after further load development resulted in higher velocities than the original test series. The 85gr TSX has not tested at yet at 300 yards because the bullet exhibited limited expansion and over penetration at 200 yards. Average muzzle velocities, BCs, and bullet lengths are below and shot from an 18" barrel.

85gr Nosler E-Tip - 2860 fps (31.0gr AA2200) [BC 0.273] 0.982"
85gr Barnes TSX - 2920 fps (32.0gr AA2200) [BC 0.246] 0.886"
95gr Barnes TTSX - 2850 fps (30.5gr AA2200) [BC 0.292] 1.035"
110gr Barnes TSX - 2740 fps (28.6gr AA2200) [BC 0.323] 1.082"

Caution - these loads worked in my rifles but this is no guarantee that they will work safely in yours.
Go to the First Page for Quick Links to all the bullets tested.

 

[Xman]

Velocity vs Energy vs Momentum

Here is a comparison of bullet velocity, energy, and momentum. The Barnes 110gr TSX clearly is the leader of the monolithic 6.8mm bullets with respect to energy on target and expansion out to 200 yards.

 

[Xman]

What Defines Bullet Expansion?

Manufacturers typically advertise a minimum velocity at which a bullet type will open up or mushroom. I have found that bullet velocity is not a consistent parameter in determining when a bullet starts to open up, e.g., the Barnes 110gr TSX opens up and has greater expansion at lower velocities than the 85gr TSX even though they both have the same expansion cavity design with an advertised 2100 fps minimum velocity for expansion. To better understand what is occurring on impact, bullet expansion was charted with respect to velocity, momentum, and then kinetic energy to see if there was any correlation of data. When charting bullet expansion compared to velocity and momentum, there was no correlation. When expansion was charted with respect to the bullet's kinetic energy, there was positive correlation and the 85gr and 110gr TSX matched each other. As seen in the charts below, expansion of monolithic copper bullets is determined by the bullet's kinetic energy on impact not velocity, e.g., heavier bullets at lower speeds can out expand lighter bullets of the same caliber at faster speeds. This now seems obvious after looking at the data - work has to be expended to peel open and fold back the pedals of a solid copper bullet. Work is energy (1/2 mass * velocity ^2).

Instead of one chart showing all the compiled data up front, 3 charts are used to best show the data and build on the observations. Below is the first chart completed which compares just .277 Barnes TSX bullets. 6.8mm tests were conducted at 100, 200, and 300 yards. Bullet tests with the .270 Win were at 100, 300, and 500 yards. This has been an enlightening exercise and shows why the 85gr TSX has a limited range. Note, the 85gr TSX was tested twice with two different powder weights during load development.

From 6.8mm SPC II
85gr Barnes TSX - 2815 fps (31.0gr AA2200) [BC 0.246]
85gr Barnes TSX - 2920 fps (32.0gr AA2200) [BC 0. 246]
110gr Barnes TSX - 2740 fps (28.6gr AA2200) [BC 0.323]

From .270 Win
110gr Barnes TSX - 3375 fps (60.0gr IMR4350) [BC 0.323]
130gr Barnes TSX - 3070 fps (56.0gr IMR4350) [BC 0.431]

Caution - these loads worked in my rifles but this is no guarantee that they will work safely in yours.

Observations Regarding Barnes TSX Bullet Expansion

o The 85gr and 110gr TSX are designed for the 6.8mm and the 130gr TSX for the .270. Note that the 130gr expansion curve parallels the 85gr/110gr TSX but the 130gr TSX needs about 40% more kinetic energy for the same expansion.

o As seen in the collective picture above, the 110gr TSX fired from a 6.8mm with an impact energy of 1500 ft-lbs (100 yards) has expanded to the bottom of the expansion cavity. When fired from a .270 Win (2300 ft-lbs at 100 yards), the bullet expands well beyond the bottom of the expansion cavity. Just over 0.6" seems to be the practical expansion limits of Barnes .277 all-copper bullets. If you want more expansion, you will need to go to a larger caliber.

o To achieve a minimal expansion of 0.4", at least 800 ft-lbs of energy is required for 6.8-designed TSX bullets. The 85gr TSX achieves this around 200 yards while the 110gr TSX will have the same expansion around 300 yards. The 85gr TSX has a higher muzzle velocity but its low BC [0.246] causes the bullet to decelerate more rapidly resulting in less energy and reduced expansion.

 

[Xman]

6.8mm Monolithic Bullets with Ballistic Tips

The chart below has the test data add for the Nosler 85gr E-Tip and Barnes 95gr TTSX which are tipped 6.8mm bullets designed specifically to open up at lower velocities.

85gr Nosler E-Tip - 2845 fps (31.0gr AA2200) [BC 0.273]
95gr Barnes TTSX - 2890 fps (30.5gr AA2200) [BC 0.296]

Caution - these loads worked in my rifles but this is no guarantee that they will work safely in yours.

Observations Regarding 6.8mm Monolithic Tipped Bullet Expansion

o Both bullets out expand the TSX bullets at lower velocities and energy states . A point for consideration - the data suggests that expansion will occur at energy levels below 700 lb-ft (beyond 300 yards) which is less energy than what many recommend to humanly harvest deer.

o The Nosler 85gr E-Tip out-expanded the Barnes bullets below 1200 ft-lbs of energy and particularly the 85gr TSX at ranges greater than 100 yards. The E-Tip's expansion advantage is achieved even though the E-Tip's copper-zinc alloy is harder than the Barnes' pure copper bullets. This has to be due to the E-Tip's massive expansion cavity hidden behind its ballistic tip. Below is a cross-section of .277 monolithic bullets. The 85gr E-Tip and 95gr TTSX have the largest expansion cavities. The amount of expansion the TSX bullets achieve is impressive for their small cavity size. A discussion on the benefits of ballistic tips can be found here.

http://68forums.com/forums/showthre.../showthread.php?33178-6-8-SPC-Bullet-Performance&p=455172&viewfull=1#post455172

o The 85gr E-Tip did not expand to the bottom of its expansion cavity in any of the 6.8 tests indicating that it can still expand further if shot with higher energy levels, i.e., it still should perform well if you launch it from a .270 Win. This would be a great round for a youngster

o The 95gr TTSX does hold an energy advantage over the 85gr E-Tip that equates to about 75 yards.

o The 95gr TTSX does expand better than the TSX bullets at lower energy states until the expansion becomes full-bodied, e.g., when the copper web emerges between its four pedals. Then the data suggest its expansion is similar to Barnes' 6.8mm TSX bullets. Note in the picture above that the 95gr TTSX expanded to the bottom of its expansion shot from a 6.8 at 100 yards.

o A small point. Two 95gr TTSX bullets were tested and recovered at 300 yards. The bullet that expanded above 0.5" at 300 yards (850 ft-lbs, dotted-line) was that wide because two of the four pedals did not fold back along the bullet's body like the other recovered TTSX bullets. When expansion was measured across the other two pedals, it was similar to the other bullet recovered at 300 yards that expanded to 0.456".

 

[Xman]

Heavier Monolithic Bullets Designed for the .270 Win

Here is the charted data with the Barnes 129gr LRX, Hornady 130gr GMX, and Nosler 130gr E-Tip added. All were fired from a .270 Win. They were tested at 100, 300, and 500 yards. Note, the E-Tip not tested yet at 500 yards and I just started load development and am working up.

129gr Barnes LRX - 3100 fps (56.0gr IMR4350) [BC 0.463]
130gr Barnes TSX - 3070 fps (56.0gr IMR4350) [BC 0.432]
130gr Hornady GMX - 3080 fps (55.5gr IMR4350) [BC 0.453]
130gr Nosler E-Tip - 2990 fps (54.0gr IMR4350) [BC 0.459]

Caution - these loads worked in my rifles but this is no guarantee that they will work safely in yours.

Observations Regarding .270 Monolithic Bullets Expansion,

o All three bullets are designed to expand at energy levels greater than those achievable in a 6.8mm. Thus, if fired from a 6.8, they would not expand as well resulting in limited or no expansion and over-penetration. This has been the typical result with several other .277 bullets that are designed for the velocities in the .270 Win range, e.g., Hornady 110gr HP, Barnes 110gr TTSX, and Berger 130gr and 140gr VLDs. These bullets are still good for target shooting in the 6.8mm but don't expect consistent or effective results if they are used for hunting.

o The softer copper Barnes 129gr LRX and 130gr TSX expanded to larger diameters at higher energy states than the tipped 130gr GMX and E-Tip bullets which are made from a harder 95% copper, 5% zinc alloy.

o The LRX provided superior expansion achieving the largest expansion of any .277 monolithic bullet tested, 0.611" well over doubling its size. To test the LRX's advertised minimum opening "velocity" of 1600, testing would have to occur out to 800 yards (800 ft-lbs) or I need to develop a light load. Note, if shot with a lower muzzle velocity, the bullet's stability will be less which may have a negative effect due to its length. Pictures of the recovered LRX and TSX bullets can be seen at this link.

o I had planned to test modified 130gr E-Tips in a 6.8mm with the assumption its expansion would provide similar results as the 85gr E-Tip. However, this data suggests the 130gr E-Tip performance will be disappointing at the lower velocities achieved with heavier bullets in a 6.8nn.

o A GMX recovered after over 30 inches of penetration in a cow elk compared well with GMX bullets recovered from the bullet trap. This was a 400 yard shot at 8500' MSL which was 200 fps faster on impact than if the bullet was shot at sea level. This resulted in higher impact energy similar to a 300-yard impact.

 

[Xman]

6.8mm Lead-Core Bullets that Expand

I redid the graphs above and edited the text to improve this section on bullet expansion. I realize this is a lot of detail. I also wondered if expansion of lead-core bullets like the AccuBond and Fusion MSR/GD would hold true to the paradigm that energy defines how much they will expand. At first the data didn't make much sense. I have always listed maximum expansion of the recovered bullet. The monolithic bullets are very symmetrical but that is not the case with the lead-core bullets, especially the Federal Fusion family. When I averaged bullet expansion based on the widest and narrowest side of the mushroom, the data correlated surprisingly well. So I have added a 4[SUP]th[/SUP] chart with the Nosler 100gr and 110gr AccuBonds (gray) and the Federal Fusion 90gr Gold Dot, 115gr MSR, and 120gr MSR (purple). I did it slightly differently and kept the bullet family a like color and labeled the specific bullet on the chart. Yes, the chart is a bit cluttered but it is worth a look.

90gr Federal Gold Dot - 2915 fps (Factory) [BC 0.236]
100gr Nosler AccuBond - 2700 fps (30.0gr AA2200) [BC 0.323]
110gr Nosler AccuBond - 2600 fps (29.0gr AA2200) [BC 0.370]
115gr Federal Fusion MSR - 2490 fps (Factory) [BC 0. 378]
120gr Federal Fusion MSR - 2550 fps (27.5gr AA2200) [BC 0.400] COAL 2.350"

Caution - this load worked in my rifle but this is no guarantee that it will work safely in yours.

Observations Regarding 6.8mm Lead-Core Bullets Expansion,

o The 100gr AccuBond always hit harder inside 200 yards. Now we know its design is slightly different than the 110gr AB and the 100gr expands more at the higher energy levels. Both bullets expand the same at lower energy levels.

A "group" picture of the AccuBonds showing terminal performance results can be seen at this link.
http://68forums.com/forums/showthre.../showthread.php?33178-6-8-SPC-Bullet-Performance&p=438749&viewfull=1#post438749

o The Federal Fusion bullets may have similar lead-cores and construction but they all perform differently. I would guess their nose shape and copper jacket design are responsible for the difference.

o The Federal 115gr MSR expansion is very similar to the Barnes TSX but has the potential for great expansion at higher energy levels. It will be interesting to see this bullet's performance when it is available as a component for handloading.

o The Federal 90gr Gold Dot's expansion is very similar to the 85gr E-Tip just slightly larger. I think their curves would match except the Gold Dot recovered at 200 yards had one of its 5 pedals that didn't fold back. The 90gr GD's expansion is well controlled, does not shrink much as energy decreases, and is well matched for the 6.8mm SPC.

All the Fusion MSR/GD terminal performance results can be seen at this link.
http://68forums.com/forums/showthre.../showthread.php?33178-6-8-SPC-Bullet-Performance&p=453355&viewfull=1#post453355

 

[rvrrat14]

Thanks for all the leg work. I'm more convinced the 110 ABs will be in my weapon this season. Deer, hogs, dogs, and cats, oh my! Good data and well communicated. First class.

 

[Aspp]

Hey XMan, if you traded energy and expansion on your table I think it would make a lot more sense. Energy is your fixed metric and should be on the bottom, while expansion is the variable your studying and should be on the vertical.

Sent from my DROID RAZR using Tapatalk 2

 

[Xman]

Aspp, hope this helps.