6.8mm 150 grain experiment

[floatpilot]

I loaded some of the old Barnes X bullets into the 6.8mm just just giggles. They are very , very long.... see photo. They did not like the 1 in 11 twist rate and tumbled pretty good. I am sure they would REALLY HURT within 25 yards.

I also tried some regular lead core 150 grain Speer bullets and they worked just fine. So far I still have not reached a peak velocity with them. Oddly enough they recoil enough that it brings the impact point up to the same area as the lighter bullets at 100 yards.

150 grain bullets from 24 inch BHW barrel:

150 grain Speer SP flat base
24.0 grains N-133
SSA Brass / Br-4 primer
2.290 col No Crimp
Vel: = 2,060fps hi 2,045 fps lo
1.65 inch group
Semi flat primers, no ejector marks
Clean brass.


old straight X bullets. So I started with a mild load of 22.0 grains of WW-748 and a COL of 2.300 inches. I used SSA virgin brass and a CCI-41 primer. The average velocity was 1,686 fps



150gr old X bullets.... (short range zombie shredders)
23.0 grains of Xterminator
SSA brass / CCI-41
2.295 col, Lee Crimp
Lo= 2,040 fps Hi= 2,052 fps. Yawing at 50 yards. No pressure signs. Feeds well.

Attachments:

[floatpilot]

150 grain LOADS: From a 16 inch barrel
A:
Bullet: 150 grain Winchester Round Nose, flat base
Powder: 24.0 grains AA 2230
Primer: CCI-400 small rifle, hand seated
Brass: SSA
COL: 2.255 inch Lee Factory Crimp
Velocity average: 1,800 fps 28 fps ES
3 inch group. OK primers

B:
Bullet: 150 grain Winchester RN, flat base
Powder: 27.0 grains, WW-748
Primer: CCI-400 small rifle, hand seated
Brass: SSA
COL: 2.255 inch Lee Crimp.
Velocity average: 1,920 fps 39 fps ES
2.0 inch group Some Pressure Signs,

C:
Bullet: 150 grain Winchester RN, flat base
Powder: 22.0 grains H-322
Primer: CCI-400 Small Rifle hand seated
Brass: SSA
COL: 2.255 inch Lee Factory Crimp
Velocity average: 1,766 fps 22 fps ES
1.2 inch group, Some Pressure signs


D:
Bullet: 150 grain Winchester RN, flat base
Powder: 22.0 grains RL-10x
Primer: CCI-400 Small Rifle hand seated
Brass: SSA
COL: 2.255 inch Lee Factory Crimp
Velocity average: 1,845 fps 30 fps ES
2.75 inch group, Clean, Some Pressure signs,

[sandsock]

UDo you think a 150gr BTSP would sit too low inside the case?

[Deleted]

That is cool but it is going to need a 1:9.5 or 1:9 for subsonic use.
Anyway, do you know what is the max length you can chamber. Find out and try some with .002 off the lands. Just for fun/curiosity if you want since this would have to be repeated with the proper twist.

Do you know if the BHW makes a 20" 1:9 for the heavies?

[Brandon Sneed]

Dec 24, 2011 20:18:01 GMT -8 @sergiomartinez said:

That is cool but it is going to need a 1:9.5 or 1:9 for subsonic use.
Anyway, do you know what is the max length you can chamber. Find out and try some with .002 off the lands. Just for fun/curiosity if you want since this would have to be repeated with the proper twist.

Do you know if the BHW makes a 20" 1:9 for the heavies?

I don't think it's be worth the hassle doing a 20" 9 twist. If you'd like one then Model 1 still sells the 9.5 twist.

I think loading a 20" 10 twist bolt gun for suppressed work would be interesting. However honestly suppressed I'd want out of a short barrel.

[Deleted]

I am happy with the ones I have I just would like to find out what the poly magic would do in a dual purpose type of barrel. 1:9.5 might be enough, I agree. I do not think that shooting solids in subsonic makes a lot of sense, unless they are mandated by law wherever I am shooting.

[zj762]

Bison Armory has a 1 in 7" barrel for sub sonic use. They call it the 6.8bsp. I believe it's a spec ll chamber. Bison made it for shooting 200gn bullets sub-sonic, but you can also run full power loads. Last I checked M1 Sales was still selling the 1/9.5 twist barrel also, but this is spec l. I'm actually waiting on a m1s barrel I'm buying used, n the guy I'm getting it from reamed it 2 the spec ll chamber. Once I get it n load up some heavies I'll share how things go w/ it.

-Zach