Super Fast Twist Barrels for Hammer Bullets

[Mike Matteson]

The faster I tried to push the bullet the more the tight twist pushed back

Butterbean: I know you have a lot more knowledge in building and shooting than me by far.
I looked and read about gain twist barrels, but from what I found out not many were using them at the matchs. So I stayed away from them
I believe that Sierra changed there twist rate from 1-14 to 1-12 I believe to use heavier bullets. AR-15 has gone to 1-7 twist rate for there 62gr green tips. I believe that was to stabilize the 62gr bullet.
I am just now changing my twist rates in my newer rifles to reflex the longer bullets and needing needing faster twist rates.
I'll be watching on what you do, with interest. Thanks for the info.

 

[RockyMtnMT]

good info Steve!. Africa in Dec, interested??

We are going in May. I'm going to hunt cape buffalo on this one. Bringing our wives and sons on this one with a couple of other friends.

 

[Petey308]

AR-15 has gone to 1-7 twist rate for there 62gr green tips. I believe that was to stabilize the 62gr bullet.

To clarify, they went to the 1:7 twist to stabilize the very long tracer rounds. The 62gr green tips don't require a 1:7 twist, although it doesn't hurt.

 

[FEENIX]

What are your MVs with that 7-twist Weatherby? ~3,500?

I am shooting 145 Black Holes at 3K out of a 22' (suppressed) barrel using powders I already have opened; load development is still in progress. Mine is specifically built for the heavies (131s, 133s/135s, 145s, etc.).

I shot a couple of boxes of factory ammo for barrel break-in and scope sight-in but did not chronograph it.

 

[RockyMtnMT]

I'm really curious about an increase in terminal performance of Hammer and Cutting edge bullets. With faster twist barrels.

I see bullets like Makers, Barnes and discreet Ballistics bullets are benefiting from high twist rates. 1:3 for 8.6 and 1:5 for 300BLK. The 8.6 with a 1:3 is spinning a 210gr Barnes 500k RPM

I myself am looking at a 416 Rigby with a 1:8-1:9 barrel. It will double the RPM and quadruple the rotational KE over the 1:16.5


I went off on a tangent. Anyways just curious terminally how faster twist rates and non conventional bullets work together

We have yet to see a down side to faster twist. It increases terminal stability and keeps point on straight line penetration longer. The only downside I see is more rifle torque with heavy bullet high horsepower cartridges. It adds another aspect of recoil that you have to control particularly in lighter rifles.

 

[Mike Matteson]

To clarify, they went to the 1:7 twist to stabilize the very long tracer rounds. The 62gr green tips don't require a 1:7 twist, although it doesn't hurt.

I have used tracer rounds in the Army. I don't remember them being any longer. Maybe they placed them farther in the case. I didn't use many of them. Learned a great many year later to use tracer in the last 2 to 3 rounds in your clip. that way you knew that the clip was getting low. That was something that worried me while in Vietnam. In the unit I was with we didn't have any 30 round clips or 27 in the clip. We had only 20 round clips with 18 round in them. I would have rested easier knowing that and doing that. I did try and note how many I was shooting. Several times running out in the clip or I would change out the clip early.

 

[RockyMtnMT]

I am not sure what to think about gain twist. We have done a few and haven't seen any problems. They make sense to me in that they "ease" the bullet into the twist rate. What doesn't make sense to me is as the twist gains it changes the angle of engraving on the bullet, increasing the amount of engraving contract area on the bullet. In my mind this should increase the engraving pressure and create more distortion to the bullet. The ones we have done are 1" of gain and we have been able to still hit velocity and accuracy expectations with Hammer Bullets.

 

[Petey308]

I have used tracer rounds in the Army. I don't remember them being any longer. Maybe they placed them farther in the case. I didn't use many of them. Learned a great many year later to use tracer in the last 2 to 3 rounds in your clip. that way you knew that the clip was getting low. That was something that worried me while in Vietnam. In the unit I was with we didn't have any 30 round clips or 27 in the clip. We had only 20 round clips with 18 round in them. I would have rested easier knowing that and doing that. I did try and note how many I was shooting. Several times running out in the clip or I would change out the clip early.

Here's some I was loading a couple years ago. They do get seated deep in the case and it's not as noticeable.

 

[Petey308]

The might A-10 features 7 gain twist barrels on its GUA-8. It definitely works well for high mass, large caliber, bullets. It's better to ease such a projectile into it rather than force it to immediately spin hard from the start.

Many tests have been conducted on smaller calibers and the results haven't shown much promise on it being as beneficial. Is it a bad idea? I doubt it. Is it worth the manufacture process? I doubt that too.

 

[FEENIX]

The might A-10 features 7 gain twist barrels on its GUA-8. It definitely works well for high mass, large caliber, bullets. It's better to ease such a projectile into it rather than force it to immediately spin hard from the start.

Many tests have been conducted on smaller calibers and the results haven't shown much promise on it being as beneficial. Is it a bad idea? I doubt it. Is it worth the manufacture process? I doubt that too.

BRRRT!

 

[jessej]

BRRRT!

 

[Mike Matteson]

View attachment 487307View attachment 487324

Here's some I was loading a couple years ago. They do get seated deep in the case and it's not as noticeable.

View attachment 487308

I don't see it fitting in a clip. I don't or can't get to them my ammo presently. There is quite a bit of difference between the two or three. I have all 3 but not here where I am at presently.
I know in the M60 there wasn't any different in the belt that feed the M60. Nor the M2 either. So they must be putting the bullet inside the case.
All we had was 55gr FMJ and tracer for our M-16A2's. Like I say I didn't use any tracer in my AR15 or CAR15. I didn't want give away my location anymore than what was being done.
Well one thing for sure, the weatherman got it right this time. I am presently in So. Cal and it's been rain all day. I have lived here most of my life, and never seen it rain like this.

 

[Mike Matteson]

View attachment 487327

I wish we had them in Vietnam!

 

[Petey308]

I don't see it fitting in a clip. I don't or can't get to them my ammo presently. There is quite a bit of difference between the two or three. I have all 3 but not here where I am at presently.
I know in the M60 there wasn't any different in the belt that feed the M60. Nor the M2 either. So they must be putting the bullet inside the case.
All we had was 55gr FMJ and tracer for our M-16A2's. Like I say I didn't use any tracer in my AR15 or CAR15. I didn't want give away my location anymore than what was being done.

I've carried them all and loaded them. They seat all the mil spec ones to the cannelure, so they all fit in the mags and feed reliable. So the extra length goes into the case.

I only enjoy tracers on the 4th of July safely in America lol. I don't like giving my position away either.

My point was only why they went to the 1:7 twist.