Question on Rifling and twist rate for Monolithic Bullets

[Walt Krafft]

Your factory rifle with the standard 10 twist barrel, might not actually have a 10 twist. Many button rifled barrels do not actually have the stated twist. Have you measured it? A 10.5 twist might have pushed you out of stability.

 

[GAnderson]

I Have had dismal tests with quite a few of the differing makers in the
real short bullets, for closer range applications. Best results though was
from long jumping, and a higher then normal twist rate......i have taken
barrel stubs and pushed solids thru them on a hydraulic press with gauge.
Results were all over the map. Best overall tests came from "Cutting Edge
Bullets" and this may be due to their oversize ring they machine in. Either
way, I was never impressed with any target I shot solids with......

The long jumping did help but I don't think I am capable of accepting the group sizes. I may just end up selling the bullets or maybe doing a re-barrel with a faster twist...that is another part of my first post...will the grooves 3 or 6 have an impact? Will the 3R or 5R help or not? I probably am going down a rabbit hole that will end up not worth it.

Thanks,
Gene

 

[Gary in MD]

That 80 grain TTSX rocks out of my 240 Weatherby at 3700 fps!

 

[GAnderson]

Your factory rifle with the standard 10 twist barrel, might not actually have a 10 twist. Many button rifled barrels do not actually have the stated twist. Have you measured it? A 10.5 twist might have pushed you out of stability.

No, I haven't measured it yet and that has crossed my mind to do so...and I will. The bullet holes in the paper aren't indicating instability but it's easy enough to check the twist rate.

Thanks,
Gene

 

[Gary in MD]

Gene, will the rifle group well with other bullets? What is your rifle and scope set up?

 

[GAnderson]

That 80 grain TTSX rocks out of my 240 Weatherby at 3700 fps!

That is why I want to use this bullet if I can...most that have gotten great results with it say it rocks.
What twist is your rifle and what powder did you find to be best?
I have used 4350, Superformance, Varget, N160, H4895, 8208...the 4895 was the best groups but still dismal.

Thanks,
Gene

 

[GAnderson]

Gene, will the rifle group well with other bullets? What is your rifle and scope set up?

Yes, it does group well with conventional bullets...65gr Vmax, 75gr Vmax, 87gr Vmax and 85gr Sierra all do exceptional.

Gene

 

[Gary in MD]

That is why I want to use this bullet if I can...most that have gotten great results with it say it rocks.
What twist is your rifle and what powder did you find to be best?
I have used 4350, Superformance, Varget, N160, H4895, 8208...the 4895 was the best groups but still dismal.

Thanks,
Gene

I have a 26” Krieger, 7.5 twist.
Barnes doesn’t list RL22 for that bullet in the 240 Wby but that’s what I’m using and is been accurate and fast. Pole axed the deer that I’ve shot with it.

 

[GAnderson]

Rifle is a Bergara B14, scope is a Leupold 6.5x20x40. Action screws torqued and stay tight, scope base and rings are torqued and tight, trigger is adjusted to 1.5#

Gene

 

[Gary in MD]

How far off the rifling are you?
All the Barnes that I’ve loaded have done very well at .050” off.

 

[GAnderson]

How far off the rifling are you?
All the Barnes that I’ve loaded have done very well at .050” off.

I tried from .025 to .050 and finally all the way to covering the last "ring" which is over .100 and that is where it has done the best.

 

[DaveTooley]

Looking at the bullet holes stability is fine. Your rifle doesn't like those bullets. Solids are a love hate relationship.

 

[GAnderson]

Looking at the bullet holes stability is fine. Your rifle doesn't like those bullets. Solids are a love hate relationship.

That's what I was thinking as well. I did check the twist and it is a true showing to be right on at 1-10.

In your opinion would possibly a faster twist coupled with one of the R riflings(3R or 5R) maybe get them to shoot more acceptable?

Thanks,
Gene

 

[DaveTooley]

That's what I was thinking as well. I did check the twist and it is a true showing to be right on at 1-10.

In your opinion would possibly a faster twist coupled with one of the R riflings(3R or 5R) maybe get them to shoot more acceptable?

Thanks,
Gene

I don't shoot solids for a reason. You just never know if they're going to shoot. Cup and core I can work with. I hear more disappointment than anything.
A different barrel would cost much more than a new supply of bullets, but........

 

[dellet]

I have a couple of Remington barrels they put on the 700, 300 BLK. Marked 1/7, measure 1/10. Very accurate even with subs up to about 210 grains.

Had the chance to send it back but kept it. A couple other people gave me there take offs.

It’s always a good place to start.

 

[GAnderson]

I did go check the twist on this barrel and it comes up at a 1-10, so it is what it's supposed to be. I'm sure it's like some have posted...just a crap shoot whether or not the solid bullets will work or not. Was kind of hoping that someone had the same issue and went with a faster twist or changed rifling configuration and had success going that route.

Thanks.
Gene

 

[Alan Warner]

I did go check the twist on this barrel and it comes up at a 1-10, so it is what it's supposed to be. I'm sure it's like some have posted...just a crap shoot whether or not the solid bullets will work or not. Was kind of hoping that someone had the same issue and went with a faster twist or changed rifling configuration and had success going that route.

Thanks.
Gene

One of the most important aspects of using solids is the size relationship of the bullet and the barrel. The bullet needs to be the exact size of the barrel to no more than .0003 larger.
Sounds to me from your results that your barrels diameter is larger than your pills.
Hth
Alan

 

[ELR LVR]

I've got a .243 factory rifle with the standard 1-10 6gr barrel that shoots lead core bullets exceptionally well. I have come to acquire a substantial stash of Barnes 80gr TTSX monolithic bullets and have tried everything to get them to group acceptable and they just won't. At BEST I can squeak out an 1 1/4" group every now and then at 100yds. I have tried all the suggestions and powders that Barnes gives on this bullet and I realize that mono bullets aren't known for superior accuracy...but I do feel as though the 1-10 twist may not be stabilizing this bullet as good as it should since these bullets are somewhat longer than traditional bullets in the same weight category...Barnes maintains that a 1-10 should stabilize them.
So I got to looking at the various barrels that are available with different rifling and twist rates. I see 6mm 1-9 6gr, 1-8 3gr, 1-8 6gr, 1-8 5R gr and 1-8 3R gr as well as faster twists in the 1-7 area. The 1-9 might work better than the 1-10 but I am thinking a 1-8 will be the best hopefully. My question is in regards to the number of grooves and potential of the 3R or 5R rifling? Has anyone been down this road with mono bullets and felt that the 3 groove is better than the 6 groove and/or would one of the "R" riflings be even better? I am thinking the 5R 1-8 might get me what I want. Please share your thoughts.

Thanks,
Gene

Find a Twist Rate / Stability Calculator that can accomodate for the Specific Gravity of your bullet.
This is a constant which needs to be taken into account in relation to its length.
I wouldnt try to guess

 

[HandgunHTR]

I tried from .025 to .050 and finally all the way to covering the last "ring" which is over .100 and that is where it has done the best.

When people hear "Barnes bullets like a long jump" they mostly think 30-50 thousandths. As you are finding out, it is more like 100-120 thousandths.
Quite a few years ago when I was trying to find a load for a .260 Remington, I was at 0.135 jump before I got a group that was less than 1". Tried just about everything and then when I hit that number, bam, it worked. Even with multiple powders. This was before I had a chrono, so it could have been that I was just eating up enough case volume to get the pressure the bullet liked, but I can't say for sure.