Hammer Bullets -Do they Work Better with More or Less Rifling Grooves??

[Veteran]

I am working on an AR10 platform build with the help of another Forum member here.

I want a 24 inch accuracy conscious barrel for this .308 build. I'm addicted to tight groups better than 1 MOA even for semi auto.

Up for consideration are either a Lilja bbl. 24 inch with 3 grooves or 3 lands of rifling in 1 to 11 twist or a Bartlein 24 inch with 5 R rifling or 5 grooves or lands with 1 to 10 twist.

I will likely use this platform on hogs and coyotes, and may use hammer bullets. I'm thinking 150-160 gr. bullets and below. But occasionally maybe 175 to 180s.

Do hammer bullets with their low engraving profile prefer more or less rifling grooves? One side of me says 5 sets will help stabilize them better than 3 but I have no experience with them, and just don't know the technical answer.

Which barrel would you get and why? I will have either fluted, and mount a muzzle brake on it.

Its all a DPMS pattern.

Opinions? Facts? Experience or actual data?

 

[RockyMtnMT]

I am not sure if I can say that we have been able to tell if one style of rifling is better than another. We have run a lot of 5 and 6 groove barrels but have never run a 3 groove. I would say the 5-6 are equal. The 3 groove has a reputation getting more speed but tough on jacketed bullets. We don't have jackets so no issue there. We have run an old 2 groove barreled 30-06 and it shot very well.

So choosing from your listed barrels I would run the 10" twist 5 groove only for the extra stability. Not because of the number grooves.

 

[Veteran]

I am not sure if I can say that we have been able to tell if one style of rifling is better than another. We have run a lot of 5 and 6 groove barrels but have never run a 3 groove. I would say the 5-6 are equal. The 3 groove has a reputation getting more speed but tough on jacketed bullets. We don't have jackets so no issue there. We have run an old 2 groove barreled 30-06 and it shot very well.

So choosing from your listed barrels I would run the 10" twist 5 groove only for the extra stability. Not because of the number grooves.

Thank You for your comments.

 

[Deleted member 115360]

Man, get a 20" barrel and a suppressor. Eventually you'll join the dark side and get a suppressor, (you know you will), then that 24" barrel will be like carrying around a fence post. You'll be ducking to walk under power lines. Youll probably never use the additional m.v. from that barrel length to shoot hogs with anyways..

 

[Mike D Texas]

I would try to get a 9 or 8 twist. I like 5R barrels but I do have a Lilja 3 groove on order for my 6.5 Grendel so we will see how that is.

 

[MagnumManiac]

My best accuracy comes from 4 and 3 groove barrels.
Whether this makes any difference to a Hammer I do not know.
Another aspect is the rifling profile, skinny lands engrave less of the shank and are often faster in velocity than wide lands.
Ballard rifling, equidistant lands and grooves, engrave the most bullet shank and distort the bullet the most. Fired bullets look hexagonal if looked at from the base.
You want the least amount of distortion for accuracy.
The amount of grooves and their size makes almost zero difference to how a bullet spins upon release in my experience, flight thereafter is another matter.

Cheers.

 

[slikmrc]

Built a 30-06 AI speced for a Nosler 165 Accubond bullet. Lilja recommended 12 twist 3 groove barrel which worked out great. Have shot Federal 175 TLR bullets out to 300 yards with great results, this bullet has a solid copper shank like a mono. Would recommend you contact Lilja for there thoughts on barrel twist for what you're wanting to shoot.