Twist rate?

[Yeah]

Twist and pressure aren't related. In 0.224" I shoot 7"; 7.7"; 8"; 9"; 12"; 14", all at max pressure, and all the loads within 0.5 grain. I have 7"; 8"; and 9" all cut with the same 223AI reamer and all make max pressure with the same load.

I have too many makes/variations to call velocity, but I don't see twist coming up high on the list of factors.

 

[DRob]

12

What twist was that Howa?

The Howa is a 1:12. It really likes 40-55 gr VMax and has done well with Barnes 36gr Varmint Grenades and Hornady 36 gr NTX. Terminal performance seems to be lacking with the NTX but that's a different story.

 

[Yeah]

i have a question..... if u shoot 55 grain bullets with a fast 1/7 twist can u over stablize a bullet, i have always been under the impression that as long as your not loading up for super high veloscity u cant have to fast of a trist, so i have always went with a 1/7.

Junk bullets can spin apart. You'd be hard pressed to do it with a SAMMI 223 Rem but you might get a Sierra to go. Or some other low end bullet.

Overstabilization is overblown. Guys shooting at the upper end of USBR type competition claim they can measure twist rate sweet spots, but the bulk of those are building around long for caliber VLD profile bullets and thus run fast twists anyway.

The few USBR shooters I still talk to don't fret it much. People putting together utility rifles fret it way too much.

 

[03A3]

I've never loaded a light, thin jacketed bullet for use with 1 : 7 twist. For a slower twist bolt gun yes. That's what they were designed for. I have had them come apart in a 22-250 but I was pushing them past their design limits. The Hornady TSSX comes to mind.
I've never had, or even heard of, a #1360 Sierra come apart in a 22-250, or a 5.56 with 1 : 7 twist.

 

[palerider0485]

good info.

 

[DCM8513]

how do mil surplus rounds hold up in 1:7 twist. M193 and M855?

 

[Yeah]

Anxious to read more about the design limits of the Hornady TSSX.

 

[03A3]

Anxious to read more about the design limits of the Hornady TSSX.

Me too lol.
I meant say SX, (SuperExplosive fragmentation) light jacketed bullets with upper velocity limitations.
I guess Barnes has infected my mind.
I appologize for passing on bad info.

 

[Hop]

how do mil surplus rounds hold up in 1:7 twist. M193 and M855?

They're built for it now. The military uses a 14.5" M4 1:7 twist barrel.