6x47 Twist

[Clucknmoan]

Having an MPA 6x47 built with an 8 twist barrel. First 6 for me, always shot 6.5's and above or .224's of sorts. Will be used for PRS, other long range steel and any unfortunate varmint close to the house...or pickup.

Originally wanted to shoot 105 Hybrids, but now seeing the 108 ELD M's and 110 SMK's I'm second guessing my twist selection. Really it will come down to what barrel likes, but I don't want to pigeon hole myself with a twist that's too fast or slow.

Question is then, who's got experience shooting the 105's out of a 7 twist and who's shot the 110's out of an 8 twist? Positive and negative appreciated.

Any input would be appreciated, should be 3000+ fps and about 3200' elevation.

Thanks Gents.

 

[swd]

I shoot 110's at 2 ranges, 4200' and 100' ASL at 3080fps. They'll stabilize out of some 8"s but not others. A 7.5" will get it done nicely.

 

[JBT47]

If not too late, change order to a 7.5" twist

 

[JBT47]

As for a 6mm 1-7" twist...read some of Robert Whitley's posts on the same re: pressure related issues.

 

[Clucknmoan]

As for a 6mm 1-7" twist...read some of Robert Whitley's posts on the same re: pressure related issues.

He had pressure issues in a 7 twist?

Moving from an 8 twist to a 7.5 moves it from 1.56 to 1.78 stability with our typical conditions. Moving to a 7 takes it right around 2.0

Never even looked it up before, I guess because I knew a lot of guys that shot 105's in an 8 twist, but Berger even recommends a 7 twist for the 105's. Surprised me.

 

[JBT47]

He had pressure issues in a 7 twist?

Moving from an 8 twist to a 7.5 moves it from 1.56 to 1.78 stability with our typical conditions. Moving to a 7 takes it right around 2.0

Never even looked it up before, I guess because I knew a lot of guys that shot 105's in an 8 twist, but Berger even recommends a 7 twist for the 105's. Surprised me.

Yes, pressure in the 7 twist barrels before reaching adequate velocity. This is not my experience or opinion...just sharing what I've read on this site. I've used 8 twist and 7.5 twist 6mm barrels but never a 1-7".

 

[Clucknmoan]

Well, I guess MPA doesn't offer anything under an 8 twist in a 6 quite yet, so 8 twist it is!

I'm 100% sure I'll be happy either way. Excited to get my hands on it.

 

[JBT47]

Well, I guess MPA doesn't offer anything under an 8 twist in a 6 quite yet, so 8 twist it is!

I'm 100% sure I'll be happy either way. Excited to get my hands on it.

My 8 twist 6x47 Lapua shoots 105 Hybrids with no issues out to 1200 yds. You should be happy with your 8 twist.