Another 6br spin rate question!?

[NC/Br Shooter]

As titled, the question Or decision I need to make is the twist rate for the next bbl.
Goal will be to shoot 68 burger, and 70g mk, bullets only. With a straight 6br , I assume needs be 0 free bore?
Iv had success shooting the 70 mk with 30g of h4895 in a 8 twist. 6br. Knowing that was about as light that one could take.
Next bbl, I want, I'd like to try a 30 inch slow twist bbl in 6br. Contour I'm thinking just a unturned straight 1.25 bbl.
One option I can do is 26inch 12 twist prefiit, Which I'm thinking of doing.
The other would be a 30 inch 10 twist, or 14 twist.
What would be my best choice?
Any suggestions?

 

[HTSmith]

One option I can do is 26inch 12 twist prefiit, Which I'm thinking of doing.

That would be a good choice. You could go up to 80 Gr bullets.

 

[Murray Brook]

I had a 6mm Br built on a short action Rem 700. I had Dave Manson fix me up with a reamer. It has a .2725 neck 0 FB with min sammi specs on the case body. I went with a 10 twist. My goal is to shoot the light 6mm bullets (Berger 64 Column) but as the throat wears I hope I can extend the round count by going to heavier/longer bullets. This was the reason for the 10 twist. A 12 twist may also have been good. Rifle so far shoots very good. Exceeds my expectations.

 

[Hoot]

Not to butt in on someone else's thread but am I hosed in wanting to shoot the light stuff in my 29" 1:8 Shilen barreled rig? Not in a position financially to get a new barrel. Perhaps later this year but not right now.

Hoot

 

[Charlie-NY]

Not to butt in on someone else's thread but am I hosed in wanting to shoot the light stuff in my 29" 1:8 Shilen barreled rig? Not in a position financially to get a new barrel. Perhaps later this year but not right now.

Hoot

I've been fooling around with 55gr BTs and 65gr Bergers in my 8 twist. There is plenty of data on this site from others who have done the same. So I wouldn't say that you are "hosed". :>)

 

[Webster]

As titled, the question Or decision I need to make is the twist rate for the next bbl.
Goal will be to shoot 68 burger, and 70g mk, bullets only. With a straight 6br , I assume needs be 0 free bore?
Iv had success shooting the 70 mk with 30g of h4895 in a 8 twist. 6br. Knowing that was about as light that one could take.
Next bbl, I want, I'd like to try a 30 inch slow twist bbl in 6br. Contour I'm thinking just a unturned straight 1.25 bbl.
One option I can do is 26inch 12 twist prefiit, Which I'm thinking of doing.
The other would be a 30 inch 10 twist, or 14 twist.
What would be my best choice?
Any suggestions?

I have a 6BR for GH hunting. 14 twist 26". Definity start to see the groups open up with 70 gr bullets. If you look at the equipment list for SR serious competition, they use 13.5 or 14 twist with 68 gr bullets. I would definitely consider a 13 twist. Don’t know if 12 twist will handle a bigger range of wts. I would e-mail someone like Sierra or Berger and ask.

 

[NC/Br Shooter]

Do most ppc shooters use 0 free bore?

 

[NC/Br Shooter]

I had a load several years ago shooting 70g Smk
6br 0fr 26 inch bbl. 30g of h4895 that shot great. That bbl is toast and gone . I'm sure it was a button rifled bbl.
So, I'm interested in going back to a straight 6br because I have the dies, a new action, and a ton of 70 g smks.

 

[Mark Buettgen]

Do most ppc shooters use 0 free bore?

I would say most run run between .020" and .070" lead.
My go to reamer uses the old std 1.525" and .035" lead.
Later, Mark

 

[AlNyhus]

My suggestion would be a 12 twist with no more than .030 of free bore section (leade).
The problem with shorter bullets in an 8 twist is that the reamers generally used for them have in excess of .100 free bore. If you're doing a 'bubble packed' (prefit) barrel, be very careful of this.

Good shootin' -Al

 

[urbanrifleman]

My suggestion would be a 12 twist with no more than .030 of free bore section (leade).
The problem with shorter bullets in an 8 twist is that the reamers generally used for them have in excess of .100 free bore. If you're doing a 'bubble packed' (prefit) barrel, be very careful of this.

Good shootin' -Al

What is a bubble packed prefit barrel?

 

[urbanrifleman]

I have made lots of 12 twist 6br and 6bra barrels. I can't imagine needing any more than 26 inches for the powders being used. Most short range guys shoot shorter barrels not longer barrels.

My barrels are shipped in bubble wrap. Btw. So beware!!

 

[Charlie-NY]

My suggestion would be a 12 twist with no more than .030 of free bore section (leade).
The problem with shorter bullets in an 8 twist is that the reamers generally used for them have in excess of .100 free bore. If you're doing a 'bubble packed' (prefit) barrel, be very careful of this.

Good shootin' -Al

My 8 twist has (IIRC) .100 FB. Using a 55-65gr boattail bullets required a jump of .150-.165" and they only have a minimal amount of bullet shank in the case neck. I'm just starting to experiment with this mismatch of bullets/throat/twist. I was primarily interested to see how much velocity & accuracy I could get in a load that would be fun to use on tiny critters. My impression is that either flat base bullets or bullets a bit heavier would be a much better option for varmints.

 

[Alex Wheeler]

You have gotten some good advice, but I would like to ask what your purpose is for this? Paper or varmints?

 

[AlNyhus]

What is a bubble packed prefit barrel?

Ones where the seller can't/won't furnish specs. on the chamber, especially the freebore length.

Good shootin' -Al

 

[NC/Br Shooter]

You have gotten some good advice, but I would like to ask what your purpose is for this? Paper or varmints?

Target, 100 yard , indoor match only