1 in 17 twist 308

[afret]

I'm thinking of putting a 17 twist 308 together for shooting paper with light 115-125 grain bullets at 100-200 yards? Would this make a pretty accurate combo or not such a good idea?

 

[dryhumor]

I have a 13T 308. 115 Bergers shoot really well. I had some 120 Eubers I loaded at the same charge on a whim, they shot well also. The 120s need a little more tweak. Using X terminator powder.

ETA Zero freebore….

 

[afret]

That's another consideration. Is the standard .90 or so freebore too much for these light bullets?

 

[AlNyhus]

This was a semi- popular approach in the Hunter class. The reduced capacity .30's (30X47-ish) were more accurate due to the efficiency, but the full length 308's were decent with the light bullets. The advent of the Lapua 6.5-47 case killed the full length 308's deader than a smelt as case making became much easier for a reduced capacity case.

The two I worked with would shoot mid .2's with the 1.00" and 1.080" based 117's through the 135's. 748, H322, N133 and N135, and Accurate 2520 were good powders. Later on, I tried some Benchmark and it was just as good.

A 15 twist would open up more opportunities for bullets and not cost you any day to day accuracy. Free bore length of zero to .025-.030 max. will be what you want. Even with theoretical 'zero' free bore length, you'll always have (unless you opt to have the reamer maker remove it) a bit of free bore due to the standard 45 degree transition from the end of the chamber neck to the start of the free bore section....this usually gives about .015-.020.

As to the .090 free bore...here's an example. My 1.00" jacket 7 ogive .30's will normally run about .410" base-to-ogive length. Keep in mind the end of neck angle (adds 'fake' free bore length) and do the math to get a ball park estimate of how much neck is in the case when seated to touch the rifling. The 1.080"-7's are right at .465" and a 150 gr on the 1.150" jacket is .585". The 1.080" jackets are for all intents and purposes, non-existent.

For what it's worth.... -Al

 

[afret]

Thank you for all the great info. I think sticking to a 12 twist and 155-175 grain bullets might be a better way to go. Just want to put a fun reasonably accurate 308 bolt gun together since I have all the reloading stuff for my 308 AR.

 

[Websurfer]

Why not get a 30BR barrel (easy to change out on a Rem 700) and enjoy the most accurate 30 caliber short range cartridge ever? A 308 can be very, very accurate, but a 30BR is tops.
Of course, this implies new dies, equipment, etc., which is an investment. And a solid reason not to go in that direction.
An accurate 308 makes for lots of fun, for sure

 

[Websurfer]

PS - a 1/12 barrel will shoot light bullets (115 grains +/-) into tight little groups

 

[afret]

Would a 1 in 10 twist barrel work well with 150-175 grain or even 125 grain bullets since this twist rate seem to be a lot more common and places have them in stock?

 

[Bill K]

Are you really talking about a 1/17 twist barrel or do you mean a 1/7 twist ? I don't think I have ever seen or heard of a 1/17 twist in 308 win.

I'm thinking of putting a 17 twist 308 together for shooting paper with light 115-125 grain bullets at 100-200 yards? Would this make a pretty accurate combo or not such a good idea?

 

[Websurfer]

1-10 is a twist which most 30 caliber owners can use comfortably. Take an average 308 owner. He/she most likely uses bullets 165 grains (+/- 20 grains) for hunting and target shooting. The 1-10 is fine there. Move to the extremes, and heaviest/lightest bullets do best with a different twist.

 

[Websurfer]

30BR shooters hover around 1-17 and 1-18 twist 30 caliber barrels. Very slow twists for very light 30 caliber bullets

 

[Websurfer]

Back to your original question:
Yes.
It’s a good idea for those weights at that distance

 

[afret]

Thanks everyone for the info and advice,

 

[SQ54]

I have a 1-17 twist .308 in which I shoot cast bullets at 2500 + fps

 

[Sniper338]

Would a 1 in 10 twist barrel work well with 150-175 grain or even 125 grain bullets since this twist rate seem to be a lot more common and places have them in stock?

I have a 10 twist. It likes nothing, nothing but 175 smk. Anything lighter it won't shoot.

 

[afret]

That's interesting. Maybe 12 twist would be better in my case?

 

[dryhumor]

I have both 10 and 12 twist 308s also. I’ve shot 125s through the 12 twist. My 13T is primarily a dedicated hunting rifle, for 150-155 grain bullets. Just a plus that it shoots light bullets well.

Krieger barrels generally has a decent selection of in stock barrels in 308.

 

[Greg Brooks]

I would do it. Slow twist 308 ‘95 Palma chamber zero freebore. They shoot really well with 112 to 118gr and V133 - just push those at a low end ppc velocity and it’ll do well. I used one for Varmint Matches from 100-400 yards best edge scoring, no personal wind flags permitted. This is a rough initial tune using thrown charges.

 

[O G]

I would do it. Slow twist 308 ‘95 Palma chamber zero freebore. They shoot really well with 112 to 118gr and V133 - just push those at a ppc velocity and it’ll do well. I used one for Varmint Matches from 100-400 yards best edge scoring, no personal wind flags permitted. This is a rough initial tune using thrown charges.

whats the twist rate?

 

[Greg Brooks]

whats the twist rate?

That barrel was a 17 twist 4 groove Kreiger at about 26”.