Gunsmithing Good twist rate for a 18 inch barrel 308?

[Mjolnir23]

I have been wanting to make my FN PBR more handy for about a year now, and the 24 inch barrel needs to go. I want to get an 18 inch so when I put a surefire break and can on it its about the same length as it is now and without its a lot shorter. Anybody know some good twist rates for 175 FGGM and 178 Hornady in that length?

 

[Papa Zero Three]

That length and that bullet weight a 1:10 twist rate will do you nicely. Give it 5 minutes and someone else might come along and tell you something different, but it works fine for me.

 

[Graham]

1:10.

 

[Ledzep]

If I was ordering a new barrel I'd be looking for a 1:11. 1:10 won't hurt, either.

 

[wxl]

1/11 should be fine for 175s

 

[wayfastwhiteie45]

Do you plan on shooting subsonic? If so then go 1:8. If not 10 twist is recomended. And going that short I would recommend a tight bore like a .298/.308 so you can build pressure faster to try to get the most possible velocity

 

[300sniper]

18.5" long, 11.25" twist and .299 bore kept 175 smks point first at 1500 yards for me.

 

[Rprecision]

1/10

 

[nashlaw]

Have 1/10 from Meredith Ind. that bugholes 155s and 175s. Cut at 18".

 

[Vio515]

+ 1 for the 10 twist

 

[Mjolnir23]

Do you plan on shooting subsonic? If so then go 1:8. If not 10 twist is recomended. And going that short I would recommend a tight bore like a .298/.308 so you can build pressure faster to try to get the most possible velocity

I have read that with the .30 "tight" barrels, you need to watch how heavy of bullets you use because of chamber pressure and fouling issues. Have you had any problems or concerns with this?

 

[wayfastwhiteie45]

I have read that with the .30 "tight" barrels, you need to watch how heavy of bullets you use because of chamber pressure and fouling issues. Have you had any problems or concerns with this?

in my experience (though it is limited) with 175gr smk's i have had no pressure issues with a 21" 308/298 1/11 barrel. that is my current set up.
i don't consider 175/178gr to be heavy.

i hope that's helpful