velocity 308 18 1/2 bbl

wtroper

Has anyone ever chronographed a 308 out of an 18 1/2 barrel? I am thinking of purchasing a Ruger M77 RSI. I am attracted to the short barrel and full-length stock of the RSI. Of the calibers available it seems to me that the 308 would be the best choice, even though I am partial to the 257 or 7x57. Because of my past experience with 14" contenders and encores, I suspect that the 308 would lose only 150fps + or - from the published 22" velocities. Anyone have any experience?

iwannausername

About the same, but the published stuff is usually off. Best thing to do is to actually chrono your loads. If you don't have a chrono, you can make one with a level, some scrap wood (1x1s), some cardboard, a calcualtor, and some highschool physics.

wtroper

Thanks. I have a chronograph, but have not yet acquired the Ruger. Thus, I do not have anything with an 18 1/2" bbl. Several years ago I have a RSI in 270. Always thought that it had too much powder for the short bbl. However, do not believe that I ever chronographed it.

My ultimate objective will likely be to rebarrel the 308 to the new 338 Federal. Probably a foolish thing to do, but not many people have ever considered me very practical. I think the 338 Federal would be a nice, efficient, and relatively unique item in the right package.

I have a M70 classic that I had made into a 338-06. It shoots very accurately. Since I seldom shoot rifles anymore (I have hunted only with handguns for the past several years), I am probably just contemplating an exercise for the sake of the exercise.

The only difference between men and boys is the cost of the toys.

CHAIRMAKER

wtroper,
FWIW, several years ago I cut a .308 barrel from 22" to 18" and chrono'ed my loads before and after. Only lost 90 FPS.

ern98

My understanding is that barrels loose between 25 and 50fps per inch in general. Some barrels because of their manufacturing and finnishing can be even more or less then that. But, you really won't know until you measure the actual barrel. I've been working with a 7x57mm 19.5" barrel Mauser 98 for some time now. It looks to be nearer the 25fps then the 50fps, but that is just this barrel. With any production full length stock rifle, velosity may not be your big concern, accuracy may be. Limited and custom full length stock rifles generally shoot well. Production rifles can be twichy and you may have to mess with the bedding to get them to shoot. Rifles on the full length stocked Mannlicher short rifle pattern are, IMO, a great addition to a hunters battery. They fuction well in the thick brush and woods with a low power scope or peep hole sights and cycle just about as fast as a lever. Good luck.......

wtroper

Thanks Chairmaker & ern98. I appreciate your comments. I understand some about the bedding issues & expect that the full length stock only makes those problems "longer." Chairmaker's experience in cutting down the 308 confirms my expectation. Have chronographed many 14" barrels & was surprised at their relative performance.