max barrel length

mark308

my 308 shoots very well with just a 22" barrel. I have shot out to 400 yds with it.deer and elk. Im thinking of a new barrel for alittle more fps out of my loads. I usually shoot a 125 or 150gr bullet. Is there that much improvement by going to a 24 or 26"? I may also change to a 1-10 or 1-11 twist. any thought? thanks for the input.

nononsense

mark308,

What are both loads chronographing currently?

What powder/loads are you using with which specific bullets.

What twist rate do you have currently?

What velocities are you looking to achieve with this new barrel?

Best.

sandwarrior

mark308,

Yes you can improve your velocities with a longer barrel. You have to know how to do it. Final muzzle velocity is based on initial pressure followed by barrel pressure at time of bullet exit. Let's say a normal case/bullet combo uses a max pressure of 55k psi. With IMR4895, for instance in a 22" barrel such as yours, the exit pressure is about 17k psi. The 55k is how much jump the bullet gets moving and the 17k is a result of how well the pressure maintained throughout the bullet acceleration to and out the end of the barrel. Now if you lengthened the barrel it wouldn't necessarily just give you better velocity. You would have to slow the powder speed down so it would still give you 17k at the end of the barrel but still give an initial spike of 55k. So lets say if you jumped to IMR4350 you could do this. If you jumped to H1000 or say IMR7828 you might actually have 18 or 19k at the end of the barrel but with initial burn only obtaining say 50k you are going to have a tradeoff that may result in lower velocity. Simply because you didn't have a high enough pressure spike at ignition in the case.

Point being once you learn which cases work best with which powders you will be more adept at getting more velocity safely from a longer barrel.

Stay tuned for more specifics as I'm sure they will come. -good luck

bpost

If you have a rifle that shoots good leave it alone. If you want more go-fast from your bullets; buy another caliber that gets heavier bullets up to the speed you want. I would suggest a 300 Winchester Magnum 26" barrel on a Encore frame. You will still have a short handy rifle and won't ruining the good shooter you have now. The most you can expect is a 25-50 FPS gain per inch. taking apart a good shooter for such a small gain seems a waste to me.

Re-barreling is not cheap and you might not have the accuracy you have now after spending all that money. If it ain't broke don't fix it [;)]

My .02

flyingtorpedo

quote:Originally posted by bpost1958
If it ain't broke don't fix it [;)]

My .02


+1

scrubberguy

mark308:

If you needs a magnum buy a magnum![8D]

haroldchrismeyer

I have to agree to this too. Don't try to fix your 308 if it shoots good, and all you want is more velocity. Rebarreling isn't cheap, and the money would probably be better spent buying a 7mm magnum, or a 300 magnum rifle.

mark308

thanks for the input. its what I knew was right. if it aint broke dont fix it. and its more fun to buy another toy[:p][:D]

sandwarrior

Mark308,

So, rather than buy a new magnum, why don't you look around and get a rifle/caliber that exactly suits your needs, set up the way you want for the velocity that you want. IOW, build you a custom. Of course if all you want is a little more velocity...and you don't mind recoil...get a magnum. But if you want a lot of mileage out of a smaller round that doesn't eat barrels when you shoot it a lot. Doesn't kick like a mule. Doesn't eat you out of house and home when buying powder for it. Then do a custom build for a caliber you like.

I guess I just assumed you wanted the same kind of accuracy as with the .308 you have now so you could reach out farther.