Home Forums Hunting & Shooting Ask The Gunwriters 300WSM and 20" barrels?

The real question is what do you want the gun to do? If you want 30-06 performance, than a 20" 300 wsm will produce that in a more compact package, though one that will be much louder and with much higher recoil.

If you want to "300 magnum" performance, than the 300 wsm needs at least a 24" barrel.

I have a 20" barreled .308 and like it for what it is. I also plan on getting a 300 wsm, but in a Kimber montanna, because I want the longer barrel for the velocity and to keep the muzzle blast from being too extreme. I'm not even willing to live with a 22" tube, and no way I'd go down to 20".

This kinda backs up what MD said about how it works "in theory", but doesn't quite work out that way in practice. (somebody has a signature about that!)
I had a model 7 in .308, with an 18" barrel. With a bit of patience- and a LOT of bedding- I inserted same barreled action into a factory plastic ADL stock. That stock is longer than the factory m-7 stock, and the rifle looked a little dufus with such a short barrel. Velocity ran nearly 2700 with 165s. It was light and handy though, so I was a happy camper...
Until I managed to snag a new 22" pull-off barrel for about $40 off eBay. I figured I'd be treading on '06 velocities with 3 1/2 more inches of barrel! How could I go wrong?
Well, surprise!!! I gained a whopping 50-60 fps with the longer barrel. Oh well, the best laid plans..., However, the new barrel does group a little (very little) better, so I have left it on.
Another experiment with a bud's 26" heavy barrel shows another 100-150 fps gain over my 22" barrel! And this is all out of the same batch of reloads.
So, there's really no telling what you'll wind up with. You might have a "fast" barrel that will run with the longer ones in an abbreviated condition. Then again, you might have a "slow" barrel, that disappoints, even in 24" length. I'd just decide on what I REALLY wanted in barrel length, then go with it, and live with whatever it gives. As long as the accuracy is there, don't sweat a couple hundred fps's. You'll soon likely forget there was a difference.

Speaking of muzzle blast, I shoot a Ruger compact 7-08, with 16.5 barrel. My bud, BMT says that the muzzle blast is deafining when standing behind me (with ear protection) while I'm shooting. With ear phones, I can't tell the difference between this rifle and my 280 with a 24" barrel. Maybe it's 'cause I've been shooting for 40 years?
Am thinking it's the "shock waves" of the short barrel.
Virgil B.

Thanks for the explanation , MD . I had thought about cutting the barrel down to 26 but 120 TSX at 4000 fps just sounds so impressive !

One reason - as if we really need reasons - for Improving a cartridge is to regain the velocity lost by shortening the barrel to make the rifle handier . A 257 AI does pretty good in a 20 in barrel .

How does 7 Rem Ultra Mag Ackley Improved sound !!