I'm curious if anyone has a 20" barreled WSM that they've chronographed, especially with 180 grain bullets.
Bfly

My guess is that you'd have a .30-06 "slightly improved" with a huge fireball and accompanying unbelievable muzzle blast with little else for your efforts.

I too would be interested in any chrono data.

Ditto what surestrike said. I don't know the answer either but I'd sure like to shoot one in front of an open shutter in the dark of night. Would be a great picture!

quote:

Originally posted by Black Fly:
I'm curious if anyone has a 20" barreled WSM that they've chronographed, especially with 180 grain bullets.
Bfly

My 22" 300 WSM "barely" made 2,900 with 180 NP's... it ran 2,970 when it was 24" (same EXACT cartridges loaded).

I expect a 20" bbl will go 2,850-ish.

Personally, having had 7 300 WSM's with 22, 23 and 24" bbl's, I'd not go below 23".

Thanks guys. I had a WSM Model 70 years ago when it first came out, but it was a 24" as I recall. It was only a bit slower than my standard 300 Win Mag. After reading about the original reason for the RCM, I was just wondering what a person might expect from the WSM in a short barrel. Since it has a bit more capacity, I thought you might be able to do better than the RCM. Although, I sort of figured you might need a flash hider and a campfire permit with the short barrel.
Bfly

The factory 300 RCM ammo is spec'd for 100% burn in a 20" barrel. The factory 300 WSM ammo is spec'd for 100% burn in a 24" barrel so with a 20" you'll likely get the fireball mentioned above. You'll need to play with faster burning powders to get maximum velocity with 100% burn in a 20" barreled 300 WSM.

A friend has a 375 Ruger factory chambered in the M77 SS Alaskan with a 20" barrel. He decided to cut the barrel to 17" and factory 270gr ammo gave the fireball and muzzle blast mentioned above. However his hand loads with 300gr Hornady @ 2400fps MV were very clean burning and still very accurate to 325yds. He was/is very happy with the end result as he has a much handier rifle for close shots in thick brush but has a combo that'll still reach across the typical clear cut area in the state forest where he hunts black bear.

If you do cut the barrel shorter, even with 100% powder burn you will take a velocity hit - basically moving from a strong 30/338 WinMag equivalent velocity to a strong 30/06 or perhaps a strong 30/06+ equivalent velocity. Only you can determine whether the shorter barrel and resulting 'handier' rifle is worth the velocity hit.

I have a Ruger Frontier in 300 WSM with a 16" barrel. I get 2600 fps with a 180 grain Accubond.

quote:

Originally posted by Kay9Cop:
I have a Ruger Frontier in 300 WSM with a 16" barrel. I get 2600 fps with a 180 grain Accubond.

And a really fantastic tan with every shot!

quote:

Originally posted by rnovi:

quote:

Originally posted by Kay9Cop:
I have a Ruger Frontier in 300 WSM with a 16" barrel. I get 2600 fps with a 180 grain Accubond.

And a really fantastic tan with every shot!

Can also be used in place of a flashlight.

quote:

Originally posted by Brad:

quote:

Originally posted by rnovi:

quote:

Originally posted by Kay9Cop:
I have a Ruger Frontier in 300 WSM with a 16" barrel. I get 2600 fps with a 180 grain Accubond.

And a really fantastic tan with every shot!

Can also be used in place of a flashlight.

And doubles as an acoustic/illumination sensory depervation weapon.

Whether all the powder burns in a given barrel length is not nearly as important as some folks seem to think.

What IS important is how much gas is generated by the burn, and whether that gas is still hot and expanding in a barrel. It is the expansion of the gas that pushes the bullet out of the barrel, not the burnt powder or unburned powder.

That is why longer barrels deliver higher velocities with almost all centerfire cartridges...the gas is still expanding down the full length of the barrel, thus still pushing the bullet faster and faster until it leaves the barrel. (And often the "fireball" of expanding gases even continues to increase bullet velocity for an inch or so after the projectile leaves the barrel.)

with .22 LR Cartridges, that is NOT always true. With them, somewhere after about 26"-27" of barrel length, velocities often start to slow down because the relatively small amount of gas has quit expanding and barrel friction is beginning to wreak its effects.

20 years ago I used to work at a 50' indoor range. Each night we had to clean up the lanes, dispose of brass, targets, etc. We'd sweep up POUNDS of unburned powder each night.

Right about that time I stopped concerning myself about "complete combustion" and really just starting enjoying shooting overall. Heck, I LOVE full house loads of H110 and 110gr. bullets in a .357 mag. Pointless? Maybe, but I could generate a massive fireball and shockwave that would gather attention 6 lanes down...and THAT was fun.