Home Forums Hunting & Shooting Ask The Gunwriters FPS loss in Weatherby barrels?

In a Weatherby rifle chambered in 7mm Wby Mag, about how many fps would you lose in a 24" barrel vs. 26" barrel, shooting Wby factory ammo?

I had a guy in a gun shop tell me that it's a lot less than with a standard throated round like the 7mm Rem Mag. He claims the difference would only be about 50 fps, rather than the 150 or so fps that I'd expect. I'm calling BS on his claim. But I've only owned one newer Wby and never had the opportunity to test this.

I think 50 fps per inch of barrel removed would be about the minimum. The gun shop gun was being an idiot; you should have asked him if a sore throat changes the pitch of his farts.

Gun store ninjas are legendary...

But, they generally don't earn a lot.

You get your money's worth, listening to their ostentacious bloviation...

DF

It really depends on the individual barrel involved.
They all produce different pressure, even with identical loads, due to internal dimensions of the chamber, throat, lands & grooves, etc.
I've clocked barrels with the same ammo after having them shortened and seen as little as 22fps per inch removed.
There is no hard fast answer, other than "it depends".......
Good luck,
-Ted

My 24" Vanguard 300 Weatherby is faster than my buddies MKV 26" 300 Weatherby, and he's a half grain higher in charge weight.... I know it's not comparable but I have a Savage 110 24" 7mm Rem Mag, the last inch of the barrel has some pitting and the crown was bad, so I cut it back to 23" and recrowned it, it lost about 15fps...

I'd expect no more than 50-60 fps regardless of who made the barrel. This link doesn't address 7 mag specifically, but does several others. The 300 WM only lost 95 fps when cut from 27" to 21". The 270 lost 114 fps.

http://www.longrangehunting.com/forums/f19/short-barrel-magnum-velocity-19346/

The individual barrel has more to do with it than 2" of barrel makes. I have 3 rifles in 30-06, all with 22" barrels. The winchester 70 sporter is consistently 60-90 fps faster than the Rem 700. The 70 Featherweight is consistently 25-50 fps slower than the Sporter. I have a friend with a 700 (also 22" barrel) that was 130 fps slower than my sporter the one time we checked them side by side with the same ammo.

I've also seen a 20" 308 match another 24" 308's speeds and beat a 22" gun.

The only way to know for sure is to measure bullet speed with one barrel, cut the same barrel and measure again. When comparing 2 different guns you may well see the 24" barrel 150 fps slower, it could also be 50 fps faster or anywhere in between.

You got all the wisdom the price you paid could buy from him.

There's a guy at the LGS that is every bit a leading expert in all things. Just ask a question, try not to start laughing histerically.

My 24" Vanguard in 300 WBY gets 3190 with factory 180 Partition ammo listed at 3240 in a 26". Like others said, individual barrels are just that. I seriously doubt you would lose more than 100 fps with the shorter barrel.

You guys have given me some really good info, and I thank y'all for it. I had forgotten about Charlie Sisk's research. Back in the 90's a shooting club I was a member of at the time bought it's first good chrono.

I have a Ruger 77 in .300 Win Mag with 24" barrel, and I was loading for two .300 Wby's, one a Wby Mk V and the other a Kleinguenther, both with 26" barrels. Using the exact same loads in the two .300 Wby's, the Kleinguenther consistently outran the Weatherby by 90 to 150fps, and my Ruger with 24" barrel, was consistently on the heels of the Wby, and sometimes could equal it.

Then another friend got a Wby Mk V in .30-378 Wby Mag and I loaded for him also. The Kleinguenther in .300 Wby could about equal or come very close to anything that the .30-378 would do, while burning 20 to 40 grains less powder. That totally blew my mind and I reshot that test several times, but the results were always the same.

People here get paid nothing at all

The clerk not only is low paid he is subjected to all the
BS the gun nuts bring to share.

Did you ever listen in on conversations at a gun show?
That's where he is getting his education.