I don't know if this is a stupid question but.... does the .375 ultra mag really need a 26 inch barrel or would it still be better than an h&h with a 24 incher?

The .375 RUM is going to out pace its older brother in any configuration. That being said, and the fact it has more powder capacity, a longer barrel would be superior from a ballistics standpoint. From a hunting standpoint, if you want a shorter barrel, go for it, the game will not know the difference.

I would still go with the H&H as I cannot see the remington cartridge surviving and who needs any more recoil.

IME if you cut a 375 RUM from 26 to 24 you would lose total at most 70 fps. Most likey more like a total of 60 fps.

You're gonna find more of a loss or gain off of your loads than this. Either with factory or handloads.

Mark D

thanks guys? The only reason I am thinking about this is that I just bought a .375 h&h but it only has a 24 inch barrel. I really want to make it into an ultra mag (just to start a pissing match with my friends). I know that if I hit any animals with it they won't know the difference but if it isn't going to affect ballistics too much I want to go for it.

I am having a custom 375 RUM built. I went with a 24" #5 contour barrel.

Remember that a .375 RUM reamer will not completely clean up a .375 H&H neck and shoulder area, unless you set the barrel back a thread.

This is due to the .375 RUM having a slightly longer neck than the .375 H&H which is actually "sub-caliber" in neck length. Yes, the .375 H&H has a fault.

So a remnant of the .375 H&H shoulder will "Weatherby-ize" the new .375 RUM shoulder, and it will be rounded or radiused looking at the neck-shoulder juncture ... unless you set the barrel back before cutting the new .375 RUM chamber.

I had a .375 RUM built early on with a custom reamer that had no freebore, just leade. That was on a 23" barrel and it did 2784 fps with factory ammo and showed flattened and slightly cratered primers.

The same factory ammo (300 grain Swift) in the Remington factory 26" barreled M700 LSS gave about 2803 fps and mild looking primers with the factory chamber, which has a modest amount of parallel sided freebore, something like 0.1750" length of freebore and 0.3761" diameter of freebore.

23" to 26", take your pick, would be good for the .375 RUM.

The .375 Weatherby reamer can indeed clean up the .375 H&H chamber without setting back the barrel, as it has the solitary fault of short neck just like the .375 H&H.

The new .375 Weatherby freebore is 0.3700" long and only 0.3755" diameter. I like that throat best of all for any .375, including the .375 Lapua.

You are really best off starting with a new barrel or cutting all the threads off the take-off barrel and rethreading if you have enough shank.

There is enough shank on a Winchester barrel to make a nice 23" .375 RUM or .375 Weatherby.

The 375 RUM has the same expansion ratio and shoots over the same velocity range as the 280 Remington. A 24 inch bbl will work fine...