Barrel length for .375 RUM

[Slooshark1]

I'm thinking of building a .375 RUM on a Model 700 action. I know that on 50 BMG rifles they use barrels up to 44" long. How much more velocity will I get with the .375 RUM with an extended barrel? What if I had a 44" barrel on a 700 action?

Valid opinions are appreciated.

Kindest regards,

Slooshark1

 

[Levi Garrett]

I would go 29" or so

 

[prosper]

I'm not aware of any .375 match or VLD bullets, so why bother with an unmanageably long barrel?

 

[gunpro]

i restocked at 338 ultramag on a Mark X action. It had a 28" stovepipe barrel. Measured 1.2 at the chamber and tapered to 1" at the muzzle.

So 28 is where i would consider starting and ending unless you have a magic bullet supply for match or VLD's as listed above.

 

[Boomer]

Some barrel makers charge a premium for barrels longer than 28", and a 30" .375 Ultra probably won't produce enough of a velocity gain to justify the trouble or the expense.

I went the other way and have a 20" barrel on my .375 Ultra. I make 2900 fps with a 260 gr bullet, and 2600 with a 300 gr. This compares with 2970 for the 260 gr and 2630 for the 300 gr from the Nosler Manual. Personally I doubt if you will see much of a velocity gain with a very long barrel. It seems that the .375 bore diameter is able to make efficient use of powder gases in normal length barrels. Geologist cut his H&H from 25" to 20" and he lost about 50 fps.

With a 28" barrel chambered for the .375 Ultra, I think you might see a 100 fps advantage over a 24" barrel. If you are having a custom rifle built anyway, it would be interesting to see what velocity a 28" barrel would give you, and if it wasn't worth while you could have the barrel progressively shortened.

 

[PeterPan]

Is this a hunting rifle?
If is a hunting rig, why do you need extra weight.
Get yourself semi-heavy bbl in 26" or max 28", then you
don't have to pay extra for longer bbl.
Longer bbl is good for magnum calibers, due to slower powders,
which can't efficiently be burned in shorter bbls.

 

[DarrylDB]

If you look at the 20 inch barrel info from boomer, it seems clear that even 26 inches seems to be beyond the point of diminishing returns on this cartridge...

I dont think you'll se ANY benifit of any barrel length over 26 inches with the 375 RUM...
Way too much bore Dia to volumetrically fill with most powders...
You may actually see no increase at all...
ON a few occasions, I've seen long barrelled rifles shoot slower than short barelled rifles due to too much bore dia for the powder charge... ...
Hotloaded 45-70's do it all the time...
The larger your bore dia, the less barrel length over 18 inches affects velocity...