My Sako Finnbear in caliber 375 H&H Mag has a barrel lenght of 58cm, normal length is 61 cm. I think that this rifle got it`s barrel cut before I got my hand on it.
It is not any big muzzelflame when I shoot.
Question: How much speed loss do I get?
I might increase the loads a bit to get the right velocity of my rifle as a 375 H&H mag.

What do you guys think ?

About 40fps-100fps for ~1" shorter barrel.

George

I think the expected velocity loss for one inch shorter is about 25 fps in this case.

610mm = 24.0"
580mm = 22.8"
30mm difference = 1.18" (25.4mm/inch, conversion factor)

That is not much difference at all. 1.18" x 25fps/inch = 29.5 fps, about 30 fps

Excuse my previous typo pointed out by Fjold's post.

(61 cm - 58 cm) * (0.3937 Inches/cm) = 1.18"

In a 375 H&H you're probably only talking about losing 25 - 40 fps

(1 Feet Per Second = 0.3048 Meters Per Second) = 7.6 - 12.2 meters per second

58 cm = 22.8 inches (I think?)

I had my .375 H&H built at 21.5 inches. It's incredibly fast-handling and well-balanced for a 9.5 lb rifle.

It hasn't not killed anything it was fired at yet, from Francolin to elephant.

Thank you guys. It`s just cosmetic the loss, nothing to worry about. My sako is vere well balanced and fast to use and reload when you aiming, With open sight it`s fabulous.

I have chornographed some loads and comparing with the reloading data in most common books i loss about 10 Meter/sec it`s really nothing to talk about, The Moose or even the big ones in Africa will not notice the diffrent.

quote:

I have chornographed some loads and comparing with the reloading data in most common books i loss about 10 Meter/sec it`s really nothing to talk about

I was pretty close then, 7.6 - 12.2 averages out at 9.9 meters/sec.

I`v just back from the shooting range, testing loads in my 375 H&H Mag.
300 grs Woodleigh RNSN loaded with 80 grs Norma 204 federal 215 primers and remington case velocity 2576 Feet/sec. 3 shots and average speed. This is maximum load in my rifle, Reloading book from Hornady has 84,0 grs with 300 grs Nosler partition, I dont even get 84 grs of powder of type Norma 204 in my cases.

I also chonographed a load with 260 grs Nosler Accubond Loaddata: 73 grs of Norma 203 B, Federal 215 primer and Remington cases
Avarage 3 shot speed was: 2700 fetet/sec

Your velocities are right on for 375 H&H with both bullet weights, no matter what your barrel length is, enjoy!