What Adjustments Do I Make W/.357 W/Short Barrel Length?

[dwever]

I have a Performance Center .357 Model 627 with a 2.625" barrel. My question is, how much do I reduce the numbers below for the shorter barrel, as I believe these tests are for a 4" barrel.

My two most common carry loads are:

Federal Premium 357 Magnum Hyd-shok Grain: 130 Muzzle Energy: 574 lbs. Muzzle Velocity: 1410

Federal Premium 357 Magnum Vital-shok 140 Grain, 609 lbs. 1400 f.p.s.

[dwever]

I was pm'd a link that would indicate with loads that hit 1,450 f.p.s. in a 4" barrel, I'm losing ca. 120-150 feet per second with my 2.625" barrel.

It was tough to compare because the link was measuring a 2.5" barrel, and measuring velocity was at 10' rather than the muzzle, however, I think the 120 to 150 is a fair guess.

[Dragon88]

Most manufacturers don't list the length of the test barrel, so it's hard to compare if the factory listing is the only data you have. Running a load out of your own gun across a chronograph is the best way to know actual velocity. But if you find a reading from a similar gun with a longer barrel, you can subtract 50 fps per 1" of reduced barrel length. This is only a rule of thumb, but it's usually pretty accurate.

[off road]

BBTI - 357 Mag

Add the length of your cylinder (around 1.75" for most .38/.357's) to your barrel length, then look that up on the table. (This is necessary, because they measured their T/C barrels from the breach face, not the cylinder gap.)