crimsondave
New member
OK. Can anyone say what the difference would be in velocity of a 18.5" barrel vs 24" barrel in .357 mag, 124 gr XTP w 22.0 gr of H110? I'm at 1500 out of a 4" S&W.
Barrel legnth vs Velocity ? for 357
- Thread starter crimsondave
- Start date
Dave,
That is a little hard to answer, because QuickLOAD's defaults give me a serious overload with 22.0 grains of H-110 in that bullet + cartridge combination. Looking at some load data, it appears that 22.0 grains is probably based on the old CUP standard, so I am not exactly sure what pressure to try to match in psi.
So, here is what I did to get you an estimate. I increased the case capacity until I got the pressure down to 44,600 psi and noticed that the velocity in a [4" barrel + 1.7" cylinder =] 5.7" barrel was about 1750 psi. QuickLOAD can't calculate the effect of the barrel-to-cylinder gap, so that leaves about 250 fps to account for that to get to what you are actually observing in your revolver. Revolvers vary a lot in velocity from gun-to-gun, so that isn't necessarily the right match.
IF that is a reasonable representation of your load, then the velocities for the 18.5" and 24" barrels are 2286 and 2379 fps.
I also tried increasing the case capacity to get the pressure down to 40,000 psi, and got 1699, 2246, and 2341 fps for the 5.7", 18.5" and 24" (unvented) barrel lengths, respectively. That seems as reasonable as the first try.
So, my best guess is that you will get something like a 95 fps difference between the two longer barrel lengths with that load. But, remember, this in only a computer program, and reality may vary.
SL1
That is a little hard to answer, because QuickLOAD's defaults give me a serious overload with 22.0 grains of H-110 in that bullet + cartridge combination. Looking at some load data, it appears that 22.0 grains is probably based on the old CUP standard, so I am not exactly sure what pressure to try to match in psi.
So, here is what I did to get you an estimate. I increased the case capacity until I got the pressure down to 44,600 psi and noticed that the velocity in a [4" barrel + 1.7" cylinder =] 5.7" barrel was about 1750 psi. QuickLOAD can't calculate the effect of the barrel-to-cylinder gap, so that leaves about 250 fps to account for that to get to what you are actually observing in your revolver. Revolvers vary a lot in velocity from gun-to-gun, so that isn't necessarily the right match.
IF that is a reasonable representation of your load, then the velocities for the 18.5" and 24" barrels are 2286 and 2379 fps.
I also tried increasing the case capacity to get the pressure down to 40,000 psi, and got 1699, 2246, and 2341 fps for the 5.7", 18.5" and 24" (unvented) barrel lengths, respectively. That seems as reasonable as the first try.
So, my best guess is that you will get something like a 95 fps difference between the two longer barrel lengths with that load. But, remember, this in only a computer program, and reality may vary.
SL1
Lost Sheep
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crimsondave
New member
Thanks for all the replies. Very helpful.
crimsondave
New member
Want a rifle in that caliber.
crimsondave
New member
"I" want a rifle in that caliber. Weighing pros and cons of barrel legnth.