Hey all! I am getting a 5" barrel .357 magnum soon and am wondering if you think a 5" barrel will push 125 grain hollow points too fast? They seem ideal from a 4" barrel, maybe perfect, but I'm not sure if I should use them (Federal C357B) for fear of overexpansion from the increased velocity, leading to underpenetration or excessive fragmentation.

Will the 1" longer barrel make enough of a difference to matter? Thank you for the help.

-Jay

You're worrying about nothing. There has never been problems of the type you describe with 5", 6", 6 1/2", 8 3/8", and longer handgun barrels, and even 16" carbine barrels. The 6" barrel was the standard length for .357s when it was introduced.

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Don't kiss smiling dogs!

5" good around magnums!

This is a pretty good site for info like that...


BBTI - Ballistics by the Inch :: .357 Mag Results

A 5" .357 in a L or N frame is perfection personified.

I'm really asking more of the performance of the 125 grain SJHPs. Seems from a 4" barrel they get excellent performance, slight fragmentation but still good 12"+ penetration. However with a 5" barrel boosting the velocities I don't know if the load will come apart and hence not penetrate to 12".

So buy 158 gr XTP's, stay together, and penetrate and less wear and tear on your gun.

Groo here
The SJHP is intended to expand/fragment at impact.
The shorter jacket holds the base together to get your 12 inches.
They make FBI spec before there was one...
The short jacket loads all work about the same way,
the heaver weights just increase the depth of the base at the same speeds.
The 125 makes a good SD load in the rifle out to as far as you can hit.
the 140/158 gives more depth of wound and helps with the K frame cracking problem.
And the 180 works best in LONG barrel handguns and rifles
where depth of wound is most important.
Think partision bullets or A-frames.

No , that inch will not push them too fast....you will be hard pressed to notice much difference between 4" - 5" - 6" unless you have a chronograph and even then the difference will be less than 50' fps at most.
Don't worry about it ! Go shooting and have fun.
Gary

Because factory SD ammo is way too expensive and not that much better than other options, I am a firm supporter of using 140gr/158gr XTP bullets for reloading and creating your own SD loads.

I am currently using 140gr XTPs, and that is because the one year they didn't have any 158gr in stock for buck season. So I'm using the leftovers for SD carry, and save the 158gr I eventually got for hunting.

My load clocks 1100fps out of a 2.5" barrel with the 140gr XTP. Not the max load, but a nice warm, controllable round for 357mag.

Speer has advised not using Short Barrel ammo in longer than four-inch barrels, as it may over expand and lessen penetration.

But that is the sole caveat of which I'm aware.

Even IF 5" barrels always produced more velocity than 4" barrels, I wouldn't spend one second worrying about it. I've tested .357 125 grain ammo in 3", 4" and 5" S&Ws, and other revolvers. Sometimes barrels of equal length give widely divergent velocities, sometimes shorter barrels produce higher velocities than longer barrels, etc.

Velocity and bullet performance difference in 4" vs. 5" barrels is a non issue IMHO...

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NRA Life, COTEP 640

BTW, JayF If you have access to the Speer #9 or #12 reloading manual, you might be interested in "Why Ballisticians Get Gray" by Dave andrews. The .357 data listed vividly illustrates what I've observed on a smaller scale when chronographing the same ammo in different guns.

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NRA Life, COTEP 640