38/357 Differences?

[GJS]

I know there are posts but cant find them. I am wondering the difference in muzzle velocity between a 2.5 inch 357 and a 4 inch 38 special +p with same bullet weight. I realize the shorter barrel may not provide length for the 357 to get to speed and maybe the 4 inch gets the 38 +p closer to where it should be. Or are the 38 and 357 from a 2.5 inch pretty much the same in bullet performance?

 

[H Richard]

That's a wide open question, depending on the bullet, load, etc. There is such a wide variety of loads available, you would need to specify comparable comparison. A run of the mill +p 158 .38 might be around 1000 fps, where the .357 might be around 1400 fps or more.

 

[Pisgah]

Pretty much regardless of barrel length, the full-power .357 will consistently outrun the .38 +P, anywhere from around 150-200 fps and up. Naturally, with a longer barrel, the .38 will narrow the gap a bit compared to the snub .357, but not equal or overtake it. Those who say, "In a snub, the .38+P and the .357 are nearly equal" are simply wrong -- but even so, the .38 is nothing to sneeze at!

 

[Alk8944]

I know there are posts but cant find them. I am wondering the difference in muzzle velocity between a 2.5 inch 357 and a 4 inch 38 special +p with same bullet weight. I realize the shorter barrel may not provide length for the 357 to get to speed and maybe the 4 inch gets the 38 +p closer to where it should be. Or are the 38 and 357 from a 2.5 inch pretty much the same in bullet performance?

You asked, so here is some chronographed data from both cartridges and 2" or 2 1/8" barrels. One caveat, this is comparing Apples and Oranges as most factory 158gr. ammunition is jacketed. and 158 gr. .38+P is Lead. You will see there is no way in He!! you will ever see 1000 fps from any .38+ or 1400 from a .357 158 gr. load from a 2" barrel. For that matter even from a 6" for both. I have the personally chronographed data to prove it!

Basic conditions, Oehler 35P Proof Channel chronograph at an average screen distance of 11' from muzzle. (2' primary channel spacing, 10' to start screen) Note that corrected to the muzzle velocity will only be ca. 2 fps higher than instrumental at 10', so varying 1-2' in muzzle to start screen distance means nothing statistically. Temperature moderate, ca. 50-60 degrees. 70-80 won't make enough difference statistically to spit at.

The .38+P fired in 2" Model 12 or 12-2.
.357 fired in 2 1/8" Model 640-1.

.357 Magnum:
Federal 158gr. Hydra Shock, 1117 fps (In 1991 8 3/8" Model 27, 1317 fps)
Just for interest; WIN 145 Silver Tip 1103 fps (8 3/8", 1343)

.38 Spl +P:
WIN 158 gr, 158 LSWCHP +P, 821 fps (M-12-2) (6" M-10, 936 fps)
Federal 158 gr, 158 LSWCHP +P, 821 fps (M-12) (6" M-10, 945 fps)
Yes, you see right, 2" exactly the same velocity, both makes.

Most of these are only 6 shot samples, and with larger, more statistically significant samples may change a few fps up or down. The 6" M-10 is a -4 for whatever perceived difference that makes.

In many hundred rounds with jacketed or Speer Gold Dot 158 gr. bullets I have found it is difficult to even reach 1400 fps in a 6" or 8 3/8" .357 Magnum revolver, let alone a 2" or 2 1/2". This is based on original Hercules/Alliant data at listed maximum loads of 15.2 gr/2400. Same goes with maximum listed Hodgdon or Winchester H-110/296 loads. I have even tried the old Lyman, Ackley and Keith load of up to 16.2 gr/2400 and found virtually no improvement in velocity over 15.2 gr. with this bullet weight.

I would have more data if I shot much factory ammunition, but I don't. Most of this was shot purely for curiosity, to see what the ammunition I carry actually does instead of what the factory says it does. Amazingly Federal and Winchester list their respective 158 LSWCHP +P loads at 950 fps as I recall, and they do an honest 945 fps and 936 fps respectively from the 6" 10-4 I shot them both in. This is actually faster than my 6 1/2" 1956 Outdoorsman (929 for Federal).

Note that the difference between a .38 Spl. 158 gr LSWCH +P and .357 Magnum 158 gr JHP is aproximately 300 fps in favor of the .357. Some loads may show even more difference but these two loads shown are quite typical for what many carry in their CCW revolvers. The .357 has a ca. 36% advantage in velocity (1117 FPS to 821 FS) and 85% advantage in energy (436 FPE to 236 FPE). I don't know about you, but I think these are figures that are hardly "So close it doesn't make any difference". Do you? This is another example of people repeating "It sounds good to me" without any factual data to support it. This has been repeated so many times that I will bet someone will want to argue with what I have posted just because they "Know" there is no real difference from a 2" barrel just because they have read it repeated so many times. Let's see how long it takes!

 

[ddixie884]

Interesting chrono data, thanks for sharing.............

 

[GJS]

Thats what I was looking for. Very informative and helpful. Thank you very much.