38 in a 357 Velocity Loss?

[chrisf8657]

Thought I'd ask this simple little question, and please excuse me if it's been asked before, the search cuts off 38 for some reason...

How much velocity do you lose loading .38 in a gun chambered for .357? I have a S&W M60, and have a choice betwen the Speer SB .357 (996 fps, 296 ftpds) or a hotter .38 (~1200 fps, 367 ftpds)...naturally of course I would love to take the .38 as it's more powerful, but the question is, would it velocity/power wither down to or below the Speer .357 considering it's shorter, and has a larger distance to travel to the forcing cone & barrell?

Thoughts appreciated.

 

[christcorp]

I'm not quite sure what you are looking at, but just about always the 357 magnum is going to be faster and more energy than the 38 special. Where are you getting your data from? Most 38 specials have velocity in the 7xx-9xx fps range. While the 357 mag starts usually at the 10xx-14xx fps range. You sure you didn't have the data backwards? Maybe I'm missing something here. Later... Mike....

 

[mavracer]

I would suspect that that 38 load won't make 1200 fps in the short bbl of your 60 while the speer SBGD load is chronoed in 2" guns.the jump in the chamber will actually increase velocity although probably not measureabe at 38 velocitys. the weatherby line of magnums haveng throtes to increase velocity.

 

[steveracer]

I think he means shooting .38 in a gun NOT chambered for .38

and if that effects velocity.
Example: Model 64 .38 SPEC firing .38SPEC 158 SWC at 1000 FPS
Model 65 .357MAG firing .38SPEC 158 SWC at ~1000 FPS.

I highly doubt you'd see any appreciable loss.

 

[SaxonPig]

I think you are asking about shooting 38s from 357 Magnum guns?

A 357 should always be faster than a factory loaded 38 regardless of barrel length (assuming full power loads, I don't know where you're getting this 357 load at 996-a total and complete wimp- or that 38 load at 1200-something no ammo company would load these days to my knowledge). A 2" 357 is still faster than a 2" 38. A 2" 357 is faster than a 6" 38 for that matter.

A 38 fired from a 357 chamber loses a small amount of velocity in my experience (and I have researched this question for myself). A given load averages about 15-25 FPS less from 357 chambers than from 38 chambers. Not really enough to worry about IMO.

 

[chrisf8657]

Gentelman,

I understand I may have confused some of you. No, the data is correct. The .357 I am refering to is the Speer Gold Dot Short Barrell Ammo, data available here:

http://www.speer-ammo.com/ballistics/detail.aspx?loadNo=23917

It is basically a very watered down .357...

And the .38 is a Double Tap .38 +P, data here:
http://www.doubletapammo.com/php/catalog/product_info.php?cPath=21_57&products_id=215

I overstated a bit on the .38 - 1100fps, 336ftpds is the correct data.

Of course, any full house .357 is going to be pushing 500 ft pds. easily and over 1000fps, my question is not about those. The question is basically should I be worried about the velocity drop of using .38 in a .357?

 

[mavracer]

I have shot both those loads over a chrono there's not much difference.I use the DT load in my 442.switched my 357 (taurus 605 2 1/4") to 145 silvertips.POA=POI issue and I figure I can handle the recoil and they do recoil.IMHO I would use the DT load as it is signifigantly cheaper $24 per 50 vs $18 per 20 and offers nearly the same performance.and you could afford to practice more with it.

 

[Maddock]

My experience mirrors SaxonPig. I expect 10 to 20 fps less out of a .38 Special load in a .357 revolver than the equivalent .38 Special revolver. More with short light bullets pushed harder, less with longer heavier bullets. This is less than the variation between revolvers of the same model and barrel length.

 

[OLD DOMENION]

Indirect answer

I don't know about a velocity loss from .38 Specials in a .357 Magnum but, I can give you a velocity rule of thumb:
If the company uses a UNIVERSAL RECEIVER then deduct 75 feet per second.
If the use a REAL GUN then deduct 30 feet per second.

 

[Gary A]

It might be worth noting that older .38 Special revolvers often had shorter cylinders than the equivalent revolver chambered in .357. This would make the jump to forcing cone longer when shooting .38s from a .357. Today, I believe most manufacturers, including Smith and Wesson for the last 10-12 years, make their .38 cylinders and .357 cylinders the same length to simplify manufacturing and reduce costs. This would mean that a .38 Special round has the same length jump to make to the forcing cone from a .38 chambered revolver as from a .357 chambered revolver, thus negating much if not all of the advantage from shooting .38s from a .38 only revolver. Anyway, that's how I see it.

 

[Steve C]

How much velocity do you lose loading .38 in a gun chambered for .357?

There's more variation in velocities from gun to gun than there is from .38 spl chambered pistol to .357 mag chambered pistol. Any observed difference one way or the other between the velocities can't be attributed specifically to the chambering.

 

[fecmech]

"There's more variation in velocities from gun to gun than there is from .38 spl chambered pistol to .357 mag chambered pistol. Any observed difference one way or the other between the velocities can't be attributed specifically to the chambering."

Steve hit the nail on the head. I have a 6" S&W K-38 and a 6" Ruger GP100 .357. The same .38 spl load fired out of both guns is actually about 20 fps faster out of the .357 than the K-38! That 1/8" extra jump (in .357's) is not a
big factor in the grand scheme of things when you figure throat to bore size, cylinder gap etc.

 

[DevilDog0402]

Today, I believe most manufacturers, including Smith and Wesson for the last 10-12 years, make their .38 cylinders and .357 cylinders the same length to simplify manufacturing and reduce costs.

I don't know about that. Wouldn't that allow someone to shoot full-house .357 mag loads in a .38 revolver then? I don't think manufacturers would do that, as it could create some serious liability on their part.

 

[Gary A]

Wouldn't that allow someone to shoot full-house .357 mag loads in a .38 revolver then?

Actually, no, because the chambers are cut differently, the shoulder inside the chamber is deeper on the .357 and shallower on the .38, so a .357 cartridge won't fit in a .38 cylinder. Often times today, though, the cylinder itself is the same length and, if so, the jump to the forcing cone will be the same distance regardless of whether it is a .38 Special or .357 revolver.

 

[DevilDog0402]

Actually, no, because the chambers are cut differently, the shoulder inside the chamber is deeper on the .357 and shallower on the .38, so a .357 cartridge won't fit in a .38 cylinder.

Ah. Good to know.

 

[MCgunner]

Here's some hard data on barrel length vs .357 magnum using a 158 grain SWC. This handload is close to factory spec. You can buy a .357 magnum revolver that is no bigger or heavier than a .38, but you won't like shooting it with these loads. My own .357 snub is a rather heavy SP101, but it's the smallest gun I like to shoot .357 in and it's the smallest I can control and be relatively fast with. It's a porky 27 ounces, but those ounces really help when shooting the thing. My hot .38 load out of a 2" barrel clocks a little over 900 fps for 270 ft lbs with a 140 grain JHP, about 360 ft lbs in a 4" gun. Barrel length makes a difference and if you're just reading advertized ballistics, chances are they used a 4" or better barrel unless otherwise specified.

2.3" SP101...........1162 fps/426 ft lbs
3" Taurus M66......1198 fps/504 ft lbs
4" Taurus M66.......1324 fps/614 ft lbs
6.5" Blackhawk......1470 fps/760 ft lbs