.38 Special out of .357 Magnum

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stephen426

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How much does point of aim change when firing .38 Special out of a .357 Magnum? I have a 6" Ruger GP100 and the gun is an absolute tack driver when shooting .357 Magnum. I can usually punch out the small red target dots at 7 yards without putting any shots out side. With the .38 Special loads, it opened up about 2 inches. Is it me or can .38 special really change the point of aim that much?
 
Regardless if the group is centered and 2 inches in size or if the group is simply 2 inches off or maybe both ...the truth is every load , 38 or 357 may shoot to a different place and some loads will shoot smaller groups than others. The shape and weight of the bullet and the velocity all conspire to group differently.
Pick your favorite 357 magnum load and adjust the sights to it. Then start trying different 38 special loads to find one that shoots close to your sights.
Sometimes a dead on hold with 357 magnum loads can be used with a 6 o'clock hold with a 38 special. Slower bullets will hit higher on the target . The 357 (faster) will hit lower than the 38 special (slower) bullet . ( I think slower is higher ) All bullet weights being close to the same.
It's just a fact of life that not all ammo hits to the same point or will give the same group size. Testing them is the only way to tell.
Gary
 
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I will go back to the range and bring different .357 Magnum loads. I have loads as heavy as 158 grain and loads as light as 110 grain. I really did not expect such a "big" difference at such a short range. Thoughts?
 
Yes , there can be and usually is, a big difference . But if you experiment with enough loads you can usually find two that will overlap closely enough to be useful.

I have some fixed sighted revolvers that required extensive load testing of bullet weights , different powders and different charges of those powders to develop loads that shot to the sights. Adjustable sighted guns are so much easier to deal with.

Gary
 
Is it me or can .38 special really change the point of aim that much?
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It's all you.....
Seriously....

When shooting the heavier recoiling .357 magnum, you are going to greater lengths to make sure you do everything right.

When switching over to the light recoiling .38 special, you are relaxing your technique and getting "sloppy".

Try mixing .38 special and .357 magnum loads, load a couple of each - or better yet, have someone else load them for you so you don't know when to expect one or the other.

This is an extremely common issue.
 
I have learned after 50 years of shooting (wait, 50 years? Holy crap...) that these sorts of questions can only be answered through experimentation. Guns, ammo and shooters all vary. No way to predict what any particular combination will do, have to see it.
 
It's all you.....
Seriously....
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Maybe.

And, maybe not. I'd have to see you shoot, and shoot your gun to be able to reasonably tell if its you, your gun, or a combination of both. No one can definitively say which, over the internet.
 
So far, .38spl wadcutter target loads hit at the same place on the target as do the .357 loads I shoot. At least this is true in my M19, 686 and M28. I don't know about the python because it has only been fired with wadcutters.
 
If the group sizes are opening up, that's not a caliber issue but it might be an ammo issue. Try some other ammo. In my experience, .38Sp ammo is as accurate as .357Mag ammo out of a .357Mag revolver and often the on-target results are better because of the effect of the reduced blast and recoil on the shooter.

You should expect the point of impact could change with different bullet weights/velocity levels when shooting a revolver.

Summary. The groups shouldn't open up, but you shouldn't be surprised if those groups to show up on a different part of the paper compared to your aiming point when switching ammo around in a revolver.
 
No, it's not "all you". :)

You should expect some divergence in POI between Mags & Specials, even at 7 yards.
How much varies with loads & guns.

Now- try it at 25 yards & see what you get.
Denis
 
I'm still not clear if the OP means just a change in POI relative to POA, or if he means a larger than expected group. When he says it "opened up" to 2 inches, that suggests to me that he's really talking about group size, not a shift in POI.
 
You guys (other than Aguila Blanca) miss the part where the OP says he "open's up" to shooting 2 inches @ 7 yards?

He says that it "opens up to 2 inches", not that the shots stay within a nice tight group that cluster 2 inches away from where he's shooting.

I take that to mean the group size opens up to 2 inches. That has zero to do with the velocity difference and/or the weight difference between slugs.

This is all either the shooter shifting his eyes from the front sight to the target to see where his shots are impacting - - or - - not concentrating on the basics because of the lesser recoil of the .38 special.

I doubt it's the former, because he sounds like a pretty disciplined shooter when he says his shooting "opens up to 2". 99.9% of the people here would brag about shooting a 2" group at any distance, so, IMHO, we're dealing with someone that is a bit above the unwashed masses.

That leaves the latter - he's fudging the shots by getting a little loosey goosey. That's nothing more than a different flavor of flinch.

& one of the cures for flinch is - - play mix it up with the ammunition, just like I stated above.

Now- try it at 25 yards & see what you get.
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Why on Earth would he even consider doing anything like that? That's a pretty ridiculous statement to make - even in jest. The whole object is to help the OP, not do something that would even further his frustration.
If he's having problems close in, then moving back - to insure he's going to not only fail, but, fail miserably, does nothing to help.
 
I don't notice any difference at my usual 50ft range.
Then again Im trying to think back the last time I shot .357's out of one of my .357's and am having a hard time recalling so *shrug*

I would definitely expect a difference with increased range though due to velocity you'll have bullet drop faster on the 38.
 
Sure, PoA for PoI need to be changed for 357 -vs- 38 . . . . but at 7 Yards? You're talking minuscule adjustments for the same gun. So, it is MOSTLY YOU . . . Don't believe? Put it into a ransom rest.
 
"...change the point of aim that much..." Yep. It's about the difference in velocity. You might find that big long barrel's weight matters too. Recoils different as well. All that adds up.
If you shoot .38's then want to shoot .357, you need to run a .45 calibre brush through the cylinders first. Moreso if your shooting cast bullets. .38's tend to leave a lube gunk ring.
 
You guys (other than Aguila Blanca) miss the part where the OP says he "open's up" to shooting 2 inches @ 7 yards?
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No. 7 yards, 21 feet with a 6" 357 magnum..... Shooting groups at that distance is meaningless.

Now- try it at 25 yards & see what you get.
Why on Earth would he even consider doing anything like that? That's a pretty ridiculous statement to make - even in jest. The whole object is to help the OP, not do something that would even further his frustration.
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That revolver is capable of 2" groups @ 25 yards. With just a general statement of " my group is opening up" there is no way to help the OP. You at least need a picture of the group to offer any constructive criticism, even that is not totally fool proof. Shooting @ 7 yards will never indicate what flaws he has in his shooting by looking at a group. He really needs coaching to see what he is doing wrong and to fix it.
If he's having problems close in, then moving back - to insure he's going to not only fail, but, fail miserably, does nothing to help.
 
38 vs 357

Velocity aside and weight being equal, firing 38 spl in a 357 revolver will always have a different poi than a 357 as the shorter cartridge's bullet "jumps" further than the 357 cartridge's bullet prior to entering the forcing cone of the barrel.
 
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