9mm bullets in a .357?

[MozPhoq]

I'm pretty sure this question has been asked, if not numerous times before, but I have 200 9mm XTP bullets left unused and no gun to fire them. So I was thinking : could I possibly reload them +p in .38 special cases?

Anyone here has tried that already? Dimensions from one and other are pretty close.

 

[VanMan]

I'm pretty sure this question has been asked, if not numerous times before, but I have 200 9mm XTP bullets left unused and no gun to fire them. So I was thinking : could I possibly reload them +p in .38 special cases?

Anyone here has tried that already? Dimensions from one and other are pretty close.

I've been doing some experimenting with various bullets and loads for my S&W 929. Even though it's advertised as a 9mm revolver, I slugged the cylinder throats and bore at .357" and .356" which is the same dimensions as their 38sp/357mag revolvers.

I've shot 9mm Campro bullets (.355") and a variety of 38sp bullets (.357") and did not find any noticeable difference in accuracy. The only difference I did find was that my typical 9mm IPSC minor reloads were ~80fps slower in my 929, so I had to up the powder charge a bit. I posted a question in the S&W forums about shooting undersized bullets, and the general consensus was no problems if they were plated. Lead (uncoated) bullets may be subject to a little cutting from the bypassing gas.

 

[Spawn-Inc]

I've done it but don't really remember the results unfortantly. Since they are higher end JHP's(or if you had 500+) i would consider selling them. If it was just plated or fmj stuff i would try it and see what happens.

 

[MozPhoq]

..... I slugged the cylinder throats and bore at .357" and .356"

What do you mean by that?

 

[VanMan]

What do you mean by that?

It's a process of forcing a soft metal slug into your forcing cones and barrel, and then measuring the slug. I posted some pics in this thread (starts on post #12). There's also some results of accuracy testing with various loads/bullets. http://www.canadiangunnutz.com/forum/showthread.php/1415442-Jerry-Miculek-S-amp-W-929-Questionable-build-quality?highlight=929

 

[MozPhoq]

Okay I'll look into that, Thanks.

 

[Moose_Master]

If you use jacketed bullets for plinking then you should have no issue. If you use lead cast bullets then you will foul your barrel with lead and you will need to scrub a lil.

 

[ykkid]

Only way to tell if they will hit anything in your gun is to load a few and give 'em a try. Or hey, if you are just whacking paper or steel against a clock, load 'em all and blow them off. Won't hurt anything, just maybe your ego if they keyhole at twenty yards!

 

[fingers284]

No experience with jacketed or plated but lots with hard cast. I consider them interchangeable, at gunshows I will buy any inexpensive 9 mill that someone has surplus and use them in .38 sp...never had a keyholing/leading issue.

 

[BCRider]

Some owners of the Ruger 9mm/.357Mag Convertibles have reported that these guns were not as accurate with jacketed 9mm as they were with .38Spl. So size can and sometimes does play a part in this. Yet others said they were fine with either size. But then each of us has a different idea of what is "good enough" and different accuracy levels in our own ability.

For sure nothing will blow up the gun in all this. So it's worth trying. At worse you'll end up with a batch of less than ideal plinking ammo you can use where ultimate accuracy isn't needed.

Ideally you'd swap the mouth sizer and flare core for a 9mm sizer/flare so the smaller bullets don't try to fall down in the .38Spl or .357Mag casings. But depending on your die set this may not be an issue. What MIGHT rear its head is a lower than ideal neck tension. And that might be where a 9mm taper crimp might come in handy. Or perhaps size the cases and bypass the neck size/flare step so the bullets fit directly in the OD sized cases for a proper amount of neck tension. Or possibly a factory taper crimp die might serve to up the amount of neck tension. But that's not ideal. To work the best you normally want the proper interference fit to obtain the full length fit and the proper neck tension.

If the neck tension is too low you'll find the bullets creeping out of the casings and on a revolver it's possible that one or more will creep far enough to stick out the front of the cylinder and lock the gun up.

 

[VanMan]

Here's some of the accuracy testing I did with my S&W 929 (.357 cylinder throat, .356 barrel bore). Shots were at 17m, 8 round groups shot in SA. Even using the 4x scope and shooting rested on the bench, the weakest link is still me. I could tell when a bad trigger press pulled me off target and gave me a flier.

 

[MozPhoq]

Okay I'll just go ahead and try it!

Thanks!