38 Special/9MM Bullets

[gaowlpoop]

This may be a stupid question, and it has no doubt been ask before but here it goes.

Can 9MM cast bullets be used in a 38 Special revolver? I was looking at the tolerances on the two bullets and there is only 0.001” difference between the upper limit of the 9MM and the lower limit of the 38 Special.

Specifically:
9MM 0.355 – 0.356 inches
38 Special 0.357 – 0.358 inches
In some cases I have seen tolerances of 0.0005”. I do not think that cast bullets can be held to that tight of tolerances – may be wrong however.

Your comment would be appreciated.

 

[Walkalong]

.356 & .358

For lead, that is a big difference. I believe you will have leading problems trying shoot 9MM cast bullets in a .38 revolver. I have never tried it, but I think it will be problematic for a couple of reasons. Diameter and lead hardness. It takes a harder alloy for 9MM than .38 Spl. Between the bullet being too hard for the pressure and also to small for the throats and bore, it should lead impressively.

 

[GooseGestapo]

double post, somehow... deleted

 

[GooseGestapo]

It depends.................

Most of my 9mm specific moulds throw bullets in the .356-.358" range with the alloys I typically use. I size them to .356" for use in the 9mm's.

Most of the .38spl specific bullets run .357-.361". I size when necessary to .358". Unless I'm using them in a .357mag at higher velocities, I find that at the pressure and velocities of the .38spl, that simply "tumble-lubing" them is sufficient. The throat of the cylinder "sizes" the bullets down anyhow, and obturation to the throat "swages' them back up".

Some of the .38spl moulds due to design or other specifics, ARE suitable for use in the 9mmPara. One of these is the Lee .358-105gr-SWC. It casts to .358" and shoots better in my S&W 5906PC than any other bullet I've tried though it (cast, that is). I use it for shooting the NRA PPC Service Semi-Auto match. I ususally "clean" the match (480-37 to 40x's). When I don't, it's my fault, not the ammo/gun.

Typically though, the 9mm specific moulds tend to run a tad too small for best results in the .38spl.

Regarding the .001" you alluded to, it's actually .3575"(.38spl) vs .3545"(9mm), or closer to .002" difference, hence the often mentioned sizing .358" for lead in revo's vs. .356" for lead in 9mm Auto's. However, the nominal differences in manuacturing tolerances blurrs this considerably further.
You really have to "slug" and "mike" your specific firearm.......
And, see if the 9mm will feed it a nominal seating depths.

Typically RN or RFN, or TC's will feed through the 9's as well as some of the SWC's. Anything SWC over 150gr will be "suspect" from the 9mm however. Be VERY cautious loading any heavier bullets in the 9mm due to very small powder capacity. Your pressures can go from mild to explosive with only minor differences with seating depths. OAL can change during feeding cycle and cause an over-pressure situation. This occurs more frequently than you might expect......

 

[TooTaxed]

GooseGestapo, Excellent dissertation! WalkAlong covered bullet hardness. Can't add anything to it.

 

[ACP230]

My first reloads were .38s made with 125 grain lead truncated cone bullets meant for the 9mm.
They shot well from my Ruger Blackhawk .357 and I didn't notice any leading. The load was mild, probably under 800 fps.

 

[ArchAngelCD]

The biggest problem shooting 9mm bullets in a .38 Special is accuracy. If the bullet doesn't antiquity contact the rifling the accuracy will be dismal and totally unacceptable.

 

[okeybug]

There are some moulds that can be used in either 9mm or 38. The cast bullet manuel from RCBS has several weghts that can be used with either. Select wisely if you havn't bought a mould yet.

 

[TooTaxed]

The fact remains that 9-mm and .38-Spl barrels are designed for slightly different diameters, and there is an ideal bullet diameter for each. You may be able to fire one of those ideal bullets through the other barrel...it will go "Bang" and the bullet will go downrange without blowing up the gun. But you will not achieve optimum accuracy except in the barrel it was designed for.

Or, you can size a bullet halfway between those optimum diameters and fire them through both barrels...and get sub-optimum results in both.

If you are really striving for optimum results in your shooting, you must be resigned to getting the optimum diameter bullets for each caliber.

 

[Galil5.56]

Or, you can size a bullet halfway between those optimum diameters and fire them through both barrels...and get sub-optimum results in both.

Or have a bullet mold like I do that drops them @ .359"-.360", and size to what you like for each handgun without compromise. In my case, I can and do use .358" for both (38 Spl/9mm) with good accuracy, and if I want to run them a bit larger I shoot them as cast for the .38 Special.

 

[Steve C]

An over sized bullet will shoot in a smaller bore better than a smaller bullet in an over sized bore. The over sized bullet will swage down and fill the bore taking up the rifling but under sized doesn't get larger with the exception of a hollow base bullet driven with enough pressure to expand the base.

My old Hornady manual had data to load a 125gr .357 bullet in the 9mm but no data for 9mm bullets in the .38/.357.

I've load some 115gr 9mm's in 38'S and as others have said experienced less than acceptable accuracy.