!!!9x19mmR 9mm Federal Rimmed reinvented. Question: Will it damage an 357 mag gun?

[AJG]

Hi ya all,

I just reproduced the 9mm Federal Rimmed for my Heritage Rough Rider 357 mag 5.5" SAA blued Revolver.

I live in Southamerica and scavenge shotshells for reloading (no powder, nor molds allowed). 9mm Luger works very well just 38spl/357 mag I could not get to enough Penetration with the same 9mm 4 grain type Titegroup (shotshell) powder Charge.

Since powder is rare I have to use the most efficient case, caliber and cartridge and till now that seems to me the 9mm Luger (good Penetration and Little powder) in a short case (case is almost full of powder and bullet sits right above the powder so no empty airspace).

So I fugured the empty airspace in the 357 mag is the Problem and cut the 357 mag case down to 19mm lengt. Deburred and chamfered it with a knife and loaded it up with 4 grain type Titegroup and 115 FMJ 9mm bullet. Now it performs better than a 9mm Luger since it has more Penetration.

My question is: Will it damage the Revolver in Long term use? It is an 9mm Federal Rimmed replica [homemade] caliber shot in 357 mag SAA Revolver. Will the pressures be about 35000 psi or below?
[it recoils quiet a bit less than an full power factory Winchester 110 grain White box 357 mag round].

[BAGTIC]

I drew a shortened .357 Magnum case on the RCBS 'Case Designer' software. It indicates the shortened .357 case would have a slightly greater case capacity than a 9mm Luger case. This, I believe, is due to the 9mm having thicker sidewalls near the head. At 35,000 psi, which is in the normal max range of the .357 the thinner walls probably are sufficient.

One concern about the 9mm Federal at the time of introduction was the fear that some users might try shooting the 9mm Federal in old .38 S&W guns which were never designed for such modern pressure. The 38 S&W case is very similar to your shortened .357 case differing only in a slightly larger head size. It would seem that it would be much easier to resize new 38 S&W brass than to do all the work necessary to modify the .357. That still leaves the concern about someone using the loads in an old .38 S&W as when loaded in 38 S&W brass it would be indistinguishable from the proper 38 S&W ammo. The remaining question is whether modern manufacture 38 S&W brass cases are capable of withstanding such loads. Undoubtedly modern brass would be capable of withstanding higher pressures than were common 100+ years ago but how much. I suspect only the brass manufacturers know and I doubt that because of liability issues they would be willing to give an opinion.

I ran a test for a 38 S&W case loaded with 4 grains of TiteGroup and a 115 grain FMJ 9mm bullet through QuickLoad. It showed approximately 1050 fps from a 5.5 inch barrel at a max pressure of about 20,000 psi with a variance of about 500 +/- depending on which bullet was used. If this is reasonably accurate there should not be any danger to the gun. As the calculated case capacity for the shortened .357 case is about 2 grains larger (14 vs 12) the pressure then should be even lower. With either case it seems that using common protocol of staring lower and gradually increasing it should be possible to develop safe workable loads.

My personal preference would be to try some loads in modern 38 S&W loads before modifying a lot of .357 brass. Here in the US Starline makes some good 38 S&W brass at reasonable prices but I don't know if they are available there.