S&W 642-1 and +P+ Federal Hydroshock Ammo

[steak-knife]

Need a little bit of help here, and to double check what SAAMI states about +P+ ammo.

I just got my brand new S&W 642-1, from the latest limited run, and have yet to take it to the range. I also have a whole bunch of Federal Hydroshock +P+ ammo that I've been feeding my Ruger SP101 chambered in .357 Mag., with good results.

So, the question is: Will feeding my 642-1 (+P rated) gun with Federal Hydroshock +P+ ammo cause this J-Frame to self-destruct (i.e. kaboom, accelerated wear)?

I've been looking for a staright answer, and read through the SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) specifications about +P pressure, which is approximately 10% higher than a standard pressure cartridge. Apparently, SAAMI does not have a +P+ pressure standard, but indicates only as a "pressure higher than the +P loading."

More importantly, SAAMI states that in both cases (+P and +P+), the pressure is always less than the proof test cartridge, which all firearms are required to withstand before they may be sold. Specifically, proof pressure is a percentage of the working pressure, so this places an upper bound on the +P+ pressures of 30-40%.

With that said, it appears that SAAMI is indirectly stating that both +P and +P+ are below proof test cartridge, and therefore it's okay to shoot +P+ ammo from a +P rated gun.

What do you all think?

 

[pharmer]

The 642 is an alloy frame gun. I wouldn't shoot +P+ in it, but that's just me. Joe

 

[JohnBT]

"it appears that SAAMI is indirectly stating that both +P and +P+ are below proof test cartridge, and therefore it's okay to shoot +P+ ammo from a +P rated gun."

No, it doesn't work that way. It might not explode, but it will stress the gun. It's an airweight, not a full-sized gun. In fact, +P stresses the airweights. I have a 442-1 and it's rated for +P and I carry and shoot some LSWCHP+P, but that doesn't mean it's a good idea to shoot a lot of +P through it. I shoot just enough to convince myself that I can still hit with it.

If the bad guys were closing in and all I had was an airweight and +P+ I'd fire away. Otherwise, never.

John

 

[Loomis]

"The +P+ designation is not currently used by the SAAMI, but is used by some manufacturers to designate loads that exceed the +P SAAMI specification. One source lists the 9 x 19 mm +P+ loading as having a pressure of 42,000 psi, an 18% increase over the standard pressure of 35,000 psi, and the .38 Special +P+ as 22,000, a 29% increase over the standard pressure."

http://en.wikipedia.org/wiki/+P

Over pressure loads are NOT to be used for target practice. You wear your gun out too fast. Use them only for self defense and maybe one box a year to keep yourself tuned up at full power defense loads.