9mm, Power Pistol and 158 gr. SWC

[David Sinko]

I'd like to load the 158 gr. SWC (sized .356") into the 9mm for my 940. I need to seat the bullets deep so that they chamber properly. If the bullet is seated firmly on top of the powder, will this create a dangerous situation? Or is this acceptable with Power Pistol? I plan to start with 5.0 grs.

Dave Sinko

 

[5906fan]

why not load the 147gr cast tc slugs? it's only 11 gr diff. and there is data for with PP, don't have mine handy. I've loaded some 147gr jhp over it though that shot fine.

 

[handgunner356]

The problem I see is that the 158gr SWC bullet is going to be at least .050" longer than the 147 9mm. And now you're going to seat it deeper I think you are going to run into excessive pressure problems. I would be more inclinded to see if you couldn't load them long and still have them chamber in you 940. I did load some 140gr LSWCs' long to use in my .356 chambered guns that worked good, but went back to 105s' for target.

 

[David Sinko]

I can cast an unlimited supply of this bullet. I have a commercial cast version of this bullet with a bevel base and a long wide driving band. This bullet gives me chambering problems even when seated down hard on top of the powder. Then I have the Lee bullet which is not a bevel base and has a thin, narrow driving band and looks like it would be a better candidate for fitting into the cylinder. I think I would be able to get that bullet to chamber just fine (they need to be lubed and sized yet) but it will be seated deep into the case. I don't have any issues with the brass bulging as long as the bullets are sized .356" and right now my only concern is possible pressure spikes from deep seating the bullets. Power Pistol has always been good to me in my 940 and I'd like to make this work if possible.

Dave Sinko

 

[pete950]

Why not try starting with 4.2 grains and work your way up and check for pressur signs.
Just a sugestion.

pete

 

[blastfact]

Or go to something like titegroup and only need 3 grains or so of powder. Just think out loud.

 

[oldRoger]

I would say that you are quite deep into uncharted territory.
I had a problem with what seemed to me to be a heavily compressed load in 10mm, what I did to check is run the neck seizer in a sample case as far as it would go and then open the case further with drill bit shanks until I had a slip fit with a bullet.
Then with my proposed powder charge in place I slipped a bullet in to a light touch fit.
It turned out that the suggested load would require a 20% compression.

I don't know but strongly suspect that this would have resulted in excessive pressure.
In your case, I would certainly back-off the powder load at least until the compression is gone, then you can think about working it back-up. It would be a dandy idea to chronograph the loads as you go. You don't want to be setting any world records for velocity of 158 gr bullets from a 9mm.

 

[shovelwrench]

I'd have to agree with these guys that your playin with an over pressure situation. I've been fartin around with .38 super, light target loads, and heavy bullets, for a little over a year now. What your talkin about would'nt even cross my mind in a target load, let alone, a "full power" load.

If your set on tryin it, start with somethin like 3gr of bullseye, and seat as long as you can and not touch the throat. With a barrel that short you could even start at 2gn. Run em over a chrony and come back with some numbers...