Flattening primers vs low powder charge

[7-30 Waters]

Can too low of a powder charge cause primers to prematurely back out and be smashed so they appear to be flattened?

[kjeff50cal]

IIRC slow burning powder like H110 can have a sudden pressure spike if loaded much below recommended starting load data. Such light loads would give signs of an over charge (ie flattened primers).

[Lloyd Smale]

im just speculating here but have heard it before somewhere that with light loads primers can flatten. What happens is that you are not getting enough pressure to allow the case to expand enough to grip the chamber and its thrusting back toward the bolt face and that slightly flattens the primmers.

[7-30 Waters]

Thanks for the reply gents.  The powder in question is Ramshot Enforcer.  I have shot this powder with standard 45 acp cases/moonclips and achieved excellent velocities and accuracy.  From a 6" barrel on my Taurus Tracker 45 acp I am able to achieve 1175 fps with a charge of 15.6 grains.  Haven't tried any other charges yet. 

Anyway I decided to trim down some 45 LC cases to 45 acp length and size them in the acp die.  The cases headspace off the rim and shoot fine.  No pressure signs or hard extraction.  The charge I chose for the rimmed cases was 15.0 grains of Enforcer.  I will start at 15.2 and work my way up.  Hopefully the flattened primers will disappear.  I'll post my results later.

[Camba]

From my observation, what I thought that happened to my gun with a non magnum primer and a  low H110 charge was:

1.  The primer fired and it pushed the bullet into the barrel burning just a little of powder.  Bullet got stuck in the bbl.
2.  I can see the same situation in item one happening and then, while the bullet is coming to rest in the tighter side of the cylinder, the powder finally ignites and it generates much greater pressure than perhaps a stout load with magnum primer.

That is my opinion on this subject.  I know I am not as knowledgeable in this type of subject but perhaps some can correct my opinion.  Thank you.

Camba

[corbanzo]

I remember hearing tell of people getting dirty cartridges from having under powered loads, and then the cartridge not expanding like lloyd was talking about, you see any of that?

[Redcap]

7-30, the 45 auto rim was designed to be a substitute for 45ACP's with half-moon clips.   The rim thickness is .089.   45LC's have a rim that is .060 thick.   Your cut down 45LC cases are not headspacing on the rim.  They are .029 short.  This, most likely, is why the primers are flat.  I don't know if the auto rim cases are still avaliable.  If you can find some it should slove the problem.

[Grumulkin]

A high charge of powder causes excessively flattened primers, loose primers and pierced primers but doesn't cause the primers to back out.  I doubt excess headspace would cause them to back out either.  If the headspace were that excessive, the firing pin probably wouldn't ignite the primer.  By backed out, I mean the primer being well above the head of the case after firing & not flattened level with the case head.

A low powder charge will cause the primer to back out every time.  Low powder charges also cause the case exterior to be sooty, the interior to be sooty and excessive powder debris on the interior of the barrel.