Kimber .45 "shrinks" cartridges???

[don]

My brand new Kimber Gold Match Stainless  causes the bullets to be pushed back into the cartridge case.  There is no evidence of bullet or case damage. ... Is the spring too strong?? Will this problem go away after the 500 round break in period??? I also have a Kimber CPD Compact that  I can cycle the same cartridge over and over and the bullet stays put.  I've tried various manufacturer ammo product, ie winchester, remington, cci    and have the same results with each pistol....Should I send it back to Kimber or shoot 200 more rounds and see if it improves.?  My theory is that the slide is hitting the cartridge too hard causing to bullet to sink further into the case...Any theories or facts greatly appreciated.

[Ron Ankeny]

One of the guys I shoot with has an STI that will cause the bullet to seat deeper (with certain shapes) when it slams into the feed ramp. Of course, the greater seating depth causes the pressures to climb. Sounds to me like you are in a position to experience a real disaster if you get a pressure spike. Personally, I would be one the phone with Kimber in the morning.

[TDean]

I have tons of problems with bullet "setback" in my P14.

When the cartridge is being pushed from the mag on the way to being chambered, it hits hard against the feedramp causing the bullet to slip into the case .005-.030" each time.  On inspection, I can see an impact mark on the nose of the bullet where it hit the ramp/frame.

I reduce the battering by shortening the OAL of the cartridge.  As the cartridge is pushed by the slide from the magazine, the lips of the magazine release the cartridge allowing it to assume a nose-up position before it contacts the feed ramp.  

If the magazine lips are still holding the cartridge horizontal when it contacts the feed ramp, then the forces of the slide comming foward are transfered to the cartridge.  It basically becomes a shock absorber between the frame and the slide forcing the bullet into the case.

Are you using reloads?  Factory ammo?

Either way, the problem won't  go away after 500rds.

Using a fast powder + bullet setback = KaBoom!

Not a big deal if your loading 1.260 when the recipie calls for 1.200, but a concern none-the-less.

How far are the bullets getting setback each cycle?

Have you tried different magazines?

[wknewbie]

If you were shooting reloads I'd say you need more crimp but it appears you're not.  Call Kimber, they seem to have a good reputation concerning customer service.

[Patrick Sweeney]

I have noticed this problem with some fatory ammo.  I have about five cases of a particular brand that will setback in half my 1911's.  In a couple, it simply refuses to work.

If it is brand-specific, change brands.  If reloads, look to belling stem diamter (reduce .002").  If it is the gun despite brand, a quick trip to Kimber is called for.

The 1911 is hard on rounds, and despite the .45s easy-going nature on reloading and loading, the trip up the ramp can be traumatic.

[Carlos]

I f you are relaoding and this occures, then it has been said here many times that the crimp does not hold a bullet in position, the crimp merely removes the bell from the seating operation.  So how do you increase the hold on a bullet if not w/ the crimp? Small base or undersize carbide resizing dies.  These dies are machined to re-size the case slightly smaller than ordinary dies. Lee sells carbide "U" dies for under $20.

Are there disadvatages to these "U" dies? 1) works brass more and might reduce its lifespan slightly 2) more press handle effort. You can ruduce this by a light spray of Hornady One Shot or Dillon case lube; the OneShot can be left on the cases w/o affecting performance.

As for a reloader's "Setback Test", it is NOT to push a loaded case against the bench! Instead, make a dummy round w/o powder or primer but resize, bell, seat and crimp EXACTLY as you would for a run of loaded ammo.  Load the dummy (or 2 or 3 of them) into a mag.  Try to rack the slide and release it as fast as possible to simulate firing conditions. Now measure OAL of the dummies. Did it change? A slight reduction is normal; major set-back will cause problems.

Back to your gun; is the problem limited to one magazine, or one brand of magazine?

[Patrick Sweeney]

Provided your sizing die already does a proper job, you can increase neck tension by polishing down the belling stem diameter.  Best done in a lathe, and measured as you go, as you only need .002" reduction.

(Edited by Patrick Sweeney at 10:05 am on Jan. 17, 2003)