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I finally got around to shooting my new EMP4 CCC. I only ran 150 rounds of PMC Bronze 115 grain FMJ ammo through it, but I experienced 3 different types of malfunctions, multiple times. I used the same magazine, as well.

A few times, the nose of the bullet would nose dive into the feed ramp, not allowing the round to chamber. I also had the slide not lock back on the last round a few times. The last malfunction, was the slide wouldnt always go all of the way back into battery, and I had to bump the rear of the slide, to get it to do so.

I called Springfield, and they recommeded trying a different magazine, and a different type of ammo. I have not had time to do either of these yet.

I was curious to hear from those of you that have had a similar experience. Thanks a lot!

If you notice in that failure to feed photo, the round is still sitting well below the magazine feed lips.

When the slide is forward, the bottom of the slide holds the top round in the magazine in a depressed position. So the top round is not sitting all the way up in the magazine as it would be when the magazine is not loaded in the gun. Then, when the slide cycles, the bottom of the slide moves clear of the top round and allows it to move up to the top of the magazine where it can be stripped off and moved into the chamber.

The same spring and follower that forces the top round into position, also forces the slide latch into the locked position after the last round is fired. So the failures in both these areas would point to a bad magazine.

The vertical scores on the breechface should not be a problem as long as there are no raised burrs or ridges extending above the surface. Likewise with the firing pin hole. If you have some type of tool with a sharp flat edge that will fit between the extractor and ejector, you can ride it along the breechface vertically to check for burrs. If any, they can be easily removed with a stone.

Springfield has a bad practice (in my opinion) of engraving the last three digits of the serial number on the bottom central rail of the slide. This can produce a roughness in the slide movement as the engraved stippling passes over the disconnector. This can also be smoothed out with a stone (if present).

To check, pull the hammer back and leave it cocked so as to not have to fight the hammer spring. The slide should move smoothly back and forth with just a minor "catch" as it passes over the disconnector. Should be no roughness.

Recoil springs can be a bit stiff initially, but should settle into a lower but stable tension.

Also "range" ammo tends to be a bit on the anemic side. If you couple that with maximum tension virgin springs and rough spots that managed to sneak past QC, they can all add up to failures.

 

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I would also agree that Springfield should take care of an uneven breechface if that is indeed the problem. I believe these are cut vertically with a broach, and can leave vertical tooling marks. I have seen many Glocks with horrible looking vertical scoring on the breechface that had absolutely no effect on operation. Unless there is a rough ridge or burr, it should be fine.

A step or score running horizontally on the breechface would be problem; however, this is very unlikely due to the manufacturing process used.

You seem to have eliminated two of the problems with a new magazine. When the slide fails to go into battery, how close does it actually get?

If the cartridge is angled straight into the chamber, but not making the last little bit, it could be a problem with the chamber.

If the cartridge is hanging up at an angle going into the chamber, it could be a tight extracter, preventing the case head from sliding all the way up onto the breechface.

Next time you have the slide off, try pushing a cartridge up into position in the slide. The extractor tension should be enough to hold the cartridge in position but not enough as to make it difficult to push the cartridge up.

 

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It sounds like the extractor is fine then.

The slight angle of the empty case should be of no concern, especially since the live round sits straight. Perhaps the primer is protruding slightly, and holding it off angle?

So it now all looks like it is in the chamber.

Does a live round drop all the way into the chamber with very little or no resistance? You may have some stubborn fouling in there that was never removed.

Chambers are hard to inspect due to the step in diameter where the chamber transitions into the barrel. That last little bit of chamber sits in the shadows when viewed from the chamber end, and that same little bit isn't visible at all when viewed from the muzzle end. It is also where fouling tends to accumulate as it is right at the case mouth when firing.

Make sure the barrel is dry when inspecting. Wet bore solvent can make everything look nice even when it isn't.

Another possibility is an under spec chamber. It will of course have to go back to springfield in that case, but on the bright side, it will most certainly be fixed.