My girl friend and I went out last weekend for a little target practice. When I was cleaning my .40cal 990L last night I noticed what appeared to be chipping or wear at the end of the barrel on the interior. Not quite sure to make of it. This is the second barrel/chamber assembly on this gun and has only seen 300 rounds. The previous assembly had over 800 rounds through it and didn't look like this. Do any of you have any ideas? I really like this pistol, fits like a glove. Would this affect accuracy? See photo.

barrel A 002.jpg

Shooting FMJ? Exposed lead at the rear of the bullets? Not TMJ loads or JHP's?

Kind of looks like deposits and not chips.

Hard to really tell without being there to look at it in person, though.

If that's the case, and it were me, I'd use my brass or bronze brush to clean the lead residue off the end of the muzzle crown.

If you have a brass tipped cleaning tool, you could use it to lightly scrape what might well be lead deposits off the muzzle, too.

Just my thoughts, looking at the image posted.

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Ret LE Firearms inst & armorer

what happened to your old worn out barrel?

Fastbolt: I'm hoping it's just lead deposits, just never seen this before. Thought I had given it a thorough cleaning both with a brass brush and pads. I use a plastic jig to center the plastic cleaning rod so I don't think that could have caused this. I'll have to give it another go tonight or tomorrow.
Rooster59: The original barrel/chamber was replaced by the good folks at S&W due to damage apparently caused by an extraction problem. They didn't really explain what they did but sent it back with a new extractor, barrel/chamber assembly. The gun itself hadn't failed to extract but upon inspection prior to cleaning I noticed the end of the extractor was chewed up and had taken a small piece of metal from the chamber housing. The pistol itself has never failed to fire or failed to eject or feed and so far has been very accurate.

Thanks for the tip Fastbolt. I used a bit of solvent with the brush and it came off just fine...again, thanks! I had never seen this on my other pistol so I'm learning a little more each day. A question though, I've never used the Federal rounds before. I picked them up because they were pretty cheap. The other rounds I usually use - Winchester and Remington - haven't done this.

Some lead cores in FMJ bullets (with exposed lead on the base) seem to melt more easily than some others.

TMJ or JHP loads generally don't produce this sort of condition since there's either no exposed lead (TMJ), or it's in the nose cavity of the hollowpoint and isn't being exposed to the burning propellant as it is with FMJ bullets with exposed lead at the base.

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Ret LE Firearms inst & armorer