HK trick

[Spr1]

I decided to do a little preventative maintenance on my P30 today. I (log book not in front of me) have about 21K rounds through it now. At about 20K rounds I had the first malfunction, a failure to fully extract a case (WW 115 gr target). The round sounded normal, and the case was left in the ejection port in line with the barrel. I have been wondering since then if it was random, as this ammunition supposedly has shallow extraction grooves (I have never measured any for comparison), or a weak extraction spring, or fouling, or?
I decided today to look into it. When I removed the extractor I was surprised by how much fouling was in the groove and on the extractor. The spring actually measured .015" longer than the replacement spring I had, so the spring is unlikely to be the culprit. I thoroughly cleaned the extractor and groove, which easily had enough fouling to prevent full inward movement of the extractor and began to reassemble things. Now, I know HK has all sorts of jigs and fixtures for doing the assembly operations and I do not. Reinstalling the extractor is definitely a three handed job and being limited to two, I needed a trick. Looking through my parts bin I found a cotter pin that was a very close fit to the pin hole and held the extractor perfectly positioned to receive the new spring pin. Inverting the slide over a bench block with the cotter pin sticking into a hole allowed me to easily drive the pin into place using a roll pin starter and finishing with the 3/32" roll pin punch. Presto.
By the way, most of the crud was deposited by the same WW ammunition, as that is my typical practice ammunition.

[Lomshek]

When I removed the extractor I was surprised by how much fouling was in the groove and on the extractor...I thoroughly cleaned the extractor and groove, which easily had enough fouling to prevent full inward movement of the extractor and began to reassemble things. For just this reason I've gotten in the habit of detail stripping my guns every few thousand rounds and cleaning all the crud like you describe from areas a normal cleaning can't get to (firing pin channel & extractor recess being the big culprits on the slide).

Looking through my parts bin I found a cotter pin that was a very close fit to the pin hole and held the extractor perfectly positioned to receive the new spring pin. Inverting the slide over a bench block with the cotter pin sticking into a hole allowed me to easily drive the pin into place using a roll pin starter and finishing with the 3/32" roll pin punch. Gunsmiths call that a slave pin. You're one up on me because I had to read about it to learn that trick (very crafty of you).

[Spr1]

Thanks.
I normally do the detail strip routine on most guns. This is my highest mileage HK, so this will become a regular maintenance action.
I use the slave pin idea on things all the time, in this case, I needed a pin that would stay in place inverted while I tapped a pin into place, the cotter pin had enough spring tension outwards to remain in place.