The thread has fallen off the page but as some of you may remember I had been having trouble with stovepipe jams in my Rock River 9mm upper with the VM HiTech mag block and unaltered Uzi mags.
Through my own trouble shooting and the suggestions of some in this forum I had been trying many cures... different types of mags, checking the ejector for position and tolerances, looking at the uniformity of the mag lips, and checking the extractor for tension and depth of grip.
Several trips to the range all resulted in the same jam several times per 100 rounds.
Although my testing showed that the extractor was fully gripping the rim I was still suspect of its function. The extractor looked to be a one piece bent type like the Uzi, but I was told that there was a spring under it like on the Colt 9mm bolt that might need to be "stretched" to increase tension.
I finally decided to take it apart to see if that was the problem. I discovered that there was no spring and it WAS like a one piece Uzi extractor. While I had the extractor out I gave it a little tweak that would result in tighter grip on the case rim.
Today I took it to the range (along with Shaggy and Dragracer_Art) and after shooting 250 rounds I was satisfied to have no stovepipe jams or stoppages. Where as before the cases were ejecting 3 - 4 feet away from the gun today they were consistantly a full 6 feet out.
I did however have two instances of failure to fully eject on the last round, the cure of which I believe was covered in the first thread by somebody. If you recognize that phenomina and have a solution please let me know.
I am feeling good about these results and that my first suspicions were probably the correct ones. I'm also liking the new 10" configuration a lot!