chipsher

Can't go wrong with scorpion. Super reliable, I've changed a recoil spring and broke a hammer spring in 15 to 20k. Works with ammo of wide power factor variance. Mags are cheap, PSA makes a nice one with steel feed lips, under 20 bucks I think. The bad: stock trigger is heavy, a little work makes it decent, heavy bolt makes recoil noticeable (no worse than an untuned AR9). I thought I wanted a Tavor in .223. Got to handle and fire one. Felt very awkward, very butt heavy. Maybe you'd get use to it. But a nice quality gun.

My guess is the bolts initial reward thrust is at very high speed and spring coil binds by it own inertia. Or maybe when the bolt first get slowed by the carriers weight. Probably both like a one two punch. One other odd thing I noticed watching the action operate. During a jam it looks like the empty never leaves the bolt face, even though there was still a pretty good ejector spring. Never saw it bounce around, always the same type of jam. A high speed camera would be nice.

No Sir, didn't try the BCM Spring. I tried Wolf and Wilson extra power springs. I wanted everything to be as standard a component as possible. And I have a stock of these from shooting 3gun.

I've given up on the RDB for now. Love the feel of the action but has never been reliable for me. Best I could get was one or two FTEs in a match of 125 to 150 rds. I've tried different recoil springs. Tried cutting a coil at a time to see if I could get a change. Different buffer weights, hydraulic buffers of different weight. Took sharp edges of extractor. Ejection port to barn door size. Different bullet weights, different charge weights. Replaced ejector and extractor spring with extra power chrome silicon (often). Mine worked best with a 115gr bullet, fairly hot load. I work as a Tool and Die Engineer and I work with part ejection all the time and this one beat me. I think the only real solution is a fixed ejector, but for a compitition gun I don't want any non-standard parts. I can't believe CMMG missed this. Or I just shoot too much. I burned over 8,000 rds. trying to get this to work. Back to the JP and Scorpion 100% reliable.

I had the same problem with an Elite. Check the round below the round that is jammed. There may be a gouge in the case where the bottom of the slide has had a chance to dig in due to the slower slide speed. I slightly rounded and polished this edge and no more jams. When the gun is jammed drop the mag and if the round chambers this could be the problem.