I pulled the 7.62x39 barrel off and it is a dual feed ramp, shaped kind of like an AR-15 feed ramp. It has the two ramps with a hump in the middle. I'm not an engineer, maybe PurpNurp could shed some light on this possibility or even experiment with it. Maybe we've been barking up the wrong tree, maybe the mags weren't the main issue?
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I was searching for information about this caliber in the XCR and stumbled onto this forum. I've had my XCR for about 7 years. Originally in 5.56. With Magul p-mags this rifle functions without a hiccup in 5.56. In 7.62x39 I have had frequent failure to feed issues. The first thing I tried was shimming the front of the mag follower to give it more of an upward cant at the front. This seemed to help. The next thing I did was take a die grinder and take out some material at the front of the magazine, underneath the feed ramps. What I have seen for failure to feed since this magazine mod is all the tip of the bullet catching on the feed ramp. This is worse with hollow points that FMJ. Just this week I took a Dremel to the feed ramps on the barrel extension and smoothed them out some. I noticed it appeared that in the feed ramp there was a "shoulder" at the transition between two different angles of chamfer. I used the Dremel to knock down that shoulder at the transition and generally smooth out the ramp. I also made the angle slightly more shallow. All of this was very small amounts of material removed. I have not fired the rifle since doing this mod. If this doesn't work I'll get a bit more aggresive, but I can't see removing the entire bit of material between feed ramps as I have not seen a failure to feed because of a bullet contacting the material between the feed ramps.
I took my x39 out today, 4 ASC 30rd mags modified, dremeled out front and filed down the little nubs on the feed lips......
And only 1 functioned without an issue , had a mix of fmj and hollow points, fmj seemed to function with less issue of course.
I have 2 30rd USA "frankenmags" that worked perfect, not one issue, I only ran fmj in them as that's all I grabbed on the way out.
I did have the range to myself thanks to the 20 degree weather and gusting winds! Got southern GA on my mind!
Freedom is all in your head
I emailed RA and they had the rifle in for investigation, they found an issue and fixed it on the spot, very professional folk in this experience (my wife took the rifle in)
Now I took it out and pit it through its paces, I put over 1000 rounds of tula steel jacket hollow point, these were hanging up on the feedramp before RA worked on it.
Good news is the rifle cycled them without issue.
Bad news is the dang ASC 30 rounders would hang up in the magazine and cause feeding issues, even the ones that I added wolf springs too.
The 10 rounder ASC magazines functioned like a dream, not 1 single issue but the 30 rounders all gave me grief, I've ordered some of the new 20 round magazines from ASC since this looks like they should work being more straight than the curved 30 rounders, I'd still love to have a magazine specifically designed for this rifle that holds 30 that I can trust, at present I 100% trust the 10 round magazines only.
Once I get to go out to the range with the 20s I'll let you know my experience.
Anyone else here tried the newer 20 round x39 magazines?
Last edited by sheldonbotha; 05-14-2015 at 09:45 PM.