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Page AR-15 » Rimfire and Pistol Calibers
AR Sponsor: bravocompany
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Posted: 12/27/2003 1:47:21 PM EDT
Using an A3 upper with a 9mm hammer and unmodified bolt, Im having jams with the last one or two rounds.  It appears that the uzi mags are releasing the round to soon and its pointing too high and impacting into the top of the receiver or top of the barrel.  This only happens on either the second to last round (rarely) or the last (most common).  I think the round may be hitting the feed ramp on the RRA block and that's launching it at too high and angle.  Im debating demeling the ramp to ease the angle that rounds are feed but thought I'd check here in case someone else has had and solved this problem before.

Thanks,

Jim
Link Posted: 12/27/2003 2:54:56 PM EDT
[#1]

[img]http://users.zoominternet.net/~picplace/9mmbarrelramp.JPG[/img]

[img]http://users.zoominternet.net/~picplace/9mmmagwell.JPG[/img]
Link Posted: 12/27/2003 3:33:30 PM EDT
[#2]
Thanks Joe!  Along the same lines as I was thinking.  Hell, at the rate Im tearing up carbide bits, I may have some mags headed your way if I can get this damn thing running - The sten mag conversion went so mauch smoother - never should have sold it.
Link Posted: 12/27/2003 6:53:28 PM EDT
[#3]
Well, I tried rampimg/throating the mag block - minimal improvement.  But after really looking at things (after spending 30-45 minutes on the block) it occured to me that the bolt was hitting the last round just past the rim and draging it forward. So I grabbed a cresent wrench and slipped th jaws over the feed lips and bent them out and up.  Voila, the problem is fixed with hand cycling - proof will be in the actual range performance....
Link Posted: 12/27/2003 7:24:56 PM EDT
[#4]
If you look a little closer, the Uzi follower could actually use a "lump' of weld or something to raise the rim of the case slightly in the rear of the mag so the bolt face can hit the case square and take it into the chamber. Place 1 round in the empty mag, and fumble around a little with the case in the mag. Look for the round to come out of the mag and the nose to contact the ramp about 1/2 way between the front and rear of the ramp, you do not want the bullet' nose to tap the ramp where the mag and ramp are touching.
Link Posted: 12/28/2003 5:35:41 AM EDT
[#5]
I have the same problem if I load more then 20 rounds in an Uzi 25 mag.

I have opened up the mag lips so that a single bullet is alligned correctly and ramped and polished feed ramp but have not notched the barrel.

I have had the same problem with 5 IMI mags.  Anyone have suggestions on UZI mag mods?

Thanks!

Gary
Link Posted: 12/28/2003 11:50:55 AM EDT
[#6]
Range Report.  She runs!  If you look closer at Joe's pics, you'll notice that the feedlips are 'spread' closer to the front of the mag.  This is how mine look now.  Reliability was 100% with 4 different mags.  Even tried bump firing - to check reliability of course - and was able to bump 10-12 round bursts with no probs.  Even more encouraging was the fact that gun was largely 'dry' and FILTHY - not so much as a hiccup.
Link Posted: 12/28/2003 1:58:14 PM EDT
[#7]
ATTA BOY!!!!  Another chapter for the repair guide.
Page AR-15 » Rimfire and Pistol Calibers
AR Sponsor: bravocompany
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