My Colt mag ran 100%!!
My UZI mag is still giving me fits but I'm one tweak away from getting it going.

Have you tried taking a sharpie and sticking your uzi mags in the adapter block (once removed from the magwell) and then marking excess areas you need to cut? My mags look like they have been cut on with a dremel, but after the hand fitting, they are 100% reliable. They are fn contract mags are about as solid and tough as any mag I have ever seen.

 I found that pre-modified mags can still be somewhat "off," and the tolerances are tight enough that the mag needs to seat just right in there for it to work correctly. Uzi mags also can't be loaded to capacity. At least mine can't, because they will "volcano" every time once the first round is stripped when fully loaded.

My Colt mag volcanoes.  My 25 round UZI mag doesn't.

I marked my first attempt to modify an UZI mag in the manner that you describe.  With my parts it was possible to insert the mag farther into the uninstalled mag block than it was with everything installed.  I have a RRA magwell adapter, Sendra lower and RRA upper.

The Colt mag seems to be made of thinner material than my UZI mag.  I just bought two used IMI mags and they're way thicker than the Colt mag.  I think that has something to do with how close the mag gets the rounds to the center line of the upper.

About the volcanoe, I've noticed that 32 round mags that have the feeding dimples in the sides at the top of the mag are prone to this.  Maybe others would comment about this too.  

Soon, I'll have a couple of grooves hacked out of my feed ramp and the UZI mag should work just fine.  The deeper I get these grooves the smooooooother the UZI mag feeds the dummy rounds.  The ramp is too hard to use a file and I don't own a dremel so I'm using a rough round stone.  Nothing but caveman stone axe techniques here!

Someday...i can only dream.

I'm going to dress a grinding wheel and grind my mag well adapter ramp on a surface grinder.  I can do this for people for $45.00 incl shipping.

[:\]

Lemme know when you get one done.  I'd love to see a pic.  In the mean time I'm going to hold off taking the stone axe to mine and possibly do some situps........

Most likely will grind two small channels for the right and left cartridge to feed better out of the mag.  I'll post pics in a couple of days...

Most likely will grind two small channels for the right and left cartridge to feed better out of the mag.  I'll post pics in a couple of days...

I was experiencing a variety of feed problems with my uzi mags.  I removed the existing feed ramp and replaced it with one that I fashioned from a solid block of steel.  It features the two channel design that was mentioned above. I polished both channels to a mirror finish. I don't have a digital cam so I can't post a pic anytime soon.  With the new ramp installed, I have not experienced any malfunctions over about 1000 rounds of fmj and hollow points.

I'll be joining the club one of these days!! Been waiting for my 11.5" Oly upper since the end of Feb.

That's what you get for using the Oly system. [slap]



Really doesn't matter.  What ever works for you.