CMMG/Colt consternation!

OK it LOOKS cool after much flusternation swapping parts on my CMMG 22LR upper with parts from Model 1 Sales (slipover flash hider, triangle handguards and front hand guard retaining ring)... which I am never doing again if I can help it taper pins and front sight removal was a bear!

Add a Bushnell Troophy Dot and it's ready to rock--NOT. When I put my CMMG 22LR magazines into my Colt 6920 magwell they stick and I don't mean a little. LIke STUCK. It's like they don't fit at all, none of the 3 magazines I purchased seem to fit my Colt. Even with the upper OFF the mags don't seem to fit properly.

Any ideas folks?

My CMMG upper did NOT come with a manual or ship with a magazine, I had to purchase mags seperately.

Did I buy the wrong mags? Is my Colt too tight? Am I doing something incredibly stupid?

Redlg155, I use Pmags and Colt mags exclusively. These mags are for a 22LR conversion upper.

Ok the backs of the CMMG mags all have these 'tabs' molded in that appear to be the problem. Colt factory 30 rd Mag for comparison.

Is this NOT a CMMG mag? A factory second?

Any opinions?

Just got a reply from Chris Kelly @ CMMG:

Those are our mags, the raised portions are a custom-fit lug that allows the user to adjust his/her mag to be snug or drop-free and also to fit various lowers properly.

He sent an attachment diagramming the magazines.

(Gets out the files)

I am going to try Black Dog as well, but I got these for $16.50/ea.

A few minutes with an emery board and checking the mags with the lower certainly seemd to do the trick. (A Dremel takes off too much material too fast.)

Range report to follow!

Heading out this weekend to try it out but I have to say I might NOT have had this problem if my upper had shipped with a manual. (The mag fitting is described in the manual on their site on-line)

For the life of me I can't fathom why CMMG would ship any such product without a manual.

See this image, take an emery board and work paralell to the length of the mag body, just a few strokes at a time on each 'hump' work slowly, it really didn't take very long.

http://www.thehighroad.org/attachment.php?attachmentid=152738&d=1321303470

Promised a range report but cussed if I could get this combination to shoot groups at 50 yards. Patterns yes, groups no.

I suspect I am 'doing it wrong' when it comes to this red dot sight. Trying to co-witness the front iron sight with the reticle makes the reticle not centered. Centering the reticle like a standard scope leaves the front sight post obscuring my target. Hmmm. even resorted to trying another rifle to make sure it wasn't me having the issue.

Fired about 150 rounds slow fire.

3 kinds of ammo, no msifires.

Federal bulk pack HV 36gr copper plated hollow point.
Federal Lightning HV 40 gr lubricated lead
Remington subsonic 36 gr lead HP

I had 2 malfunctions:

1 was while inserting a magazine I had a round pop free (potentially I didn't seat it properly).
1 failure to feed that resulted in the cartridge being stuck 90 degrees against the bolt face and without taking the upper off, it took a gentle nudge with a screwdiver to pup the round free.

Both failures were with Federal Bulk pack.