How to Adjust Feed Lips on Plastic AI Pattern Mags?

[PracticalTactical]

So the Cadex chassis finally arrived for this rifle and I put it together today.

Its a Defiance Deviant Tactical action with a 1:7 Bartlien barrel chambered for 223 in Cadex barrel contour.

It's throated to jam the lands at 2.560" with 75 grain Hornady ELDs, which is as long as the MDT and AI plastic mags will allow without modification.

The AI mags feed perfectly with 2.560" long rounds but the MDT and Ruger 223 RPR mags do not.

I measured the distance between the feed lips and the AI mags are considerably wider at the front than the MDT and Ruger versions, which looks to be the reason AI mags work and the others do not.
(FYI the Ruger and MDT mags feed fine in my 223 RPR, just not in this new Rem 700 foot print rifle. And the AI mag does not feed in the RPR)

I have a tool to adjust metal feed lips and have my arms around that for the 308 but the plastic mags put me in unchartered waters.

So how do I adjust the feed lips on plastic mags?

File them?

Any ideas?

 

[MakeSawdust]

File 'em, Dremel 'em, cut 'em with a sharp knife, or take them to somebody that has a mill that can control what they're doing well if you are worried about messing them up.

 

[The King]

I would make a rod the diameter of the bolt and heat it enough to melt the plastic. drop it in and drop in the mag. take back out and clean up the melted edges.

Viola! A perfectly functional mag! Or a totally ruined one, who knows!!!