[Bonasa]

Any tips for smoothing Mark IV mags so they don't bind or drag being inserted and removed from the mag well? I think I see some rough areas and burrs on the vertical seam along the back side of the mag, especially where it culminates at the lip at the top, as well as on the two small nipples on opposite sides of the mag, one of which contacts the mag release.

I'm thinking maybe some judicious files work to remove the burrs, followed by some emery cloth to polish up the filed areas.

Any other advice for smoothing out Mark IV mags? I'm a little disappointed that they come from the factory in apparently such a pretty crude state that requires some attention.

 

[pop57]

Go to Wirthwein Guns, They have a great info sheet on adjusting/tuning mags for the MK series of guns.

 

[Danwin22]

Is it the mag or the well?

 

[MKX-X]

Check your bolt lock under the left hand grip to make sure it hasn't come of the pivot pin. The only thing that holds it on is the grip, so make sure it's properly seated when you put the grip back on every time you deep clean the mag wells by removing the grips. If bolt release lever is not properly seated on the pivot pin it may disengage from the bolt latch link and push the latch into the side of the magazine well causing the magazines to stick. The bolt release may still function but not as smoothly as it should and could fail, or create a hazard.

When I have the grips off I also look for rub spots on the inside of the well then lightly rub some ACF-50 on, then off to remove carbon and prevent corrosion. It can be a tedious process but the mags run smoothly afterward and will almost fully eject when released.
Just be careful with the other moving parts with the grips off.