AI Mag won't Feed

[ndbwhunter]

Tikka T3x 300 win mag with Mountain Tactical AICS bottom metal and accuracy international 5 round mag. With one round in the mag the bolt will barely catch the face of the round, and in some cases it just pushes it back down into the mag. While attempting to chamber a round, the round enters the chamber at a very steep angle and will not release from the mag. Any thoughts on what to do? Is it as simple as adjusting the feed lips? If so, what is the best way to adjust them without ruining a $100 mag?

 

[Lawnboi]

Few questions.
-What stock? Action seated well? Did the stock work fine with stock dbm?
-Might seem dumb but did you remove the stock mag spring on the trigger screw?
-what’s the case head look like sitting in the mag? You can adjust the feed lips, but if it’s a major difference you might have other problems.

MPA makes a mag lip tool, lots of other stuff you can just too. If it’s just a bit you can open the feed lips so the case head presents itself more. But from what you describe it sounds like the mag is deep.

 

[JonC]

Welcome to the wonderful world of AI mags. They're still the standard, even though every other part of the gun has moved on. It could be any number of things:

Might be tolerance stacking, all of your parts may be good on their own but drift to one side of nominal and now it won't work. Could just be a bad AI mag, which happens al the time, they're not super consistent. I own about 2-dozen rifles that take AI mags (5 are actual AI rifles) and bad mags on occasion are part of the deal, even with new ones. Stock inlet could be too shallow pushing your magazine presentation height down, mag catch on the bottom metal might be too short to push the magazine catch tang high enough, could be weak spring pressure on the mag catch itself. The mag well might be too long front-to-rear, causing the front of the mag to nosedive (this is why the AIAX magazine has a front locking lug), which is very common.

I would start with the easy part and try to apply a small (one-finger) amount of pressure to the forward bottom edge of the mag and see if it feeds. That's a sign of the mag riding too low in the front. If that doesn't work apply pressure from the center and see if that helps (accounts for mag catch height). Barring those, try a new mag. It will have to be a metal mag to fit in a Tikka, Accurate Mag makes a good one that are usually readily available.

The line between these conversions working and not working is very, very fine anyways, so a tiny change might make it work fine. Once you diagnose the problem, then you can get into fixing it, hopefully with as little ass pain as possible,

 

[ndbwhunter]

Few questions.
-What stock? Action seated well? Did the stock work fine with stock dbm?
-Might seem dumb but did you remove the stock mag spring on the trigger screw?
-what’s the case head look like sitting in the mag? You can adjust the feed lips, but if it’s a major difference you might have other problems.

MPA makes a mag lip tool, lots of other stuff you can just too. If it’s just a bit you can open the feed lips so the case head presents itself more. But from what you describe it sounds like the mag is deep.

Factory Tikka T3x synthetic stock. The factory dbm and mag worked fine. I removed the stock mag spring from the trigger assembly and removed .040 of an inch per the instructions. The bolt is barely catching the top of the case head. It will catch the edge of the case head if you close the bolt slowly, but closing it fast will push the case down.

 

[ndbwhunter]

I just went out and tested it again. The round will feed if I really slam the bolt closed hard while the bullet is jammed in at an angle. It almost looks like I need to open up the front half of the feed lips so the case head pops up as the round is being chambered.