So I had one mag that was being a bastard when feeding a round or two every now and again.  Rounds were just nosediving into the feed ramps and getting chunks gouged out of them.

Turns out it is a simple fix.  I took a pair of calipers and measured both sets of lips on a mag that worked great and compared the one that was acting up.  The rear lip should have been .210, but was .195 instead.  A quick tweak with some pliers to get it in shape worked great.  (I just put a closed pair of pliers between the feed lips and gently rotated it.  Stop to measure, rinse and repeat till done)

Ran 50 rounds through that mag today without a single hiccup.  Thought I'd pass it on.

FOR THE RECORD:
Don't take this for gospel and please measure one of the mags that works for you before modifying anything.  I imagine the feed lip dimensions would be similar/identical, but rimfires are known to have some individual quirks.

Good info.

Thanks, i will check mine when i get home.

So I picked up another TacSol mag yesterday.  Feed lips were small in the back so I gave them a small tweak after writing the measurements down.  Will take it to the range this weekend and confirm results.

I just really like the tacsol bases.

You guys probably know there is a tool made just for this job. It has a little slot cut in it that the feed lip goes into and than you gently "adjust" the opening.

Here is one that is listed for an AR-15 but these things are somewhat universal. I have seen others that were specific for certain firearms. There are some made for the small magazines used on .22 caliber pistols. I have made these before with a dremel tool with a cutter wheel. But, often simple pliers can do the trick too.

Mag lip adjuster tool.