Load 29 and see if it works. Have used many precision mags in mini and before i buy i check the follower at the top (empty) with my fingers to make sure it is not hanging up near the top, if yours is sticky up there you might be able to lighly file it to smoothen it up or lube it, if that doesn't seem problem try holding mag form botton and putting pressure on it while in the gun to see if it is not hanging down too much, I had a USA do this and would jam every time, so I had machine shop weld more material on rear outside locking lug (on magazine) and filed it until it was real tight in gun now mag will fire 20 out of 30, after this I gave up on usa mags and will mark this as 20 only, will try to find Madsen or PMI in the future read old post about magazine preferences here at tfl.
Between a friend and myself we have about 30 precision mag and they all work but we checked follower before purchase, I live very close to Greatwestern show at pomona ca so I learned this after buying mags them going home and found a couple did not work so took them back to the gun show for an exchange been happy with the couple of federal brand we have purchased, we have not shot these only cycled them with ammo and found no problems, hope this helps a little
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The beauty of the second Amendment is that it is not needed until they try to take it. T JEFFERSON