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I have a relatively new to me stainless Mark II. The problem I noticed last night was that the bolt catch will not engage. With an empty mag inserted, the bolt will not lock back when pulled to the rear. With a mag out, pulling the bolt to the rear, it is difficult to get the bolt release to set in the up position. While I didn’t have time for a complete tear down and cleaning, I did spray it down and scrub it with a toothbrush. This was all tried with the Hogue and factory grips both installed and removed.

Any suggestions?

Are these factory grips or are there aftermarket grips installed? Factory or aftermarket bolt stop lever? Try taking off the left grip panel and then do the test for bolt stop engagement with an empty magazine. If it works then your panel is causing a hang-up.

R,
Bullseye

I have some real nice wooden target grips on my Mlll that were causing this problem.
Not til I took them off and gently filed out some wood, in just the right spot, did the bolt
start catching and releasing properly. I just had the Mlll out to the range today and it worked flawlessly.
Good luck,
Haka

This happens even with the grips not installed.

have you tried a different mag?

also you could take the top end off and insert an empty mag and see if it works the bolt stop correctly.

Is the catch lever being pushed upwards with the follower button of the empty magazine?

Is your follower button on the left side of the magazine body? (side where the catch is located) That last question sounds ridiculous but I once had someone experience the same issue and then later realized he'd inserted the follower button on the wrong side of the magazine after tearing the mag apart.

Ensure that the front end of the bolt stop is anchored properly on the trigger pivot pin (left side of trigger) and the spring return plunger is properly engaged in the groove. Also check the spring return plunger for smooth movement. If this plunger is hanging up in the front lug hole it will impede the movement of the bolt catch.

R,
Bullseye

This happens even with the grips not installed.

I see now that you mentioned this. BE always has good advice. The first check might be what greener said with a different magazine, it's the most simple, plus magazines have given issues to Mark owners.

BE covered it as he normally does.

I just had to replace the bolt stop on my MKIII due to the corner rounding off. A good detail cleaning is in order so you can inspect the parts.

blue68f100 wrote:BE covered it as he normally does.

I just had to replace the bolt stop on my MKIII due to the corner rounding off. A good detail cleaning is in order so you can inspect the parts.

Thanks. Spent Saturday shooting our monthly local Ruger rimfire match. Spent today working on my bathroom remodel.

Will strip and detail clean it tomorrow. Have 15 mark II mags. They are all good.

Thanks

Vic