Slide doens't lock back on empty mag

[SteamedHams]

Hey folks,

I just picked up a Mk19 in 44mag, but one thing I noticed is that the slide doesn't lock back on an empty mag unless I push up on the magazine as I pull the slide back. This happens with both the factory mag that came with the gun and a second factory MR mag, so I'm thinking it's not an issue with the mag.

When the mag is fully inserted, I can see that the slide lock is pushed up against the bottom of the slide, and there's no play. However, as the cutout on the slide passes over it, the slide lock doesn't move upward to engage; I have to push the magazine up so that the faceplate is flush with the bottom of the grip in order for the slide lock to move up and engage in the cutout.

Has anyone else run into this issue before?

[lockhart]

Seems to me that if you can lock the slide back by pushing up the slide lock by hand, your ammo
isn't hot enough to get the slide back far enough by shooting it!

[King Rat]

Seems to me that if you can lock the slide back by pushing up the slide lock by hand, your ammo
isn't hot enough to get the slide back far enough by shooting it!

Agree and that the gun just might need a little more time to break in.

[Tilos]

Stretching the mag spring has always worked for me...try it.
That, or file back the follower surfaces that contact the mag lips to allow the follower to protrude further.
jmo,
.

[GarrettJ]

Or it may just be your two magazines.

I have two factory .50AE mags that won’t lock the slide open. The other dozen or so mags I own in various calibers all work correctly. But as it turns out, these were the first and second .50 mags I bought. I thought maybe it was something with my ammo. But then bought another .50 mag and it works correctly.

[Tilos]

Looks like the OP is a one-and-done member who has not been back since starting this thread...
jmo,
.

[SteamedHams]

Forgot to update this thread, but for whatever reason after about 50 rounds (not that I'm complaining), both mags lock back on an empty mag. Maybe something needed to wear in.

I had actually been having a hell of a time getting the gun to run smoothly. With PMC 44C, AE 44A, and Federal C44A, the slide would hang up before returning to battery. Over the past year I had tried using gun grease instead of lube, deep cleaning the bolt, replacing the recoil and firing pin springs, bending the mag feed lips, and even trying different grips and holds. I had sent about 500 rounds down it in the hopes that it would wear in. Well, I found out today that the problem is that mine seems to only eat Magtech 44A. I got my hands on some recently, and and ran 100 rounds through it with zero failures. Switched back to American Eagle, and the slide would hang every single time. Switched back to Magtech, and it again ran flawlessly. Loose grip, no problem. Firm grip, no problem. One hand, no problem.