USC bolt catch doesnt work

[psk145]

I just got back from the range, and after the last shot the bolt doest stay open. It will lock open if I press down on the opposite side of the release. but doesnt work any other time. The gun is fairly new with less than 1000 rounds though it.

Any suggestions on what to look for? TIA

[GUNADDICT]

The first thing that I would suspect is the magazine. Is the follower worn somehow? Do you have multiple mags to test this theory? Have you visually inspected the bolt catch? Could be a few different things, but usually a worn, or sticky unclean magazine is the problem.

[psk145]

I only have one mag. I switched the spring orienation around, and it seemed to be the trick to get it to engage. I just spun the spring 180, if that makes sense. Maybe I put it back together wrong the last time I cleaned it, but that was several trips ago to the range, and it worked before.

Thanks for the suggestions. Dropped the damn bolt on the floor though, and kinda dinged up one corner. Hopefully it doesnt affect it any.

[Frogman7]

Hello,

I am having the same problem, but I just received the USC a week ago and put about 50 rounds thru it, it works intermittently. It seems the spring on the catch does not push it up enough without help. The mag is brand new and I only have the one that came with the new gun.

What spring was it that you turned around? I cannot see that the bolt catch assembly is even accessable. Any hep would be appreciated, I would hate to have to ship this back to HK right after getting it. Thanks

Ed

[dwillHK]

I suspect he means that he rotated the spring in the magazine.

[Frogman7]

hmmmm... thanks dwill,

I did not however; disassmble the mag like psk reported.

When I first received the USC, I noted the bolt release seemed to be somewhat odd with the overall action of the assembly, it did not seemed to press out like one would on a AR-15 when engaged with the bolt to keep it back.

Also, on one occasionb yesterday, when the bolt remained open after thelast round, I inseted the clip and the bolt released itself withut me even touching the release lever, it just engaged on its own!

I have to call HK and see what they say, I never dealt with them before.

E

[nerd0606]

Frogman, Do you have a brand new usc or is it used. What is the date code on it? I'm just curious if it is a batch of bad ones.

[Frogman7]

Hello nerd606,

It is brand new, maybe about 50 to 75 rounds through it since Ii bought it about two weeks ago. I got it off Gunbroker.
Where is the date code? the stock has a "DE" after the serial number, whick starts with 47
I called HK and they told me to remove the mag spring and strech it a bit and put it back the opposite way. I have not gotten to this yet.

Frogman

[Lee123]

I had to ask the same question myself a few days ago when I was considering buying a used USC. I didn't know where the date code was. It is 2 very small letters stamped in the plastic above the serial number. Much smaller than the numbers in the serial number. The first letter will probably be A but might be K. My new one is AI and the used one I was looking at was AA. Don't know if any were made in 1999 or if 2000 was the first year. The code represents the last two numbers of the year of manufacture:
A 0
B 1
C 2
D 3
E 4
F 5
G 6
H 7
I 8
K 9

[Lee123]

Strange coincidence. I took my new USC to the range for the first time today, a few hours after I posted the reply about the date code right above this. After 2 or 3 mags the mag release spring flipped around 90 degrees so it was holding the lever in the released position. I posted something about that already.

After I fixed the mag release I was trying it out at home and the bolt hold open was not consistent when I worked the action manually. Some times it would catch, sometimes it would not, and sometimes it would catch and then release the bolt when I removed the mag. It was obvious the mag was not pushing the bolt hold open all the way up. I've seen the same thing with slide stops on 1911's more than once.

I took the mag apart and reversed the spring as psk145 suggested. That seems to have fixed it. I'm wondering if someone put a bunch of mags together with the springs in backwards. I did not take the mag apart prior to this, so it came from the factory as it was. That's two problems with a brand new USC in less than 100 rounds. Someone must have been having a bad day. The date code on mine is AI.