Remington 572, not resetting hammer

[crestoncowboy]

Hello,
A friend recently brought over a new looking 572 pump action that he had given his sister. He has many guns and generally when he brings one its just filthy and won't function. He only said that his sister told him it didn't work all the time, he didn't know why or what it was doing. I took it out and shot a tube full into a hill just to see. Out of that 13 or whatever the tube holds the gun didn't catch the hammer about 5 times. Requiring you to pump and eject the live round. I took it completly apart figuring it was just dirty. It was actually in good repair. The only build up was around the bolt. I cleaned it well and reassembled and out of one tube it still done the same think once. I ran out of time and decided to ask for help as to what to look at next.
Working the hammer and sear manually with the triger pack out it seems to engage positively. No parts show any real wear. Most still have their bluing. Any ideas?

 

[DM~]

Did you clean the trigger?? That's where I'd be looking...

DM

 

[crestoncowboy]

I cleaned everything up good. But surprisingly it was fairly clean already. The hammer engages strongly when you work it manually. Perhaps the bolt is riding slightly higher than its supposed to and the hammer isn't quite pushed far enough backand down. Idk I'm not familiar with this particular rifle, but it's a very simple design. Ill take it apart again this weekend. Just wondering if anyone else has had this problem. And anything in particular to look for.
Internet searches bring up plenty of double feed, fte, and light strike problems for 572s. But none like this rifle shows

 

[351 WINCHESTER]

Check to see if the bolt is going fully into battery. If not, clean the bolt face, chamber really well. .22 ammo is all over the place in dimensions, so maybe the problem is the ammo?

 

[crestoncowboy]

That's possible, I wasn't looking into the bolt angle so much as the trigger pack angle. And when it malfunctions I don't have to hit the slide release to pump again, so maybe it is out of battery.

 

[entropy]

Disassemble, clean, OK, you did that, inspect the sear spring. It being weak can cause both out of battery and the hammer to not engage the sear.

 

[Picher]

It seems that the action locking bar and spring may not be working properly, causing the disconnector to prevent firing. That could be caused by thick ammo rims, a chambering problem, or just a weak disconnector spring. If everything works well without ammo, concentrate on headspace or ammo issues.