870 Express Magnum issue

[Markl]

Hello,

I wanted to see how the Royal Buck 00B and the Sellior Bellot 00B ran in my 870 Express Magnum. The shotgun is 13-years-old, but has only about 175 trouble free rounds through it. The rounds have been a mixture of Remington, Federal and Estate. I loaded a couple rounds of the Royal Buck then topped the magazine off with Sellior Bellot. After firing two shells, the slide will not move backward by pulling on it, even with depressing the slide release (which at this point isn't moving at all) it will not come back.
After taking off the magazine cap and unloading it, the slide release will not move to it's normal position. I then took out the trigger assembly to inspect but can't find anything out of the ordinary. Trigger assembly seems to work fine. After reinstalling, it still happens. Can't rack the slide and the slide release won't budge.

Any ideas about what may be wrong? Help.

Thanks,

Mark

[Synchronizor]

Is the fired shell still in the chamber?

[Markl]

I will sheepishly admit that it indeed was! I was very frustrated that my "never any problem" 870 had a problem. So I didn't pick
it up for a couple of days. Shucked the slide, whereas before I couldn't, and out popped the shell!
I guess after cooling, the fired shell contracted and came out as it should.
The next question is, has anyone had these issues with the Sellior Bellot 00B?

Thanks for your reply.