Any ideas?

Is the rim on case thicker maybe?

That was my guess in the video, but it's not noticeable to the naked eye, side by side each other they look identical.

Have you measured the thickness of brass?? If nothing else maybe save your spent hulls that chamber and have them reloaded?? Or figure out which shells your gun likes... so to speak and just stick with those..
I've never seen that with my double barrel 12.. it's an older rossi..
Hope this helps.. sorry I don't know anymore.

The rim on the base was my first guess too. That is what I was thinking before you brought it up. Put the shells in the barrel and lay a straight edge across and see if you can see a difference in them.

Might only take a couple thousandths to make a diff

There is a tiniest bit of difference, like the thickness of a hair. It sure don't seem enough to effect it but I can't figure anything else. Can a gunsmith ream that little lip just a hair deeper? I'm thinking of making it more safe for others who may shoot it some day. I wouldn't want anyone to pull the trigger without it fully locked accidentally.

Is the overall length of the brass to high? Not just the rim

Those are the same at least on the winchesters.

Then you might cause shells to be loose in the breach.. that might end badly.

I can't see that making a dangerous difference, I mean all other shotguns must have enough space for various shells. Right?

Good luck trying to understand this guy and don't burn your house down.

Tighten the Bite

I may have just posted the most worthless link possible....

However maybe worth a chuckle.

lol, thank goodness for subtitles. I don't think that's this gun's trouble though.

ADC you mentioned in the video that the overall length of the shells was a little bit longer on the ones that did not lock up properly. Try the test again, one barrel at a time. Close it slowly and gently and see if you feel resistence like the shell is being forced into the barrel. Compare the force with shells that do lock up properly. It's possible that the forcing cone or chamber in one or both barrels isn't cut quite deep enough. The slight variations in rim thickness could cause it to do the same thing. With the variety of ammo you tested with it makes me think it is a machining problem. Headspace, chamber, or forcing cone. Is there any possibility that the the gun is chambered for 2 9/16 instead of 2 3/4?

In the video the OAL was actually shorter on some of the ones that wouldn't lock. I had it measured and it is 2 3/4" chamber.

I think I've determined the issue as the lip on the casings varying ever so slightly. You can see that hair line of light on the right barrel when I load one that locks and one that doesn't. It goes to the other side if I swap the shells. You literally can not see it without that straight edge. Crazy that could make the difference.

If it's an older gun, it could have 2 9/16" chambers. That is the original chambering for 16 gauges.

Beyond that, it's probably the ammo.



Charlie

Yep. I had that chamber length checked it's 2 3/4". I guess it's the ammo.

It only takes a thousandth or two to cause problems. Another thing to consider is that the quality control on ammo seems to have gotten progressively worse in the last 20 years. More so in the last few years. An experienced gunsmith might be able to cut the chamfer for the rims a little deeper without getting it excessively deep. A good pair of calipers, and a little careful measuring of rim thickness and diameter, should definately let you know if it is the ammo. Shotgun chamber specs are easy to lookup on the internet.

The brass is probably inconsistent, but the picture shows a lot of variance in the barrel that could easily cause the problem, as far as fixing it any gunsmith or machinists worth their salt can fix that.