This is a .410 that comes in with the complaint that it ejects 2-3/4″ shells but not 3″ magnums. The customer supplied his own ammo for test firing (an unusual bonus). The carrier had a little bit of a hangup on the left side which was relieved with a little polishing. Otherwise everything appeared to be OK other than dirty. So, I stripped it, did a clean and oil, reassembled and the gun cycles fine…except for 3″magnums. At this point I started looking at spent ammo and sure enough there was my (his) problem. A slight bulge about 1″ from the rim in each of the brass casings. Unfired shells cycle flawlessly.
So, my question is, is the barrel kaput? Did he bulge it with a hot load? Should I tell him he needs to stick with 2-3/4″? -RN
So is it a problem with extraction or ejection? The bulge is 1″ above the rim, so 2 3/4″ shell should also have it. How much a difference in diameter between the bulge and the other part of the shell? Were you shooting brass shell or plastic shell? -TL
Answer
This may sound like a dumb question, but is this gun marked for 3″ shells? DC
Question Follow Up
I think the problem is extraction. I didn’t have my micrometer with me when I happened to notice the bulge, but it is noticeable and consistent. I think the reason the shorter shells are cycling is that the plastic is more flexible and forgiving. The magnum shells are brass and, once they’ve expanded, they’re not so cooperative.
The barrel is marked to accept 3″ shells. –RN
Answer
How large is the bulge? Ken
Question Follow Up
I didn’t have to pound the shell out but it took some finagling to get it out of there each time. Polishing might help, but I think the best solution at this point is to use plastic shells. I’m thinking that he reloads his brass ones, and maybe a little too hot.
The bulge in the shell is .012″. I can tell you that it’s a very discreet bulge approximately 1″ up from the rim and .125″ in length. It’s pronounced enough that it’s visible (shiny). In retrospect, I should have picked up on it sooner rather than trying to figure out what was wrong with every other part of the gun.
-RN
Answer
That is a fair size for a bulge. Check with your customer and see if he wants you to try and polish out the bulge and save this barrel or if he simply wants to find a new barrel. Probably not going to be able to save this barrel, but worth the try. Ken
Question Follow Up
Ken,
How would you go about polishing out the barrel? Are we talking about increasing the chamber diameter up to the bulge?
Answer
I’m not Ken, but I do it with a Foredom tool and a piece of rod with sandpaper taped to it. I’ve been using 400 or 600 grit, but have recently started with 220 grit and then moving up. It takes a little feel to get this to just polish and not cut metal, which is why I started with finer grits – I couldn’t make a big mistake quickly.
The goal isn’t to change the size but to smooth the imperfections. In other words, trying to get just to the point where there is a slight or no bulge without ruining the barrel. If the bulge actually is .012″, and depending on whether it’s concentric (around the entire shell), you may not be able to polish it out safely and replacing the barrel might be wiser. Though part of me wonders what happened to the barrel for it to get that far out. I’ve only had (limited experience so maybe not a good measure) a few thousandths at most. Jeff
Answer
What Jeff said…start with 220 or 320 grit and work up to 400. Ken
