doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Boswell won’t close with Win AA hulls

Hey guys, I just received a Charles Boswell box lock I had brought in. Gun was made in 1905.

I am going over the gun and everything is as advertised. The peculiar thing is the gun won’t close all the way with a Winchester AA HS hull. No problem with an RST (Cheddite) hull. Upon closer examination, the O.D. of the Winchester brass rim is .002” larger than the RST. The rim diameter is just large enough that it won’t fit into the rim cut in the chambers of the barrels to allow the gun to close. I filed down the rim on the Winchester .002” and then it fits properly to allow the gun to close. Does anyone know if it is an easy fix for a gunsmith to open up the I.D. of the chamber rim cut .002”, as to allow the use of Winchester hulls? Has anyone else run into this?

Would you rather modify it than just use appropriate loads in it that will seat properly? I'd think over that decision very carefully if it were mine.

Are you handloading the AAs? Will RGL's fit? If you aren't a high volume shooter, rather than remove metal in the gun you can't put back, consider chucking an AA into a drill and make a few passes on a stone. In order to hold the shell, find a short dowel that will snugly fit the inside of the AA. Drill a center hole axially through the dowel and run a 1/4" bolt down the center with enough out of the drill end to be able to be chucked. You may have to tape or hose clamp the hull to prevent the dowel from spinning inside the hull. Or swap the AAs for Cheddies or RGLs if they fit. Gil

I have a William Evans from 1901. Chambers still 2 1/2". Remingtons (Gun Clubs and STS) drop right in. So do Herters (Cheddite), Federal Top Guns, and Winchester Super Targets. I don't have any AA's on hand to try. But with a lot of options that work well in my gun which is the same vintage as yours, I think I'd try other hulls before modifying the chamber. I do get a very tight fit on once fired Fed Gold Medal hulls. That's the only "problem child" I could find.

It is an easy fix. It is not an uncommon problem in older guns. Winchester rim diameters have generally been larger than average since I first measured them in the 1970s. Opening up the rim diameter a few thou will be undetectable.

Hi guys, I appreciate all the advice. I am very leery to have the gun modified and just wanted to see other opinions. I am hand loading the AA’s for my other 2 1/2” guns by trimming them short and using a Hartin crimp. I am not a high volume shooter, so I was thinking about buying a small jewelry bench grinder and just turning the hull by hand to grind the rim down smaller to fit the gun. Eventually, if this ammo shortage let’s up, I will buy some Cheddite hulls and RST ammo (I am down to 250 rounds of RST) and just reload those.

Seems a shame to mess with something that`s been ok for almost 120 years !!!! Personally I`d be using approprate cartridges .

My first thought; Is this a once fired AA hull you're using? If that's the case it may be fire-formed to the chambers & rims of the gun the hull was fired from.

I have a model-21 Winchester that I had a similar problem with. The once-fired AA hull was tight in the chamber & it wouldn't let the gun close. I then tried a new AA shell and it dropped right in & the gun closed without an issue. My conclusion was the once fired hull had expanded to the chambers of the gun it had been fired in previously.

Just a thought.

Some photos for those interested