What is making these marks on my brass?

[fourfive8]

I've thought about that. Do you think that's something I can do myself as long as I'm careful and deliberate? I have some honing compound if I could figure out a good way to get at those corners.

Yes. If it were mine, I'd be pretty aggressive with rounding off those pointed edges (actually they are kind of pyramid shaped) with a ball shaped grinding stone on a rotary tool... just to get it done. Put the barreled action in a padded vice more or less vertical with good light source on the work area. A small ball grinder chucked long for some working length will probably work best because of the cramped space and odd narrow angle you have to work with. Then smooth the surface with some polishing compounding on a fiber or felt bob. Since it is not mine, I have to be conservative and so suggest only doing what you are comfortable with. Taking an 1/8" inch off each peak (as in the sketch) then finishing in a smooth radius will not affect strength or safety nor will it affect function. After all, the ramp already has had some significant reshaping done so I wouldn't worry too much about rounding off those points. Even if one is not the gouging culprit, rounding them off won't hurt a thing.

The easiest way of course would be to take the barrel out of the action- it then would be a piece-o-cake to work on. Although rounding the points off would be fall-off-a-log simple and take very little time, I think most gunsmiths charge about $100-150 for removing a barrel. Not hard to do but really should use a dedicated barrel vice and action tool.

 

[John P.]

Impressive photos.

A tube of Prussian bluing compound is handy for sorting out things like this. The compound is similar to a light grease and is used in the machining industry for spotting in bearings and close tolerance fits. Smear some on the bullet nose and the forward end of the case, slowly chamber the cartridge, remove it, and look for traces of the bluing compound in the suspect area. This will be your area that is scraping.

Your chamber mouth looks like it has a slight chamfer, which is good.

 

[CJW]

To get the photos that sharp I had to actually move my phone at the point I anticipated the shutter closing instead of holding it still. I discovered this by accident and it may take a few tries but you'll get it. I was holding my phone upside down at about 60 degrees with the flash pointed into the chamber. Worked well.

I ordered a borescope and will take a look before I go modifying anything just so I'm not missing something blatant and I'll pick up some Prussian bluing the next time I'm in town. If it's nothing as simple as rounding off those corners I guess I'll have to find another gunsmith.

I just heard back from the previous owner and he said he never noticed anything like what I'm talking about. Strange considering the limited number of rounds that have been in it and each one has a gouge plus each of my snap caps has multiple gouges. Oh well.

Thanks for all the help guys.

 

[fourfive8]

You can also use a thin mirror to look into the chamber/throat area. I use a piece of a mirror about 2" long by 1/2" wide glued to a Popsicle stick. Open or remove bolt. Set rifle in cradle. Put bore light in muzzle. Position mirror in port just behind chamber for view into chamber. Gives surprisingly good view of chamber and throat area. The oblique angle enhances any surface irregularities.