Home Forums Hunting & Shooting Gunsmithing Scrape marks on brass when chambering

I just rescued a custom Mauser 30-06 from a local pawn shop. Pics are over in the Hunting Rifles forum. Problem is when chambering a round, the shell will load about halfway then stick. With a little pressure it will fully chamber, but leaves a pretty good scrape along the bottom side of the brass. I've marked the top of the brass with a marker when loaded in the magazine and when the shell is removed the scrape is almost dead center on the bottom of the round. I am loading correctly from the magazine and not trying to drop the shell into the chamber and then close the bolt. Any suggestions on a fix by a novice tinkerer, or is this an issue for a professional?

The pics are of two different factory rounds and it also does the same on my FL sized handloads from my other 30-06.

Your Mauser was made to feed 7.92x57 ammo. The longer 30-06 case is not coming out of the feed rails at the proper time and is scraping on the transition into the chamber. A little judicious polishing with fine Cratex on the inside of the feed rails and the feed ramp in the front of the action will smooth the feeding. There could also be a rough place on the bolt face or on the hook of the extractor that is preventing the cartridge from slipping up into place properly. Be careful not to take off any metal, just polish what is there.
An experienced gunsmith can reshape the fed rails to produce very smooth feeding, good luck on finding him. Lost art!

I would pull the barreled action out of the stock and look for any places that could cause it and polish the area.

Sounds like either the feed ramp needs addressed or the chamber mouth was not chamfered after chambering.

Ok guys, I've been playing with this thing a little bit this afternoon. I've noticed that during the forward working of the bolt when the bolt face grabs the base of the round to guide it in, the base of the shell is not going completely up into the bolt face. It lacks about 1/16 inch from the top of the bolt face. If I stick a small screwdriver under the round and pop it up to where it is fully seated in the bolt face, it feeds like it is supposed to. I removed the bolt and tried to slide the base of the shell into the bolt face and it takes pressure to make it "pop" in. It doesn't just slide in easily. This being my first Mauser, I don't know if this is the way it's supposed to be or not. It seems that if the round would slide into the bolt face with no extra pressure, the round would probably seat fully in the bolt face when it is picked up out of the magazine and solve my problem. BTW, I looked at the rails and they appear to have been polished when the rifle was built.

On a mauser i think it should have a little pressure going into the bolt face. If you take the bolt out and insert a round into it should have enough pressure to hold the round without it falling out.

I would take Kp321 advice and polish very gently. I think this can be pretty common on the crf rifles that i own.

Check the edge on the barrel when it goes to chamber.

It probably was not broken any if at all.

If it hangs up half way in ^^^ this sounds like your problem

So i have a rifle with the similar issue, it hangs up with about a half inch to go and takes a quite of bit if force to chamber the round, the case is really scratched up about 3/8" back from the shoulder. So how does one "Chamfered" after the fact?

That wouldn’t bother me.

Look at the edge of the chamber. If it looks square then it needs chamfered. It should have a narrow shiny ring at the chamber mouth with a rounded profile. The way it is done is spinning the barrel pretty fast in a lathe and then using a multi-folded piece of 320 grit sand paper about one inch square then pressing it against the mouth of the chamber, making sure it does not enter the chamber. Do this only a very short time and then repeat with 400 grit, again insuring it doesn't enter the chamber. I do not think there is an acceptable shortcut. The multi-folds are to stiffen the paper. It will tend to want to push in with a single layer. That is how I was taught to do it anyway. I am not a professional.

In addition to the chamber and feed ramp I would polish the contact surfaces of the extractor claw also. I would be tempted to put hard finger pressure only on the curved portion of the extractor parallel to the bolt body to just imperceptibly bend the claw outward. Go easy as a slight over adjustment can be fixed but a major bending and you may be Fubared. I am a gun butcher so let's see if the gunsmiths think this is a bad idea. The rim of your brass may be slightly larger or thicker than the parent case. The 7.92 has a .470" rim the 30-06 a .473" rim. Usually there is enough tolerance for this not to make a difference but if the extractor is tight to begin with this could be a factor.

If the cartridge is 1/2" from going into the chamber, the problem is with the extractor no allowing the round to slip under the hook

Any modification to the bolt face should be done on a lathe. I would be tempted to roll a case in fine valve grinding compound wipe off the head or primer side and chuck it in a drill. I would give it a spins with the extractor in place and then remove the extractor and do another quick spin to the bolt face. Do this as a polishing procedure not a metal removal operation. I would repeat with a clean case, bolt, extractor and use Flitz or JB compound. Then a manual polishing and test, good idea to test every minute of polishing. Overdone and you will need a good gunsmith or machinist.

Do all the things previously recommended before doing this, it may not need it.

Interesting. My rebarreled 6.5x57 does the same thing. It's a ZKK 600, a Mauser copy. The cartridge stops half way in and then when I push it in the case is scratched. Nice RWS cases as well at $4 each.

Interesting. My rebarreled 6.5x57 does the same thing. It's a ZKK 600, a Mauser copy. The cartridge stops half way in and then when I push it in the case is scratched. Nice RWS cases as well at $4 each.

JKob explained what the problem is. Listen to him. The extractor should hold the cartridge in the bolt but it should JUST do so. It should not be at all difficult to slide the shell up under the extractor but you should feel slight resistance. GD

Thought I would post an update since I got my problem solved. It was a two part solution. First, my gunsmith took some metal off the bottom of the lip of the extractor, see pics. First is the original, second is after the removal. Second, he slightly chamfered the edge of the chamber. Feeds exactly as it is supposed to now.

This ^^^^^^^^^^^^^

But it's also very possible & likely that the chamber edge was not properly chamfered, especially if the breech was faced off to set headspace on a pre-chambered barrel.............a sharp edge will result & needs to be chamfered.

If not, it will scratch the case on both loading as well as extraction.

MM