Is This A Problem?

[AlaFan92]

Hey guys, just reamed my first barrel. It's a Turk 8mm that I cut to 23.5 inches and cleaned up on the lathe. Headspace seems to be perfect, and it shot great at the range yesterday. In looking at the brass this evening, however, I noticed that each cartridge had a ring just below the case neck. A picture of three of the cases is shown below -- these are pretty typical of the 20 I shot (this is all new, unfired brass). The picture actually makes it look worse than it really is due to the lighting in the photo.

 

I assume this was caused by reaming the barrel, but can anyone confirm that for me? If so, is it dangerous as is, or should I not be concerned? Thanks!

 

[Doble Troble]

Looks to be attributable to reaming the new chamber.

 

The reamer you used is a few thous slimmer than the previous chamber. This shows in both the neck (about 1/10 above the top of the shoulder) and below the shoulder into about 1/10" into the body.

 

You've had an unfortunate combination of a big chamber and a little reamer. I've seen this with a few of the reamers that I've made to Clymer specs when reaming a military chamber. A few thousandths of variance can really show up on fired brass.

 

All of the tools we use are plus and minus. Reamers get more minus each time we use them.

 

Of course this isn't an ideal situation and you should be careful about it - but just the fact that you noticed is clear evidence that you're more careful than most - which will help keep you safe in future projects.

 

For now, if you're going to want to run a lot of milsurp through it I'd consider taking it back further so that the neck and shoulder aren't involved. Reaming further will eventually clean-up the old chamber.

 

You're not showing any signs of separation around the head, which is where I've seen brass let go (but I haven't seen that much brass let go either).

 

If you want to keep it as is, my opinion is that it may be safely done, but caution is required. I would only handload for it. I'd consider the first loads as fire-forming loads and would keep them under book max. After the cases are formed I'd neck size only and work up cautiously. What I'm saying is that if it was my rifle I'd treat is as a wildcat - which is really little inconvience for the hand loader.

 

If it was mine the barrel would go back into the lathe and the chamber would be reamed another 1/10. If that didn't work, I'd do it again. If you've got sights on it I'd go one thread at a time.

 

Look at all the "extra" fun that you're getting to have at no extra expense (this is why sporterizing is so addictive - there's always at least one more thing you can do to make it "better").

[AlaFan92]

Thanks, DT. I think I figured it out on my own last night laying in bed that the reamer must have been undersized -- that is the only logical reason I could come up with for the markings on the brass.

 

I'm up in the air about whether or not to ream deeper. I think the chamber is probably ok as is, and I can always neck size as you suggested (the rounds shown above were reloads). However, I would prefer to have a "clean" chamber that leaves no marks on the brass. I just don't know how much deeper I need to ream to get rid of the mark. Unfortunately, the reamer is due back on Friday (its a renter) so even if I ream it deeper I probably won't have the opportunity to shoot the rifle again before the reamer is due to be returned. I guess I could always just keep it a little longer and pay the another rental fee.

 

By the way, can you explain how you make your own reamers or direct me to a site where it is explained? I would like to learn how to do it myself.

 

Thanks,

 

AlabamaExile

[Doble Troble]

AE,

 

Here's a link to my reamer making method. I've made a couple of minor improvements, and should probably update the website. The most important of which is that I've figured-out how to relieve the flutes with my belt sander. You want to get the lands much thinner than what it shown on the website.

 

You might consider contacting the outfit that you rented the reamer from about this problem and have them send you another reamer to try. It seems like you've gotten an old one - which will probably serve well for finishing a roughed in chamber, but is too worn for taking back an existing chamber.

 

Another option is to buy a reamer for your next project now, donate it to the reamer Co-Op, and check-out the 8 mm reamer from the co-op. I donated that one and so I know that it only saw one chamber taken back just like you're doing now - and it worked great. See the Tool Exchange forum for more info. It's a very well run operation, and if you're going to do a few more rifles will be well worth your investment. It seems to be a much better deal than the renting route.

[AlaFan92]

That's a great site you made. I've bookmarked it for future reference. Unfortunately, I don't yet have a mill so I don't know that I could make a reamer at this time. I plan on making a milling attachment for my mini-lathe (like the one shown on Varmint Al's website) but I don't know that it would have enough travel to mill out the flutes for a reamer. I'll probably build one anyway since I keep coming up with projects that require basic milling capability.

 

I probably should have just gone ahead and bought a reamer for the co-op instead of renting one, but I had too many other things I wanted to buy to finish my rifle. My plan for my next project is to build a 6mm Remington for my son, so maybe I'll buy a 6mm reamer and contribute it to the group (assuming that caliber is needed -- I haven't checked). I think a 6mm should be a great round for the Mauser action since it was developed off the 7mm Mauser round, IIRC. Plus, there is some nostalgic value since my first rifle was a Remington 788 in 6mm.

 

Thanks again for all your help.