Chamber Reamers the Easy Way

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Forum: Your Projects Topic: Chamber reamers the easy way started by: Murphy Posted by Murphy on Dec. 28 2005,16:19 Here is a short write up of how I made the reamer for my buckmark project. I started out by finding the right dimensions, went to clymer and got the dimensions they use for their.22LR reamers. I found the middle values between the bbl and match reamer and used those. For material I used a M12 bolt which turned out good and was easy harden as long as it wasn't stainless (which I have also tried).

Then it was just a matter of turning it to the correct dimension and polishing the area that would have the cutting areas milled out so they where smooth. Before removing it form the lathe I tested that the pilot would fit in the barrel and kept going over it with emery paper till I had a nice tight fit. Then I set it up in the vice and using the dial indicator made sure it was perfectly level with the mill. and cut the chamber area down to it was exactly to the middle. With this set up in the vice I had to take very light cuts to avoid flex, the max I took was .01 in a pass.

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Then I milled flats in the other end so it could be turned or held by a wrench. After the milling was done I honed all the edges with a very fine stone. Here it is ready to be hardened.

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For hardening I put it in a small drill press, and heated it with a propane torch till it was glowing orangy red and turned non magnetic.

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Somehow it turns out purple on the camera. Then it was down in the can for cooling while still turning in the drill press to get an even cooling on it. I used coolant from the lathe to cool it in. A mixture of water and soluble cutting oil.

Next up was polising it and a new check that the pilot would go smooth in the barrel. Honing all the cutting edges with the stone again and temper it. Put the reamer back in the drill press and used the torch on it til I got a very light straw color, Had to turn down the lights to be able to see the changes. Let it cool and chamber.

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These reamers are quick and easy to make, they are not as durable as the regular ones but will last for a few barrels. Will soon make some larger ones as I have been thinking of a new project for about a year now and have a spare 50BMG barrel laying about and looking to make a short round for it. Which means I will have to make both chamber reamers and reamers to make forming and loading dies.

Posted by Murphy on Dec. 28 2005,16:22 Oups almost forgot the most important part, here is how it shot, this is a five shot group at 25 meters with the suppressed buckmark.

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Posted by nevadablue on Dec. 28 2005,21:54 Murphy, thanks!!! for that excellent writeup. Should save us some $$$

Posted by Mr Fudd on Dec. 28 2005,23:16 I'm going to try that! Posted by drake on Dec. 30 2005,11:18 You rock man! I'm going to try this on my next build as well... maybe I'll do some more wild-catting with an easy way of making chamber reamers... Posted by maarten221 on Dec. 30 2005,14:13 That is a really nice writeup! Thanks! I'll have to try it at some point. Can anyone say 5.56x25? muahahahaha in my dreams! I've got so many projects on the backburner it makes me cry! Posted by rodgervich on Dec. 31 2005,00:49 Nice write up Murphy! I've made a bunch of this type of reamer and they are easy to do. I never thought of using a bolt though! I always make from drill rod and quench in water, I skip the temper step. I experimented a lot with the temperature (color) to harden them, books all say "cherry red" but I have no idea what that is supposed to be. I had the best luck like you, orange red, then quench. I tried tempering to the lightest "straw" colors but ended up twisting the pilots off in the bore all the time (talk about a major pisser! quench and they work great. Nice job on the pistol too!

) I now just leave them full hard from the

Posted by MADJACK on Dec. 31 2005,00:58 Most excellent writup, and use of scrounged materials Posted by Fuzzbean on Jan. 05 2006,08:20 This looks like good info, especially for when the going gets rough.

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Posted by henryblowery on Jan. 05 2006,09:56 Nice write up! Does anybody have a source of diminsions for differant calibers? Gray Posted by Murphy on Jan. 05 2006,10:55 If you go to the clymer tools website they have listed the reamer dimensions for a lot of calibers, makes it very easy as it is just to follow the drawings. < Clymer > Posted by bsstan on April 14 2006,01:39 Please excuse me for not knowing, but is a M12 bolt a 12 mm bolt? Posted by Fuzzbean on April 14 2006,02:04

Quote (bsstan @ April 14 2006,01:39) Please excuse me for not knowing, but is a M12 bolt a 12 mm bolt? Metric threads are often expressed that way, like M6x1 etc. But metric bolts come in different grades just like inch bolts. They got some system with numbers stamped on the heads -- I don't know the details off hand. Posted by bsstan on April 14 2006,13:45 I just wanted to understand what type of bolt they were talking about. I thought they may be talking about grades. I didn't know you heat treat bolts hard enough to cut 4140 steel. Posted by hammermill on April 14 2006,14:21 for a quick treatise most bolts are rated by grade ie a grade 3 bolt is not as high a quality and stregenth as a grade 8 bolt that said most metals will get quite hard by being heated then quenched to soften you heat then allow the metal to cool slowly then reheat and quench to hardened again

Posted by bsstan on April 14 2006,14:45 I have been doing machine work for a long time, but I learn something new everyday. I enjoy learning things that save me time and money. I was going to spring for a stick of O-1 for a project. Now I will try the new trick of the day. Thanks Posted by J. Valentine on Sep. 10 2006,17:58 This address should get some bolt head marking info < http://shopswarf.orcon.net.nz/boltid.htm > Posted by Murphy on Jan. 04 2011,03:56 The pictures from my early projects have been missing for a while now, and I have finally gotten my act together and got the pictures back up. Posted by poor_boy_gunsmith on Jan. 04 2011,13:38 Definately go with the clymers or some other actual chamber dimesnions, I made a .22 reamer by measuring a cartridge and adding about .002 and ended up with a really tight chamber that wont accept some bullets. Powered by Ikonboard 3.1.2a Ikonboard © 2001 Jarvis Entertainment Group, Inc.

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