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To all, Just finished fitting and chambering a Lilja chrome-moly barrel last night in .257". I chambered the barrel to the 257 STW. Everything went great but when I finished and cleaned the bore out I noticed that on the tailing edge of each rifling where the reamer cut the leade, there was a burr on each of the rifling. I am relatively new to building rifles but I have not seen this up till now and was wondering if some of you more experienced smiths have seen this and how can you get rid of those small burrs? I am using a relatively new JGS reamer with a floating pilot. The reamer has cut five chambers and still seems very sharp but I was wondering if it could be getting dull. I test fired the rifle and noticed that most of the burrs were removed just by firing. Will following rounds fired clean up the rest of these burrs or will I need to do something to remove them myself? Thanks for your information! Good Shooting!!! 50 | ||
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50, It is normal to have at least some tooling marks in the leade. That is the direction of the cut. What you are now doing is "breaking in" the barrel. Since you are using a custom barrel, the only breakin is the leade. Shoot it once, and clean the barrel of all copper fouling by using Sweets or some other ammonia cleaner until there is no more blue patches. Then lightly oil the bore and shoot again. Depending on how bad the throat is, it may take 10 shots, maybe 5, maybe more. You did nothing wrong. Next time, try a faster rpm while reaming. I use a barrel flush system, and chamber at 200rpm's until the last .050", then I kick it to 300rpm's, all in an effort to make as smooth a leade as possible. Some carefully use polishing paper and smooth the leade after chambering. Others just shoot. By the way, I caught a lot of flack about lightly oiling the bore before firing while breaking in a barrel on this forum. Clearly from the uninformed and those who believe everything that is printed in a reloading book. I suggest you go to PacNor's website and read their breakin procedure. There you will find they recommend oiling the bore while breaking in. | |||
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WayneShaw, Thanks for the reply and information on your breaking process. It makes total sense to me as a machinist to use oil in the barrel. We use oil whenever cutting metal to get a good finish. I did have one question for you though, are you using high speed steel reamers or carbide. From what I have heard, which is not from a large pool of fellow smiths, is that all chambering should be done at 80 RPM or so. Am I going way to slow at 80 rpm? I played around with the rpm from 42 up to 150 rpm and it all seemed about the same but did not get anywhere near 300 rpm. Will have to try it if its ok to do it with HSS reamers. Again, thanks for the response. 50 | |||
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50, I use reamers from Pacific, which is HSS, but m47 I think. Kinda like cobalt. I used to chamber at about 60rpm's when I was using regular cutting oil. If you clean often while reaming, it does fine. I bought the flush adapter from GreTan and it's great. Constant flow of fluid, clears chips, etc. I chamber mostly stainless barrels, and haven't had a problem at these rpm's. CM may act differently. Perhaps a call to JGS or Pacific would shed some light on the speeds they recommend. My reamers don't seem to suffer from my way of doing things. I've never had to have one resharpened. | |||
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