I think PTG has it cheaper than I've seen elsewhere, 15 maybe. Dave pointed me in the direction of dark cutting oil, which is a bit harder to find in CA these days. But I found a reference to Oatey on PM, that its the only one left that's still chlorinated. Got a couple pints at HD. 8 bucks? Seems to be a bit thin, but got the job done.
A D reamer should work well. Classic screw machine solution for deep bores. A friend pulled a liner out of an old barrel, and the thing looked like a snake inside. I bored it true on one end, and made a drill with a v groove from A2. Overall, it was a failure to straighten it out, but the finish was nice.
I was too poor to buy one:
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541-X from CMP. Threaded the receiver, put an 18 twist Lilja on it, Calfee chamber. Gutted the trigger and started over. I had access to wire EDM back then.
Shot a couple smallbore matches with it in a Ross Precision barrel bedded stock, and then it sat gathering dust for quite a few years. Then I got the idea to make a junior sized tube gun out of it. Cut the barrel back to 22" for balance and made a few small piles of aluminum chips. The only CNC work is the trigger guard/grip mount, and the buttplate and rocker. Dialed out all those slots in the forearm with an indexer, rough, finish, and chamfer.
Couple weeks ago, prone with sling and irons. Aquila SE (meh). 200 yards. I know it will do a lot better with good ammo, and a kid with good eyes and steady hands.
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