m1903a1 tryout results

[ssgross]

reamer came in the mail today...that was fast. I didn't get an email that said it shipped, figured I was waiting on one to come in.
The T-Handle had 2 set screws on the bottom. One of them was longer than the other, and bumped the side of the action...no good. The fit in the socket of the handle was tight enough I thought it would be OK with just the one set screw.
This is my first time finishing the chamber on a barrel, so hopefully this helps other newbs get up the courage to do it.
1) I polished the chamber with a bore hone, and then fine emery paper in a slotted dowel, first to see if that would work, but knowing if it didn't I'd polish smooth any small pits or raised area from former corrosion. Didn't work, so I ordered reamer rental.
2) I thoroughly cleaned the chamber. Then, I used tap-magic oil cause that's what I had - liberally coated the reamer and inserted carefully, rotating clockwise as I did.
3) I gave it about 5 full turns without pushing it in - just the weight of the tool. I could feel it "grab" on the chatter marks...likely on the shoulder as you can see from my initial pics in this thread. Removed, flushed the chamber with clp (only cause that's what I had in a can with a straw), followed by air from my compressor. Checked with the go gauge, no progress.
4) clean the reamer, re-oil, and repeat. this time applying pressure...basically just hanging my hand on the t-handle. I could feel it grabbing, first it was jumpy as it removed the chatter, but by the 3rd turn it was smooth. Rotate clockwise while removing, clean out and check. No visible progress (bolt was in the same place), but there was a bit of grey dust in the flutes around the shoulder.
5) Repeat. 3 turns, same pressure. this time I could tell it was cutting smoothly the whole time. clean out and check progress.
6) OH NO!!!! the bolt closes easily!!!! Panic. Panic. Did I go too far? how could it be? Plenty more powder on the reamer flutes...only at the shoulder though.
7) Quick...grab the no-go gauge. Whew!!! it doesn't close...not even close!. Check with a live round (firing mechanism removed...only the bolt sleeve) from my dies. perfect.

My phone died just as I was going to take pics. I'll take final pics with my bore cam too...I owe you all pics of the stock after final shaping...raw linseed oil been doing its thing for over a week now.

Conclusion...I think I got very lucky. After the perceptible change from chatter to smooth cutting, I should have gone one turn at a time. I think the result would have been the same (total number of turns required), but my momentary heart ache would have been avoided! I did learn to turn the reamer a few more turns with no pressure before backing it out (still turning while pulling out). This helps to make sure there are no burrs.

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[browningautorifle]

I think I got very lucky.

Maybe, but that's how you start with reamers if you have no one there to instruct you. You move slow and careful and the end result is the same. I had an M1 rifle come to me that had a perfect barrel, except someone had thought it too tight and overdone it a couple turns. New brass showed a separation line...no issue with military ammo and not reloading but that's not here in Canada.

I did learn to turn the reamer a few more turns with no pressure before backing it out (still turning while pulling out). This helps to make sure there are no burrs.

That also brings out the bits. You could have used brake cleaner for the cleaner, it has pressure and a long tube to reach inside. Go muzzle down and it blows everything out and leaves it dry for testing. Next time... Anyway, well done. By the way, it might still want a touch of polishing.

[ssgross]

By the way, it might still want a touch of polishing.

I did indeed polish it again. Very happy with the results.
I also double checked the the max CBTO again with my Hornady gauge. It is about 6 thous. less free bore now than there was. Assuming that I didn't cut the throat at all, (I didn't notice any debris on that part of the reamer), this must have been how much more I pushed the shoulder in. I was tempted to put steel blue layout fluid in there to take pics, but decided against the high likelihood of making a big sloppy mess of it.