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MWF FEED
13th Mar 2021, 09:40 PM
My nephew came around today and we spent the afternoon making a die to resize some 0.312" copper covered lead heads.

He's been rolling his own ammo for a few months and discovered that one of his rifle bores is slightly undersize and it was recommended to him by one of his gun club members to try reducing the the size to 0.311 or even 0.310".

My smallest boring bar is 8mm so that was not going to work so had to settle for drilling and reaming.

It only took 4 goes to get it working.

try 1) Using some 1" diam free machining steel, drilled a 7.9mm (nominally 0.311") hole using the lathe, but of course that came out slightly over size (0.313") so that was no good . I could of course regrind the bit - :oo:

try 2) Using a stub of 1" plain old black bar, drilled a 7.8mm (nominally 0.307" ) hole that came out to 0.310" (looking good) so we gave that a try with a press and basically mangled the bullet head ie mushrooming the back of the head in contact with the press. Had to grind the mushroom off s we could push the remained through.

Several things we looked at were
- entry point - slightly rounding and smoothing the entry way, didn't help much - mangled another bullet.
- the rough finish inside the hole, - it was after all just black bar. By the time I cleaned it up with a reamer it was closer to 0.312" so start again

try 3) Back to the FMS, 7.8 mm hole agin came out to 0.309", reamed to 0.310" - nice smooth hole, smooth entry way, a drop of machine oil, - Nuh - still mushrooming head. I tried reaming it out some more but the I accidentally went over size DANG!

Try 4) same as try 3 (0.310" sooth hole rounded entry) but this time I also used the die from try 2 as a former/feeder placing the bullet head inside that and placing all that on top of the the actual die to prevent mushrooming. Worked very well. A turned down 5/16" bolt acted as the plunger pushing the head from the former thru into the die.

Now this has to work at my nephew place where he has no press so we tried it with a small lumpy. I was surprised that it worked. It took us about 3 hours all up but nephew went away really chuffed. We didn't have time to make the 0.311" die.

I don't know how a long the FMS die will last. It's not like he's making heaps of these.


Read and reply to the full thread at metalworkorums.com.... (https://metalworkforums.com/showthread.php?t=206399&goto=newpost)