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BobL
13th Mar 2021, 09:16 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.

China
13th Mar 2021, 10:57 PM
Has he fired any yet, would be interested to hear the out come, while it is not a common practice it is not uncommon, Lee make dies for their single stage press.
Main problem I have heard of is "Spring back", on release from the die the jacket can spring back and separate from the lead core leaving it loose inside the jacket.

BobL
14th Mar 2021, 12:30 AM
Has he fired any yet, would be interested to hear the out come, while it is not a common practice it is not uncommon, Lee make dies for their single stage press..
Yeah he showed me pics of one of these on his phone.


Main problem I have heard of is "Spring back", on release from the die the jacket can spring back and separate from the lead core leaving it loose inside the jacket.
Yep he told me about this - haven't seen any evidence of this so far from the half dozen we put through teh working die.

A J in WA
16th Mar 2021, 03:58 PM
RCBS make a 0.310" lead bullt swaging die. It might work - for a few. Roy Alexander (himself) and Sons in Maylands sold them. I have one.

Often it is easier to "bump up" a smaller projectile, but the dies take ages to polish, and you need a hydraulic swaging press. See Corbin Presses in the USA.

303 British projeciles would be worth investigating even though they are slightly greater diameter, they will swage when fired, but depending on the rifle chamber the neck may need to be thinned - to prevent excessive pressures. Prroceed with caution!

BobL
16th Mar 2021, 06:48 PM
Thanks Al, I don't think I want to into the bump up game.

Nephew contacted me last night - it sounds like he has scratched the die after resizing about a dozen heads - plunger must have been going through at a slight angle and scarred the sides of the soft die.

Now he wants me to make a die and punch out of hardenable steel but I've told him the steel alone will cost $50 and for that he can buy a proper 0.310 die setup from the US. I wish he had done that in the first placed - would have save me half a day.

A J in WA
16th Mar 2021, 08:42 PM
My friend who made the "Tough" drillpress badges also has the technology (that he made himself) to make 0.3120" projectiles. If you fail in your endeavours he may be willing to share his knowledge with you. I can only ask.

BobL
16th Mar 2021, 09:20 PM
I might do that but currently I'm hop my nephew will just buy one. I don't really need more projects.

Karl Robbers
17th Mar 2021, 03:39 PM
As nobody else has asked yet, what caliber/cartridge is he loading for?

China
17th Mar 2021, 08:28 PM
At a guess 32 cal

Karl Robbers
18th Mar 2021, 04:04 PM
At a guess 32 cal
That's definitely a possibility, although the diameters match 7.62X39mm as well as the good old .303 British, hence my curiosity.

eskimo
24th Mar 2021, 02:06 PM
did it shoot okay with .312's" with minimal or acceptable fouling, or was there any problems associated with the .312's in any other way...if not why did he want to change it?.

Might be best to make the projectile smaller and then swage/re-size, to increase its diameter?

BobL
24th Mar 2021, 05:14 PM
did it shoot okay with .312's" with minimal or acceptable fouling, or was there any problems associated with the .312's in any other way...if not why did he want to change it?.

Might be best to make the projectile smaller and then swage/re-size, to increase its diameter?

I don't know if they have worked or not. He's currently besotted with an original (OTT $$ wise) telescopic sight he's bought for one of his rifles and is getting a mount made for it. He's has the mount itself made by a chap using an EDM setup and nephew is polishing the mount and organising for a gunsmith the drill and tap the M5 0.5 screw holes in the barrel sides - don't worry it's a thickened part of the barrel and designed to take this mount.. He wants that particular screw size for authenticity purposes. I'm slated to blue the mount a make these screws because they have a short treadless shank and has not been able to find them.

BobL
4th May 2021, 01:09 PM
I finally got around to make the M5 0.5 screws for my Nephews Telescopic sight.

Following on from Anorak Bob's suggestion I purchased 10, M5 0.8 hex head bolts (26c each) with a long enough clean shank so could cut off the 0.8 threaded section, and then thread all bar 3mm of the remaining shank with a 0.5 die. (from these 10 we needed 6 good ones)

Then holding the 0.5 threaded portion in a threaded slug in the lathe, turned the hex bolt head to round, and then shaped it to pan head shape using a file.

Then cut the slot in the head with a 0.8mm slitting saw in the mill.

After we'd made 4 of the screws, fussy nephew decided these screws were too loose so we adjusted the die, luck we still had 6 "good" screws left although he was still not 100% happy.

Then during the slot cutting of the 2nd "good" screw head the slitting saw went blunt and work hardened the end of teh screw head! In desperation I did the remaining slots with a hacksaw. curiously Nephew was not that fussed by this - he was mostly concerned the screws would be too loose.

This morning I remembered that the thread hole in the slug was drilled by me with a 0.1mm oversized bit. I did this because I was worried about breaking the M5 0.5 tap.

I also found out the gunsmith who was going to drill and tap the rifle body and fit the sight was going to use Loctite!!

The two short screws are close to the final size
391908

Horaldic
10th May 2021, 01:39 AM
I also found out the gunsmith who was going to drill and tap the rifle body and fit the sight was going to use Loctite!!



That’s not uncommon in my experience. I’ve taken a number of factory mounts off rifles to replace them and a decent proportion of the screws holding them in place have had some form of thread locking compound applied to them.

Just last month I took some weaver mounts attached using countersunk Allen screws off a rifle to replace them with a picatinny rail and they had a small amount of thread locker applied.

BobL
10th May 2021, 08:22 AM
The screws have arrived at the gunsmiths and the word is that he is more than happy with the screws. And yes he is going use Loctite.