for a tapered bullet design what is the most one would consider sizing down a bullet?

critter68 wrote on Jan 13^th, 2019 at 2:52pm:


      Hard to tell about sizing down a tapered bullet.   I have sized down some 40 cal "straight" bullets from .410 to .3995 for a muzzle loader, and fired, scope/bench, two consecutive 5-shot groups that could almost be covered with a quarter.
       If a feller went to size down tapered bullets, the big challenge would be keeping them straight.
       Why do you have to size them down?   One of my rifles shoots FIXED ammo VERY well with bullets that are almost 0.020" larger than groove diameter.

CHRIS
RGChristensen

I size down my .409" Baco money bullets to .408" using a Lee sizing die that pushes the bullet up through the die nose first, therefore you don;t need a special nose punch, works a treat.
Mike.

Frank, what does sizing nose first do to the base shape on bullets? And if you're sizing them down a fair amount does it have even more effect on the base shape with metal being pushed back past the base?
Seems to me it might have a detrimental affect on accuracy, but I've never sized nose first, so really just asking the question to get some input.

Vall,
The first reason that I size nose first, is that the punch face and the base of the bullet, can be parallel to each other, to push straight through. I use a 10 deg taper down to the size I want. It will also install GC's that way and crimps them square, even with .0005 to .001 of sizing difference. So long as the GC and the bullet, maintain contact, it will crimp the GC square and parallel.

I don't use lubrisizers. I use either my arbor press or a old Redding/Lachmiller, two post press that I converted to do my sizing. With it, I can partial size and push the bullet back out, with that press.

I don't need nose punches and I don't have to worry that the nose punch and die, are aligned. 

I NEVER size w/o pan lubing first. The lube being incompressable supports the bullet and keeps distortion at a minimum, while sizing.

For harder alloys like #2 and Lino, the nose won't be marked or distorted that way.

If I have to size down a lot, .004 or more, I make a die that has a parallel area, the as cast size, to hold the bullet true to the die, then I cut a 1 deg taper, to the size that I want the finished bullet to be. I did that with a 323471 bullet, .326 diameter, in #2 alloy, sizing it to .3215, with a .321 die. The GC was installed at the same time. Sizing in two steps, caused the bullet to be sized with the bands being on one axis and the bottom of the lube grooves on and other.

Frank

40-Rod I tend to agree when it comes to sizing and altering a nicely as cast match bullet just something I have always avoided having to do. Does it create any ill effects in accuracy honesty I cannot say. But being one who continually tries to eliminate all of the variables to increase it I felt it might it add one to decrease it and have just always shyed away.

I size my .323 diameter bullets with a .323 H&I die to take off any flashings plus lube the bullets using a luber-sizer.

Soft alloy bullets can have the nose punch push the noses out if you shave more than a .001 off due to the pressure you are pushing down on the bullet.

I believe if you are starting to shave .002 off you are starting to deform the noses.

I see Frank is using a much harder alloy when he was shaving off .004 with his custom dies.