Lubesizer bore

M

Mainiac

Well-Known Member
Is it normal for a lyman/rcbs lubedie,,to be bored on a taper?
Ive just noticed that my .357 sizes .3583 on top half of wadcutter,and .3572 on bottom.
If this is normal,,then what harm is it doing?
Only reason i caught it,was because i was measuring mod 14 throats,,which are .3575,,and couldnt under stand why a .357 wouldnt slip threw,without pounding.
Lightbulb moment,it was!
I run it way down,and didnt help,btw
 
M

Mainiac

Well-Known Member
Brad said:
Bet they get straight as bullets go in deeper.
need some taper to prevent shaving lead on sizing.
Click to expand...
I rum em way down in,,didnt really change the taper,at all.
I think im gonna pay more attention,in this area!!
 
B

beagle

Active Member
I've never noticed that on RCBS dies. Might make them size easier if that's the case. They would produce a lightly "nose large" shape. Might make seating easier. Would undoubtedly "bump up" the base on firing and I doubt if you would know the difference. I do know that the ones we made on the Sunnen grinder are straight and they work mighty well. Now, that's home made, untreated dies.
And of course there are the Eagan tapered dies made for sizing the nose, front driving band. These will give you a taper as they're suppose to.
If these aren't dies somebody has modified, they should be straight./beagle
 
P

Petrol & Powder

Well-Known Member
I think Ian hit the nail on the head.

There’s a little bit of taper/radius at the mouth of the sizing die to get the bullet started. But once you get the bullet down in the bore of the die, the walls of the sizer bore must be parallel for the stem to fit and work.

Measuring sized bullets might not be the best method either. There could be some inconsistent spring back of that sized bullet.

Also, I set the depth that the bullet is pushed into the sizing die as deep as I can without forcing bullet lube above the top driving band. This is done to ensure the top driving band is pushed down beyond the initial taper at the top of the sizing die. (making certain the top driving band gets sized appropriately)
 
JonB

JonB

Halcyon member
Bubba here!
I have a drawer full of Lyman H&I dies. Years back, I had Lathesmith open up three of them, then I got courageous and have opened up 2 or 3 myself, using Redneck techniques...but never more than 0.001 ...Imagining my technique, I can't imagine them being tapered as much as Mainac has reported in the OP. But still, I believe I've only measured the base of a sized bullet...I might have to checkout the size of the driving bands?
I'm just thinking out loud here.
 
M

Mainiac

Well-Known Member
Ive so far found a 358 sizer i have,,.3582,,,consistant,so i assume that this 357 was honed tapered.
 
You must log in or register to reply here.