Roll sized brass

[Johnch]

I was offered some rifle and pistol brass by a guy on another forum tonight

He stated that some of the rifle brass was roll sized
But not deprimed or trimed

As I have till Monday to tell him what I want if any
I was trying to figure out the roll sizing

Is it bad or good for brass ?
Why would it be done ?

As it is 308 and 223 Mil brass
I was thinking ....maybe fired in a full auto

John

[Down South]

IMHO, Roll sizing is the best way to size brass. It sizes the whole case where conventional dies only size most of the case.

[duckndawg]

ok I will bite please explain

[danski26]

I've not seen it done with bottle neck brass but comercial reloaders use roll sizing for straight wall pistol brass. It is a machine that rolls the case between two pieces of steel instead of a conventional die. It does do a better job "i am told" and much faster. Picture two rings of steel, the inner one rotating or "rolling" the case around against the outer one until it is back within spec.

[TAWILDCATT]

its roll sized because a standard die wont size the case,to big a bulge.I cant answer for whether its good.roll sizing cant resize whole rifle cases.just the base.
I suppose a rifle case could be roll sized like using small base dies.:coffee:[smilie=1:

[garandsrus]

I have only seen roll sizing done for pistol brass, mostly 9mm. The process gets rid of the "Glock bulge" if there is one. I believe that you still need to conventionally resize the brass also.

John

[MtGun44]

As I understand it, it is used to resize all the way down to the rim, where a std sizing die
can't get that far down because of the shellholder. Ammo that has been run through large
chambers can be bulged so much that std dies have trouble bringing it back to new brass
size. The classic case (no pun intended) is the small base dies sometimes required for
tight chambers. A friend had a Garand rebarreled with a match barrel. He had to run all
his brass through a small base die to get it to chamber.

Bill

[evan price]

Roll sizing is also how large commercial processors like Scharch do it. Ever see a high-speed machine for making screws? There are two plates of steel that are adjusted so the gap between them at the output end is a smidge smaller than the desired OD of the brass (because of elasticity and "springback"). One plate is stationary. One plate moves back and forth across the stationary plate. There is a bit of taper so the input end of the two plates are a bit farther apart than the output. Raw brass goes into the roll sizer at the larger taper end. The brass is trapped between the two plates. The moving plate rolls the brass along the stationary plate until it rolls out the end and drops in a hopper- while the brass is rolling, it works its way down the plate's taper getting smaller until it falls out the end. No lube is required because there is no force involved except for the pressure between the two plates. The process is amazingly fast (we're talking, need a strobe light to see it working).

Imagine taking a wad of play-dough and rolling it on the table to make a snake. The pressure you put on the dough determines how skinny (and how long) the snake gets. Same thing with the brass.

This resizes the OD of the case to the proper diameter (all the way to the rim) however it does not resize the neck. Most bulk military machine-gun brass is sized this way.

[TAWILDCATT]

The machines I saw sized 40 cal and were three rollers with the case between them.:coffee: [smilie=1:

[arcticbreeze]

This might explain

http://www.wolfbullets.com/rollsize.htm

and

http://www.casepro100.com/index.html