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1bluehorse
09-24-2012, 08:08 PM
Was over reading another thread about sizing bullets to, or over cylinder throat size. Good read and good ideas from all. My question (probably been covered many times but I haven't a clue where to look) takes the next (or maybe previous) step. Sizing the brass. I just measured the cylinders on two of my 45 colt revolvers and both measured .481 using minus pin gauges, whereas the .481 pin was a bit of a "loose" fit the .482 wouldn't start at all. So here's the question, with a .481 cylinder what do you all think the "optimum" size would be for the sizer die? I measured the ID of both an RCBS and Lee sizer. They were both .467 albeit the Lee was a "loose" .467 and the RCBS was "tight". Hopefully I have asked this question correctly..sometimes the distance between brain and fingers is enormous...

geargnasher
09-24-2012, 08:22 PM
Yeah, the .45 Colt often has such issues. If you stay in "standard" pressure range and segregate brass for each revolver, just size "neck" size the brass enough to hold the boolit. This means use a tapered, steel die and back it off so it only sizes the part of the case that will be holding the boolit, leave the rest of it untouched. Decap in a separate, universal decapping die or do it by hand with a decapping rod, shellholder, and brass hammer. Make sure your chambers are relatively close to each other in size first.

The other option is buy the RCBS "Cowboy" die set, the sizer die (steel, requires lubing cases) and the expander both are made for the bigger, lead boolits and don't size the brass as much. OR, you can take your RCBS die (assuming it's steel and not carbide) and hone it out until it only sizes the brass enough for about .002" tension on your preferred boolit size while only sizing the middle and base of the case enough to chamber easily, sort of a "custom fit" job that will pay off in spades with accuracy and saved wear/tear on the brass.

Gear

1bluehorse
09-24-2012, 09:41 PM
Thanks Gear, I have tried the "neck" sizing thing, didn't really care for it. Nothing negative really, just looking for a better "mousetrap". If my math isn't to faulty (?) and I'm thinking this correctly, check my numbers..ID of fired brass measures .453, OD is .479 (difference of .26 so brass is .13 thick?) bullets sized to .452 (checked)so for 2 to 3 thou neck tension (say .450) add .26 for an optimum brass sizing of .476???? thats still 5 thou under cylinder size. I have no clue to whether thats a lot or not..Wonder what Freedom and Linebaugh bore their cyls to?? Just something else to think about I guess..again, thanks for your input.

runfiverun
09-24-2012, 09:49 PM
so you have a 481 cylinder.
getting to 479- 480 loaded round size maximum is about right.
you have 467 sizing happening plus some spring back. 468-469 maybe.
then seating a boolit opening the case back up.
how much outer diameter does seating a boolit give you 472ish ??
leaving you 7-8 thousandths to fill??
you could partial length size or measure and go with the .005 case clearance.

runfiverun
09-24-2012, 09:49 PM
looks like you were typing while i was.

1bluehorse
09-24-2012, 11:18 PM
Well, a couple more probably meaningless measurements. Loaded rounds from my dies, at bullet .475, brass below bullet is .470...the reason I say it's meaningless is, the only way I can see where you would make any difference would be to have smaller cylinders to begin with. What would be the benefits to having tighter cylinders?? I have read where some are taking 44mag cyls and reaming them for just that reason..curious..

geargnasher
09-24-2012, 11:29 PM
The chambers ought to be about .476" or so and the dies ought to size to about .472" for lead boolits. I actually have a .45 Colt revolver with .477" chambers. The reasons are accuracy and case life, although the accuracy gain seen with the average revolver doesn't amount to much. It can make WORLDS of difference in a rifle, though.

Gear

runfiverun
09-24-2012, 11:53 PM
it kinda is meaningless unless you can do something about it, by changing the sizing die or the way you size the cases.
otherwise it is gonna be new/custom parts.