RCBS regular seating die and Cowboy die

[Broomhandle]

What is the difference in these dies, besides price ?

[Pettifogger]

Supposedly the expander is sized for cast bullets.  I have both the Cowboy and the standard RCBS dies and can't tell any difference.  The expanders measure the same.

[Litl Red]

What is the difference in these dies, besides price ?

Are you asking about just the seating dies?   And what caliber?   There are about 20 sets of RCBS for different cartridges.

I've gotten sets for 40-65, 38/357 and 32 but only measured a couple of things.   Such as the OD on resized cases for the two pistol cartridges.  Both were larger diameter after sizing and same after expanding.   In other words, the brass is squeezed down less from the cowboy sizing dies, and stays wider open through the expanding. 

Seating dies are adjusted to give more or less crimp and don't really have to be different for cast versus jacketed.   Also, since a lot of cowboys use auto presses, and they are often setup to expand using the mfg's powder station, the die set's expanders aren't always used.  

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[Litl Red]

Since switching to the Cowboy dies for my 32s, testing has shown a minor (but statistically significant) improvement in accuracy with my Ruger and a better improvement with my Dan Wesson.    What is actually more valuable is the number of split cases has dropped greatly.   That not only means the brass is being worked less, but the dies aren't trashing it little by little. 

When it comes to measuring the dies, measuring the OD of the brass being reloaded is how I usually find out how they're working for me.   I start with the clean fired cases and check each step from there.   About a year ago it dawned on me that the .313 sized cast bullets were probably being resized by the brass that wasn't being sized to suit by my dies. 

It turned out I discovered the sizer was too small, the expanders (in both the Lee and Dillon powder-thru expanders) were too small, and the Lee factory crimp in the last station on my Dillon was best replaced by the simpler (and more adjustable) single die.    (either seater/crimper die works, from the regular or the Cowboy die sets)

After a general swap out of dies, that Dan Wesson now is the most accurate pistol I've ever shot.   

It baffles me why there aren't any specialty reloading dies available from an industry that to a man recommends we size our cast bullets to match our barrels, yet seldom offer anything other than one size of dies.

[Litl Red]

Had a need for some jacketed 32s, so decided to see how they fit in the brass that was being sized for cast.

Loose.   

Roll crimp into the cannelure holds 'em however.  Velocity spread is not very good, but not too bad.   

This is probably why so few die mfgs make dies for lead diameters.

[rickk]

I am at work where I don't have access to the numbers, but the Cowboy die expander plug  (which is unmarked for diameter) is about .001 bigger than the biggest expander plug available from RCBS.    If you get the Cowboy dies and the bullet seems loose, you can get tighter plugs in I believe two different diameters from RCBS for a few bucks each.   

[Litl Red]

I am at work where I don't have access to the numbers, but the Cowboy die expander plug  (which is unmarked for diameter) is about .001 bigger than the biggest expander plug available from RCBS.    If you get the Cowboy dies and the bullet seems loose, you can get tighter plugs in I believe two different diameters from RCBS for a few bucks each.   

Those numbers really would be appreciated. 

My RCBS Cowboy dies for the 32H&R came with two expander plugs.   Both of them are marked 314 and both of them measure .313".   One has a longer plug before the flare than the other otherwise they appear to be identical.   I was able to find some RCBS expander plugs ($10.50 each) in a couple of sizes, but they're an entirely different configuration than the two that came with my dies.  They were made to use in something other than CB die.  There would be no way to use them in the CB die.   Those two plugs in my die set are screw in with knurled finger knobs.  The $10.50 ones look to be drop ins with no threads and not made for the CB die.   

The guide that comes with the CB dies makes no mention of optional plugs only one part is shown with only one part number.   RCBS' website has hidden any info about the plugs near as I can tell.    So your parts numbers and source are really important.   

[Litl Red]

Anybody know how to get different size expander plugs for the RCBS Cowboy Dies?

[rickk]

http://www.midwayusa.com/product/284929/rcbs-cowboy-expander-assembly-45-s-and-w-schofield-45-colt-long-colt-454-diameter

http://www.midwayusa.com/product/285678/rcbs-cowboy-expander-assembly-45-s-and-w-schofield-45-colt-long-colt-452-diameter

I will try to measure the expanders I have some time this weekend... fighting off a bad cold right now so my daily routine atm is get up, go to work, come home, go to bed.

The expander that came with the cowboy set is not marked with a diameter. The other two that I got (452, 454, are marked). The one that came with the die set seems bigger than 454.


RCBS's web site used to have more info about the expanders but it seems to have disappeared in the last couple of years.

[Litl Red]

Thanks

http://www.midwayusa.com/find?userSearchQuery=rcbs+cowboy+expander+assembly

The sets Midway list appear to be an odd assortment of plugs for some of the Cowboy die sets.   The two listed for the 32S&W and 32L cartridges don't have enough info to tell if they match the two that came in my set.  My set is listed as being for the 32Long/32Mag.      The two I got are both marked 314 and measure .313", the only difference being the length of the plug's .313" section.

Midway's list only show different diameters for two cartridges and they're calibers that have different barrel sizes floating around.     

[rickk]

I believe the RCBS expander plugs come in two styles... one with threads and one without threads.

 I think the one without threads is intended for the bottleneck cartridge rifle type dies.

[rickk]

I took the time to measure the expander plug that came with the cowboy die set.  Unlike the .452 and .454 plugs, it is simply marked  ".45".

It measures .457

As far as I know, they don't sell this particular expander separately... maybe part of the whole marketing strategy... if you want one this big, you need to buy the entire die set.

Anyway, I have all three sizes of expanders and it is the .457 one that works for me. I am using "big lube" bullets sized to .457.  I am certain that if you run a .457 expander plug thru a brass case, the brass springs back a bit so there is still a fair amount of neck tension. I do crimp as well of course (Lee "factory crimp" die).  I run these rounds thru both single action revolvers and also an HRA "Big Boy" and have no problems with the bullets staying in place.

Rick