cowboy dies

[JimB..]

Jim. As I stated before, I measured the expanders of my cowboy and steel carbide, they measure the same diameter. I load .359 cast, sized with the Cowboy FL die and no bulge.



Guess the only way to know for sure is to pin gauge them and compare.

What max diameter can a cast be that won't bulge the case ?

I’ll get out there and measure a couple expanders today, but I can’t answer the question about bulging a case because I really don’t know exactly what it means. Can you post a pic or describe it in detail? Is it just a loaded round that won’t plunk because the diameter is too great at the case mouth?

[castmiester]

The bulge is from an oversized bullet. The whole length of the bullet bulges the case not to chamber.

[BK7saum]

It is incorrect to assume generally that carbide dies do not size pistol brass consistent with Sammi spec, the 9mm issue being the exception. Otherwise SAMMI calls for straight cases, and carbide dies deliver straight cases. Now they may be over or under sized, that’s a different issue. I also tend to doubt that steel sizing dies are tapered, that would make them out of spec (again 9mm excepted) but perhaps they wear such that they become slightly tapered in use.

I can neither confirm or refute the assertion that chambers are tapered. I wouldn’t be surprised either way, but that doesn’t affect the question of fired and sized brass being within spec or not. Many of us have brass that is dedicated to a specific gun, we prep that brass for that gun and happily ignore the SAMMI specification.

@castmiester asks “how to prevent bulging cases from being “seriously undersized.” I think he means how to prevent case mouths from being sized down more than is necessary to give him the bullet tension he desires. He doesn’t want a die that returns the case mouth to spec, he wants it left oversized. In the rifle world this can be handled by having one sizing die for the body of the case and another for the neck, but for pistol just hone the die to the size you want. You can probably do an acceptable job increasing the size of a steel sizing die, but I’d contract out for a carbide die.

Redding was selling dual carbide ring sizing dies for a while, one larger ring for the full case and one smaller that just sized the neck. Cool idea, but without the ability to order a specific size ring size I’m not sure it’s all that useful. I bought a few, but haven’t used them yet.

@castmeister, I have the RCBS cowboy dies in several calibers and I believe that they have the same size carbide ring as their standard dies. The expander is larger in the cowboy set, so the brass is sized down as usual and then expanded more than usual. That extra work reduces the life of the brass, so you might want to have the die honed to a larger size.

RCBS steel 45 colt dies definitely size the "neck" of the case smaller than the body, i.e. a very slight bottleneck case. I have not measured the body for taper, but am sure there is some taper to the die/body after sizing. Other steel dies, I am not sure about, but the 45 colt steel fl dies do not size a cylindrical "straight" case.

I think I have some steel 44 dies that are similar to my 45 colt dies as well.

[BK7saum]

BTW, The cases sized with RCBS steel dies fit the chambers of my Ruger blackhawk and Smith 45 colts like a glove, with no excessive clearance of the cartridge in the chamber.

[JimB..]

The bulge is from an oversized bullet. The whole length of the bullet bulges the case not to chamber.

So the sum of the diameter of the bullet plus the thickness of the brass exceeds the size of the chamber, this can’t be solved by any case sizing die. I think folks often (mis)use the Lee FCD to fix this, but of course that just swages down the bullet and reduces neck tension, but they do chamber.

I measured a couple expanders, stayed with RCBS to be consistent.
RCBS Carbide Die set, expander measures .3555 with a step up to .3602
RCBS Cowboy Die set expander measures .3566 with a step up to .3610
RCBS Cowboy expander purchased sep measures .3565 with a step up to .3610
Just for grins, Dillon Powder Funnel “D” measures .3547 and has no step.
Was going to measure a DAA powder funnel but saw that they sell the same one for both 38 and 9mm and decided not to bother.

RCBS 454 exp measures .4491 with a step up to .4535
Cowboy version measures .4523 with a step up to .4564

Small sample, but at least for mine the cowboy expanders are slightly larger.

I don’t have a pin gauge to check the sizes of the carbide rings.

My 147 and 158 gr loads in 9mm def make for wasp-waisted cartridges, but they chamber so I don’t worry about it.

[JimB..]

RCBS steel 45 colt dies definitely size the "neck" of the case smaller than the body, i.e. a very slight bottleneck case. I have not measured the body for taper, but am sure there is some taper to the die/body after sizing. Other steel dies, I am not sure about, but the 45 colt steel fl dies do not size a cylindrical "straight" case.

I think I have some steel 44 dies that are similar to my 45 colt dies as well.

I don’t doubt it, next time I see a set of steel dies in 45 or 44 I’ll buy them just to play with, but I doubt that they make better shooting ammo even if they might make better looking ammo.

[castmiester]

So the sum of the diameter of the bullet plus the thickness of the brass exceeds the size of the chamber, this can’t be solved by any case sizing die. I think folks often (mis)use the Lee FCD to fix this, but of course that just swages down the bullet and reduces neck tension, but they do chamber.

I measured a couple expanders, stayed with RCBS to be consistent.
RCBS Carbide Die set, expander measures .3555 with a step up to .3602
RCBS Cowboy Die set expander measures .3566 with a step up to .3610
RCBS Cowboy expander purchased sep measures .3565 with a step up to .3610
Just for grins, Dillon Powder Funnel “D” measures .3547 and has no step.
Was going to measure a DAA powder funnel but saw that they sell the same one for both 38 and 9mm and decided not to bother.

RCBS 454 exp measures .4491 with a step up to .4535
Cowboy version measures .4523 with a step up to .4564

Small sample, but at least for mine the cowboy expanders are slightly larger.

I don’t have a pin gauge to check the sizes of the carbide rings.

My 147 and 158 gr loads in 9mm def make for wasp-waisted cartridges, but they chamber so I don’t worry about it.

when you say "step up" you're talking about the taper to bell the case mouth ? Or are you using a Redding or Lyman with an actual stepped expander ?

Below the taper is the expander, which the diameters are the same on cowboy/carbide/steel expanders below the taper that bells.. The taper just puts a bell or expands enough to accept the bullet, so it doesn't expand the case to prevent a bulge the length of the bullet.

[JimB..]

when you say "step up" you're talking about the taper to bell the case mouth ? Or are you using a Redding or Lyman with an actual stepped expander ?

Below the taper is the expander, which the diameters are the same on cowboy/carbide/steel expanders below the taper that bells.. The taper just puts a bell or expands enough to accept the bullet, so it doesn't expand the case to prevent a bulge the length of the bullet.

Your RCBS expanders are apparently different than mine. On mine, starting with the expander (which is absolutely larger on the cowboy dies) then a short step that’s a little larger, and then the taper that flares the case mouth. The step doesn’t expand enough length to matter, but it makes a tiny ledge for the bullet to sit on when seating I suppose.

[Chill Wills]

There is an image in my VS "RIX" that shows the two diameter cylinder with the flair above it.

It is for the 45 rifle but handgun expanders work the same.
I'll post it here.

I had a question of brass spring back and how much the bullet may get squeezed down when using large bullet diameters and very small case necks.
Expanders and case necks: Using gauge pins I found almost no spring back on a sample of 44 special brass that was sized up from the RCBS Carbide die to 0.427" using a 0.427" expander.

Bullets getting reduced in diameter during seating: In an extreme example, bullets mic'ing 0.434" then seated in the 0.427" case, pulled and re-measured were reduced to 0.431 and 0.4315". So expect some reduction of bullet diameter with the greater squeeze the stock expander puts on cast bullets. BTW- the bullet hardness was 12 - 13 BHN.

[castmiester]

Chill Wills

Your expander looks like the better way to go. Gotta measure chamber diameter before ordering. What is max you make them over groove diameter for neck tension ? And I take it you make custom die bodies too or you make them to thread in existing die I have ?

[castmiester]

Your RCBS expanders are apparently different than mine. On mine, starting with the expander (which is absolutely larger on the cowboy dies) then a short step that’s a little larger, and then the taper that flares the case mouth. The step doesn’t expand enough length to matter, but it makes a tiny ledge for the bullet to sit on when seating I suppose.

I'm stumped. The insert has to be larger then. I have to have them pin gauged.

[Chill Wills]

Chill Wills

Your expander looks like the better way to go. Gotta measure chamber diameter before ordering. What is max you make them over groove diameter for neck tension ? And I take it you make custom die bodies too or you make them to thread in existing die I have ?

They can be made to fit your die body.
PM me. I will be back on tonight.

[JimB..]

There is an image in my VS "RIX" that shows the two diameter cylinder with the flair above it.

It is for the 45 rifle but handgun expanders work the same.
I'll post it here.

I had a question of brass spring back and how much the bullet may get squeezed down when using large bullet diameters and very small case necks.
Expanders and case necks: Using gauge pins I found almost no spring back on a sample of 44 special brass that was sized up from the RCBS Carbide die to 0.427" using a 0.427" expander.

Bullets getting reduced in diameter during seating: In an extreme example, bullets mic'ing 0.434" then seated in the 0.427" case, pulled and re-measured were reduced to 0.431 and 0.4315". So expect some reduction of bullet diameter with the greater squeeze the stock expander puts on cast bullets. BTW- the bullet hardness was 12 - 13 BHN.

I like, but how is this better than simply having a larger expander? If I were to take yours and chop off the front section would the only difference be that it’d take more work to expand it in a single step?

[Chill Wills]

I like, but how is this better than simply having a larger expander? If I were to take yours and chop off the front section would the only difference be that it’d take more work to expand it in a single step?

I am not sure I follow.
I drew an exaggerated quick and dirty draft of a sized case (L), which the mouth and bullet holding neck is too small for a bullet to enter.
Middle drawing, the case has been expanded with a two diameter expander.
The expander (R) is the part that enters the sized case.

The lower diameter cylinder ( D-2) needs to be long enough to expand the sized case to support the body of the seated bullet.

The upper diameter cylinder (D-1) needs only enter the case mouth enough to start the bullet straight and without shaving lead from the bullet.

The lower cylinder (D_2) expands the case to a diameter a few thousandths smaller than the bullet.
The upper cylinder (D-1) expands the mouth about 0.002" larger than the bullet to be seated. The flair, (trumpet bell) which is the part above the larger cylinder D-1 really is not needed nor desired.

[JimB..]

I am not sure I follow.
I drew an exaggerated quick and dirty draft of a sized case (L), which the mouth and bullet holding neck is too small for a bullet to enter.
Middle drawing, the case has been expanded with a two diameter expander.
The expander (R) is the part that enters the sized case.

The lower diameter cylinder ( D-2) needs to be long enough to expand the sized case to support the body of the seated bullet.

The upper diameter cylinder (D-1) needs only enter the case mouth enough to start the bullet straight and without shaving lead from the bullet.

The lower cylinder (D_2) expands the case to a diameter a few thousandths smaller than the bullet.
The upper cylinder (D-1) expands the mouth about 0.002" larger than the bullet to be seated. The flair, (trumpet bell) which is the part above the larger cylinder D-1 really is not needed nor desired.

Thanks, not sure why that didn’t click earlier, I have a couple stems like this for wadcutters, they produce zero tension at the case mouth and about .002 in the body. Have never thought about doing the same for larger/longer 9mm bullets. I’ll shoot you a PM, but do you make them in custom diameters and lengths?

[Chill Wills]

Yes, and there is more info in my VS section under RIX, but YES, any size and length needed. You call out the numbers and I can make it to screw into your die set expander body.

[castmiester]

Yes, and there is more info in my VS section under RIX, but YES, any size and length needed. You call out the numbers and I can make it to screw into your die set expander body.

Carbide ?

[Chill Wills]

Carbide????
Oh My!!!
$$$$

[castmiester]

Carbide????
Oh My!!!
$$$$

figured I'd ask, but ok, I'll use lube.

[JimB..]

figured I'd ask, but ok, I'll use lube.

We’re talking about the expander, not the die. No need for carbide, and if you dropped it you’d cry for a week. I sometimes get a case that’ll grab on the expander, usually if it’s been recently wet tumbled with pins and soap. Either dry tumbling, or using a wax with wet tumbling, will mostly eliminate the problem.