38-55 Seating Die Problem

[DAVIDMAGNUM]

I am loading Starline short brass and .381 bullets. Using the RCBS Cowboy seating die I am experiencing a problem. The die is taking the flare out of the case. This is causing the case mouth to scrape off some lead just as, or before seating is completed. I have adjusted the die up as high as possible, to the point of the seating stem being bottomed out. With the die up so high I know that it is no where near crimping with the bullet seated to the crimp groove.
So I guess that I have a couple of questions.
Is anyone using a seating die with .381 or larger 38-55 bullets and not having this problem ?
As this die is (hopefully) hardened steel what are the chances that it could be opened up a few thousandths . I lapped open a Lee steel 44WCF sizing die with very good results. The RCBS die besides being more expensive to replace if I destroy it , is most likely harder steel ?

Appreciate Your input.
David

[skeettx]

Have you tried a 375 H&H seating die?

Might be able to be opened up, but some are WAY HARD.

[pworley1]

I use a 375 winchester die.

[cwtebay]

That is an odd problem with those dies. I believe that the expander button is a bit larger with the Cowboy dies to account for using lead or powder coated lead without shaving - but maybe not as much as you are asking for.
Curious - is the 375 Win die set larger in diameter than the 38-55?
I have opened up a few dies, and as noted by others - that steel is harder to remove than a bad renter in January. Perhaps running your problem by RCBS may help?

Sent from my Pixel 5 using Tapatalk

[country gent]

My rcbs cowboy dies show a case harden colors meaning the dies surface is harder than hens teeth, Im thinking it is probably a chemical hardening so .010 or less deep.

What size is the expander stem of your die. A slightly larger expander may help. A 381 dia bullet and .379-.380 stem may help.

The other thing to check is the bullets fit in the alignment portion of the seater die. The die may be shaving the lead inside if the bullet dosnt fit in the die correctly

[garandsrus]

I have used .381 bullets with the RCBS Cowboy dies and not had the problem you describe. If you run a case through the seating die without a bullet, does the case flair get removed? Is there any resistance on the case? There shouldn’t be.

If you flair the case mouth too much, the seating die could remove some of the flair based on the die diameter but shouldn’t remove all of it before hitting the crimp portion of the die.

I flair cases to where the bullet sits on the case easily but not more.

[DAVIDMAGNUM]

I am using the .379 expander, this is with once fired brass that is unsized. The brass has good bullet tension without sizing. The .379 plug more or less centers the case as it is flared.

The RCBS seater die is most definitely acting like a taper crimp die. I flared a case and can set a bullet in the mouth with more that half of the bottom driving band in the case. I ran the case without a bullet into the die. The case mouth makes contact with the seater die less than 1/4 of the way in. It feels , sounds and acts just like a taper crimp die I use for 45-70 black powder loads. Any how, after running the empty flared case into the die the flare is gone. I can not begin to set the bullet base into the case mouth.

As far as trying a 375 Winchester seater? I won't go that route. The 375 Winchester is designed for .376 jacketed bullets. The RCBS Cowboy die designed for cast bullets is too tight. Chances are the 375 is even tighter.

I will email RCBS next week and see what they say ( or don't say).

[Mk42gunner]

I will email RCBS next week and see what they say ( or don't say).

This sounds like the best option. You may have a slightly undersized seating die, it can happen even with RCBS. Although I do believe they will make it right for you.

I haven't had any problems using my set of RCBS Cowboy dies in .38-55, but I am only loading .379" diameter boolits.

Robert

[AZ Pete]

have you chamfered the case mouth?

[DAVIDMAGNUM]

Yes, the case mouths are evenly chamfered and deburred. All cases have been trimmed and uniformed with the RCBS Trim Pro Three Way Cutter. The seating die is effectively taper crimping the cases.

[garandsrus]

I think your flair is too big, but the die also seems to be undersized.

[Lefty223]

If you can resolve the die diameter issue, you can always crimp as a separate step using the Lee factory crimp die (FCD).

For my rifles and pistols using cast lead, I now always crimp separately, using the FCD or a taper crimp on my 44 Mag loads (as brass lasts longer … ).

[warren5421]

I load for both lever and single shot .38-55. It sounds like you are using a seating/crimping die body. Back the die body out till it is not takiing the flare out of the case. I bought a 4 die set that was doing the something. The seating die had the wrong body from the factory. Hope this helps.

[garandsrus]

I dropped a 38-55 fired, not sized, not flaired, piece of Starline (long) brass into my Cowboy seating die and the brass dropped to the rim so the die wall didn’t touch it. You might try the same thing.

[Tar Heel]

Look on the die ring near the top end and see if it says "38-55" or something else. They may have put an incorrect die body in there.

[DAVIDMAGNUM]

Okay guys, again it is an RCBS seat and crimp die. The die is backed out so far that the seating stem is screwed in all the way/bottomed out. The case is not reaching the crimp ring/step. The flared mouth is contacting the inside of the die and is being taper crimped. I experimented with a flared empty case. The flare is being gradually taken out as the case goes into the die.

[Kraschenbirn]

I don't own/shoot a .38-55 levergun but I do load the caliber for a repro Highwall. My boolits are 305 gr. RNFPs from an old NEI single-cavity mold, pan-lubed and loaded 'as cast' (.3805-.381). Essentially, I 'neck-size' my Starline brass using a .375 Win sizer die, swaging down approx. 3/4" of the case and, then, expanding to .380 with an NOE neck expander set to flare the casemouth just a bit. After that, I seat with an RCBS (standard, not COWBOY) seating die...set shallow so as not to engage the crimp ring...and remove any remaining flare from the case mouth with a Lee FCD. My boolits are fairly soft...like 10-12 Bhn...and I've never had any lead shaving during seating which, as other posters have suggested, causes me to suspect your seating/crimp die. I've always had good response from RCBS Customer Service so shoot them a resonably detailed description of the problem (including your loading procedure) and see what they have to say. BTW, it might be possible to open up your seating die by some judicious lapping but, for me, that would be a last resort. (Don't ask how I know...)

Bill

[DAVIDMAGNUM]

......... BTW, it might be possible to open up your seating die by some judicious lapping but, for me, that would be a last resort. (Don't ask how I know...)

Bill

If I go that route I might pay a machinist to do it. Let me see what RCBS has to say first. A few years ago I lapped a Lee steel sizing die for my 44-40 rifle. I figured if it didn't work I was not out a lot of money . It worked very well and was fairly easy. I took three fired cases , drilled out the primer pockets and installed hardened screws from the inside. The screws were long enough to secure with a nut and still have plenty for my drill to grab. I filled all three cases with hard cast alloy. I used (1500 grit?) lapping compound and slowly lapped the Lee sizing die. I repeatedly cleaned and checked the die. It only took two of the three laps I made. I now have a custom sizing die for my Uberti 44-40. The brass lasts longer and the ammo is more accurate.
Somehow I think trying this or something like it with the RCBS die would be very different. Not putting down Lee dies, and this is just a guess. But I think that the RCBS die is made of a harder steel and/or has been surface hardened.

[Walks]

Don't do anything yet.
Talk to RCBS 1st, Call on Thursday. Be prepared to wait. Have dies, brass and bullets on hand. Also micrometer and calipers.