Old school RCBS dies

[Noah Mercy]

So, I'm loading for a friend's old Colt 1873 in 44 WCF (44-40). He scored a cherry RCBS three-die set that is probably 40 years old (pasteboard box, no part number) but no instructions were included. The problem is, I have never loaded with dies like these. The sizer die is straight-through- no decapping pin- and the expander die has the decapper. Brass I have run through the sizer (lubed with Imperial Sizing Die Wax) drops into the chambers fine, but the loaded rounds do not want to chamber fully, even with firm pressure. Bullets are moderately soft .427" 200 grain RNFP seated on top of 5.7 grains of Trail Boss. I ran a loaded round into the sizer die far enough to just feel contact, and then it dropped into the chambers. I ran my calipers over that cartridge fifteen ways to Sunday and couldn't find any dimension that was measurable different from the rounds that wouldn't go. I went ahead and "bumped" five of them in the sizer so they would chamber, and after firing, the cases required very little pressure on the ejector rod to pop from the chamber and fall out freely, and the cases were in great shape. So everything seemed to work just fine, except for the issue with needing to "size" the loaded rounds to get them to chamber.

A Google search has not turned up any info on this antique set. Anyone with experience using these older dies who can give me some insight? Does the seating die not apply a crimp?

Thank you for any help!

[Pavogrande]

My set is 1964 -- 64 stamped on top of sizing die -- this is about the time three die sets for "straight" cases were becoming standard -- the expander die is alum and has a larger diameter thread than the threaded sizing dies --
Anyroad, to your problem, the expander plug bells the mouth of the case so perhaps you are
running the plug too deep into your case giving it too much bell to chamber?

RCBS paper boxes were a light green - about like usmc mess ware -- then went to a dark green paper then to plastic --
my ha-penny

[Skunk1]

Length (all specs for the loaded round are right)?

[Noah Mercy]

Light green box, yup. Only ran the expander in far enough to allow the bullet to start without shaving lead...not even a visible bell at the mouth.

[Noah Mercy]

Length is good-to-go. I checked it against several manuals, including an old Lyman that lists the exact bullet I'm loading. The base of the bullet does not extend beyond the neck either...I thought maybe it was pushing against the cannelure and forcing the case outward there, but I've got a solid .030" clearance.

[country gent]

Watch the crimp pressures also. The 44-40 is a thin case and may buckle a little with a heavier crimp

[L Erie Caster]

I think you need to apply just a little more crimp with the seating die. The seating die works just like modern dies.

[Noah Mercy]

Super-thin...I can read a newspaper through these suckers... :p I seat and crimp in separate steps, and it looks like there is a crimping chamfer in the die, but it appears to be very abrupt and I don't want to get too aggressive so as to avoid buckling (or bulging). Might have to invest in a Lee FCD for this project...no danger of crunching anything with them.

[Wayne Smith]

I had a very similar problem with a mixed set of dies. I'm loading BP so I took an extra RCBS seat die, filled in the seat stem with JB Weld and smoothed it flat and use it as a powder compression die. I think my Lee seat die crimped too much and caused a very sight bump at the crimp that prevented successful loading in my guns. The Lee FCD and using the Lee seat die to only seat fixed the problem.