RCBS and Lyman priming arms interchangeable?

[FergusonTO35]

Hey folks. I have a late model Lyman Crusher press which needs a new priming arm. Are Lyman and RCBS arms interchangeable? They look nearly alike but the RCBS one is alot cheaper for some reason.

[Pressman]

They should be, the priming arms are a universal design first used on the 1931 Pacific press.

Ken

[salpal48]

> As stated above There Universal But some are No so Universal as Others. I recently tried to Fit My lyman Universal into Older Rock Chucker. . I found That the lyman was slightly Too Thick.. since The body was Made of aluminum I was able to file down the side to fit smoothly. The arm Fit well in the lyman.
Now My Older arms , Pacific, Bair and Lachmiller Steel arms Fit Universally. So To answer The question. They are Universal as Long as you make them That way
Sal

[SARuger]

The arm on my Spartan is longer than the RCBS but you might be able to readjust your feeder to meet up with it, if you use the tube feed. I think otherwise they are interchangeable

[FergusonTO35]

Well, got me an RCBS primer arm and it fits my Lyman press like it was made for it. Tried to prime some .38 Specials and, this has got to be the worst priming system ever designed. Or, far more likely, I'm doing it wrong. I chose the smaller of the two punches and collars and put it on the arm and mounted it on the press. Resized a .38, placed a primer on the top of the punch, and pushed the arm into the press ram while lowering it. At best the primers take considerable effort to seat. At worst they are getting seated cockeyed or the cups are crushed. Is this the norm for this method of priming? Is there a long learning curve to it? Or, am I making some huge mistake and just don't realize it?

[FergusonTO35]

Tried it again last night priming some .30 WCF cases with CCI primers and it worked great. Mebbe those .38 Special primers and cases just don't get along with it, stranger things have happened.

[EDG]

>>>this has got to be the worst priming system ever designed<<<
some single stage presses can have the linkage reversed to the work in the down stroke for priming.
That is a much better way to prime. I quit priming with the press because the best press is worse than the worse hand primer.

[Rattlesnake Charlie]

I've primed tens of thousands with my RCBS Rockchucker Jr, and now more with my RCBS Rockchucker Supreme. Like it better than the only hand primer I tried, a buddy's Lee. The Jr gives a little better "feel" than the Supreme due to less mechanical leverage. I have tried reversing the linkage to prime on the downstroke, didn't seem to make a difference to me. Everyone to their own.