RCBS 3-die rifle set; seating depth plug - why no locking ring?

Something I've always wondered is why there is no locking ring on the depth plug on the RCBS seating die, off the 3-die rifle set. I don't crimp with this die, using instead the Lee Factory Crimp die to roll crimp my 45-70. After going through trying the set the bullet properly within tight tolerances to a proper depth, I don't get why RCBS doesn't just put a lock ring to set the plug in place. As it is, I plan to just use a line of white out to make sure the plug and the die body are properly lined up (along with measured COAL).

But I don't get the lack of a locking mechanism. Am I missing something?

I think you're missing the lock nut from the seater plug.
Any RCBS 3 die rifle set I've had came with a thin hex-shaped nut to lock the seater plug in place, and if yours is missing just phone RCBS and they'll send you one.

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Originally Posted by DaveF

I think you're missing the lock nut from the seater plug.
Any RCBS 3 die rifle set I've had came with a thin hex-shaped nut to lock the seater plug in place, and if yours is missing just phone RCBS and they'll send you one.

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Sorry Dave, I misspoke. I should have said the Cowboy 3-die set. I can't remember what the standard rifle sets have. Here's the seater die with its lock ring for the die and just a "set" ring without the hex-nut lock setup.

Attachment 308714

The lines are a band-aid to help me keep the depth.

The top brass colored ring is meant to lock the seating stem in place once you get it adjusted, similar to the old school way of double nutting a bolt. Trust me, it doesn't take much torque on the jam nut to lock the seating stem in place. Probably why most used die sets have plier marks on them.

Robert

The knurled brass nut is your jam nut to lock the seating stem.

OK thanks guys.

I snug it up with channel locks.

I don't have any of the cowboy dies but I would think snugging the nuts up finger tight should hold it well.
Rick

i use lee lock rings on all my dies now no tools needed the oring does the job fine

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Originally Posted by robg

i use lee lock rings on all my dies now no tools needed the oring does the job fine

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That’s the die body.

The OP was referring to the seater plug itself. Turns out he has on after all if I am reading correctly.

Three44s

Thanks guys. Three, right, I'm talking about the seater plug. I may have just not known any better last time (few years ago now), as I almost killed the nut tightening it as it felt unstable. So far just finger tightening and watching the seating depth with each new session. So far, A-OK.

I dunno how good the RCBS nut works in this situation. I find the similar nut on my Lyman M dies doesn't stay put.

I find the nut stays tight if you install a leather washer under it. Before that, I tried a rubber O-ring, and that doesn't seem to work for this particular nut. I also install a leather washer between the expander plug and stem on the M dies.

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Originally Posted by robg

i use lee lock rings on all my dies now no tools needed the oring does the job fine

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This. The seater plug fixed in place with the o-ring is just genius. Easy to change seat depth for different bullets and it holds its setting. But it’s Lee so many overlook it. Fools.

Thanks, I'll try it.

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Originally Posted by swOhioMatt

This. The seater plug fixed in place with the o-ring is just genius. Easy to change seat depth for different bullets and it holds its setting. But it’s Lee so many overlook it. Fools.

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Do you mean Lee has seater plug lock rings? Or you mean just o-rings?

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Originally Posted by huntinlever

Do you mean Lee has seater plug lock rings? Or you mean just o-rings?

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No lock ring/nut on the seater plug. A groove is machined into the threads of the seater plug and an o-ring installed in the groove. It provides an interference between the die body and seater plug so the plug will hold its position. The top of the plug is knurled to improve your grip. Just turn it in or out as required and forget.

https://leeprecision.com/seat-die-only-45-70.html

Quote:

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Originally Posted by swOhioMatt

No lock ring/nut on the seater plug. A groove is machined into the threads of the seater plug and an o-ring installed in the groove. It provides an interference between the die body and seater plug so the plug will hold its position. The top of the plug is knurled to improve your grip. Just turn it in or out as required and forget.

https://leeprecision.com/seat-die-only-45-70.html

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Oh I see, thanks Matt. I'd thought you use some sort of Lee lock mechanism on the RCBS seating die, replacing the RCBS nut.

Quote:

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Originally Posted by huntinlever

Something I've always wondered is why there is no locking ring on the depth plug on the RCBS seating die, off the 3-die rifle set. ... After going through trying the set the bullet properly within tight tolerances to a proper depth, I don't get why RCBS doesn't just put a lock ring to set the plug in place. ... Am I missing something?

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First, no one need use a wrench or pliers on any die adjustment, it just isn't needed or helpful. If you really want a nut take the stem itself to a good hardware store and find a matching nut.

Second, there is no "set the bullet depth properly" dimension for you to target. Seating depth isn't twitchy for anything but small case, high pressure loads for the 9/10mm cartridges that are already loaded right up to "KABOOM!" levels! Chambers differ so, like varying powder charges as is helpful, testing different seating depths and crimps for our own rifles is just another way to custom tweak our own reloads for best accuracy.