I've added Lyman's expander "M" die to virtually all my pistol cartridge reloading sets. I like that their expander plugs are longer (expand deeper) & have the stepped diameter feature, which is particullarly good for loading cast bullets.
One thing that is a little annoying though is making depth adjustments on the fly. The locking nut usually ends up either too loose or too tight to smoothly tweek the final setting. During my last reloading session I got an idea & rummaged thru my parts bin & found an O-ring to try. I removed the expander stem & slipped the O-ring over the tip & slide it over the threads, butting it against the locking nut. Screw the stem back into the body & lightly snug the locking nut down, against the O-ring & die's body. Now, turning the stem's adjustment screw nets a smooth positive feel, either way you turn it. No need to mess with the locking nut again.
The O-ring I used measured: ID= 9/16", OD= 3/4", & thickness= .100". Went to Lowes & found a package of ten #11 O-rings ($2.49) that were a good match & installed them on my remaining dies. It even worked great on my .41 Mag RCBS expander die (new ones are have the "M" die feature too). I did notice, while going thru my die set boxes to see which ones needed the upgrade, that Hornady uses a similar feature, a flat rubber washer, on the adjusting stems of their seating dies, so maybe that was in the back of my mind when I did this?
I dislike the style lock rings (body) that Lyman uses (with the allen head setscrew) & have always changed them out with Lee's Finger Tighten Lock Rings (#90534) especially on dies that are frequently adjusted.
One last item, the Lyman expander tip screws into the stem. I've never been able to keep them tight. It always comes loose in the middle of a batch of brass & wildly flares the brass before I realize what happened. Now when I get a new one I degrease the tip's threads & but some threadlocker on it & haven't had that problem reoccur.
These few simple mods make a great die even better.
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Lyman Expander die mod
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One thing that is a little annoying though is making depth adjustments on the fly. The locking nut usually ends up either too loose or too tight to smoothly tweek the final setting. During my last reloading session I got an idea & rummaged thru my parts bin & found an O-ring to try. I removed the expander stem & slipped the O-ring over the tip & slide it over the threads, butting it against the locking nut. Screw the stem back into the body & lightly snug the locking nut down, against the O-ring & die's body. Now, turning the stem's adjustment screw nets a smooth positive feel, either way you turn it. No need to mess with the locking nut again.
The O-ring I used measured: ID= 9/16", OD= 3/4", & thickness= .100". Went to Lowes & found a package of ten #11 O-rings ($2.49) that were a good match & installed them on my remaining dies. It even worked great on my .41 Mag RCBS expander die (new ones are have the "M" die feature too). I did notice, while going thru my die set boxes to see which ones needed the upgrade, that Hornady uses a similar feature, a flat rubber washer, on the adjusting stems of their seating dies, so maybe that was in the back of my mind when I did this?

I dislike the style lock rings (body) that Lyman uses (with the allen head setscrew) & have always changed them out with Lee's Finger Tighten Lock Rings (#90534) especially on dies that are frequently adjusted.
One last item, the Lyman expander tip screws into the stem. I've never been able to keep them tight. It always comes loose in the middle of a batch of brass & wildly flares the brass before I realize what happened. Now when I get a new one I degrease the tip's threads & but some threadlocker on it & haven't had that problem reoccur.
These few simple mods make a great die even better.

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Lyman Expander die mod

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