Author Topic: Old vs. new Lyman sizing dies?  (Read 492 times)

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Offline mdatlanta

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Old vs. new Lyman sizing dies?
« on: January 11, 2007, 02:34:52 AM »
Is there a big difference in old vs. new Lyman sizing dies?

I came across a "good deal" on a few older dies (they don't have "O-Rings") the other day, so I bought 'em. Well, last night the new Handloader mag shows up and I was scanning an aritcle about boolit casting where the author mentions older Lyman sizing dies, without O-rings, which he said sheared or shaved the bullet instead of squeezing or swaging it to size (I can't remember the exact wording). The author clearly implied that those older dies were inferior to the newer ones, and that he was basically snookered by the guy he bought them from. I wonder if I just made the same mistake. Are the dies without O-rings inferior?

Mike


Offline JBMauser

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Re: Old vs. new Lyman sizing dies?
« Reply #1 on: January 11, 2007, 03:23:33 AM »
I have read the same info you did I think and I also picked up an old 450 with dies.  I have it in my mind that if the dies I have are stepped rather than tapered I am planning on spinning some emery paper on a dowel with an electric drill and soften the mouth.  I know that it will be more oval than circular but I am thinking I just have to prevent shaving, the die will correct as I will not touch the actual sizing section, just the mouth.  But to answer your question, their newer dies are improved over the older dies by having a taper as do SAECO and others.  I have yet to fire up this sizer.  JB

Offline wncchester

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Re: Old vs. new Lyman sizing dies?
« Reply #2 on: January 11, 2007, 04:32:07 AM »
Original Lyman (Ideal) sizer dies had a diameter reduction in the form of a hard "step" about .1" inside the mouth of the dies.  It shaved away excess metal to attain the finished size and tended to make bullets slightly out of ballance.  That stepped design was eventually changed to a taper but I don't know when. 

I bought my first Lyman sizer, a #45, about '65 and it came with the new style dies.  They gently swage oversized bullets to the final diameter.  It seems very unlikely that an even newer #450 would have old style dies, at least as part of the original purchase.  Of course, sizers don't come equiped with dies, we have to buy them seperatly.  If some dealer still has/had old style dies in stock it is quite possible those would be quietly fostered off on an unsuspecting buyer.

JB has a good idea to soften the older die's steps into a tapered style by honing them a bit but it will require honing inside the sizer just a little bit to reach that stepped part.  You will be able to see the step and know when it has been reduced to a taper.  Since bullets go far below the top of the die I don't think you would harm anything even if your taper reaming work is somewhat  less than perfect.

The only purpose of the "O" ring is to seal the pressurized bullet lube in better, it has no impact on the die's primary function.  If I remember correctly, I've read that the insides were modified at or near the same time the "O" ring seals were added so checking inside those without a ring would be wise.   
Common sense is an uncommon virtue