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View Full Version : Case resizing and crimping woes with oversized TL, PP and PC boolits.



LoopSoosStroop
08-23-2013, 04:45 AM
Ok, I shoot .303 Brit and have recently acquired a 160 gr Lee TL mold. Drops at about .312-.313.

My first loads were with neck re-sized cases, flared, bullet seated and flare closed. I'm sure that this procedure sizes the bullet down, as there is a LOT of neck tension wen seating the bullets. I pulled one and the TL grooves mic at .311.

Now, the only alternative is to leave the cases un-sized. But then the boolits sit very loose, and I have to crimp with the Lee seater die to keep them in place.

Questions:

Will this crimp not damage the boolit and remove the GC when the shot is fired? The brass case rim is much harder than the lead, and I'm thinking that it will swage the boolit down anyway.

Same problem with powder coated and paper patched boolits, how do I get neck tension (so that I get a consistent COL when chambering) without crimping excessively?

This really is an art getting these things to go out straight.

I've loaded a few different loads up for this weekend using different techniques, will post results here.

dromia
08-23-2013, 05:39 AM
What you need is a Lyman "M" type expander die.

Your neck tension needs to be 1-2 thou so get an "M" expander that will open the case up 1-2 thou under boolit diameter, the "M" die has second step 2 thou over boolit diameter so the the boolit seats square to the case.

Lyman do a "M" dies for standard calibres and may suit if not Buckshot and others on here will turn you expander spuds to your specifications that will fit your "M" die.

I never crimp boolits to get neck tension it is an elastoplast covering the symptom rather than addressing the cause.

popper
08-23-2013, 10:45 AM
You could order a M die, 31R IIRC, I'm still waiting for the 41WM plug. You could powder coat which adds a couple thou. and size to 312-313. You can also use unsized or Lee neck sized cases. You can wrap tape around the mandrel to get the right consistent size. Crimping is just to prevent setback, not neck tension. Eventually you will have to FL size, without the proper expander you could just put up with the leading from swaged pills or use hot glue bullets to fire form.

mroliver77
08-23-2013, 10:58 AM
The first problem is your size die. It is sizing the neck down too far! It needs opened up. I would like to see .001 - .002 smaller than you actually want and let the M die or spud open it to the desired I.D. The reason is that brass differs a bit in thickness and thicker brass will result in a different neck I.D.

Like Dromia stated .001 - .002 is a good fit and crimping is only needed in certain applications.
J