M-Dies, Full Length Dies, and Neck Sizing Dies. Confused...

[TomBulls]

For my whole reloading career I've only used full-length sizing dies. Having recently gotten in to loading bottle neck rifle cartridges with cast bullets, I've started to use an M-Die to help with seating cast bullets.

I'm confused on when/why I should or shouldn't use full length sizing, neck sizing, and M-Die neck sizing.

Naturally, using a full-length sizing die in conjunction with an M-Die will put extra work on the brass and shorten the life of the cartridge. I don't know if it would be anymore appropriate to use a neck sizing die in conjunction with an M-Die neck expanding die. With all of my shooting being done in bolt action rifles, is there a preferred method to the madness?

-thomas

[mustanggt]

Full length sizing isn't necessary near as often with bolt guns. Neck size the same cases to the same rifle only and you will work the brass very little. Plus if you are shooting cast in it that works the brass even less as the powder charges are alot lower than full jacketed loads. Also the M-die isn't too hard on the brass either. Some guys have used the same cases for many years without a problem.

[Crusty Deary Ol'Coot]

In answer to your question, it depends ------------------

Now that that is solved ------------- :kidding:

But yes, it does depend.

As per full length sizing dies or neck sizing dies, I have NEVER seen a situation where a neck sizing dies proved usefull during my reloading. And yes, I have bought some of them and it only served, in my case, to move money from my pocket and into the pocket of the retailer/manufacture.

I will say this, ALWAYS!!!!!!!!!! size your bottle neck cartridges the minimum amount needed to allow brass fired IN YOUR CHAMBER to again chamber IN YOUR CHAMBER!!

This will in many cases, mean NOT following some of the manufactures instructions for die set up.

Properly set up, a set of "full length" sizing dies will do just fine and is almost always, like well over 95% of the time, all you need for bottle neck cartridges.

For example, the instructions I have from RCBS ( and I do like RCBS ) tools are really off the mark, while those from Hornady are much closer to reality.

For my 45/70 with cast boolits, using a 3 die set of dies from Hornady, there is no need for a die such as the "M" die.

For bottle neck cartridges typically loaded with "J" boolits, the 2 die sets will possibly need the addition of an expanding die ("m" die) if cast boolits are to be used.

I have answered and written so many times about proper die set up for bottle neck cartridges, that I finally just made a document about it, which I will gladly send on to anyone sending me their personal "E" address.

In the document, I give the reasons for proper die setup and have quoted instructions from a couple of manufactures and outlined the reasons those instructions fall short of reality.

Keep em coming!

Crusty Deary Ol'Coot

[Longwood]

When I was competing at Silhouette pistol shooting using specialized rifle rounds, I neck sized only and used the same brass every weekend for many months.

[williamwaco]

Old Coot +1


.

[MtGun44]

I agree with William and Old Coot.

Bill