Trying Lyman M Dies on Rifle Brass

[GunAdmirer]

I have never liked pulling the expander button through the neck when resizing rifle brass. It seems that it causes the case length to grow more than I want even though I carefully lube inside the necks. I hate trimming cases often. I thought about using the dies with neck bushings, but it seems like the necks have to be turned to be consistent. It’s another step, but I am going to try Lyman M dies to expand the necks on my .223, 300 BLK and .270 Win brass. I plan to set it to expand the necks only, not using the second step to expand the case mouth to bullet diameter. I handload for hunting and range shooting, not precision target shooting at this point.

Am I on the right track? Will I be able to use less lube inside the necks? Will it be smoother than pulling an expander button through the necks? Will case length grow less? Any tips about using M dies will be appreciated.

 

[Blue68f100]

If your going to size with a std sizing die, you will make the mouth of the case around 0.008" under size or more. Trying to expand this will require lube and you run the risk of collapsing the shoulder as you run the expander down. If I'm using a lot of brass that has a great deal of wall thickness variations I pick a bushing to do the thinnest one. This way the expander is not pulling out of an overly reduced neck ID. This is the options you have with a bushing die. You can use the bushing only if your necks wall thickness is uniform and no expander. Or you can go slightly under size and use the expander to get the final size. In any way your not over working the brass as near as much as a std sizing die.

 

[MtnCreek]

Sinclair expanding die with neck turn mandrels will give you .002 tension and you have the option to get carbide mandrels.

 

[redbullitt]

I use the M dies all the time for loading cast bullets... They do the job very well, ie let me use a .310 bullet without damaging the bullet during seating. They are accurate and consistent in my experience.