Using an M die instead of an expander button.

[Bazoo]

I use an M die to expand the necks of my 30-30 casings when loading cast, and I've done it even when loading jacketed bullets. Would there be any benefit to not using an expander button? I could get a spare and sand it smaller so it wouldn't expand the neck but would still open up an occasional squashed neck.

In the research I've done I've seen someone doing it this way, but is there any benefit?

Thanks for the info, Bazoo.

[Czech_too]

I have started to use the 'M' die in place of the expander button in the belief that it may help with concentricity of the case mouth.
Can I prove this, do I have evidence to support this belief, no, not at this time.

[uscra112]

I have sized without the decapper / expander stem for many years. Decap as a separate (first) operation, then wash and tumble, then size and expand, then wash again to get the sizing lube off.

For cast, the expander supplied with most die sets doesn't expand the neck enough anyway. They assume you will be using metal patch bullets which want the neck to grip the bullet tightly.

If you have a lathe, it's no trouble to make M-die expander mandrels to the exact size need for proper fit to whatever cast bullet you're using. Buy raw threaded-rod stock from McMaster-Carr. Part # #98957A407, 9/16-18. Good steel, cuts like a dream.

[cwlongshot]

I have begun usinf a M-Die in all my loading and I am finding IMPROVED accuracy across the board.

Im aslo filling a cigar box of factory expanders pretty quick!!

Altho we speak CAST BULLET here the M die benifits our J Word fodder just as well!!

CW

[smoked turkey]

Like some of the above posts, I too decap with a universal decapping die. I then clean the cases with a vibrator and quickly inspect and clean the primer pockets with an appropriate primer brush. I might anneal the case necks at this point if needed. I also check the case length to see how the batch is running against specifications. After these steps, I have clean cases to run through my sizing die which I like to think results in less galling on my dies. As a last step in the case preparation process, I run the cases through the "M" die or more than likely I will use one of NOE's neck expander dies to get the cases ready for priming/reloading. I agree that the expanding operation using the die expander button is largely for j bullets and not the cast variety we mainly use here.

[Martin Luber]

I found the decap expander ball pulls the necks outward in the case you just sized. Leads to cases that don't chamber if the brass is soft or necks thin. Prefer the expander plug. It's An extra step in single stage though.

[MGySgt]

The M Die is designed to bell the case mouth so that lead or powder coat doesn't get scrapped off the sides of the boolit during the seating process. I would not reccomend that you seat cast or PC's boolits with out the bell in the case mouth.

[30calflash]

I used an M die in loading '06 jacketed ammo with flat base bullets. No trying to balance them on the case mouth like the std full length size treatment.

I shot them in an M1, never tested the accuracy difference between not using an M die and using one. Would need a decent scoped bolt gun to see any change.

[fatnhappy]

I load .308 win for precision rifle competition, lapua neck turned cases, the whole nine yards. I tested concentricity with a few different loading techniques. With standard dies I got my best results with a Redding die sans the expander ball. I expanded with a M die in a separate step and seated with a Forster micrometer benchrest seater.

I don’t really enjoy adding the extra step of expanding so now use a Redding S die. Measuring has not demonstrated the S die significantly better

[Iowa Fox]

I quit using the expander ball years ago. All it does is stretch necks and shoulders plus it pulls them crooked. I tried polishing the expander ball and every lube known to man but it still pulls them. The M die works perfect for both cast and jacketed not only does it not pull neck,s run out on the concentricity gage is vastly improved. There are a lot of accuracy companies making expanders now but the M die may have very well been one of the first. I also use Redding bushing dies and Lee's collet die. Do yourself a favor and ditch the expander ball, plus full length sizing is the best.

[Bazoo]

Thanks for the replies everyone.

I hadn't thought about concentricity, but I had thought of reduced case stretching. The extra step doesn't bother me, as I most often shoot cast anyway. I'll have to do some experimenting.

[MostlyLeverGuns]

Decapping rods that DO NOT neck expand can be found or made for most dies. Lee sells a decapping rod for ?2.50 for their dies. Redding includes the option with their bushing dies. I just install a smaller expander 'ball' on most others or reduce size by spinning in a drill press while using file or coarse stone on the expander. I do not normal drag the expander through the neck from the inside. Use both Lyman and NOE expanders. I only use the Redding bushing dies for .308, both neck and full length, same for .243 and some .223. I use dry moly powder to lube case necks when I do drag an expander through when sizing. The bushing dies work well to reduce 'overworking' brass. I use the 308 bushing dies for other 30's though the whole neck may not be sized.