Modifying dies for neck sizing

[corbinace]

Greetings,

I need to neck size 7x57 brass to a larger than normal size, for 0.290 bullets.

I do not want to buy a new neck sizer and start whittling on it, so...

I have an old RCBS 7mm mag die set.

My thought is to cut the 7mm mag die in two pieces (so the 7x57 reaches the neck) and sand out the neck to my larger size.

I have never used a neck sizer before and am looking for advice as to whether I am proceeding on the right path.

Thanks, Tim.

[country gent]

While that may work its going to be alot of hand work. there are neck size dies that use bushing to adjust set the size sized to. Redding makes several that neck size bump size and full length size with interchangable bushings. Other wise start out with a die like you have and then ream or lap the neck to size desired. Keep in mind brass has some spring so it may need to be slightly smaller neck die in die to obtain the size you want. I have bushing dies for 223 243 308 40-65 45-70 and 45-90. the last 3 are all the same die body just diffrent bushings or settings. It does work the brass a little more but a standard die and expander of wanted size to expand back up to needed diameter works also. The easiest way to do this conversion would be in a lathe and keep it centered up and held ridigidly.

[Artful]

https://www.youtube.com/watch?v=bUyXZdQ00s0

or just buy a LEE Collet neck sizer
http://www.midwayusa.com/product/766129/lee-collet-neck-sizer-die-7x57mm-mauser-7mm-mauser
Lee commercial
https://www.youtube.com/watch?v=iMIfLATAAOU

Ammo Smith videos on lee collet neck sizer
https://www.youtube.com/watch?v=mhTUgytUGnM
https://www.youtube.com/watch?v=MgHR43TN5Zk

[EDG]

What diameter do you need in the neck?
Dies vary some times there is something that will work like the Rdding Type S Bushing neck die for the .308 Win.
That die will neck size about 40 different cartridges, including the 7X57, just by changing the bushing.

If you are looking for about .315 look for a RCBS 7mm Rem Mag trim die to cut off.

The RCBS trim dies are about .010 larger in the neck than the RCBS FL sizers.

[corbinace]

Thank you for the advice gentlemen.

I was ignorant of the availability of an adjustable collet type of die, such as the Lee, for neck sizing and only thinking along the lines of what I could scrounge up in the drawer.

I will look at both the Redding and Lee dies. The Redding may be more economical if I can just get different bushings for the same housing, because I also have other oversize milsurp rifles to load for.

Thank you for opening my eyes and expanding my horizons to a new way of doing things.