Neck dimension spring back

[kbstenberg]

I am going to order several custom expanders for my M dies. And was wondering how much spring back after case necks are run over a M die sizer.. I am working with 223- 300 sav - 30/30 - 3006 - 7TCU. and all cases have been loaded previously but have never been annealed. Kevin

[Wayne Smith]

Can't be precise. This changes and the neck hardness changes. About the best we can do is hit a medium.

[Calamity Jake]

As stated above no sure way to tell due to neck wall thickness/hardness, I use .001 and call it good.

[geargnasher]

A lot of it has to do with how much the necks were sized down before expanding. Brass can be many degrees of elastic, and whether you reached the elastic limit when working it or not will determine how much it springs back.

Gear

[Chicken Thief]

No more than .002-.003.
Soft brass is less.

[kbstenberg]

Thank you for the information.
So I will probably order my sizing studs .002 under my cast size.

[Chicken Thief]

Thank you for the information.
So I will probably order my sizing studs .002 under my cast size.
No no no mate!
As cast size, it will spring back to a smaller size and grab the boolit.
Thats the feature of springback, use size and the brass wil go to a smidgen under size and hold the lead!

[W.R.Buchanan]

We have had extensive discussions on this topic.

It is impossible to predict what YOUR brass will do. There are too many variables.

All you can do is try one and see what hapens then make adjustments. Another way is to buy a range of sizes so you can cover several outcomes, which may come in handy for other situations.

Randy

[popper]

The one for 303 has worked for my 30-30 & 308. I size .311 & .310. Don't know what they have standard for 7 & 223. It will never be exact.