Most reloading sizing dies are designed for jacketed boolits except for the RCBS Cowboy dies. I do not have any experience with the Cowboy dies.
Last spring I started out with a new batch of brass for my .30/30 Hi-wall. After about 20 firings I started to get about 10% loss each loading due to split necks. I annealed the brass and the loss has been reduced to about 2%. Annealing is another story that I will not cover here.
I got wondering if there are other things to consider such as overworking the case necks. I pulled the expander units out of my sizing dies to see what the necks were actually being sized to.
0.333” = fired case neck diameter
0.320” = neck diameter using RCBS neck sizing die and no expander
0.320” = neck diameter using RCBS full length sizing die and no expander
0.318” = neck diameter using Forster Benchrest full length sizing die and no expander
0.3245” = neck diameter using above dies with expander installed
0.3285” = neck diameter after using RCBS 0.311” expander die
0.3115” = sized diameter for Eagan MX3-AR boolit
0.331 = neck diameter after seating Eagan boolit
I do not need to have the neck sized below 0.328” for my loading procedures. I considered Lee Collet dies and neck bushing dies. My understanding is that the Lee Collet die is not very friendly to adjust. I have Star sizing dies from 0.309 thru 0.3115” and RCBS expander dies from 0.309 thru 0.311”. It makes sense to me to get a neck bushing sizing die with a series of bushings. No die adjustment, just change the bushing.
Neck bushing dies are available from Redding, RCBS, Wilson, and CH4D. I do not have an arbor press so the Wilson was not considered. RCBS does not list a .30/30 die and Redding has a 50% premium for it.
I decided to order the CH4d neck die. The CH4d die is a universal die and can be used over multiple calibers. I ordered on a Friday and got my things the following Friday. Shipping was very reasonable. The workmanship on the bushing die and the bushings is very good. There is a very noticeable difference between the effort required using the neck bushing die and the neck sizing die. The neck bushing die is a little finger finger type operation.
I believe that by using a neck bushing die that the brass life will be extended and the intervals between annealing can be increased.