Redding bushing sizes

[rgv]

been away from anything precision related for some time, need some help here...

What size bushings do I need for unturned Lapua .308 brass using Sierra matchkings? I suppose I need two or three different ones.

I will need enough neck tension to be able to feed out of the magazine without the bullets getting pushed in under recoil.

Also, why does the die have an expander ball? Isn't this redundant/unnecesary?

thanks in advance

 

[cdnredneck_t3]

You will have to take a fire formed brass and measure the ID. This will tell you how much you need to neck size to get what you want for retention. Measure the OD and subtract what ever clearence you have in the ID along with what you want for retention and maybe another 2 thou to allow for spring back (I think Forster has a step by step on their website). And on the type s die the expander ball just un-threads off the de-capping pin so you don’t have to use it. I guess it is just there in case you oversized it and want to open it back up because you are peeling the copper jacket off the bullets while trying to seat them.

 

[Obtunded]

Measure the brass thickness. You can likely do this with a plain set of calipers . Double that, add the bullet dimension and then subtract 2 thou.

 

[rpollock]

Measure across the neck with the bullet seated, subtract .002-.003.

Decapping pin is normally undersize so as not to expand the neck at all.

 

[peterdobson]

You need a .335" bussing and smaller later, when the brass has been fired a lot. Really should try Lapua bullets.

Regards,

Peter

 

[maynard]

Measure the brass thickness. You can likely do this with a plain set of calipers . Double that, add the bullet dimension and then subtract 2 thou.

X2. Since I use moly bullets I subtract .003". I am running a .334" bushing with Lapua brass.

 

[carbonrod]

There are about 100 ways to select a bushing. Found it kind of odd the first time I bought one. Below is a couple of methods from Redding:

http://www.redding-reloading.com/techlinepages/bushingselection.htm

 

[rnbra-shooter]

I use a .334" bushing, it gives moderate neck tension. I only single-load my ammo, so I am not sure if this will work from the magazine; I expect it probably would, but I don't know for sure. The other bushing I have is .335", it works too, I use it when I want lighter neck tension.

If you're going to order only one bushing, and if you have an expander ball (are you sure that you do? my Redding bushing dies has a decapper but not an expander ball), you might be best served with a .333" bushing.

 

[CyaN1de]

Seat a bullet in a sized case, mic the neck with the bullet seated, subtract .001 or ,002 off the mic'd size.

 

[redman]

Seat a bullet in a sized case, mic the neck with the bullet seated, subtract .001 or ,002 off the mic'd size.

+1

I used the exact same technique, worked like a charm... It's a good idea to get an additional one that's 0.001" smaller.

 

[Max Owner]

Should the cases be fire formed first? Then measure?

 

[CyaN1de]

Should the cases be fire formed first? Then measure?

I doubt the neck thickness is going to change enough to warrant firing it first.

 

[rgv]

thanks guys!