How much can you push a shoulder forward?

[Ua26fitter]

With a 300 RUM case how much could you safely push the shoulder forward with fire forming.
Let's say I'm thinking about building a 30 cal. wild cat on that case and want to make it longer and choot a small bullet.
Let's say I'm using ADG brass.

Kris

 

[L.Sherm]

Are you talking just AI to 40 deg. or the whole shoulder and taking in some of the neck into part of the shoulder?

 

[FEENIX]

With a 300 RUM case how much could you safely push the shoulder forward with fire forming.
Let's say I'm thinking about building a 30 cal. wild cat on that case and want to make it longer and choot a small bullet.
Let's say I'm using ADG brass.

Kris

As long as you can secure the bullet, go for it. Below is my .338 Thor.

L-R: .338 NM virgin brass, .338 Thor after hydroforming, and .338 Thor after fire-forming off the chamber.

 

[Ua26fitter]

Are you talking just AI to 40 deg. or the whole shoulder and taking in some of the neck into part of the shoulder?

Yes everything. Like Feenix did.
Thanks guys!!
I want to run a little Hammer bullet but keep the OAL the same so bring the brass up and use that powder capacity. I've got a 26" new factory take off barrel I will try it with.

Kris

 

[L.Sherm]

Dies and reamer im assuming are gonna be biggest problem.

 

[FEENIX]

Dies and reamer im assuming are gonna be biggest problem.

Yep, it's also costly and has a long lead time. Since I have all the reamers, my GS built me hydroforming, sizing, and seating dies from blank dies.

 

[Ua26fitter]

I figure I'll have to have a custom reamer made and then a custom die set.
It's a goof around project I have most of the parts for. I think I've got everything now and have around $250 into it including the brass.

Maybe in another year or so I'll have the reamer made.

Kris

 

[Mikecr]

I want to run a little Hammer bullet but keep the OAL the same so bring the brass up and use that powder capacity.

Moving the shoulder forward will not lengthen the case, if that's what you're thinking.
Doesn't work that way

 

[Ua26fitter]

Moving the shoulder forward will not lengthen the case, if that's what you're thinking.
Doesn't work that way

I see what you are saying.
It should still add powder capacity since I'll be using a short bullet that won't protrude into the case.

Kris

 

[L.Sherm]

I figure I'll have to have a custom reamer made and then a custom die set.
It's a goof around project I have most of the parts for. I think I've got everything now and have around $250 into it including the brass.

Maybe in another year or so I'll have the reamer made.

Kris

The " best" way to get a custom die made is off 3 fired cases problem is the time to get the dies made. I had whiddens make me a FL die off my print and it worked out well, BUT I know JGS reamers are as about as spot on what they say whats on there print, not so much with one other in particular so if you go the reamer print route pick wisely.

 

[P7M13]

As long as you can secure the bullet, go for it. Below is my .338 Thor.

View attachment 501912
L-R: .338 NM virgin brass, .338 Thor after hydroforming, and .338 Thor after fire-forming off the chamber.

View attachment 501911

View attachment 501913

That's awesome.
Who do you order hydro-forming dies from?

 

[L.Sherm]

When its time for your reamer to be made i would send a dummy round with the boatail- bearing surface junction in the neck were you want it and JGS could make your reamer off that and your freebore

 

[FEENIX]

That's awesome.
Who do you order hydro-forming dies from?

My first was made by Whidden. I know Hornady makes them via special order. I am not sure if all major die manufacturer does. My GS built my last using blank dies from Newlon and Whidden hydraulic form die plunger set-up.

 

[QuietTexan]

IMO the 30 Gibbs is about as short of a neck as you want with a a 30 cal. - 217" is getting down to 2/3rd of call for neck length. I know the Wolf Pup uses zero neck at all, but an issue there is durability of ammo. Not an issue for a bench gun, but if you're running Hammers you probably want to put them on fur and need something that can hold up through a recoil cycle.

You could also talk to the reamer maker about looking at a 30BR print for ~100gn bullets and see how they think they can change the throat to shorten it up some.