338 LM dummy for throating

[PhilKeil]

My smith is wanting me to provide a dummy. When calculating to make one do you place bottom of the bearing surface at the neck shoulder junction?
I was measuring some Berger 300 otm and the boat tail portion of the bullet is close to .300. I am trying to max case volume. How much bearing surface could I get away with in the neck? I would appreciate some advice
thanks

 

[moondog]

I do the same with all mine. You get kinda locked into whatever bullet you choose.
I send my "dummy" rounds in with the bullet seated with the bearing surface right at the neck shoulder Junction. Tell your smith how much jump you want with it there. It allows for you to move it out as the throat moves. As far as the 338 goes, I don't think you'll see the throat move very fast. My 338 Imp.with the 300 grain OTMs hasn't really moved or cracked. FWIW, mine likes the 300 OTM in about .007"

 

[PhilKeil]

I do the same with all mine. You get kinda locked into whatever bullet you choose.
I send my "dummy" rounds in with the bullet seated with the bearing surface right at the neck shoulder Junction. Tell your smith how much jump you want with it there. It allows for you to move it out as the throat moves. As far as the 338 goes, I don't think you'll see the throat move very fast. My 338 Imp.with the 300 grain OTMs hasn't really moved or cracked. FWIW, mine likes the 300 OTM in about .007"

Thank you

 

[PhilKeil]

I do the same with all mine. You get kinda locked into whatever bullet you choose.
I send my "dummy" rounds in with the bullet seated with the bearing surface right at the neck shoulder Junction. Tell your smith how much jump you want with it there. It allows for you to move it out as the throat moves. As far as the 338 goes, I don't think you'll see the throat move very fast. My 338 Imp.with the 300 grain OTMs hasn't really moved or cracked. FWIW, mine likes the 300 OTM in about .007"

Moondog, question are you saying in.007 to rifling or in case and jumping?

 

[moondog]

Into rifling, yours maybe different but that's what worked in mine

 

[PhilKeil]

Thanks will try it

 

[DirtySteve]

Phil, I would just load to the neck shoulder junction with the bearing surface. Or al least one caliber (.338) of bearing surface in the case mouth... Seems to me this would aid in keeping concentricity of the round...

Just a thought... I would post this in the ELR section as well...

 

[PhilKeil]

Thanks Steve.

 

[rardoin]

If you seat with the bearing surface above the N/S junction by some margin it will give you room to jump the bullet if needed. Save the dummy and your smith has a ‘gage’ to cut the throat exactly the same on the next barrel. Just another way to skin the cat.