Throat too short in my .30-.378 ?

[Marine sniper]

I just finished building a .30-.378 Weatherby, 34 in. Pac-nor 3/3 land groove barrel 1.1 in. muzzle, Hall single shot action. I did not want the typical Weatherby free bore but may have had the throat cut too short. This being a single shot rifle I am not too concerned about OAL, but the throat is so short when I tested seating depth with the OAL gauge (200 gr Accubonds) the bullet is so deep in the case that the boatail extends below the shoulder appox 1/8 in. This appear to be taking up a considerable amount of case capacity ?? I plan on shooting Berger 210's-Sierra 220's so the problem will probably be worse with the longer bullet.

I did not put a 34. barrel on the .30-.378 only to turn around and cripple its potential buy having a throat that is too short.

Am I killing some velocity potential with this short throat ?

Thanks,
John

 

[robbor]

To many Qs

When you are talking about the normal feebore and then add long VLD id think they would do fine. But you got a short throat, which is what i would do. Isnt 30-378 a huge honkin cartridge that you dont noramlly use all the case capacity anyways? I thing with berger or similar you will be seated to a longer OAL because of the olgive of the bullet. Reduction in cartridge capacity normally adds to efficiency, so id would not worry about this setup until you get bergers. The only concern would be if you are shooting a really tight neck chambering you could get doughnuts and maybe cause problems. I would not worry about being below the shoulder at all. I bet it will do fine and the long barrel will work fine with your chamber. If after shooting and chronographing its not showing what you want you can have it throated.
I think it will be fine though.

 

[Marine sniper]

When you are talking about the normal feebore and then add long VLD id think they would do fine. But you got a short throat, which is what i would do. Isnt 30-378 a huge honkin cartridge that you dont noramlly use all the case capacity anyways? I thing with berger or similar you will be seated to a longer OAL because of the olgive of the bullet. Reduction in cartridge capacity normally adds to efficiency, so id would not worry about this setup until you get bergers. The only concern would be if you are shooting a really tight neck chambering you could get doughnuts and maybe cause problems. I would not worry about being below the shoulder at all. I bet it will do fine and the long barrel will work fine with your chamber. If after shooting and chronographing its not showing what you want you can have it throated.
I think it will be fine though.

Interesting thoughts.....particularly in regards to the unused potion of the .30-.378 case. I have never reloaded one so I do not know.

 

[Hired Gun]

You doubt you ever get a full case on this one anyway. I wouldn't worry about it. Look how much longer you will be able to chase the lands before the case won't hold the bullet anymore. I would be looking into some real heavies for it like 240 and up. I would check with Richard at Wildcat bullets. I think he is cooking up some 30 cal bullets in the 290 grain range. I would be very interested to see how those work in the 30-378.