Problems with 338-378 weatherby and 250 grn otm

[DUNEZRUNNER]

I am just getting setup to start loading the 250 gr otm tactical for my 338-378 weatherby accumark. I sized a piece of brass, inserted a bullet and proceeded to find out my max length that would fit into the magazine. I set it up and found out my max oal. After this was done I pressed the bullet onto a board to "test" the tension on the bullet. The bullet pushed right into the case. It seems that if I seat this bullet to fit into the magazine, the bullet does not have enough tension on it to hold it securely in the case. If I do not seat it the last few thousandths and try this push test, the bullet holds firm. Problem is, I cannot use the magazine, and I will have to pull the bolt to eject a live round.

Has anybody ran into this problem before? Am I SOL on using this bullet? Any words of advice?


Thanks

Thomas

 

[MagnumManiac]

What type of dies are you using? FL with expander, FL with a bushing and expander or FL with bushing only. Or a Neck die with any of the above?
I can't see how shallow seating provides enough tension and deeper seating doesn't provide enough tension. I don't think you are sizing your necks enough, if you measure a cases neck after sizing and compare it to a case with a bullet in it, what is the difference between the 2? This difference is the amount of neck tension, or interference fit.
I run .002" of interference fit in all my hunting rifles, and .0015" in my long range rigs due to them being single fed.

Cheers.
gun)

 

[idaho elk hunter]

What type of dies are you using? FL with expander, FL with a bushing and expander or FL with bushing only. Or a Neck die with any of the above?
I can't see how shallow seating provides enough tension and deeper seating doesn't provide enough tension. I don't think you are sizing your necks enough, if you measure a cases neck after sizing and compare it to a case with a bullet in it, what is the difference between the 2? This difference is the amount of neck tension, or interference fit.
I run .002" of interference fit in all my hunting rifles, and .0015" in my long range rigs due to them being single fed.

Cheers.
gun)

+1 if the Bergers do not work, switch the Barnes LRH. They will always out shoot the Berger in a Weatherby. 265 or 280gr Rl 25 is a good starting powder.

 

[bigngreen]

The issue your experiencing is caused by the bullet having a .0006 pressure ring at the base of the bearing surface of the bullet, this effectively is acting to size the case up a touch but your cases have no spring back in them so once you push the bullet all the way through the neck you loose significant neck tension.

 

[DUNEZRUNNER]

The issue your experiencing is caused by the bullet having a .0006 pressure ring at the base of the bearing surface of the bullet, this effectively is acting to size the case up a touch but your cases have no spring back in them so once you push the bullet all the way through the neck you loose significant neck tension.

This is exactly what seems to be the problem, the base of the bullet is larger than the rest of the bullet and sizes my case larger as I push the bullet through it. Now how do I fix my spring back issue? These are once fired in my gun weatherby cases. I wouldn't think they would have issues already. Should I anneal them? Find a new bullet? Only use factory ammo?


Thanks for the help

Thomas

 

[DUNEZRUNNER]

One other thing, I did pull a bullet from a factory case and seat a berger otm in the factory case. It seemed to hold the bullet for me just fine. I guess I have issues with the once fired brass. I do notice that when I am seating these bullets, that I can "Feel" when I pass the pressure ring. The effort required on the handle is noticeable lighter on both the new and once fired brass. It is looking like I am going to have to try a different bullet that doesn't have this pressure ring.

thanks

Thomas