340 WBY HELP

[kuduman49]

I have a custom chamber, Hart barrel, in a 340 WBY caliber. I want to load Hammer Shock, 225 gn. bullets that can be loaded to a .020" jump. The traditional Wby freebore is gone so I can no longer use the loads from the loading manuals as a guide. I am all about being safe and I am not confident in knowing where the starting loads should begin. I would like to begin with IMR 7828. Maybe I should use the loads for the 338 Win Mag as a starting point. Don't want to be too light but certainly not tooooo much. Any guidance will be appreciated. THANKS

 

[MagnumManiac]

Reduce the START loads for the Weatherby by 10%.
Why you would mess with the throat is beyond me, works very well as is.
All of mine have the .376” throat except my 375 Bee, it has the .500” throat and gets velocities out of a 24” barrel you would get with a 26” or longer. Prints nice little clover leaf groups.

Cheers.

 

[kuduman49]

I have a Mark V Accumark in a 340 with the free bore so I thought I would try another rifle without the free bore and make some comparisons ..

 

[MagnumManiac]

Fair enough, I doubt you’ll see similar velocities with the short throat though.
My 340 Weatherby struggled to get 100fps more than all 3 of my 338WM’s using RE19.
Even using RE25 wouldn’t push them faster without trashing the Norma primer pockets.
I still have the barrel, and a 300 Bee barrel for the same rifle, but they rarely get screwed in these days unless I’m at a demonstration/training day at the range.
I like Weatherby rounds, also have 270 Bee barrels as well.

Cheers.

 

[DaveTooley]

I've built and shot a few 340's. No sure why you'd be concerned about getting MORE.

 

[LCazador]

I have a custom chamber, Hart barrel, in a 340 WBY caliber. I want to load Hammer Shock, 225 gn. bullets that can be loaded to a .020" jump. The traditional Wby freebore is gone so I can no longer use the loads from the loading manuals as a guide. I am all about being safe and I am not confident in knowing where the starting loads should begin. I would like to begin with IMR 7828. Maybe I should use the loads for the 338 Win Mag as a starting point. Don't want to be too light but certainly not tooooo much. Any guidance will be appreciated. THANKS

So when Hart did the barrel didn't they give you some chamber dimensions? Find the lands start .020" off and use the middle load between start and maximum. Forget velocity and accuracy till you have fireformed brass for that custom chamber then work on a load.