7-378 Weatherby, Long Range 7mm

lgloutfitters

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Anyone have experience with this round? I noticed PT&G has a reamer, but I couldn’t seem to find any dies. I would think a simple neck down of 30-378 would make this a long range killer of whatever you need it to. I would guess push 180 Grain Berger to prolly 3400 FPS or better. If you could get bullet to stabilize.

Any insight into this caliber would be greatly appreciated.
Also, I know it will be expensive to shoot and will be a barrel Burner. That doesn’t concern me, it will be a hunting rifle.
 

lgloutfitters

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Might be too much of a good thing. This coming from a fast rifle guy. Also brass could be an issue. I think if you are going to do the wildcat thing a 7mm-338 Lap imp would serve you much better.
Seems to be quite a bit of brass out there. I have mostly all the Roys, my favorites being 6.5-300 and 240. I want to stay with Weatherby, just would like to know if anyone has ever chambered it and how they shot if they did.
 

RockyMtnMT

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What I mean by the brass being an issue is the Wby brass is pretty soft and probably won't hold up to the pressure that is needed to run this kind of fire breather. The 338 Lapua will.
 

lgloutfitters

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G
What I mean by the brass being an issue is the Wby brass is pretty soft and probably won't hold up to the pressure that is needed to run this kind of fire breather. The 338 Lapua will.
Gotcha. I can attest to the softness of their brass. 6.5-300 loaded hot doesn’t keep primer pockets very well. But it will run 143ELDX 3450-3500. Maybe get two firings out of it.
 

adam32

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It's been done a lot and like RockyMtn stated the soft brass is the issue, hence why the 7/338 Lapua Imp (aka 7mm Allen Mag) and others with better brass are more popular.

But by all means, if the brass issue doesn't bother you then yes it'll outrun every factory 7mm in existence and pretty much every wildcat. The Lazz Firebird is basically a beltless version with a conventional shoulder so it's pretty much it's ballistic twin.
 

lgloutfitters

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The 7rum is annoying enough to get a good load for... I'd venture to say you've got a good chance of wiping out a barrel in 7x378roy before you get a stable load for it...
Prolly so. Prolly just go with 7-300 Roy. Already have the brass for 300 Weatherby, and 6.5-300. But can’t go straight to 6.5 from 300. Shoulders crush. Takes 7-300 dies then 6.5-300 dies. I have the dies and the brass. I just wanted something that would be far and away faster than the 7STW or 28. Looks like 7-300 will be just on par with those two
 

imartin

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If you want to do a Weatherby, I would use the 300 Wby case, not the 378. 7-300 Wby makes the most sense to me if you want to use a Weatherby case. Call it a 7-340 or a 7-6.5-300 ;) if you want. Just my $.02.
 

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