wmag79
Active Member
I want to build a custom 378 Weatherby Mag. Which actions can I use? Any custom or factory actions? Where can I get one?gun)
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Action Question
- Thread starter wmag79
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MudRunner2005
Well-Known Member
I would suggest finding a Weatherby Mark-V action that was previously for a .378 case round and using it...Such as .30-378, .338-378, or .378 Wby. not sure, but the larger caliber Weatherby might be based off the same parent case, but I'm not positive.
wmag79
Active Member
I like the weatherby actions but I am curious if any other actions are capable of handling it.
MudRunner2005
Well-Known Member
I am a big fan of the Mark-V actions as well. I love the 60* bolt-throw. I have a Mark-V AccuMark in .257 Wby Mag, and it's one smooth shooter. I want another AccuMark in .30-378 Wby just for fun.
Well, there's alot of guys building custom .338 Lapua's on trued Remington 700 magnum actions, and having great success with them. So I would assume that it would be able to handle the .378 Wby as well. Plus, the 700's are a tried & true action. Parts are readily available. And every smith knows how to true one of them up. Personally, I'm a huge Rem 700 fan. Alot of guys on here aren't for some reason. I've always have good experiences with them over the years.
Well, there's alot of guys building custom .338 Lapua's on trued Remington 700 magnum actions, and having great success with them. So I would assume that it would be able to handle the .378 Wby as well. Plus, the 700's are a tried & true action. Parts are readily available. And every smith knows how to true one of them up. Personally, I'm a huge Rem 700 fan. Alot of guys on here aren't for some reason. I've always have good experiences with them over the years.
wmag79
Active Member
I am actually researching the m700 ultra mag action. I am not having much luck finding anyone who has built a 378 on anything other than weatherby actions. I am still hoping more possibilities out there to build on.
MontanaRifleman
Well-Known Member
For what purpose are you building this rifle?
wmag79
Active Member
I am building the rifle for a couple big game hunting trips we are scheduling as well as pretty much one upping my two buddies who have 375 h&h and brag endlessly.
MudRunner2005
Well-Known Member
You should go for the .30-378 Wby Mag if you wanna 1-up them. It's a monster. Make sure you put a radial brake on the skinny end.
MontanaRifleman
Well-Known Member
I'm guessing by "hunting" you don't mean Long Range Hunting? The 375 Ruger has greater case capacity than the H&H and the 375 RUM has greater case capacity than the Ruger. If I was picking a 375 "hunting" round for large game, say out to 400 yds or so, I would pick one of these. My first choice of action for any 375 build would be a custom. After that it would be a Mark V or 700. In the case of the 700, I would replace the bolt and recoil lug.
A 378 Wby would top the heap of common factory cartridges but very spendy compared to the the RUM or Ruger. If you went with the 378 I would recommend a custom action first followed by the Mark V.
My smith who is currently building a 300 RUM on a 700 action for me is a big Mark V and 378 series fan. He has done hundreds of them.
If I was going to build that class fo 375, I would do a 338 Lapua Imp version on a custom action. I would not do a Lapua class cartridge on a factory action and if I did, it would be a Mark V.
For a LR 375, I would look at 408 Cheytac or something in that class like a 375 AM.
A 378 Wby would top the heap of common factory cartridges but very spendy compared to the the RUM or Ruger. If you went with the 378 I would recommend a custom action first followed by the Mark V.
My smith who is currently building a 300 RUM on a 700 action for me is a big Mark V and 378 series fan. He has done hundreds of them.
If I was going to build that class fo 375, I would do a 338 Lapua Imp version on a custom action. I would not do a Lapua class cartridge on a factory action and if I did, it would be a Mark V.
For a LR 375, I would look at 408 Cheytac or something in that class like a 375 AM.
wmag79
Active Member
I am set on the 378 wby. I am aware that it may not be the greatest choice for L.R. or at least not much over 500-600yds. However that is not my concern for this gun. I want it to stop a Buick in its tracks and look good doing it. I have two long range rifles at this time chambered in 257 Wby. and 300 RUM. My next project will be 338-378 Wby. which will be built matching the 378. I have did a little research on 408 and as impressive as it is I am turned off by the availability of components for it as well as the service of the company.
bb204
Well-Known Member
A Stiller TAC 338 action has a bolt face that will work. That's what I used.
Good Luck.
Good Luck.
wmag79
Active Member
I checked on the Stiller tac 338 action this afternoon. I also checked with Montana rifles and will most likely go with them unless I can locate a stainless mark v action.
