Which 375?

[ishootkittens]

I agree with you about the Lapua, especially a improved version, but if you want to shoot 350 to 400 grain bullets case capacity is very important. and 15 to 20 gr more case capacity will make lots of difference especially if you want velocity without excessive pressures.

In the case of the belt, Some of my most accurate rifles are belted and for fire forming, it is the easiest because the belt does the head spacing and once the case has been fire formed, as long as you don't full size the case it is no longer a belted case (It head spaces on the shoulder).

I build both the Lapua and the 378+ Weatherby on Mark 5 actions because of the size and strength
of the action, So that is why I recommend it.

I would not want to talk you out of ether cartridges because they are both great and neither are proprietary and brass is available and if you stay within SAMMI pressures, both have good brass life.

Just saying

J E CUSTOM

Thanks alot! How much more capacity do you think the Weatherby would have over the lapua? With both being improved of course. I think the mark V action is great too, I'm definitely considering it. I just don't know about the price of the brass. I know it's not much more than lapua brass, but it's not lapua brass either

 

[Deleted member 46119]

Thanks alot! How much more capacity do you think the Weatherby would have over the lapua? With both being improved of course. I think the mark V action is great too, I'm definitely considering it. I just don't know about the price of the brass. I know it's not much more than lapua brass, but it's not lapua brass either

I laid out my version of a 378Wby Improved for 145+ grains. Note this is starting from Jamison "basic" brass for a case length of 3"

Regular 378Wby Improved for 140+

The 375-338LM AI in my QuickDesign comes in at 125+

So, 15 to 20g more for the 378 improved vs the 375-338.

 

[ishootkittens]

I laid out my version of a 378Wby Improved for 145+ grains. Note this is starting from Jamison "basic" brass for a case length of 3"

Regular 378Wby Improved for 140+

The 375-338LM AI in my QuickDesign comes in at 125+

So, 15 to 20g more for the 378 improved vs the 375-338.

Wow that much huh...I was thinking the Weatherby had the advantage by 8-10gr but ****...never thought it would be 15+

 

[RockyMtnMT]

Here is a couple of pics.





Here is the rifle. 31" Rock Creek medium palma.
Pain Killer brake.
Defiance Deviant action.



Fully formed cartridge loaded with 394g Hammer Hunter.

Steve

 

[ishootkittens]

Beautiful rifle. Wicked looking cartridge. What does the rifle weigh? Why doesn't anyone take videos anymore!!! I'd love to see the muzzle blast from this thing

 

[RockyMtnMT]

Beautiful rifle. Wicked looking cartridge. What does the rifle weigh? Why doesn't anyone take videos anymore!!! I'd love to see the muzzle blast from this thing

I just barely got the pic thing down and now you want me to post a video?

Haven't weighed it, but I would say that it is about 13lbs scoped.

We did load development the other night as it was getting dark and there was surprisingly little flash. Burning the powder very nicely. Like any other cartridge burning in the area of 100g of powder, the concussion is definitely noticeable. The PK break is very efficient and makes the rifle shootable without having to grip it hard to control recoil. Sending a 400g pill at 2780fps still lets you know it is there. We are thinking it maybe better served with a bullet that we can get a bit over 3000fps for long range hunting. Something 370g +-. We will see.

Steve

 

[Deleted member 46119]

Is that with the 375-338 Lapua Improved?

 

[ishootkittens]

Is that with the 375-338 Lapua Improved?

Yes. With a 394 hammer bullet doing 2780fps

 

[TXAoudadKlr]

Dude 6,800ftlbs who and where do I send a check to?

 

[ishootkittens]

We got our 375 BigDog loaded up today. It is shooting the 394g Hammer Hunter at 2780fps comfortably. We used Win 780 Supreme and the rifle has a 31" 8" twist Rock Creek barrel. Right now I think we will be making a bullet that we can get over 3000fps for it. I think it will work better out to hunting distances. We will work with it more in the future. Now it is shooting well out to 1000y and will hopefully get to shoot a deer in the last few days of the season.

Steve

There is the post. I didn't test any of this. He is testing on a 31" barrel

 

[RockyMtnMT]

If any of you guy want one of these things send me an email to [email protected] or pm with your email and I will get back to you. We can put together the rifle to your specs and ship with custom ammo.

Fred,

Yes it is the 375-338 Lapua imp. Our pet name is the 375 BigDog.

Steve

 

[J E Custom]

Wow that much huh...I was thinking the Weatherby had the advantage by 8-10gr but ****...never thought it would be 15+

I went back and looked at all of the Lapua improved cases and there case volume to the base of the neck (Usable space) was on average 115 to 117 grains. even though it is a large case it is also much shorter than the 378. In the 338 version it has almost the same case volume as the 338 RUM
(The 338 RUM is much shorter than the 300 RUM).

Just More Info

J E CUSTOM

 

[ishootkittens]

One thing I've always wanted to know. Is that weatherby mark V really that strong. I've heard that it can easily match custom actions in terms of strength. IF i were going to go the Weatherby route, should I go for a custom action or try to find a mark V out there somewhere? I wonder if the ejection port is big enough to extract a loaded cartridge.

 

[trueblue]

One thing I've always wanted to know. Is that weatherby mark V really that strong. I've heard that it can easily match custom actions in terms of strength. IF i were going to go the Weatherby route, should I go for a custom action or try to find a mark V out there somewhere? I wonder if the ejection port is big enough to extract a loaded cartridge.

I am not sure how easy these Mark 5 actions are to find.
I can't recall ever seeing one listed for sale. I would just go custom, and get what you want. If you are doing one of these builds, a little more money for a custom action is not that big of a deal.