What cartridge for high speed 30 caliber

[J E Custom]

what exactly is a 30-378 improved? i'm kind of ignorant i guess

It is a standard 30/378 with the shoulder move forward and the neck shortened, The rounded/radius shoulders are also changed to 35 or 40 degrees for more efficiency and capacity.

I have built a few and here is a post about some of these improved Weatherbys By member Doublezranch.

30 378 weatherby

Been shooting the 180 gr ballistic tips for about 10 years from mine. Can’t remember exactly what charge but it’s a decent dose of 8700. Absolutely devastating on whitetail near and far

www.longrangehunting.com

J E CUSTOM

 

[jessej]

30-338 lapua improved on a Bat repeater. Krieger 28" 10twist .835 at the muzzle.
210 bergers over us869 produced 3600fps. It was a warm load, but with lapua brass, I had some last as much as 19 shots. never annealed. Shot in the

300 RUM. 150 grain accubond over 100 grains ofRL22 produces 3800 FPS in a factory Remington light weight. 1/2 moa.

30-338 lapua UNIMPROVED. 24" hart 12 twist. 165 accubonds over RL 22 producing 3700 FPS. Mild load. Shoots in the .0s

Next project on my mind is a remodel of the 30-338 improved. Maybe a 8 twist to try the 250 a tips.

 

[jessej]

30-338 lapua improved on a Bat repeater. Krieger 28" 10twist .835 at the muzzle.
210 bergers over us869 produced 3600fps. It was a warm load, but with lapua brass, I had some last as much as 19 shots. never annealed. Shot in the .0s.

 

[jessej]

Keep us informed on your decision and results.

 

[distantfoe]

I had a 300 Thunderhulk. It was a 408 Case shortened and necked down to the same dimensions as the 300 Norma Mag with an improved shoulder. My rifle had a 33 inch barrel. I was able to push a 215 Berger over 3600 FPS with H1000. My accuracy load I was shooting 3578 FPS. I also tested the 230 Berger and was able to shoot that over 3400 FPS. I only tested this rifle to 1 mile but what I will say is the 215 in my rifle was flatter and more accurate at 1 mile than the 230s. There are lots of good bullets out there but there comes to a point that you really don't need to shoot the heaviest highest BC bullets out there how far do you really want to shoot? Another thing you want to look at is.......you do want to run an efficient case where there isn't a lot of extra case space because there really isn't a lot of really slow temp stable powders out there to choose from.

if it weren't for the cheytac bolt face, I'd take a hard look at this! Proven temp stable powder hurling proven killing bullets at crazy speeds.

 

[JJMoody]

I get chasing speed. I get looking for peak performance. I totally understand the giggle- factor. My head is wrapped around the "'cause I wanna..." , but man, who's shooting a 300 lapua improved going, "Nah, just not enough punch for a .30cal...."?

 

[Doublezranch]

It seems lately there's always another .30 to check out.

I just built a 30 wildcat one for my youngest. JE Custom and I will be presenting it to him Friday. Should push those 230's pretty darn quick!

 

[ILVTOHT]

I am going to build a 30 caliber that can push a 230 Berger 3300. I was thinking of a 30-338 lapua improved. Don't know about the accuracy of this case at that speed if it can even get there. Looking at a benchmark barrel 3 groove 30" long. Looking for a single shot action to build on too. Please let know what you know or what case you would do and why.
Thanks Jack

Not a 30... but my son's 338rum runs 225 Nosler Accubond's at 3250fps.

 

[IdahoCTD]

I get chasing speed. I get looking for peak performance. I totally understand the giggle- factor. My head is wrapped around the "'cause I wanna..." , but man, who's shooting a 300 lapua improved going, "Nah, just not enough punch for a .30cal...."?

I've been down this road and it's not for the faint of heart. If you shoot ball powder your cleaning the barrel every 20 rounds or so to keep it from forming a carbon ring. Then your wasting a couple rounds to foul the barrel. Now that there are stick powders like 20N29 and slower available the hot rods become more attractive but your still cleaning way more frequently then a 300wm, 30 Nosler, etc. Shooting a 230 3300+fps is hauling the mail. I actually had plans to make a 30XC but decided against it over a more portable 30-338 Lapua Imp, my other one is super long and heavy. The main reason is powder selection for each.

 

[Doublezranch]

One warm load and the primer pockets are loose or gone.

I disagree. Both my kids shoot Weatherby wildcats. Both shoot loads that equate to around 60k psi (Quickload est.). We have not thrown one piece of brass away. Primer pockets are still as tight as the first primer seated. 340 Weatherby Improved (340 Zaylea Ann) has a capacity of 112 grains. 378 Weatherby Improved (375 Zayne) has a case capacity of 142-144 grains. They have been reloaded 3-5 times and still in mint condish. These are Norma and Norma/Weatherby brass.

 

[HARPERC]

.....I just built a 30 wildcat one for my youngest. JE Custom and I will be presenting it to him Friday. Should push those 230's pretty darn quick! .....

I look forward to it, you guys always make it interesting.

 

[IdahoCTD]

I disagree. Both my kids shoot Weatherby wildcats. Both shoot loads that equate to around 60k psi (Quickload est.). We have not thrown one piece of brass away. Primer pockets are still as tight as the first primer seated. 340 Weatherby Improved (340 Zaylea Ann) has a capacity of 112 grains. 378 Weatherby Improved (375 Zayne) has a case capacity of 142-144 grains. They have been reloaded 3-5 times and still in mint condish. These are Norma and Norma/Weatherby brass.

Maybe they've made them stronger since the late 90's when I ran them but there is no way I'd base a wildcat case off of a .378/.416/.460 Weatherby today. There is no up side to using one when there are long Lapua cases available like the XC cases made by Peterson from Tubbs. The XC case is already "improved". Bertram makes a long Lapua case as well and their brass is known for it's strength but typically at the cost of case capacity.

 

[TXAoudadKlr]

500 Jeffery necked to 30 would be a beast

 

[IdahoCTD]

Swamplord did 500 Jeff wildcats 6-7 years ago. My guess is brass quality and too much of a good thing is why you dont hear about them anymore.