Big 338 powders??

[B23]

Soooooo, if the 378Wby case is "HUGE" what do you call the 338-408?

Ginormous, Gigantic, Monstrous, Humongous, Gargantuan

 

[Long Time Long Ranger]

Enormous, heavy barrel burner! I'd still love to have one though!

 

[Kiwi Greg]

Enormous, heavy barrel burner! I'd still love to have one though!

Thats why I built a custom 416 Barrett over two years ago & tried 24N41, 20N29, 50BMG & US869 & settled on the 869 but the 50 BMG is nearly as good, without some of 869s gremlins.
I would like to build a 375 VM type rifle but the lack of suitable pills is what is holding me back for now, I had/have the same trouble with the 416 & have learnt maybe
The 416 is still heaps of fun though with 420-435 pills going 3250fps ish

I use the 338s to try & learn as much as I can without breaking the bank lightbulb& they are more consistant

 

[RDM416]

I've got one of those ginourmous, monsterous 338AM's on order from Kirby, can't hardly stand the wait!!

 

[B23]

Oh ya, sureee, rub it in why don't ya. For now I can only dream of having a 338AM.

Funny thing is I've got one of those 338Lapua imp with their not so "HUGE" case and it will blow the doors off my Accumark 338-378 and it has that "HUGE" case. lol

 

[Long Time Long Ranger]

RDM416, Let us know how it shoots. I would love to have one of those some day.

Kiwi, that Barret sounds like a great long range elk rifle to me. I would love to smack one with a 420 grain bullet at 3250. I think that is when I would start doing the mile thing during cow elk season.

B23, During the 90's when the Lapua case came out me and several others tried every possible configuration of the Lapua imp. case trying to beat the old tried and true 338-378 wildcat that had set the standard for big 338's since the 70's. We could not do it. You might get a super fast lapua imp barrel and a super slow 338-378 barrel and make them equal. But on average the 338-378 wins that velocity battle every time. Not by much but a consistent 50-75 fps average with best accuracy loads and equal length barrels. Negligible but neither is going to blow the doors off the other. Bottom line it is much safer to load down the 338-378 wby to shoot right with a maxed out 338 lapua imp. The Accumark has a 26" barrel. What barrel length is your Lapua imp? The 338-378 wby I hunt with most has a 28" Hart Barrel on it and the best accuracy load is 3064 fps with H-870 powder and a 300 smk. The 338 Lapua imp versions we tested all hit 2950-3000 fps with 30" barrels with safe pressure loads. You may have a very slow 338-378 and a very fast lapua imp. But still at that neither is going to blow the doors off the other. Or the barrel lengths are different. What are your velocities in each? The 338 Lapua Imp is one of my favorite cartridges but it will not blow the doors off a 338-378 wby all else being equal.

 

[idaho elk hunter]

Loading for the 338-378 Weatherby has changed alot over the past 2 years. With todays new powders one can upload todays new bullets to higher velocitys and accuracy than back in wildcat era. H570 and rl33 really changed the game with todays new high BC pills. the 300 gr accumark and 280 gr barnes pushed to 3100 fps in a freebored barrel is very safe and doable. NO LAPUA even if imp version can touch this safely. THis data that I just stated above is 26 in barrel!

 

[Broz]

. NO LAPUA even if imp version can touch this safely.

Hmmmm, bold statement there. I am fully aware of the capabilities of the 338-378, as well as its shortcomings. I am going off memory here but I believe the 338-378 has an H20 case capacity of around 122 gr. Now if we had a Lapua based case that was equal to it or even a few grains more, would you still stand behind your statement?

Lets not forget the much stronger Lapua brass that can be safely loaded to levels well above the Norma brass. Also the shorter fatter more efficient Lapua case design. Now lets consider the +P throat from Defensive Edge???? I like the 338-378 and have been a Weatherby fan most of my life. But it is possible your post statement is as dated as some of the powders you spoke of. My new rifle in 338 Terminator +P was not something we did on a whim without research.

Just saying,

Jeff

 

[busse fan]

I have read this thread with great interest. I just bought a 338 lapua weatherby accumark and several boxes of 300gr otm (based on the work Broz did with them).

I want a powder that will get me 2700fps or more with good case life and of course accuracy. I also hunt in cold weather (up to -40) and have always used hodgdon extreme powders in other guns to cover the large temp spread from summer to winter temps.

I am intrigued by rl33 and vv n570 but rl33 has no data and n570 supposedly isn't temp stable. Are retumbo and h1000 my only real options?

 

[Broz]

I have read this thread with great interest. I just bought a 338 lapua weatherby accumark and several boxes of 300gr otm (based on the work Broz did with them).

I want a powder that will get me 2700fps or more with good case life and of course accuracy. I also hunt in cold weather (up to -40) and have always used hodgdon extreme powders in other guns to cover the large temp spread from summer to winter temps.

I am intrigued by rl33 and vv n570 but rl33 has no data and n570 supposedly isn't temp stable. Are retumbo and h1000 my only real options?

H-1000 will do it with ease and will be cleaner than Retumbo.

Jeff

 

[busse fan]

Thanks. Will start with the Berger data and see if I get where I want to go. Their data is kind of slow.

 

[Broz]

Thanks. Will start with the Berger data and see if I get where I want to go. Their data is kind of slow.

Seat them -.040" off the lands to start. Work up from 88 gr. watching for pressure and when you get to 90 gr you should be close or a bit over.

Jeff

 

[busse fan]

Thanks for the info.

 

[longrangehunterII]

Hmmmm, bold statement there. I am fully aware of the capabilities of the 338-378, as well as its shortcomings. I am going off memory here but I believe the 338-378 has an H20 case capacity of around 122 gr. Now if we had a Lapua based case that was equal to it or even a few grains more, would you still stand behind your statement?

Lets not forget the much stronger Lapua brass that can be safely loaded to levels well above the Norma brass. Also the shorter fatter more efficient Lapua case design. Now lets consider the +P throat from Defensive Edge???? I like the 338-378 and have been a Weatherby fan most of my life. But it is possible your post statement is as dated as some of the powders you spoke of. My new rifle in 338 Terminator +P was not something we did on a whim without research.

Just saying,

Jeff

Hey Jeff,

A friend sent me this today for my TRG-42 LM, I am a Lapua fan because it's a MIlitary round, but it is not even close in capacity to the Wby. which I could care less about, the recoil is already a lot with a 14 1/2 lbs. gun.

Cartridge : .338 Lapua Mag.
Bullet : .338, 300, Sierra HPBT LR MK 9300 G7 Litz
Useable Case Capaci: 92.057 grain H2O = 5.977 cm³
Cartridge O.A.L. L6: 3.681 inch = 93.50 mm
Barrel Length : 27.0 inch = 685.8 mm

I chose to brake in the barrel w/IMR 4350 since Sierra showed in a most accurate, which in my case it was rather accurate, but slow as snails pace; 78 grains only produced 2525 fps but put three out of twenty in the same hole even with cleaning the barrel.

I have on hand H1000, RL 22, 25 and 33, IMR 7828 and 7828 ssc, N170, 780 Supreme and almost anything else except the really slow stuff.... US869, and such. What would you suggest I try for shear accuracy and nothing else, bullet drop means almost nothing. I have 28.5 Mils of scope adjustment even with the 2525 fps 300 SMK round.