30-378 WBY Load Development

[cmahussier]

Hey Everyone.

Looking for some advice for some load development advice for a 30-378 WBY. I’ve had my Accumark for several years but it’s a project I seem to put on the back burner. I have equipped it with a Timmney trigger, rail and Nightforce with long range hunting if required to be my goal, but have yet to find a pet load for it. I have been trying 7828 ssc with 210 LR Accubonds but they seem relatively inconsistent. Might be me? As you know this riffle isn’t a dream to shoot even with a muzzle break.

Recently paid an arm and a leg for some Retumbo and was hoping to try some 205 Berger Elite Hunters to try but that’s impossible to find. Thinking of going with Hornady Eldx. 200 or 220 as I have access to them. Maybe just try the LR Accubonds with retumbo?

I have over 5000 rounds of reloading under my belt and have some very good results over the years but so far this one has eluded me. If anyone on here has experience loading for this cartridge please feel free to lend some advice.

Thank You!

[obsessed1]

IMO while reloading/ finding a pet load is important the shooter is more than likely the biggest variable in these cannons. If you cant manage the recoil and flinch during the shot all loads will be inconsistent. In these days before I threw tons of money at different powders/ bullets in an attempt to find that load I would verify that it is the load not the shooter that is inconsistent.

[wally338]

Let me guess. The almighty Nightforce is a 2nd focal plane scope.

[Smokinyotes]

I think I would try us869, H50bmg, and retumbo. As far as bullets I think there are better bullets than the EldX. The eldx are accurate but I find them to be pretty frangible and not hold together great. I have been disappointed with the accuracy with the long range accubonds. If you could find some swift A frames they may work well..

[Dean2]

If you find the gun unpleasant to shoot, even with a brake on it, I would try a different brake. A proper brake should bring it down into 308 recoil territory. I would fix that, cost is only 2-400. You could easily burn up that much in components looking for a load. Once I got the recoil organized I would focus on seating depth, working with the best load you have developed so far. You aren't going to get the bullets close to the lands, but COAL still has quite a big effect on group size even with the Weatherby free bore. Most Weatherby rounds I have loaded for are not real picky on loads, in terms of powder or bullet.

[rugerfan]

Retumbo is definitely the go to power for that cartridge, and federal 215 primers are the most consistent ignition in my experience. My usual method for load development with any Weatherby is to start the c.o.a.l as long as it can be and still eject a loaded round, often slightly shorter than the mag box will actually allow. Find the charge weight that produces the best results and then shorten the seating depth a little at a time to dial things in if necessary.

[marky_mark]

I would be using a 215 Berger at a minimum

[cmahussier]

Originally Posted by wally338

Let me guess. The almighty Nightforce is a 2nd focal plane scope.

Maybe I’m missing something but what does second focal plane have to do with load development?

[cmahussier]

The recoil is very manageable with the muzzle break but it’s the percussion that somehow gets in a guys head. I’d say it’s comparable to a 30-06.

As you all know it’s a lot of time and effort to try a certain projectile. Would like to try the Berger’s but in the current shortage we are in I think that I may have to try something I can get my hands on. Still leaning towards the 220 ELDX as it’s something I can actually get. Thanks for all the good input fellas.

[marky_mark]

Originally Posted by cmahussier

The recoil is very manageable with the muzzle break but it’s the percussion that somehow gets in a guys head. I’d say it’s comparable to a 30-06.

As you all know it’s a lot of time and effort to try a certain projectile. Would like to try the Berger’s but in the current shortage we are in I think that I may have to try something I can get my hands on. Still leaning towards the 220 ELDX as it’s something I can actually get. Thanks for all the good input fellas.

Try a different brake
The radial, factory accubrake is old technology

If it’s getting in your head already that’s not a good sign

[KegRiver]

I have not tried reloading for that cartridge as yet but I've been looking into it.

My BIL owns a rifle chambered for that cartridge but does not reload so I do whatever reloading he requires.

Don't know if this will help, but the best information I have found so far indicates that 108gr of H50BMG produced the best groups in one test rifle when using a 200gr Nosler Accubond or Partitian spitzer bullet.
Listed nuzzle velocity was 2,965.
Load density was 95% and it was the recommended starting load.

Greatest velocity was achieved with 94gr of IMR 7828, which produced a mv of 3,102.
That was a max load. Load had a density of 82%

Max load for H1000 and H50BMG was only 34 fps slower.

With a 220 Nosler partition bullet the most accurate load was achieved with 91gr of IMR7828 which was the max load for that power.

If you would like to have those load data sheets they are from the 2019 Nosler reloading guide.

[brewster29]

Wow, that's a lot of powder and noise to gain 100-150 fps over a 300 Win Mag. Ouch! I understand the rule of diminishing returns but this is extreme.

[marky_mark]

180gr factory ammo is running at 3400 fps

[birdseye]

Go with the retumbo,play with seating depth,start out as far as the mag will allow,I’ve owned one of these bad boys since 1995,well until my son took it over a few years ago lol,there is no 300 wm that can push any weight projectile within 100-150 FPS,180 gr for example can be pushed to almost 3500 FPS,a win mag might hit 3000 and change,send me a PM and maybe my son or I could help with a pet load and OAL

[Snap Shot]

I have had a 30-378 for close to 10yrs. RL22 & Retumbo are the answer. OAL as long as possible to fit with in the box mag. I’m using 190grn nosler long range accubonds @ 3425 FPS. This cartridge is amazing & the knockdown power is unreal