Home Forums Hunting & Shooting Long Range Hunting 338-378 with RL33 and 300 Gr SMK

Here is a load I worked up with the New RL33 powder 338-378 with a 300 gr SMK. I am going to run them at 3020 fps this load was just a touch too warm, but it was also hot outside too.3020 fps is a gr less. That is a serious can of whoop ass out of a 26 inch barrel !! 30 inch barrel I would be 3,100 + fps

What rifle you using? I have an Accumark 338-378 Weatherby and at 3000 ft/sec using 300 gr SMK, I have a hard time to extract the spent cartridge.It has a 28 inch barrel with brake. Are you sure about the accuracy of your chrono?

Yes chronograph is accurate and so are my long range drops. I have a factory accumark they are 26 inch plus brake.The best I could do before RL33 was 2920 fps that was RL25

I used 7828 SC compressed loads to achieve that speed. Like I said I had to back off due to bolt sticking at 3000 ft/sec. Are you FL your brass on reload? Can't figure out how you can do it and I can't. What brass you using?

The trick is the RL 33 have you tried it? weatherby/Norma brass, fed 215 primer, seated mag length at 3.80 ,yes I full length resize

I use the same primers and reneck only. I COL at 3.9, why is your mag so short? Mine measures 3.92. I will try the RL 33 and COL at 3.8, maye thats the ticket.

I'll check again but pretty sure 3.8 is about all my mag box allows. I really do think RL33 is getting my velocity up there.

I have been helping a friend that has a 338-378 with a new Bartlein barrel finished @ 28" with a proof research wrap. the only powder we have used is RL33 with 300SMK's and never hit 3K even with excess pressure, but then we are using an Oehler for a speed gun.

Hmm interesting how different rifles do different things. RL25 topped out at about 2920 fps without pressure signs.You would think with a 28 inch barrel 3000 would be easy in the 338-378 with a 28 inch barrel. 118.0 gr of RL33 gave me 3,020 fps with no sticky bolt lift or ejector button stamp.I was 20 feet from chrony and it was about 80 deg out.

With the new Bartlein he probably doesn't have the factory weatherby freebore right? If that is the case the pressure will be quite different

Well I can't figure out how you can get over 3000 ft/sec when my bolt wants to lock up at 2900 ft/sec in the same rifle shooting the same 300 grain SMK bullet?????

Did you work up some loads with RL33? Before I used RL33 I could not reach that velocity.

Probably just have to mark it up to the black magic we all see with rigs shooting the same loads at different speeds. I'll never understand it either.

FWIW, Quickload shows a little less than 2900 fps with RL 33 as max with the specs you gave.

That's some performance.

Speaking of big 338s, one of the local LR guys is running the 300gr Berger Hybrid at 3200 fps. He's using a blown out 338 Lapua case, N570, and a 32" barrel.

RL 25 and 33 do things that other powders can't quite match. 25 is a wonderful 300 H&H/WinMag/Weatherby powder in a correct barrel (26" minimum) and 33 works very well in the big 338s.
As several have pointed out, the barrel means a lot. There is a world of difference between a conventional 4 groove 24/26" and a Nitride treated 30/36" 3 groove.
A 245 gr 338 Bore Tech bullet easily exceeds 3000 fps in a 338 Lapua or RUM carrying a state of the art long barrel and shoots flatter to 1000 or more than any 300 gr Berger alternative. BT BC is .869 Berger is .818.
RL 33, Retumbo or H 869 will do it.
Not "hunting rifles" but still lighter than a Barrett.

Yeh that 3200 fps rig is using the +P version of the Lapua improved right?I am very impressed to go over 3,000 with a 26 inch barrel the RL33 does seem to working as claimed.But all that being said if it doesn't shoot as accurate as my 2920 fps load it doesn't matter because the accuracy load I have found with RL25 will be the go to.

Yes, I guess you know I'm talking about Broz's rifle. 338 Terminator +P.

I just acquired a WBY Accumark in 338-378 . What would be the starting load with Re#33 and a 300 gr bullet ?

Hate to jump in when not asked but if you go over 2800 ft /sec with that 300 smk in that 338/378 you will see that bolt starts sticking and cratered primers. i have the exact same rifle. No matter what powder you use. Have you an accurate bullet speed equipment?