Sadly I own just one Weatherby rifle, but it is the rifle of my dreams, so life is good. It is a .340 Mark V, stainless/synthetic, topped off with a Leupold long range target scope.

I'm hanging' with Oregon Jim. I have one - a lefty Mark V Accumark in 340 topped off with a Burris Veracity 4-20. I needed an elk rifle, so I got the hammer.

I've dumped another 50 rounds down the tube with different powders, so I have some more load data for the Cutting Edge 225gr Maximus for anyone who needs it. I have not fully explored these powders with these bullets, but they all shot sub-moa at 400yds (I don't bother shooting at 100 yds after I get the seating depth close).

86.7 gr Alliant RL19
COAL: 3.658" with Ogive @ 3.005"
Average FPS: 3045
ES: 16
This is fairly hot. I worked up from 83.9 gr (~2935FPS) in 1.9 gr increments. Velocity and group orientation told me so, shown in the first two pics.

86.5 gr IMR7828ssc
COAL: 3.650" with Ogive @ 3.0045"
Average FPS: 3017
ES: 16
Group in 3rd pic. Tomorrow I'm going to jack up the charge a touch. I'm looking to see where the velocity flattens out.

For those who may consider CE bullets in the 340 Weatherby, I'll share some load data that I've worked up over the past couple of years. These are long solid copper projectiles that I've seen used to compete and win in the King of Two Miles competitions. they offer several hunting projectiles, and I chose to try the Maximus line for long range accuracy potential. As Mr. Whelen once said: "Only accurate guns are interesting". My rifle is a LH Weatherby Mark V Accumark, and the loads I've developed are those achieving maximum accuracy in my particular rifle.

Cutting Edge 260 gr Maximus:
OAL - 1.722"
Projection Length from Seal Tite band - .940"
G1 BC is not listed, but it's about .700
Preferred Powder: Norma MRP @83gr.
Velocity @ 2830fps

I bump the fired cases back 4 thou in a FL sizing die and cut and chamfer to 2.8165" in order to seat the bullet far enough in the case such that the Seal Tite band sits in the chamfer of the neck mouth. This is only necessary if you want to fit the cartridges in the Mark V magazine. The cartridge OAL I settled with for accuracy is 3.717. I tried up to 85gr.  IMR 7828SSC, and 85gr MRP, but the 83gr MRP proved more accurate in my gun - less than 1MOA. This bullet carries a lot of energy downrange.

Cutting Edge 225gr Maximus:
OAL - 1.494"
Projection Length from Seal Tite band - .820"
G1 BC - .640
Powder: Norma MRP @ 86.2gr.
Velocity: ~3140fps
This is a HOT, HOT load, but shoots .6MOA consistently in my particular rifle without any over-pressure signs. I DO NOT suggest this as anywhere near another's starting load! I'm going to try RL19, RL22, H4831SC, and H4350, because I'm running out of MRP!!  There is no case interference issue with the Seal Tite band due to the shorter projection length (than the 260gr Max), and I settled on a 3.658 COAL, which has no problem fitting in the Mark V magazine. I still bump the fired cases back 4 thou, but I trim and chamfer to 2.825". This has grown to become my overall preferred cartridge for my 340 Bee, considering ballistics, consistency, accuracy and recoil. I have yet to experience terminal performance, but the Maximus line is intended to be frangible at all velocities, and down to 1400fps, making it an ideal projectile for long range hunting. Hopefully this year will be the year I get to drop a bull elk with this round!

Has anyone else had experience with the CE bullets? Thanks. 

Edited to add a pic of the CEMax 225 gr MRP load group at 400 yds:

A variety of Sierra Game Kings have done everything a hunting bullet needs to do for me on deer. My son shot a Mulie buck in the heart with his 243 WSSM using an 87 gn Interlock, which I think very close to a Game King as you. It was about a 125yd shot. The buck too five steps and crumbled. Game Kings at 60 and 390 yards on big bucks from a 7mm Rem Mag did the job too. I had a 150gn Game King from 135yds move from R shoulder to L hip through another big buck. He was another one that took four or five steps and was done. Bullets were recovered from under offside hide on the 60 and 135yd shots. The cores were with the cup but not secured by the cup. Still, the mushroom effect was perfect and the deer were down quick. As Zonie stated, accuracy is king. Period. The Game Kings will do the job on deer or pronghorn if you make the good shot.

Are you referencing the SGK or the Tipped Game King? The Tipped Game King has a much thicker copper jacket than the SGK.

I've been getting factory velocity with loads using MRP and 7828ssc, with 250gr SGK. The SGK has been the most accurate projectile in my Accumark. I've settled on 85gr MRP @2950fps for he most accurate & consistent load. I've loaded up to 86.8gr MRP, but the ES grew and there was no consistent velocity gains or accuracy improvements. My back-up SGK load is 86.8gr 7828ssc @ 2990fps.

I use a Forster Ultra Micrometer seating die, and a FL sizing die along with an Innovative Technologies (Larry Willis) belted magnum resizing die for my 340 Accumark.

Thanks everyone!

Don't get me wrong, I'm not for pushing the safety limits, but the numbers I've seen are from Cor-bon claims 3100fps, but folks are stating that they're getting 3200 out of their 26" barrels. That's screaming, and I'm puzzled about how they do it safely.

Before I was fortunate to find a NIB lefty 340 Wby, I've hunted elk with my trusty Model 94 XTR in 356 Win., so I'm in with the fat, slow and close. I have bagged many animals at long ranges here in the Northeast, with many different rigs. My favorite for big game is my '47 03-A3 NRA Sporter with a NM barrel that I was gifted with 35 years ago. It's a tack driver - even with various factory ammos. I own a 550-acre farm, and shoot a lot, especially at those small criitters.

This is my first Wby, and although Ive reloaded for a long time, it seems you can push them far with that freebore. It's just incredible that an old cartidge like that in such a manageable and accurate package remains unreplicated.

Jim, by benefit I mean for my scope setup, not terminal efficiency. Don't laugh, but my trusty mount is a Japan-made Tasco TR 4-12 trajectory ranging scope. The correct "A" turret is good on a 340 with 250gr factory pills. I've tried that and other turrets with the 225s, and they're off significantly. If I could get 3100, I would have dead-on shooting to 600yards. But after Chris and Jim's gentle persuasion, I switched over to a Tasco Titan 3-12, 30mm tube, with #4 German reticle (also Japan-made). Oh, the scopes are cradled in Near Alphamounts. I'll just measure the thin portion of the verticle post @100 yards and work up a chart for my 3000fps cartidgeI'm liking the 7828, because my gun and cleaning kit do. No biggie, just a tactic change. Like Pat said, call it a day.

Thanks for your help, and especially your concerns for safety. Now I'm just waiting for my Devcon bedding job to cure, and I'll screw in some tamer loads on Saturday!