I was thinking about recoil energy for some cartridges.

.700 BMG IMPROVED "1000 grain bullet at 3000 f/s " Recoil nubmer: 390 joule.

.600 BMG IMPROVED "900 grain bullet at 2900 f/s" Recoil number: 320 joule.

These two cartridges with a rifle weight of 22 pounds " 10 kg "

.585 NYATI " 750 grain bullet at 2520 f/s" Recoil number: 213 joule. Rifle weight 13 pounds " 6 kg "

.460 Weatherby " 500 grain bullet at 2600 f/s " Recoil number:129 joule. Rifle weight 11 pounds " 5 kg "

The .700 BMG IMPROVED have 3 times as much recoil energy than a .460 Weatherby... The muzzle brake has to be very good on a rifle like that and if the weight was 16 pounds as Robgunbuilder said. Then the recoil number is 534 joule.

Robgunbuilder...!

How can a muzzle brake be so effective...???

Overkill- I've never fired a .700 BMG Improved, but Monte Kyser has and has lived to tell about it. I think his gun weighed 26 lbs, but then again he even fired 1900 gr bullets at 2000fps. I just shoot the .50 BMG in a 16-20lb rifle. George Vias made my break and it's effective enough for me. With that said, I don't find it's or the Nyati's recoil unmanageable in the least. The combo of good gun weight, good brake, good butt pad and past recoil shoulder pads make these things shootable for us meer mortals.
I'm really thinking hard about the .600 overkill in a 13lb rifle. I'm aiming at 900grs at 2400 fps. That should be impressive. We want to give you the honor of being the first to pull the trigger on it. -Rob

I can't remember if I found this here, or posted here before, sorry if redundant, but if you want to see recoil energy, go to:
http://www.gunshop.com/videoclips/4bore_ouch_240x180x12fps.mov
Haven't figured out what the poor guy seeming to 'spot' for the shooter is doing, but he got the worst of it.
rob the guy who got to get a 4 bore

Robgunbuilder...!

A 900 grain caliber .620 bullet at 2400 f/s have the right name .600 Overkill

But the .577 Tyrannosaur have more kinetic energy.

A 900 grain bullet at 2400 f/s will have a energy of 11500 foot pounds energy. And the .577 Tyrannosaur will have 12 140 foot pounds of energy. Even if the 900 grain bullet were going at 2500 f/s it still not have more energy than 12 500 foot pounds. If you load the .577 Tyrannosaur up to 2750 f/s with a barrel lenght of 28" it will give 12 600 foot pounds.

Yes yes I know that it is almost the same energy and the .600 will hit harder anyway. But it was just a thought. And if the .600 Overkill is possible to make on a Brno CZ 550 Magnum action it is much more easy and cheaper than the .577 Tyrannosaur. And there is just hornebear who make brass for the .577 Tyrannosaur

What velocity do you think is possible to get in the Heym Express rifle .600 NE ????

Overkill- I have not finished the case design work yet, but preliminary data suggests at least 2400fps with a 900 gr bullet in a cartridge that will feed through a CZ550. OAL 3.600. I used Quick load and it's quite conservative for this estimate. It also looks to be a quite efficient cartridge. You could drop the bullet weight to 750grs and also pick up about 200 fps. With a .620 diameter bullet this thing will hit darn hard but probably not penetrate far. My bet is that it will be a close match to the T-Rex and clearly beat the NYATI. Horneber will probably still have to make the cases though.-Rob