Two years ago this week, I shot my OverKill for the first time. So, I thought it was fitting to shoot it this weekend.

I haven't been active on this forum in a while, been busy with work, family, and USPSA matches. Here's a pic for anyone who forgot what it looks like or any of the new posters who haven't seen it.




The barrel is 23", there are two 11oz mercury recoil reducers in the butt and the rifle weighs 13lbs.

Last time I posted chrono data I had tried 160grs and 166 grs of H4350. That gave me a three shot avg of 2159fps for the 160gr load. I never chronoed the 166gr load. That was as much as I could fit in a virgin case.

This year I neck sized a once fired case and was able to get 170grs of H4350 in it. That gave me an avg of 2247fps with a 900gr WW. If I had a 26" barrel like Rob and John I have no doubt this would be over 2300fps.I loaded up some Woodleigh solids but didn't get a chance to chrono them.

Still one of my favorite pics:

It is still a nice looking rig - glad you took it out for a spin! Thanks for posting.

WOW

Enter Bullet Weight in Grains: 900


Enter Muzzle Velocity in FPS: 2247


Enter Powder Weight in Grains: 170


Enter Gun Weight in Pounds (example 9.25): 13.0



Recoil Energy (in foot-pounds): 176


Recoil Velocity (in feet per second): 29



This is too much of a good thing, for ME.


Hog Killer

How does that muzzle break factor into the equation?

quote:

Originally posted by Tex21:
How does that muzzle break factor into the equation?

It's funny you ask that. Today after the match, I had 900gr Woodliegh solids loaded over 163grs of IMR7828. I fired one with and two without the brake. There was a difference without the brake, but not a huge difference. I'd give it a 20 to 25% at most, probably the lower end.

I used the turned brass for the solid loads, I shot 3, I had a case head sep with one of them, right at the belt.

I fired 8 rounds total, 3-170gr H4350(with brake on, I wouldn't even try it without the brake), 3-163gr IMR7828(1 with, 2 without brake), 1-160gr H4350 900grWW soft, 1-160gr H4350 WW soft hollowpointed (approx 850grs.)

A few other guys tried the rifle today, a few with the 170 loads and 1 or two with the 160's.

The gunsmith had the barrel off the other day to ream the throat, the chamber was too short to shoot the solids before. The lugs look fine, no set back, the bedding was perfect (it looked like new), the only problem was a small crack in the tang. He found the rear crossbolt had loosened up, the rear of the mag mortise must have been expanding. That's been taken care off now.

There are over 110 rounds shot through this gun to date. We figured that there has been right around 1,000,000 lbs of muzzle energy through this gun now. Think about that for a minute...

quote:

We figured that there has been right around 1,000,000 lbs of muzzle energy through this gun now.

quote:

Originally posted by GeorgeInNePa:

I'm assuming that your rifle is built by AHR??? If so, they have seriously changed the brake from when yours was built. SEE HERE.

quote:

Still one of my favorite pics:

THAT'S SICK!!!!!!!

George,

Good to see someone posting 600 OK data again.
My chrono data for the 7828 and H4350 falls in with yours. 165 grains of H4350 gave me 2263 fps (no pressure signs) in a 23 inch barrel.

Surprised that you had a head separation with the machined cases, probably around 1950 fps, but then Robgunbuilder estimated that the machined brass had a max limit of 2000 fps, good guess!!

Never shot mine with the brake off, just never had an urge to dtermine the velocity at which my eyes cross

Have shot a buffalo (bison) with it, but am not taking it to Africa this time, just cautious about the harrassment about the 600 caliber.

Good shooting!

Dak

I never get sick of seeing that cannon George.

quote:

There was a difference without the brake, but not a huge difference. I'd give it a 20 to 25% at most, probably the lower end.

Hi George,

That sure is a nice looking rifle. I enjoy your idea of "not a huge difference" in that 20% to 25% reduction from 176 foot-pounds is the equivalent recoil of a 375 H&H

quote:

Originally posted by woodsracer:

quote:

Originally posted by GeorgeInNePa:

I'm assuming that your rifle is built by AHR??? If so, they have seriously changed the brake from when yours was built. SEE HERE.

quote:

Still one of my favorite pics:

THAT'S SICK!!!!!!!

Hi, a local 'smith, a good friend of mine, built this rifle. See here:

1st thread

2nd thread

3rd thread

4th thread

quote:

Originally posted by dakota45056:
George,

Good to see someone posting 600 OK data again.
My chrono data for the 7828 and H4350 falls in with yours. 165 grains of H4350 gave me 2263 fps (no pressure signs) in a 23 inch barrel.

Surprised that you had a head separation with the machined cases, probably around 1950 fps, but then Robgunbuilder estimated that the machined brass had a max limit of 2000 fps, good guess!!

Never shot mine with the brake off, just never had an urge to dtermine the velocity at which my eyes cross

Have shot a buffalo (bison) with it, but am not taking it to Africa this time, just cautious about the harrassment about the 600 caliber.

Good shooting!

Dak

That's what gets me, 170gr should be a bit more than 2247fps. I was thinking more along the lines of 2300.

After becoming comfortable shooting this thing several times and not severly flinching I bet you dont have the slightest of problems with your other "kinda large" rifles... That thing is something else!!

Amazing rifle,
Justin

George,

If I remember correctly using H414 got me higher velocities, about 2320 fps. But that is a guess. Never tried 170 gr of H4350 that I can remember. That was last year and I lost my notes on it. But did experience a lack of velocity for my 23 inch barrel when using 7828 and when comparing data to Robgunbuilder's and Bridger's. Same result when using 7828SCC too.

Anyway, shooting the 600 OK around the 2250-2300 fps limit is about my comfortable limit. Will take everyone's word that the 2400 fps level is a real treat
If you run a search on 600 OK loading data I'm sure you will track it down.

Dak

quote:

Originally posted by dakota45056:
George,

If I remember correctly using H414 got me higher velocities, about 2320 fps. But that is a guess. Never tried 170 gr of H4350 that I can remember. That was last year and I lost my notes on it. But did experience a lack of velocity for my 23 inch barrel when using 7828 and when comparing data to Robgunbuilder's and Bridger's. Same result when using 7828SCC too.

Anyway, shooting the 600 OK around the 2250-2300 fps limit is about my comfortable limit. Will take everyone's word that the 2400 fps level is a real treat
If you run a search on 600 OK loading data I'm sure you will track it down.

Dak

Yes, I agree, 2250ish is fine and dandy. It's a real handfull at that level. IMR7828 wasn't the trick in mine either.

I'm going to buy a pound of H414 and give that a shot. I'd like to experience 2300 just one time. There must be something wrong with me...

quote:

Originally posted by Lion:
After becoming comfortable shooting this thing several times and not severly flinching I bet you dont have the slightest of problems with your other "kinda large" rifles... That thing is something else!!

Amazing rifle,
Justin

After shooting this, you just chuckle when someone offers you a round or two with their .460WM