About May 24-26, Fritz 454, Rob, jeffeosso, and Dak had a discussion on loading the 600 OK with IMR 7828. Seems like Fritz could get 2260 fps with his bullets with 168 grs of 7828 and a 28 inch barrel and I with a 25 inch barrel could only get 1949 and 1946 fps with the long cut 7828 and 900 gr FMJ Woddleigh's. Well today, I went out to a private range with a friend and we checked out our chrony's first of all and then produced some curious results with several powders.

long cut 7828- 168 grains gave only 1954 fps and signs of primer bulging and flattening, the first signs of excessive pressure in the 600 OK case I have seen. This is only a small increase over the 165 gr load which gave 1946-49 fps. Yes, there was some powder compression.
However using the 7828 SSC, I got 1965 and 2085 fps with the 165 and 170 gr loads, respectively. No powder compression and no signs of pressure or added recoil.
Other powders:
165 gr of H4350 gave 2263 fps, no pressure signs.

150 gr of H414 gave 2134 fps, no pressure signs.

Does anyone have a clue as to what is happening during the max loads of long cut 7828?? I thought that I was going to make that my hunting load powder, but now it appears that the H4350 powder may be more interesting.

Also, I think that 2200 fps should give enough penetration with the 900 gr Woodleigh's. Or are there better loads for that????

Comment's???

Dak

Dakota-Did the cases with the load you
are concerned about extract easy?
As long as you have H-414 work up a 2250 load with it...Also W-760. You can't beat ball
powder for good velocity with minimun case
expansion and stretching.In straight cases
7828SC will seem slower at same wt of powder
at full loads, compared to 7828..Ed.

Doc- Very strange. I've shot quite a bit of those 168 gr IMR 7828 loads and never saw any flattened primers. This load should be rather low pressure in fact. Wonder if your having some ignition problems. Try 2-3 grs of bulleseye over the primer before adding the IMR 7828. For Ha ha's also check the primer pocket depth of those cases. It's always possible some may be of variable depth.
Yes H4350 and H414 will deliver pretty good velocities. Keep going up a grain at a time with H414 till you can't hold on any more.-Rob

Something sounds very wrong here.168 of 7828 shoud not be giving you anything close to high pressures. You just can't stuff enough in to make that happen.
I did confirm my velocities last weekend and 2250s with 168 gr of sc 7828 and 5grns of bullseye as Rob sugests.
414 is, in my mind, the best of the powders to get your velocity up there but H4350 is a good powder as well. I have not tried W-760 but may at some point.
John

Hubel454,
No Ed, there was no problem with case extraction. Curious! Agreed, 7828SSC seems slower than the long cut. Since I can get more in the case, am going to load maybe up to 175 gr loads.

Rob,
Agreed, real strange behavior, since the 7828 SSC showed no pressure signs. Will go up cautiously with it and the H414 and H4350 powders, up to maybe 2300 fps. 2400 fps, I will leave to you
Yes, could be an ignition problem, so will check the primer pocket before the next series of loads.
Have a good hunt, my day in Africa is next year. The wife is taking me on tour this year until July!!

Fritz454
As Rob said, may be an ignition problem. But at these loads want to proceed cautiously. To date I like the H4350 powder. Some folks load it in their .585 Nyati rifles. Will also pursue the H414 powder loads.

Thanks for input guys, helps with the loading project. So far nothing adverse in any recoil behavior to make it a problem in hunting. Shoots just like any plain ole 500 Jeffrey or AHR

Dak

After thinking about this some more, I tend to think you are experiencing some ignition problems. Check the primer hole for uniformity and try the same load with 2-3 grs of bullseye over the primer. My guess is the 7828 is not igniting properly and you are experiencing a form of what .50BMG shooters call double concussion. The bullseye should fix the problem. I'd suggest you stick with IMR 7828ssc and just use a longer drop tube or as Fritz 454 suggested keep on trucking with H4350.-Rob

Rob,
Agreed, after looking at some of the data, it looks like an ignition problem and I bet a few grains of Bullseye will solve it. If I remember correctly, you had used the Bullseye some time ago with the slow powders. Will continue with the loading project when I return,

Also, will try to determine a comfortable max with H4350 and 7828SSC powders. A friend gave me some Win large rifle WLRM primers to try. Claimed that these were hotter than the Fed 215.

Thanks, Dak

Doc- when I first invented the .600OK, I was concerned with ignition problems based on similar problems with the .600NE and 585 NYATI.
I started off using a Bulleseye priming charge with 7828. I had no ignition problems and deceided that it was not necessary. It seems likely that with 7828 reliable ignition with Fed 215 primers may be marginal in some guns with some primer lots. No such issues with H414 or H4350. -Rob

Rob,
That's probably when happened, poor ignition. Not the most reliable combination of primer and powder for hunting DG, but it does make a nice low pressure loading at approx 1900 fps, for practice. For hunting loads, I am going to pursue the H414 and H4350 powder loads for hopefully the best penetration, ie. 2100-2300. fps

Dak