Just picked up some 7828Super short cut

[grubbylabs]

Any one use this in a 300 win mag?

Do you like it?

Does it load the same as regular or standard 7828?

Where are you finding the sweet spot?

This is the first time I will be developing a load for this rifle so I have not used any other powder for it.

I am starting out with a 165 grain Hornady SST since I have some of those. But I will probably witch to either a interlock or a 180 grain inter lock.

[Saltydog235]

I load it and standard 7828 for my 7Mag and cannot see too much difference other than it takes up a little less case capacity. 7828 has been the only powder I have found that gives me acceptable accuracy with a Barnes TSX.

[Unclenick]

A note of caution with the .300 Win Mag. For some reason the capacity of cases for this round vary a lot from maker to maker, running from about 88 grains of water capacity (Remington) to about 95.5 grains of water capacity (Norma). Whatever data you use, be sure to use the same brand of brass. That capacity difference is enough to cause serious pressure differences.

The SC and SSC powders have different formulations and are adjusted in burn rate so the same charge weights tend to produce the same performance. This is despite the difference in grain geometry, which otherwise would tend to make short grains burn faster due to their greater surface area per unit volume. The traditional long grains tend to fill the case better and to ignite more easily which can make them more forgiving of charge weight errors. Good thing, since they are harder to throw accurately from a measure in the the first place.

Since I have good means of metering long grains accurately (electronic dispenser and the JDS Quick Measure), I use whichever version of a powder turns out to fill the case better. I confess I tend to be biased toward the longer grains because of a story in Hatcher's Notebook, but actual testing is the only thing that ultimately tells the tale in your gun.

Hatcher's story tells how, when working up a load for one year's National Match ammunition between the wars, he had narrowed the powder choice down to two very similar powders that were about like later IMR 4320 in burn rate and pressure/velocity characteristics. One was long grain and the other was short grain. The powder measures in the arsenal loading equipment could throw the short grains with a precision of 0.6 grains extreme spread*. The long grain powder was so coarse, the measures would only throw it within 1.7 grains extreme spread. Nonetheless, in 100 round mean radius test groups, the ammo loaded with the coarse grain powder consistently did better, and so was chosen for that year's NM ammunition.

Hatcher reported some flak when a know-it-all at the National Matches pulled some bullets and spread the word on how inconsistent the charge weights were and how that year's ammo couldn't possibly be any good. Nonetheless, by the end of the matches, several new records had been set with it. Hatcher believed the ignition characteristics of the long grains, which let flame fronts move more easily between them, made this powder's performance more volume dependent and less weight dependent. That is, a heavier charge weight packed into tighter space burned enough more slowly to compensate for the weight difference by the time the bullet got to the muzzle.

I don't think you can count on that in any particular powder or chambering combination. You have to test. But it's interesting to see that it can happen ever. Hatcher is not the first person ever to report volumetric measuring resulting in more accurate loads than charge weight measuring. Many benchrest competitors still use volumetric measures today.

Anyway, I wanted to make the point that we handloaders put a lot of store in precise charge weights and on what powders we can meter to a precise weight in a powder measure on the assumption that accurate weight will necessarily produce superior accuracy to accurate volumetric of powder, and that it just ain't necessarily so. If I had the time and facilities to test a wide range of powder and chambering combinations for this particular trait, I'll bet we'd find some some prefer volumetric dispensing, while others do better by weight. Some of the sphericals, like 748, meter to weight so consistently when measured by volume, that dispensing by measure and weighing are interchangeable.


*That's not untypical even of modern match ammo with stick powder. 20 rounds of the old Federal GM .308 loaded with 4064 that I pulled spanned 0.4 grains, and that was all in one box. I expect a larger sample that included rounds loaded further apart from one another would have been about like Hatcher's result for his short grain powder.

[Doodlebugger45]

Very interesting theory on the long grained powders vs. the short grained powders. It seems to correspond to my own observations for rifles. This spring I have been doing load developments for several rifles using several different powders. I was particularly interested in the shorter grained and spherical powders because of the way they meter in my powder measures. But I have noticed that their "sweet spot" tends to be much narrower than the sweet spot for longer grained powders. I had noticed previously that in my 7 mm mag for instance, if I was varaying the charge weight in 0.8 gr increments, it was rather typical to get 2 or 3 different weights that were basically the same grouping using H-4831. But if I vary the weight by 0.8 gr using Hybrid 100 V, the groups vary dramatically as you change the weight. In fact for some bullet weights, I never have found the sweet spot for the shorter grained stuff. Maybe my weight interval was too big and I missed the narrow sweet spot.

So I guess the lesson is that the shorter grains can meter more consistently, but the downside is that they NEED to meter more consistentnly. To date, my work with the smaller grained stuff is that I have found some very good loadings for various .243 applicaations using Hunter powder. I have found a few decent loads for various rifles using W780. Only one mediocre load using Hybrid 100 V. And the jury is still out for my H-4831 SC. I haven't given up on the short grained stuff by any means, but I think I will stick with H-4831, RL-22, etc for quite awhile for a lot of things.

[jimbob86]

I have not used the 7828 short cut, but like the regular version of 7828 for 150's in my .270.

I have used both versions of H4831, and found the long version more consistant for velocity ....... I weigh my charges for hunting ammo, and development of same. I use the meter or dipper to get close, and trickle up to be exact.

[Unclenick]

I still run a lot of 4064, myself, though Varget has been a pretty good near equivalent for me and it meters better from the weight standpoint. But it's also a bit different in some respects. Thanks, guys, for confirming the trend I've observed but don't have the data in place to quantify in detail (as I haven't anted up for the SC and SSC powders except where I was getting a lot of compression with the long grain version). Again, not fixing what ain't broke.


Doodlebugger45,

Try Newberry's 0.7% to 1.0% charge increment range. That usually seems to find something.

[grubbylabs]

Thanks for the great info. If I don't get good results with this powder then I will try the regular before I abandon it completely.


I too had great luck with the 4064 in my 308 but since Hornady does not list it for their bullets I picked up a pound of Varget to try.

I also am in the habit of dropping a charge close to what I want and then trickling up to the final weight.

[Kevin Rohrer]

Unclenick: I bought one of these awhile back and am about to start using it. Do you have any hints on setup or use that would be helpful to me?

[A_Gamehog]

If you switch powders try R-25. In my 300 it does make a significant difference.
Federal 215M primers also. good combo.

[Unclenick]

Kevin,

It's a great tool. I bought mine on Rocky Raab's recommendation specifically to meter long stick powders for reasons outlined in the above posts. I got the benchrest kit, so I got a few extras with it, like the setting gauge. I find I mainly use the thing for dispensing into larger batches of rifle ammunition, and for me that means .223, .308, or .30-06 production for match shooting. The money for the gauge element of the kit might have been better spent on extra charge tubes for those rounds.

Extra tubes are so I can just leave one set up for a particular load for a particular rifle that I use repeatedly. I don't change the settings on those until the next lot of powder has to be switched over to, and then only if it needs to tweaked. I tend to adjust the set screw on the tube without removing it, which is why the gauge doesn't see much use. I like the stand mount on the benchrest carrying case, though. I find I like to take a sandbag with me to set on top of the box to make it more rigid on the bench.