AA8700 in .458 Win Mag

[richhodg66]

I have quite a bit of this powder. Dad got it when it was dirt cheap years ago and I inherited it from him. Used some in jacketed 7mm Rem Mag loads years ago and it worked OK for that. Always figured it would only be good in large case capacity, over bored things like that.

I've been playing with a .458 I got from a member here a while back, lots of fun with a 500 grain RN cast and 18.5 grains of Unique. This is a pure range toy, no intentions of ever loading it to full potential.

I seem to remember Dad mentioning back when he was using the stuff that the best thing he used it for was .45-70 and that he pretty much used a compressed load, all he could get in a case and used a small priming charge of some faster burning powder under it. His memory is pretty foggy about such things now, but I do remember the conversation and remember he was pretty happy with the accuracy, but did mention it was dirty.

Would this recipe or similar work in my .458? I'd use magnum primers, but would a light kicker charge be good? What kind of powder and how much? I also just got a bag of fiber wads for shooting BPCR loads in .45-70 from an old guy at a yard sale, would these help with the plain based bullet?

I really don't like the idea of making up load data, though I have sometimes carefully interpolated from other things and been OK. This stuff, though, I just can't see how you could get enough of it in a case to be dangerous.

Anyone have experience?

[swamp]

I use it in my 50-140-3.25 rolling block rifle. I have a AA manual and will see what I can find for the 458.

No loads listed for 8700. I would give them a call and see if they can help.
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[stubshaft]

8700 is a very slow powder to be loading 458's with. It seems to work best with overbore cartridges.

[curator]

While I have not tried it with 8700, I have had good results with Accurate 870 and WC860, very similar powders in .458 WinMag, .45-70. 11.7X51R Danish, and .40-65 Winchester all with cast boolits. By themselves these very slow powders do not produce a lot of pressure and not quite black powder velocities in big straight cases. They also leave behind a lot of unburned powder in the bore and chamber. I "duplexed" them with 5 to 6 grains of SR4759 or Reloder7 and got better velocities and much cleaner burns. I measured the "kicker" charge with Lee powder scoops and filled case to the base of the boolit allowing for a tiny bit of compression when fully seated and crimped. Just as duplexing with black powder, the kicker charge needs to stay next to the primer and not mix with the main charge. These duplexed charges shot quite accurately. I am not really sure that the kicker actually burned up more powder or just blew the unburned granules out of the bore. When I shot some of these loads over my old Chrony, the screen got sand-blasted so I only got a couple of readouts. The ones that did register showed about 20% increase in velocity.

[richhodg66]

While I have not tried it with 8700, I have had good results with Accurate 870 and WC860, very similar powders in .458 WinMag, .45-70. 11.7X51R Danish, and .40-65 Winchester all with cast boolits. By themselves these very slow powders do not produce a lot of pressure and not quite black powder velocities in big straight cases. They also leave behind a lot of unburned powder in the bore and chamber. I "duplexed" them with 5 to 6 grains of SR4759 or Reloder7 and got better velocities and much cleaner burns. I measured the "kicker" charge with Lee powder scoops and filled case to the base of the boolit allowing for a tiny bit of compression when fully seated and crimped. Just as duplexing with black powder, the kicker charge needs to stay next to the primer and not mix with the main charge. These duplexed charges shot quite accurately. I am not really sure that the kicker actually burned up more powder or just blew the unburned granules out of the bore. When I shot some of these loads over my old Chrony, the screen got sand-blasted so I only got a couple of readouts. The ones that did register showed about 20% increase in velocity.

Good info. Pretty much what I was looking for. I'm a little leery of using the "Kicker charge", but I really can't see getting into trouble with a powder this slow.

I've been shooting this rifle with the Lyman 500 grain round nose plain base, sorry, can't remember the mold# at the moment. The rifle seems to like it and I've been using Unique which I had good data for. Fun, but I think the rifle will shoot better, and I have a lot of this powder that isn't going to get used in much else here.

I don't care about velocity. I just got a single cavity NEI mold that is pretty similar to this Lyman, which I don't have the mold for. I'm kind of hoping to cast some with it soon and give this powder a try.

[Nobade]

I typically duplex that powder with imr4227, just because I have a lot of it. But anything in that general burn rate works fine. I'd start with .5cc and see how it goes. If it's still dirty up the dose a grain at a time until it cleans up. It'll work fine once you figure out the load.

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[curator]

The .458 WinMag usually has a 1 in 14" rifling twist. Heavy plain-base boolits need a slow start to shoot accurately. I have found that about 1250 fps is optimal for Lyman 457125, 500 grain slug. I consider my .458 nothing more than a .45-90 bolt action, and often shoot it with FFg black powder loads as well. Factory-level loads stop being fun after shot #2 but black powder level loads can be shot all day.

[richhodg66]

Tried a few today. Load was a Winchester magnum large rifle primer, a kicker of five grains of 5744, followed by 61.5 grains of 8700, a vegetable fiber wad followed by a Lyman 457125.This is pretty heavily compressed, it seems but didn't give any real pressure signs. The 18.5 grains of Unique loads shot better, but to be fair, these bullets were some I got from a gun show that were someone's estate sale and he wasn't the caster my Dad was which I shot up the last of his (I think). I'll shoot these up playing around, but eventually will get some cast up with that NEI mold and see what I can get it to do.

The smoke signature was impressive. Recoil was a lot more than the Unique loads, but not oppressive. I only shot nine rounds, need to do more testing.

[richhodg66]

Later that afternoon, after I had swabbed the bore and dried it, I loaded five more with the same load minus the kicker and the card wad. It was obvious I wasn't compressing it nearly as much on seating. Shot those five, and even allowing for the fact that the first one from a cold, clean barrel went out of the group, it was the best group I've had from that rifle yet, three of the remaining four were touching each other and the fourth not far from it.

There was a lot more unburnt powder and when I swabbed the bore again, a lot more ash and soot. Gonna play with this some more and find the sweet spot combo and best use of the kicker charge.

For kicker charges, why would it not be OK to use something fast like Unique or 700X?

[Nobade]

The pressure spikes really fast with powder like that. The idea is basically to make a really long lasting primer, not to blow the whole unburned mess out the muzzle. Not to say you can't do it but be super careful.

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[725]

How about just a charge of 5744?

[MT Gianni]

I does a good job with cast in the 30-06. I use a 4-6 gr kicker and WC870 data. Check on loads at Castpics, lots of surplus data loads there.

[richhodg66]

The pressure spikes really fast with powder like that. The idea is basically to make a really long lasting primer, not to blow the whole unburned mess out the muzzle. Not to say you can't do it but be super careful.

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OK, I have quite a few bits and pieces of powder cans around to try. You mentioned 4227, but is there kind of an upper and lower limit of burn rate that works well for this purpose? Seems like IMR4895 would be great in this application, but I love the stuff and hate to use it on something like this.

[richhodg66]

I does a good job with cast in the 30-06. I use a 4-6 gr kicker and WC870 data. Check on loads at Castpics, lots of surplus data loads there.

I did try it in a .30-06 and also a Mosin, both with the 311284. Accuracy wasn't great, but wasn't terrible either and I didn't pursue it much further. Yesterday was my first foray into using a kicker charge. Guess I'll have to try it again in the '06.

[Nobade]

I haven't tried anything as slow as 4895, but I'd imagine it would work. But you'd need so much of it you may as well use it straight. For an upper and lower limit, personally I wouldn't use anything faster than blue dot and slower than 4198. I'm sure good results can be had outside of that but I haven't seen the need to go there.

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[richhodg66]

OK. I'll try various stick rifle powders and see where it works best. I need to cast some more bullets for this rifle and get the time to systematically test this.