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US869 thoughts, anyone?

Gregg C

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Nov 15, 2017
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Tucson AZ
At range yesterday, seating depth test. 4 rd groups, .030 length increase between groups. At lands length is thought to be known. Last group is .010 off lands. Started at shortest length, working my way up one group at a time, have twelve groups loaded. Ok, so I get to the tenth group- first shot velocity is 100fps faster than the previous shot. Next shot is 20fps less, shot 3 is 7fps slower, and number 4 is 50 feet slower yet. No hard lift or hard close on bolt. First cartridge in group 11- I couldnt get it to chamber. Thought maybe I got math wrong on to-lands-length, just packed and went home. Then got to thinking, this makes no sense. Built a dummy rd shorter than last shot fired, it would not chamber. Sharpied up the bullet, and just above the case neck, I see marks, looks like lands, but way way shorter than the ogive.m must be the leade, right ? So now, I clean the rifle up, new dummy round at .008 longer that longest test group, and bolt closes. Obviously chamber was so powder fouled, the rounds would not go home. Or at least, that is what I hope. Is US869 a dirtier powder than others ? Any one else with a similar experience? Really scratching my head over this. Rifle was clean when I started, and only 40 rds thru it ?
 
I've used it a little in a 25 RUM.

It's a very slow burn rate ball powder.
Not well suited to many cartridges, to my understanding. Mostly used in very large cartridge cases.

I do think it burns dirty and inconsistently unless run at high pressure, like near maximum pressures.

What cartridge are you shooting, and which bullet weight?
 
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I've used it a little in a 25 RUM.

It's a very slow burn rate ball powder.
Not well suited to many cartridges, to my understanding. Mostly used in very large cartridge cases.

I do think it burns dirty and inconsistently unless run at high pressure, like near maximum pressures.

What cartridge are you shooting, and which bullet weight?
It's a 338-378Weatherby , and a 300SMK. That part you mentioned about higher pressure makes sense, these were all 110gr charged, and not really warm, even.
 
I'd crank it up a bit more with US869.
Consider other powders possibly, also? I think there are less finicky powders that will give equal MV. I'm using RL33 in my 338 Lapua Improved with 300gr bullets.

Maybe someone else will chime in. Or research the Forums for additional powder options?
 
I agree. And I appreciate your input. I like US869, because of the low pressure vs velocity, but I am not married to it. I've thought about Retumbo, and I use it in my " plinker" loads, 115grs under a 225gr Hornady leaves the barrel at 3480, also used rl33. Really liked that one, and I think the rifle did too, but it seems to be really hard to come by. H1000 left me nonplussed . So....cranking up. That was next step any way, Hopefully it will clean up, if not, maybe .....a different powder. Thanks again.
 
I have had good luck with US 869 in my 7 RUM - usually at full pressure loads.
I am running the WC 872 pulldown in a 7 ultra rogue. it is a lot like the 896. I started my testing with RL33 and 896 and it shot decent but in my rifle. the rl33 was really dirty, the WC872 and US 896 burns cleaner once you get to good running pressure. the 33 is prone to bridging. so I stuck with the ball powders
 
I've run US869 in both a 26 Nosler and a 28 Nosler. No problems. In fact US869 was the only powder that could get the 26 Nosler to behave and I tried them all. Interestingly Nosler's latest handbook shows all compressed loads for 300 grain pills and US869 in the big Weatherby. It is also the highest velocity load listed with 115 grains giving a velocity of 2,830 fps out of a 26 inch tube.
 
GC, the tightest group I've ever had in my 30/378 Wby was with US869. The problem I had was temp sensitivity. I switched to Retumbo with great results and no temp sensitivity.
 
Temp sensitivity, and larger ES/SD in MV fall within my characterization of finicky.
If you shoot a smaller caliber, large capacity cartridge, you might have to use a ball powder to prevent powder bridging and pressure spikes. But with the 338 bore, no worries about powder bridging.
Which is why I'd seriously consider another powder.
I used to use IMR 7828 with my 338-378 with lighter weight bullets, but that was 25-30yrs ago. More powders and choices are available today.
 
I ran 12 pounds of US-869 through a 270 Allen Mag with bullet weights from 130 to 170 grains. Main reason for using was prevention of "bridging".

At lower pressures 869 burned, it seems to me, like coal. Cleaner at higher pressures.

Extreme velocity spreads were excessive. Couldn't get less than 40 and not that often.

Had similar results in any cartridge in which 869 was used.

It shot good with all bullets but at long ranges vertical spread was the deal breaker.

I wouldn't think "bridging" would be a concern in the 338-378. RL-33 is working well in some people's 375 Allen Magnums.

I'm messing with a 378 Way, simply for personal punishment, and RL-25 and 370 gr Hammer Hunter ahead of 117 grains (RL-25) gets 3050 FPS and a bruised index finger base knuckle. (Enfield dog leg bolt handle).

Don't know how it groups ... yet... don't have the courage to shoot it again. :(
 
roy

By my calculations that beast is putting out 7,642 ft lbs at the muzzle. Please tell me it is braked or weighs 50 lbs! By the way RL-25 is a high performing powder but sucks for temp stability. Seeing any issues there?
 
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