Home Forums Reloading Big Game Rifles H870 and the 264WinMag help........

Guys I scored on 3lbs of unopened H870 and was wondering does anyone have and load data for 140grn bullet in the 264win mag!?

Popapi, I have some data, but at present I'm fishing in Montana..will be home in 10 days or so..would be glad to look this up if you don't locate some by then..My neighbor helped his then son-in-law develop some 140 grain loads for a pre 64 westerner, and vel. was right up there...I have heard that H870 can leave a difficult to remove fouling in the bore, but never experienced it my self...

Speer Manual #12 lists 73gr as max
Nosler #3 lists 74gr as max

start low and work up, etc.

WyoYote sounds great, southtexas thanks Guy!!!!!

The old lots of 870 had a calcium carbonate retardant and those lots are the source of the bad fouling reputation. Newer lots don't have this. Still it is a dirty powder but works great in the 7Rm at around 80 grains with 160 gr. bullets. It is a powder that needs pressure and bullet resistance to perform so find your max load and tweak around it. At lower pressures it can have a double pressure spike but evens out at higher pressures.

I am hoping for a new temperature tolerant clean burning replacement for it. Maybe R33??

I would like to learn more about the "pressure spike", could you refer me to the article that addressed this?

Thanks.

Here is an example of a "secondary" pressure spike. Detonation is a potential issue with slow burning powders with low case volume densities.



Pic from: http://www.shootingsoftware.com/pressure.htm
http://www.shootingsoftware.com/barrel.htm

Okay, that was discussed looooonnnnggg ago on accuratereloading.com when the software came out. It is an artifact in the software. The discussion at the time pointed towards a strong annular vibration/contraction due to the bullet exiting the bore.

So there's NOT a double pressure spike, trying to understand you clearly Kid.

Can't help on the 264, but it's the goto powder for my 30-378.

Most H870 data has one load only so I would be carefull about reducing it. Have used it for years in my 7 Rem Mag. I get accuracy and velocity.

Correct. The strain gage works by measuring the change in resistance through the thin wires of the gage. When the bullets exits the gas pressure drops extremely rapidly as the gas is traveling roughly twice the velocity of the bullets. This causes the barrel to rapidly relax and this is where the anomoly is found. You'll see this thing occurs some time after the bullet has exited by looking at the graph.

I had several email exchanges with one of the individuals involved with promoting the software on the open forum, and told him to try a simply experiment that would show how the above is working. Take a rifle/load that is displaying the anomoly and cut the barrel shorter in one inch increments. The hypothesis is this "spike" is occurring at a specific point in the barrel, so the idea is to cut the barrel down past that point, then you wouldn't see a "spike". Of course he wouldn't do that as the "secondary pressure spike" is a big selling hook.

The owner of Mountain Molds actually did try my experiment. He posted the graphs on his website and guess what? Cutting the barrel shorter made no difference whatsoever in the shape of the graph. It is an artifact in the software. If it was real you know it would have been widely discussed in the literature when piezoelectric gages began to be widely used. But it didn't because the engineers knew what they were seeing.

AWESOME! Thanks Kid!!!!!!! Had me worried.............

Thanks I didn't know that. What I wrote was based on the Piezo electric anomaly. It was from a really old copy of Hand Loader when affordable strain gauges were relatively new. Not sure if that article had any .264 data in it, it was a "powder profile" article.

Yet another case of everything you think you know could be wrong.

Agreed. It still seems to be an open debate however. There seem to be plenty of smart people out there that think it is real.

I am a True Believer in Pressure Trace. These folks brought accurate/precise pressure testing gear to the market for the masses. While not inexpensive, it was less expensive than the next available set-up from Oehler. I own the original version of the Pressure Trace hardware and software. It works perfectly.

With this gear you don't have to guess what your load is, you can see it for yourself.

My Hornady book list loads from 65.2 to 77.3 gr of H870 with 140 gr. bullets.

I have used up to 78 gr. of US869, Hodgdons replacement for H870, with 140 gr. bullets. I am currently working with WC872 which is working out to be a little slower burning powder.

Thanks TJay!!!!! Guys I did have pretty good luck with 74grns of H870 today! Shoot .565 with a 140VLD will try to duplicate and chrono after I get back in town!!!!!

In the Hodgdon NO 20 reload manual lists 73gr H870 140gr speer at 3163fps

WHOA!!! Thats good stuff!!!!!!! Thanks 264!!!