powder for 7STW

DWM: I have tried H50BMG in my 7/338 and had less than satisfactory results. Switched back to the 872 and problems went away. Dunno what the problem was. I do know that it was VERY inconsistent and I had massive ES's. Haven't gone back since.

TH
 
I bought a one pound can of H50BMG and worked up a load with it. The results I was seeing were as good as I was getting with WC872 at the time. I did run out quite fast because of the shear amount of H50BMG that is required to get a 7MM RUM fired up. I liked it because it burned real slow and I could run up the velocity without much pressure at all.

I bought an 8 pounder of WC872 because of the high recomendations it gets on this forum and because it is cheap. It is quite amazing with a long barrel. I am uncertain what to think of it because I am shooting in warm to very hot weather and WC872 has been reported to not perform well under those conditions.

Went back to Retumbo as this has about the right density and burn rate that I am looking for. Retumbo is much easier to get into pressure problems with. Maybe it is the cheap Remington brass that is the problem, too soft .......?

Am going to try RL25 also this spring. It is close in burn rate to Retumbo.

I am not as serous as others on this site, mainly just experimenting in high velocity 7mm projectiles. I like to try different stuff. So far I have not been able to find a combination that just clicks with the 7mm RUM.

It could be me or my setup also. I need a different stock that has a much more repeatable return to battery. Maybe a nice benchrest stock for the REM700 LA.

I am done rambling ...
 
I, too, am in the process of pushing the 7mm envelope as far as it can go. I tried the Retumbo, and, like you, ran into pressure ceilings VERY quickly. I found that I could not achieve the case capacities that I needed with my case that I needed to get good performance. I was getting around 70% fill when I started seeing problems. Since I run a .338 Lapua necked to 7mm in relatively tight twist bbl, I find that the slower burning powders seem to work pretty well. With your RUM, the 872 should work pretty well with the heavier pills if you have the bbl to make use of it. I have a 7RUM and it loves the 872 with the 168 SMK's. I found that I had Cu fouling VERY quickly with this rifle, which a Rem M700 as well. I usually seat the bullet right on the lands, and drop back on the powder charge to compensate, but I still have seen bad fouling from the throat to about 8 or 10 inches down the bbl. Here again, the pressure curve on the 872 burn rate seems to help this since the burn of the powder charge is more evenly dispersed down a greater portion of the bbl instead of just blasting it through the throat so quickly. As you say, there ARE a few problems with temp sensitivity with the 872, but it seems to do the trick. One other powder I have had great results with (but also had hangfires and temp sens problems) is H870. Though it is no longer mfr'd, you can still find it right now on clearance at most reloading supply shops. I would grab a few lbs. of it and give it a try while surplus is still abundant. This might help give you some insight into what is going on. Now, I too must step down off my soap box! Peace bro!

TH
 
wc 872 did not work well at all in my 30" lilja but retumbo sure does...i'm shooting 81.5 grains and 162 amax at 3320 fps and shoots under half inch every time 5 shot groups
 
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