Question on mil surp powder and flame temp

[R willy in CO]

I recently started loading a lot of mil surp wc872-wc860-wc857 and imr 7383 in a 264 win mag mod 70 (26" barrel) and a 270 win mod 70 24" barrel. I have ran about 250 rounds through my pre 64 264 win, most in 2950-3225 velocity range, with 140-147 grain bullets. A few 120s. This powdermight be my new favorite, so far it is primer sensitive but I have been able to get accuracy down to 1" at 300 yards 3 shot groups. Seems to burn clean except the wc860, it seems dirty. charge weights were 60 grains (7383) up to 75 (wc872)-respectively. Very good extreme variation. No loose primer pockets, no heavy bolt, acceptable case head epansion. Both of these old rifles I have bore scoped and they have Very good barrels still. Now, I have had the exact same charge on same day under same bullet go wild on chrono but changing from a cci to a federal or changing from a wlrm to a 215 primer seems to do the trick to a ES down in the 15 range, sometimes down to 10. I put some ammunition on a ice pack in cooler and fired it, very small deviation in muzzle velocity. The ball powders meter well. Now, for my question of the day, Does anyone know the actual flame temps of this powder compared to others for throat life? I don't want to roach my pre 64s but at the same time, I sure enjoy shooting them. I feel like the wc872 is a good powder for this rifle and barrel temps don't seem to build heat as badly in 3-5 shots as some extruded powders like retumbo or 4831. Thanks and happy shooting.

 

[SeabeeKen]

7383 data pages

Good read. Stay safe

 

[R willy in CO]

yes it is. I have loaded several loads of 7383 and been very impressed so far. pressure does spike quickly but working in 0.1 grain increments achieved a very stable, very consistent load. Case capacity to near full has been helpful. Have not fired it at night. I bought more of it I like it so well. I have not noticed the cleanliness issue as of yet. seems to be temp stable and I am planning on deer hunting with this pushing 140gr nosler accubonds this year.

 

[mikecr]

I dug into Mil Surp powders and severe overbore cartridges (like 264wm) in the past. I have no idea how they work, but they are magic for large overbores, esp. with longer barrels.
Kind of like(but opposite of) N133 is for severe underbores (like 6PPC).
With them you can get higher velocities than possible otherwise, while the powders actually run cooler.

An analogy I formed for myself about this is with supercharged engines.
With pump gas you can only make so much power from a given engine. You can supercharge that engine and squeeze out more, but at the cost of frequent failures. Unreliable performance.
Now add huge injectors to practically flood cylinders at higher boost levels, and you can outright double the power of a good build alone -while keeping the engine together. It's not efficient, few would consider it a good build, but it works, and now you have way way more power.
MilSurp powders somehow function like giant fuel injectors. Their burn curve is all different.

But what I seen then was that they exhibited touchy ignition issues, and could not be relied on to find in same batch, and you didn't know what any particular batch of it would act like (what it would be good for).
It was like you could just buy it here or there and find out for yourself. If it wouldn't work for you, it might work for someone, and this seemed to be the source path of it.
You bought what wasn't working for someone, and maybe it worked for you.

The closest I've seen to WC872 was H-870, which WAS magic for many large wildcats.
It was sad when discontinued.

 

[R willy in CO]

thanks for the replies i am still loading these powders i havent died yet or damaged any rifles it is a fav thing of mine to be able to affordable shoot these bigger rifles since they cost so much for over the counter powders; with those prices approaching $60 per pound

 

[Webster]

I recently started loading a lot of mil surp wc872-wc860-wc857 and imr 7383 in a 264 win mag mod 70 (26" barrel) and a 270 win mod 70 24" barrel. I have ran about 250 rounds through my pre 64 264 win, most in 2950-3225 velocity range, with 140-147 grain bullets. A few 120s. This powdermight be my new favorite, so far it is primer sensitive but I have been able to get accuracy down to 1" at 300 yards 3 shot groups. Seems to burn clean except the wc860, it seems dirty. charge weights were 60 grains (7383) up to 75 (wc872)-respectively. Very good extreme variation. No loose primer pockets, no heavy bolt, acceptable case head epansion. Both of these old rifles I have bore scoped and they have Very good barrels still. Now, I have had the exact same charge on same day under same bullet go wild on chrono but changing from a cci to a federal or changing from a wlrm to a 215 primer seems to do the trick to a ES down in the 15 range, sometimes down to 10. I put some ammunition on a ice pack in cooler and fired it, very small deviation in muzzle velocity. The ball powders meter well. Now, for my question of the day, Does anyone know the actual flame temps of this powder compared to others for throat life? I don't want to roach my pre 64s but at the same time, I sure enjoy shooting them. I feel like the wc872 is a good powder for this rifle and barrel temps don't seem to build heat as badly in 3-5 shots as some extruded powders like retumbo or 4831. Thanks and happy shooting.

Try to space your shots with 30-60 seconds between them. It helps barrel life a little.