Loaded CMR 100 for IMR 4895

[JackSprat]

I bought several boxes of the CMP Lake City 69 M2 ball at a sale for cheap this summer..I figured I would pull the FMJ,and replace it with a 150 gr soft point..I pulled some bullets,and weighed the charge,and was averaging just shy of 45 gr..I assumed the powder was IMR 4895,and they were just loaded light.I got a box of Sierra Pro Hunter 150s,and started working on some loads using the salvaged powder..I settled on 48gr. because I was getting good groups,and no pressure warning signs ..Well just today while fiddling around on the computer I discovered that Lake City used a powder called CMR 100 from 67-69,and this powder is about like IMR 3031..I loaded these for my 7600 figuring they would be a nice mild round for the pump..I have shot at least 10 of these through it with no extraction issues,or extremly flat,or cratered primers.I've not noticed a hard kick either..I have over 60 rounds of these loaded..Am I good to go,conciderin the gun seems to like them,and I'm getting no warning signs from extraction,or brass?...I don't have a chrono,so I don't know the velocty

 

[Sunray]

"...assumed the powder was IMR 4895..." Don't assume anything. And 'similar' or 'about like' doesn't count either.
If there's no published data(and there isn't), pitch the powder. IMR4064 is your friend.

 

[mdi]

I'm cheap, but reusing an unknown powder from military pulls just ain't good sense to me. I believe I've heard that some military ammo, even with the same headstamps use different powders, and many blend powders to arrive at a specific velocity/pressure. Could be wrong, but I only use powder with an unbroken seal, newly purchased...

 

[JackSprat]

I feel sure it's all the same powder,because I have weighed the charge from at least one from every box,and they all weigh right about 45 gr..and I did do some research before using it,and was sure from all I read that it was IMR 4895.I also read that it was good powder for the 30-06,and since I didn't have any on hand I figured I would re-use what I did have.. I was real tickled at how they shot,and like I said the showed no signs of pressure..I would still think it was 4895 if I hadn't stumbled onto the information about some of the L.C. stuff being loaded with 45 gr.of CMR100 which would explain why they were loaded so light..I was only worried because Hodgdons has 47.5 listed as max for IMR 3031with 150s,but after checking Lymans,and Lees online manuals today I see that they have max at about 50gr.so that's a little weight off my mind.

 

[Laphroaig]

I have heard that some of the Lake city M2 ball ammo was improperly stored which caused it to lose some of its original potency. This statement came from Mark Johnson, the current CEO of the CMP, who was giving a sales pitch for the HXP ammo they are selling but certainly should know what he is talking about. I have shot a fair amount of LC69 (thru a Garand) and thought that it was milder than the HXP ammo that is currently available, which supports that theory.

So, what you have is some unknown powder that has changed its properties with age. Ultimately, the proof is in the pudding and if you are satisfied with your loads, and are certain that they are not exhibiting high pressure signs then you should be OK, IMO. But I think this is certainly a situation where chronographing them would be a good idea.

 

[Swampman]

When you say you "settled" on 48 grains does that mean you worked up to 48 grains gradually from a somewhat reduced charge weight, say 42 grains (since you changed bullet type)?

As long as the pulled powder is in good condition and you follow safe practices in working up your loads, I don't see a problem with using powder that you've pulled from a single lot of rifle ammunition.

I do see a problem with equating charge weights of different powder types and thinking you can judge a safe charge level because of what you "think" the powder is and then looking at modern load data as verification.

Most modern cannister powders are very consistent from lot to lot and year to year. They have to be that way for safety when used by handloaders and because published load data would useless if they weren't. Keeping powder consistent from lot to lot costs more because that's the nature of manufacturing, tighter tolerances and greater consistency costs more.

The powder used to load large lots of military or commercial ammunition isn't held to the same tolerances because it doesn't have to be. Factories have trained ballisticians and the pressure testing equipment needed to load safe, consistent ammo using powder that varies a bit from lot to lot.

The IMR-4895 that was used to load M2 ball was similar to current cannister grade IMR-4895, but using current data to load the old powder (even assuming that it's in perfect condition) will give inconsistent and possibly unsafe results.

 

[ArchAngelCD]

This is just a suggestion because you can do what you want but never ever load a powder when you are not 100% sure of it's identification. It is an extremely dangerous practice that could hurt you or someone near you. It is fairly safe to replace one bullet with another of the same weight and similar profile but changing the charge weight is dangerous. Be safe...

 

[JackSprat]

I did not reduce the charge any lower than 45gr.,but I did work it up in stages,and as I increased the charge my groups got tighter..It was shooting better than I expected the gun was capable of at 48, so I called it quits,.