IMR 3031 Temperature Stability

charlie brown · 09-03-2005, 09:12 AM

I believe I may have a load worked up for my .30-06 and 8mm Mauser using IMR 3031. I have a question concerning how sensitive to temperature this powder is. I have had problems with hangfires with WIN 748 in warm temperatures in both of these cartridges, haven't even tried cold temps!! I like the 3031 because I am getting plenty of velocity for what I need, and the recoil is quite managable, plus the rounds I have put together, and will further work with seem to be plenty accurate. Any thoughts would be great. Thanks.

Roskoe · 09-03-2005, 02:13 PM

Just about all of the IMR series powders develop a little more pressure in hot weather, so I like to establish maximum loads in August and know they will be fine in November. This hangfire thing is not normal - particularly in warm weather. You may have a bad batch of primers or powder. Or a flake of tumbler media stuck in the flash hole? Something is amiss here.

charlie brown · 09-03-2005, 04:58 PM

Thanks for the info.

Also, as for the 748, I think the problem could be related to the primers. In the manuals, it states they used magnum primers with WIN 748. I use standard primers in all of my loads. I use CCI 200, 300, and 400 primers. I think that actually may be what is causing the hang fires, not necissarily bad primers, but an improperly matched primer for the powder/load. I use standard primers in my .223 with 748 and have no problems, but that is 27 grains vs. 45 grains or so in the 06 and 8mm. I think that is just too much 748 powder for the standard primer to ignite. I also do know that many of the Winchester powders (231 and 748 in my experience) produce much lower velocities in colder weather than in warm weather, to the tune of almost 150 fps from January toJuly in my .223. For that reason also, I am going to start working with a powder in my .223 that is a little more stable in temperature extremes than is 748 or 231(for my 45). I know that every powder will have some variations, but I am wanting powders that has less extreme variations. I hope I cleared that up, maybe explained it a little better to you. If you think that could still be a proble as for the hang fires let me know.

Marcial

Roskoe · 09-03-2005, 08:18 PM

I don't know . . . the regular CCI primers are, IMO, the worst primers ever made. Their benchrest ones are OK, but the CCI 200's have caused me and others in this areaa lot of problems. Especially if they are old. I have used WW 748 extensively in the .308 Winchester - with Remington 9 1/2 primers, which are some of the "coldest" primers out there - with no problems.

You have something wacky going on here. Could be the powder has gotten some moisture in it? Is it possible there is something in your bolt that is causing the firing pin to not protrude far enough. Normally, about .030 is sufficient. Or do you have a weak mainspring? Maybe some gum inside the bolt slowing the striker down?

Basically, you need to determine if the problem is ammuntion or firearm related. If factory ammo goes bang every time, then maybe try a new can of 748. And some new Winchester primers.I have never had a misfire or hangfire on gun that was working properly, in warm weather, with any good powder or good primer.

charlie brown · 09-03-2005, 09:10 PM

Well, I went through my notes again. After looking through them, it appears that only my 8mm Mauser has had hang fires. This could be firearm related, and there COULD be some gum still inside that bolt, even though I have cleaned it out twice and gone through an entire can of carb cleaner to get that cosmoline crap off!! I will take apart the bolt again and see what it looks like inside. I can't see it being the powder, because I have some .223 loaded from the same can and every round has gone off flawlessly.That is with CCI 400 primers. Moisture here is almost a non issue. The powder sits on the bottom shelf of a cabinet, and the lids are on tight. The humidity here rarely gets over 25%, and unless it is raining, it doesn't get above 50% at all. I have not yet had a problem with any other powder in the 8mm either. That is what I find that is weird. Either way, I have not had any problems with CCI primers before AT ALL. And I have only had the 2 hangfires. Who knows, maybe it was just a fluke, maybe there were two bad primers, I don't know. It is hard to say, considering it has only been one isolated occurance where I have had this problem.

One thing I do know is that my 8mm likes the RP brass, CCI 200 primers, and 48 grains of IMR 3031 behind a 150 grain Hornady!