Reumbo pressure spike below freezing!

I just check as you suggested, ran it back 4 times no resistance at all. Smooth, even flow all the way to the chamber.

Cant believe I'm saying this but , I almost wish that it was a carbon ring because at least I would know what the promlem is.
 
Tbrice,

Have you taken any of the suspect batch and warmed them before shooting to rule out if temperature actually was the culprit. If you could warm the rifle as well that would probably be a good idea.
 
Please don't be offended by my questions and forgive my wordiness... What type of scale are you using? Do you weigh each load? Have you moved anything that would--or could--change the atmospherics around your loading area? Same for powder storage area? Change electronic layout in any way within five feet of your scales? Ferrous metal storage change?

This long-winded and there's several influential factors at work here left undeclared for brevity, but the reader will no doubt pick them up. A short time ago I had my Sartorious begin acting up. I checked the balance's calibration; it would verify and then continue to travel up and down, sometimes as much as two grains, with the 1000 grain weight on. This happened in late August. It starts getting dark at night in late August and my Toyo kicks in some nights. It was a "dark" fall, and wet, this year so the Toyo ran more frequently than normal. I was also making up loads later and in greater number than normal as well. I keep the temp 51F after the butchering is done until around May first. Then I move the thermostat to 60F because I'm sitting (not skinning, butchering, or other shop work). It was set at 60F. I set three milk crates one atop the other and have a board fitted to act as a table top. This year I misplaced it so just put a couple short sticks and a sheet--galvanized--metal over them making my storage excess table up again. Alas, when the the Toyo began running it drafted the scale (just a short glass shield on this one) differently than ever before. I moved the table/stand farther away after trying other things. It reduced the span of change, but didn't eliminate it. Then one night I came across my fitted top and put it back, removing the galvanized sheet and sticks. The span diminished more, but still didn't go away returning to normal. However, I just set the galvanized sheet aside--still within four feet of the scale. Only when I used the sheet for another purpose did the scale return to normal. I found that moving ferrous metals within five feet of the scale could effect it. That bugged me so I started experimenting. You know those little cylinders on wall chargers and some computer electronics? They're magnets. They definitely influence electronic scales. I found when I put one three inches from the service line's entry into the scale it "calmed" the scale considerably and when I put a "genuine seal" magnetic money clip about a foot from the wall outlet on the same line the scale worked the best--and most accurately--I ever experienced.

I'll spare you an experience I had a few years ago with a powder that was considerably more hydroscopic than others I've used. suffice it to say high humidity, maybe coupled with high atmospheric pressure, added weight to this powder. I lost over 40 fps with these loads. Happy it didn't go the other way.
 
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Please don't be offended by my questions and forgive my wordiness... What type of scale are you using? Do you weigh each load? Have you moved anything that would--or could--change the atmospherics around your loading area? Same for powder storage area? Change electronic layout in any way within five feet of your scales? Ferrous metal storage change?
No offense taken.
I drop charges with a Hornady Chargemaster then I double check EVERY dropped charge on a Gempro.
I calibrate both scales before each use and both are turned on to warmed up an hour before use. I keep a 20g weight beside the Gempro to verify calibration during its use.
Nothing has changed in my electrical layout. My outlets are about 6 feet away. I bring 2 rifles to the range always for a couple of reasons. The 300wm I shot the same day had rounds that were loaded with the same equipment on the same day. Other rifles loaded with the same equipment recently with other powders show no change.
When I dumped these rounds I re-weighed the charges, they all weighed good.
 
Someone tell me I'm crazy.
I have worked up a load for 264wm with140vld and Retumbo up to 71.5 gr in 65° with mild pressure signs, so I backed down to 69.0 grains at 3250 fps average.

Today 30°F I shot some of the same ammo loaded 3 weeks ago and the velocity spiked to 3340fps and blown primers. This barrel is completely cleaned, no copper or carbon with a dry chamber verified with my bore scope.
Same lot of brass, primers, bullet and powder.

The only thing that changed is last week I did a several groups of RL 25, but I always clean to bare metal when I change to a different powder.

*** !! Help!

Perhaps I missed it, but I reread all the posts in this thread trying to determine whether you tried returning to the R 25 loads you had tried in your rifle prior to the issue surfacing. If you had measured velocity with the R 25, it would be interesting to see if the results are the same, perhaps helping to isolate where the problem is occurring.
 
When I read your initial post "powder bridging" jumped to mind. I have personal experience with this in the way overbore 270 AM. (Kirby warned me about it.)

Same symptoms as you described except. . . the 264 WM is way less overbore than the 270 AM.

However RL-25 kernels are smaller than Retumbo kernels, I measured them.

------kernel------
Powder Length Diameter
Retumbo 0.065" 0.044"
RL - 25 0.043-0.059 0.049"
7828ssc 0.057" 0.040

IMR 7828ssc was the only stick powder that could be used in the 270 AM. RL-25 bridged 2 out of 2 shots. Took a dead blow mallet to open the bolt both shots.

While the 270 AM is a vastly different animal than the 264 WM I wouldn't rule out powder bridging though I'd consider other things first.

Good luck on your quest.
 
Perhaps I missed it, but I reread all the posts in this thread trying to determine whether you tried returning to the R 25 loads you had tried in your rifle prior to the issue surfacing. If you had measured velocity with the R 25, it would be interesting to see if the results are the same, perhaps helping to isolate where the problem is occurring.

No, but I loaded some 25 to shoot Wednesday allong with a 2gr reduced Retumbo load.
Temps will be around 25°
 
When I read your initial post "powder bridging" jumped to mind. I have personal experience with this in the way overbore 270 AM. (Kirby warned me about it.)

Same symptoms as you described except. . . the 264 WM is way less overbore than the 270 AM.

However RL-25 kernels are smaller than Retumbo kernels, I measured them.
Roy,
------kernel------
Powder Length Diameter
Retumbo 0.065" 0.044"
RL - 25 0.043-0.059 0.049"
7828ssc 0.057" 0.040

IMR 7828ssc was the only stick powder that could be used in the 270 AM. RL-25 bridged 2 out of 2 shots. Took a dead blow mallet to open the bolt both shots.

While the 270 AM is a vastly different animal than the 264 WM I wouldn't rule out powder bridging though I'd consider other things first.

Good luck on your quest.
Roy, bridging crossed my mind also. And you are correct 25 is bigger.
 
Just my opinion, after further review it seems that you may have Retumbo acting like Retumbo acts close to peak pressures. I did a little further looking and reading here and on other forums after your original post and found a wealth of information. There are several old threads that document similar issues to what you've experienced of late with Retumbo. It is one of the primary reasons I chose not to work with it beyond preliminary piddling and chose to explore other powders. Here is a link to just one thread that I believe to be germane to this thread. Best of luck, I'd like to see what you figure out. http://www.longrangehunting.com/forums/f28/h1000-retumbo-96540/
 
Retumbo is my go to powder, love the stuff and I shoot from winter lows below zero to 80's in the summer and never seen a pressure spike like that, I find I have a very wide high end, never seen it all of the sudden spike, in most of the stuff I load I go in increments of 1/2 grain and I usually see a couple grain warning as I climb in pressure. I'm more suspect of how the primer is lighting it and changing something than I am Retumbo!
 
It happens that I was testing Br2, WLRM, 215m thay day and blew one of each. The Br2 was loaded 3 weeks ago and the other two was loaded last Saturday.
 
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