IMR 8208 XBR Lot # 4736 Test Session
I found the lot # in the archives.
jackie schmidt12-15-2009, 10:46 AM
There are some small stamped numbers on the label, 581 308 4736.
Under the bar code are the numbers 54486 08201.
The usual orange tag on the bottom was not there.......jackie
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Lot #4736 test session;
jackie schmidt12-13-2009, 07:52 PM
First, the weather man needs to get a new dart board. It was supposed to start out at 50 degrees, then clear up to a bright and sunny 70.
Well, it did start out at 50, overcast, and dreary, and it never got above 54, still overcast and dreary. But, the conditions were really nice, just a gentle ebb and flow. Really a miserable day to be out, but all in all, a good day to shoot.
I first started out with my '08 133, just to see if the Rail, (and I), was on it's game. After a few three shot groups to find the window, I settled in on 30.4 grns with a 65 grn Barts Boat Tail. I then nailed a nice 5-shot "zero" that you can see on the far left, second row up. Average velocity was 3470 fps.
I then switched over to the BRX 8208. I started with a load that Tom Libby recommended, 31.3 grns. While it did not nail a 'zero", you can see it shot pretty well. The average velocity for the five record shots was 3430 fps.
I then decided to drop the load down into another window, a flat 30. grns. The average velocity was 3320, and as you can see, the group opened up. I felt like I hit the condition just right on each shot. Maybe a little cool for this light of a load.
We then decided to up the charge untill it matched the velocity of the 133. This took 31.9 grns. With a slow trickel this was just about 1/2 way up into the neck. The group was really nice, so I decided to try the load again, only weighing each charge. The results were the group you see on the far right. That is really probably about a .040, pretty darned small. The average velocity on both groups was about 3470fps.
I then decided to go back to the 31.3 charge, only weighing each charge. The results were another nice "zero". The velocity was the same as before, but the total spread on this group was only 12 fps.
I then pulled out my Sporter, and put the 31.8 grn load in. I shot a couple of three shot groups that were about .110, then shot a 5 shot group that was a "zero" for the first four. But, since the condition was now the "straight accross right to left", I missed the last condition, (a let-up), and openned it up to about a .180. straight to the right.
Since the conditions, and the temperature, were not going to vary, I decided that I would call it a day and save the rest of the powder for a day that was at least 70 degrees.
So, what did I find out. First, this stuff is more dense than 133. I can barely get the 30.4 grn 133 load in the case, but there is no problem at all getting the XBR in at darned near 32 grns. But, this shows that by weight, it is slower than the '08 133.
It also burned just as clean as 133. I could not tell the difference in the patches that came out after shooting 133 and the BRX.
Also, this stuff meaters VERY WELL. Much more consistant than 133. While I started weighing charges, I could count on the BRX out of my Hensler Measure to be within plus or minus .1 grn. I simply can not do this with 133.
An added note, the Rail Gun has a 23 1/2 inch barrel, the Sporter a 21 1/2. With the same load, I saw an average 70 to 80 fps slower velocity out of the shorter barrel. These two barrels are just about identicle in the land and groove diameter, both .237 4-groove Kriegers that took a .2371 bushing. I guess this shows that some of the powder is still burning at 21 1/2 inches.
I showed that yes, at 52 degrees overcast and dreary, I made the stuff shoot pretty darned good. But, I do not have a clue what will happen when the weather changes. Only time will tell.
That about covers it. This new powder will shoot, and velocity is certainly not a problem. I had zero problems with any pressure signs, the handle on the Diamond Back on the Rail and the Bat on the Sporter lifted really easy on all loads, and the the primers looked nice, with a generous radius still on the outside edge.
I wish the temperature would not have stayed the same all day, I really wanted to see a 20 degree change so I could see how the load was affected. But, it didn't happen, so we settled for what mother nature gave us.
All in all, a good day at the range. Some other shooters with me and watching,, Gary Walters, Vic Smith, Ed Bernabeo, Geramo Villareal, and World Champion Gene Bukys, who had a couple of 375 H&H mags, which are a hoot to shoot...........jackie
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