8208 XBR 6PPC velocity
- Thread starter JonathanK
- Start date
jackie schmidt
New member
Jonathan
Getting velocity sure doesn't seem to be a problem with the new powder, and it doesn't seem to show any ill affects at 3450.
But, my last two range sessions have not been that good. As the temperature got colder, it seems the shine went off the new penny. At around 70 degrees, I was getting really good groups. As the temperature dropped to 50 and below, the accuracy suffered. Could not seem to tune it out.
I personally think the stuff is on the slow side for cold weather work, I am waiting for warmer weather, more in tune with what we will be shooting in during the actual shooting season.
If you read any of my initial test on this powder, one thing I noticed was a substantial drop in velocity when going from the 23 inch Rail Gun Barrel to the 21 1/2 inch Sporter Barrel. around 70 f ps. With 133, all I expect to loose is about 25 fps. To me, that shows that the pwder is slower in actual, real world burn rate than 133.
That is probably why it shows fewer pressure signs at the same velocity as 133. The pressure spike is a little further up the barrel, and probably not as sharp.
For what it is worth, I shot my favorite load of 133 last week end during testing, and shot a couple of small "ones".........jackie
Getting velocity sure doesn't seem to be a problem with the new powder, and it doesn't seem to show any ill affects at 3450.
But, my last two range sessions have not been that good. As the temperature got colder, it seems the shine went off the new penny. At around 70 degrees, I was getting really good groups. As the temperature dropped to 50 and below, the accuracy suffered. Could not seem to tune it out.
I personally think the stuff is on the slow side for cold weather work, I am waiting for warmer weather, more in tune with what we will be shooting in during the actual shooting season.
If you read any of my initial test on this powder, one thing I noticed was a substantial drop in velocity when going from the 23 inch Rail Gun Barrel to the 21 1/2 inch Sporter Barrel. around 70 f ps. With 133, all I expect to loose is about 25 fps. To me, that shows that the pwder is slower in actual, real world burn rate than 133.
That is probably why it shows fewer pressure signs at the same velocity as 133. The pressure spike is a little further up the barrel, and probably not as sharp.
For what it is worth, I shot my favorite load of 133 last week end during testing, and shot a couple of small "ones".........jackie
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JonathanK
New member
Jackie
That makes a lot of sense to me, because a couple of weekends ago when it was cold I was having trouble with that 31.8 node, I kept getting a verticle flyer here and there. I had better luck with 31.2 that weekend but velocity was 33xx. This past weekend it got up to almost 80 here and that 31.8 node worked like a champ.
Thanks,
Jonathan
That makes a lot of sense to me, because a couple of weekends ago when it was cold I was having trouble with that 31.8 node, I kept getting a verticle flyer here and there. I had better luck with 31.2 that weekend but velocity was 33xx. This past weekend it got up to almost 80 here and that 31.8 node worked like a champ.
Thanks,
Jonathan
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warmer temps, HOPE?
I shot my ppc with the new powder for the first time yesterday?? Velocity was ok, 3350's highest load. but man, Ive seen it said before and denied, but this stuff does not clean as easily as 133!! and accuracy was not good at all. I cleaned every 12 to 15 rounds, 3 times and every time took 3 to 4 times as much to clean as with shooting 133. I realize this is going to be a better warm weather powder, and maybe it will burn a little cleaner in warm weather. It was only 30 degree's, but last 6 shots were with 133, cleaned up instant and shot better. I realize some of this could be loading technique, jam, touch, off, but already showing me if it will shoot it is definetly more picky than N-133. Just what I am seeing, and again this is very early testing, but see no problem with velocity and 68 grain bullets.
I shot my ppc with the new powder for the first time yesterday?? Velocity was ok, 3350's highest load. but man, Ive seen it said before and denied, but this stuff does not clean as easily as 133!! and accuracy was not good at all. I cleaned every 12 to 15 rounds, 3 times and every time took 3 to 4 times as much to clean as with shooting 133. I realize this is going to be a better warm weather powder, and maybe it will burn a little cleaner in warm weather. It was only 30 degree's, but last 6 shots were with 133, cleaned up instant and shot better. I realize some of this could be loading technique, jam, touch, off, but already showing me if it will shoot it is definetly more picky than N-133. Just what I am seeing, and again this is very early testing, but see no problem with velocity and 68 grain bullets.
JerrySharrett
Senile Member
I think a more careful relook for the new 8208 is in order. I see two issues above that do not "seem" normal. First is the velocity. I fail to see where anyone is getting close to 3500 fps in a 6PPC with a 65-68 grain bullet and, second. the temperature variation on tune does not jive with controlled lab tests by Hodgdon.
Below is Hodgdon's controlled lab test on a known winning load;
68 gr. Hottenstein bullet, Fed 205M primer, and 31.0 grains of IMR 8208 XBR powder
0 degrees F.--- 3333 fps @ 4 standard deviation--- 53,700 CUP @ 607 standard deviation
70 degrees F.--3340 fps @ 8 SD--- 55,300 CUP @ 713 standard deviation
125 degrees F-3347 fps @ 14 SD--- 55,800 CUP @ 994 standard deviation
Now then, is another 1/2 grain going to give an additional 120 fps and is a temperature change of 20 degrees is going to change the velocity enough to effect tune?
I'm not saying either of the above posters didn't get what they saw. I'm just thinking, that in the process of all this we are not seeing something. Several weeks ago Jerry Hensler speculated that moisture in the fouling in the bore may have more effect on tune change than temperature does, especially in V133.
In just a very few weeks thankfully, we will see on target paper how this new powder does. Hopefully very well.
Below is Hodgdon's controlled lab test on a known winning load;
68 gr. Hottenstein bullet, Fed 205M primer, and 31.0 grains of IMR 8208 XBR powder
0 degrees F.--- 3333 fps @ 4 standard deviation--- 53,700 CUP @ 607 standard deviation
70 degrees F.--3340 fps @ 8 SD--- 55,300 CUP @ 713 standard deviation
125 degrees F-3347 fps @ 14 SD--- 55,800 CUP @ 994 standard deviation
Now then, is another 1/2 grain going to give an additional 120 fps and is a temperature change of 20 degrees is going to change the velocity enough to effect tune?
I'm not saying either of the above posters didn't get what they saw. I'm just thinking, that in the process of all this we are not seeing something. Several weeks ago Jerry Hensler speculated that moisture in the fouling in the bore may have more effect on tune change than temperature does, especially in V133.
In just a very few weeks thankfully, we will see on target paper how this new powder does. Hopefully very well.
jackie schmidt
New member
Jerry
If you remember, Ron Hoehn experienced much of the same phenomina when he did his test with the powder he was sent. That included a velocity in the 3500 fps range. You can dismiss many of us off as keyboard wannabes, but Ron does tend to know what he is doing.
Granted, none of us have the "controled lab" testing facilities that any of the major Powder Manufacturers poccess. All we do is go to the range, set up a Chronograph, and shoot groups. If the stuff goes from shooting mid ones, to mid threes, with nothing more than a 20 degree temperature drop, you figure maybe it is a tad temperature sensitive toward the cool side.
There has always been a problem with powder manufacturers not understanding the concept of "agging capability". They think that just because they can maintain a constant velocity under lab conditions,, that all of the bullets will continue to go on top of one another. Any experienced Benchrest Shooter knows that this is not nessessarilly so. The concept of "tune", when discussed in terms of 1/8 minute of angle, is something that transcends many of the normally held assumptions in the shooting world.
I agree, the problem now is few of us have had a chance to see what 90 dregree+ temperatures will bring. I hope that it is "just right". In fact, I think that is exactly what will happen. The "slow" tendency that many of us are seeing will come around and be perfect when things warm up.........jackie
If you remember, Ron Hoehn experienced much of the same phenomina when he did his test with the powder he was sent. That included a velocity in the 3500 fps range. You can dismiss many of us off as keyboard wannabes, but Ron does tend to know what he is doing.
Granted, none of us have the "controled lab" testing facilities that any of the major Powder Manufacturers poccess. All we do is go to the range, set up a Chronograph, and shoot groups. If the stuff goes from shooting mid ones, to mid threes, with nothing more than a 20 degree temperature drop, you figure maybe it is a tad temperature sensitive toward the cool side.
There has always been a problem with powder manufacturers not understanding the concept of "agging capability". They think that just because they can maintain a constant velocity under lab conditions,, that all of the bullets will continue to go on top of one another. Any experienced Benchrest Shooter knows that this is not nessessarilly so. The concept of "tune", when discussed in terms of 1/8 minute of angle, is something that transcends many of the normally held assumptions in the shooting world.
I agree, the problem now is few of us have had a chance to see what 90 dregree+ temperatures will bring. I hope that it is "just right". In fact, I think that is exactly what will happen. The "slow" tendency that many of us are seeing will come around and be perfect when things warm up.........jackie
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JerrySharrett
Senile Member
Jackie
I have chronographed 2 different lots. Both are slower than what Ron Hoehn got for velocity. For the 2 lots I have, one is from the Hodgdon data above, For the two lots I have I'll bet my money on the Hodgdon data which agrees with my Oehler 35 within about 10 fps. Both lots I have shot well but they are not whizzers.
I have chronographed 2 different lots. Both are slower than what Ron Hoehn got for velocity. For the 2 lots I have, one is from the Hodgdon data above, For the two lots I have I'll bet my money on the Hodgdon data which agrees with my Oehler 35 within about 10 fps. Both lots I have shot well but they are not whizzers.
jackie schmidt
New member
Jerry
As it turned out, the 96 pounds of powder that I actually bought turned out to be slower than that initial 1 pound jug that was sent to me for testing. By at least 1 grn, I would estimate. When dealing with small capacity cases such as what are found in 100-200 yard Benchrest, that is no small amount..........jackie
As it turned out, the 96 pounds of powder that I actually bought turned out to be slower than that initial 1 pound jug that was sent to me for testing. By at least 1 grn, I would estimate. When dealing with small capacity cases such as what are found in 100-200 yard Benchrest, that is no small amount..........jackie
goodgrouper
tryingtobeabettergrouper
Wow, what different results we can get. I've been shooting XBR since last November at 70 degrees and through the last few weeks down into the low 30's and I have been able to find good tunes with two bag guns and one rail gun every trip out thus far. During this time, I've been thinking this stuff works good in cold to mild weather but maybe it will fall apart at 80 degrees and above like some lots of H322 extreme I've had.
Now people are telling me they think XBR will work better in hot temps and can't get it to shoot in the cold? Seems we haven't even really got a good feel for what this powder will do for competitive agging and already some are getting varying results. Sounds kinda like the story we get with that Finnish made stuff?? Some can get it to work and others can't...............
Well, I'm going to limit myself to only several pounds of XBR until it gets more play time. I'd hate to sit on a stack of it only to find out that it falls apart when the temps get above 80. In the meanwhile, I've got enough of that purple lid stuff to last..........
Now people are telling me they think XBR will work better in hot temps and can't get it to shoot in the cold? Seems we haven't even really got a good feel for what this powder will do for competitive agging and already some are getting varying results. Sounds kinda like the story we get with that Finnish made stuff?? Some can get it to work and others can't...............Well, I'm going to limit myself to only several pounds of XBR until it gets more play time. I'd hate to sit on a stack of it only to find out that it falls apart when the temps get above 80. In the meanwhile, I've got enough of that purple lid stuff to last..........
Jerry Dailey
Southron
Wildcatter
My experience is the same as yours. Mines burns as dirty as Benchmark. After very slowly running it about 3/4 way up the neck it got a little better but not much. This really surprises me because every one says that it burns clean.
My experience is the same as yours. Mines burns as dirty as Benchmark. After very slowly running it about 3/4 way up the neck it got a little better but not much. This really surprises me because every one says that it burns clean.
W
Wildcatter
Guest
Jerry Dailey, looks like there are 2 wildcats on this board. The one above has one t I have 2 t's.