POSITION SENSITIVE POWDERS for pistols.

[happie2shoot]

Something else that can make things worse is use a 110gr boolit and
seat it out of the case farther rather than the heavier wc, heavy boolits
usually help ignition. talking about the 38sp

What 35rem said.

[nitro-express]

Low pressure, long straightwall cartridges are the worst. In the 38, the upper end standard charge of 4.7-4.8 grains Unique under a 158 gave up to 80-90 plus fps variations with extremes in positioning. Universal is worse than that. What bothers the .38 barely affects the teeny tiny case of the 9mm with its tiny powder volume and much higher pressures. Acceptable in the short cases like 45 ACP is in the 50 fps range, yet Universal will give over 100 fps variation with loads neither mild nor maximum with 200 LSWC HG 68's. That's how to weed out bad selections in powder........results below the normal.

Don't pursue unattainable goals in powder position sensitivity. Rather, know what is acceptable and attainable and go with that as you will not find perfection in this area. Chemistry and physics tends to deny it.

Those that postulate "no position sensitivity" for this or that powder haven't done much testing. Titegroup is often feted as being beyond compare, but I can produce variations with it too, most recently in the small powder space of the 32 Long using none other than deeply seated RCBS 98 WC's. Consistent as the rising sun as to velocity with powder position variation? Don't bet on it.

I ask no one to take my word for it.....rather, do what I do and test for it in a variety of cartridges. Know it occurs, and if you know the relative severity of the problem you can avoid it by judicious handling of the gun or a better powder selection. For example, anyone that deliberately chooses Universal for standard velocity 38 loads and is complacent about the true potential for variation has a big shock coming when position variation is deliberately modeled. After so doing, you'll never use Universal for such employment ever again.

But first, you gotta know it's happening.

I was experiencing some powder position variations and my research brought me to this thread. Since reading the above post, I did some of my own testing. And as is stated, some of the test results were enlightening to say the least. 35remington pretty much nailed it.

Having discovered that most of my Cowboy loads were pretty poor performers, the first shot out of the holster was a wild card. My testing consisted of 5 shots powder forward, against the bullet, and the next string powder back, against the primer.

With the testing out of the way, and quickly running out of powders to try, I sat down to ponder the results. Some loads were worse with the powder forward, but others were bad with the powder to the rear. My next step was to repeat some of the loads that showed good results with either the powder forward, or towards the rear. One load I had tested initially was good, forward, rearward, about 5 fps difference for average velocity, and Es approaching single digit. Single digit is the goal, 11 or 12 is good enough for Cowboy work.

Just about every component used can be a factor, including the brand of the case. The shape of the internal space, the length of the space, the amount of powder, obviously the powder, the weight of the bullet, and to a large extent the primer; the brand and whether standard or magnum.

My testing regime, while not entirely scientific, didn't result in finding the best primer. All the primers worked, and all the primers failed. 1 primer would work in a certain combination, but fail in another. I couldn't see a pattern, except that the WSP primer works better for certain powder forward combinations.

I did try some small rifle primers, and in one combination they were the ticket. Light charges of Universal need a "hot" primer, small pistol magnum of a small rifle (for some brands, they are the same).

In conclusion, testing and component substitution, especially primers, can yield some favorable results.

My Cowboy load for my hipguns (357 Mag) is a little faster than I'd want, but the numbers are good, and it shoots pretty accurate. My '66 in 38 Spl, well believe it or not, my old load was the charm, no change.

Unfortunately; when I run out of 452AA, I'll be testing again.

[nitro-express]

Something else that can make things worse is use a 110gr boolit and
seat it out of the case farther rather than the heavier wc, heavy boolits
usually help ignition. talking about the 38sp

What 35rem said.

For sure. A lighter bullet lacks the inertia required to built pressure when light charges are used. I tried to use 125 cast in the 357 for Cowboy action, nothing I tried seemed to work. I had better luck with 132 gr bullets, but 147 worked even better.