Thrown charges are the rule in short range benchrest, where the most accurate load may not have the smallest ES. In longer range shooting, preloading and weighed charges are more the rule, certainly the former. I have spend a lot of time working with powder measure technique, and a friend's electronic scale, that weighs to .02 gr. Since the amount of powder that a given setting will throw is technique dependent, perhaps it would be a good start to take a load that you already know is a good one, and try different measure techniques, weighing and recording every charge, to determine what works best for you.
As a starting placed, on my Harrell measure, I found that removing the baffle gave better results. I have not looked at the one that you have, so I do not know if it has one, or if it is different than mine. The second thing that I can tell you is that I keep an eye on the powder level in the bottle. I try to keep it between 3/4 and 1/4 full, no more or less. The next thing to remember is to throw about 20 charges to settle the powder in the bottle, each time that you assemble the bottle to the measure, throwing a few when it has been sitting for a while is a good idea as well. Some loaders tap the handle on the stop on the up stroke. The problem is that harder taps throw more powder, and keeping taps uniform, from session to session can be a problem. I find that slowing way down and getting in a rhythm improves results. One myth that I really have taken a look at (with a scale) is the idea that when you cut a grain you should discard the charge. First of all, big stick powders should be thrown light and trickled, on a scale, and when you get down to the granule size where throwing starts to become feasible, what you will get is more of a grinding crunch as the measure cavity closes. Contrary to more common practice, I only USE charges that crunch, when the cavity is closed for the last time before the charge is dropped. Incidentally, I think that 133 is at the outer limit of what should be thrown, as far as particle size goes. 322, 8208 (the old stuff), and Benchmark are less of a problem in this respect. Now, after you have practiced all of this for a while, with a good scale, if you are not satisfied with your results, email me, and we can put some finishing touches on what you are doing. Have fun.
Boyd
Added later: I think that you will find that 4831 is too coarse to throw reliably, but I have been wrong before. Let us know about what sort of thrown charge variance you get. Remember, the Culver type of measure were developed for a specific sport, short range benchrest, that is shot with powders that are easier to throw than 4831. Even so, it takes some practice,with proper technique, to achieve good results.
