I may shoot H4198 this w/e

[Eric Leonard]

I shot a 491 with LT32 today at Buck Creek,,with the passing of my FIL I hadnt shot in 2 weeks and shot 4 five shot groups with LT32 and picked the one that looked best and I am not sure it was best,,it will shoot a tiny group but it seemed to move up and down on the target between relays,,3 shot groups on sighters were in the same hole about 2 bullet holes high between ever relay at 100,,

I was shooting 28.7 with Fed 205s,,I may back down to 28 and shoot groups at 28.28.2 28.6 and 28.8 ever 15 minutes or so and repeat from 9AM til 3PM one day soon and see which charge is the best or if I will have to shoot different charges through the day or switch back to 133 as it seemed to stay level all day at Gallatin 2 weeks ago,,

 

[LHSmith]

Let me tell you about LT-32 . . . bought 16# of Lot #6 two years ago to use in my Hart 1A and later in my BAT, both HVF Score rifles. Hart has a 1:14" twist ss Hart bbl, and the BAT has a 1:13.5" twist Krieger. Bullets used were Berger 64 gr. Column, Bart's 68 gr. Ultras, and Ulrich 67 gr, BT's, jammed 0.005" or thereabouts. The powder flowed through the measure like pepper and was easy to keep within 0.1 of a grain and most times right on the nose. Favorite load was around 28.5 gr. (+ or - a tenth or two) for both rifles, depending on the bullet. Shot the lights out at a warm, dry, practice session on Wed afternoon, and then would start with a bullet or more of vertical at the Match on Sun morning! I'd struggle through the warm-up and the first paper or two then it would smarten up, but by then I'd lost a point or two, of course . . . Thought is might be the scope, rest, front bag, rear bag, bullets, cases, primers, me, etc., etc. Changed everything along the way, but the same pattern always returned. I was about ready for the Rubber Room when I finally figured out that it was acting up when it was cold and damp, or warm and humid! If it was cold and dry or warm and dry it shot great. At the suggestion of another 6 ppc Score shooter I tried IMR 8208 and have been using it ever since. Group shooting folks in the southwest and west use LT-32 and do very well with it. Very few here in the east do so. That kind of says it all. My theory? The small powder grains create a lot of surface area and thus require a heavy deterrent coating to control the burning speed. Under cold and damp or warm and humid conditions this coating absorbs more moisture than other powders in the same burning range. This increased moisture is what causes the inconsistency from one session to the next. No (easy) way the prove that, but it makes sense. Oh - there's still a Rubber Room available if someone out there is struggling with LT-32 and hasn't figured out the moisture thing yet . . .

Chris Mitchell

I use Lt-32 in the 6 PPC in VFS matches here in the N.E. because it is easier to keep in tune in both MY LV and HV guns. I checked the IBS group equipment lists from this year and last, and found Lt-32 and N-133 are equally listed. AFAIK there is no powder made that will net the same velocity through temperature ranges normally experienced during the course of a match. The one powder produced that was the most forgiving in this was the famous "T-32" powder where on a bad day (large temp swing) you might have to adjust the measure once. And yet some barrels didn't respond to "T" as well as others. There is no question relative humidity plays a role in a powders performance, both in affecting charge weights thrown at a match and it's ability to stay in tune. A prime example is N-133 and it's unpredictability when the RH drops below 30%.