RobT

Reloading partial mags between stages is the scenario where I saw a use for witness holes - if they worked. It would be slightly more convenient just to glance at the mag and load up to full capacity, then to empty the mag and start over. However, looks like it will be empty the mag and start over. FYI - holes on Glock 10 rd 9mm mags are numbered 4 - 10. RobT

New GLOCKster here. When I look at the witness holes of my stock Glock 10 rd. 9mm magazines, the witness holes do not seem to indicate the number of rounds actually in the magazine. Usually they indicate one less than the actual number loaded - although I have not really made a study of it. Anyone else notice this? (A search of the Glock forum showed no discussion) RobT

I stand. Standing, with my 650, I'm just the right height to verify there is powder in the case before seating the bullet. Powder Check System not withstanding, years of reloading habit require that I see powder before placing bullet. RobT

Recall that the motto of the sport is "Accuracy, power, speed". Just as we quantify accuracy with match points and speed with seconds, power is quantified with power factor. It takes shooting a minor pf just to get into the game and shooting a major pf creates the possibility of a greater reward for points outside the A zone. searching for Celeritas. RobT

Carlos Thanks for the good info. The 1.100 OAL came straight from the Hornady Handbook 6th Ed. They give a Max OAL for 9mm as 1.169 and then quote an OAL for each bullet. My 3.4 gr. of TiteGroup under the 147gr HPBT seated at 1.103 feed reliably but gave a shotgun pattern at 25 yds. Maybe it was just me trying to get used to a Glock trigger. More later. RobT

please. - 1.100 ? RobT

Get a set of scale reference weights and use them. RobT

Not to denigrate the Winchester rep or anything, but I would take any hear-say info like that "with a grain of salt" unless, I knew for a fact I was talking to their senior engineer/chemist. YMMV RobT

Good post Tree Rat! - What sample size did you use? Looks like there should be statistical tests that could be applied to data like this. Where is a statistician when you need one? I may have to dig out my old stat texts yet. Thanks for taking time to put together your results. RobT P.S. How did you measure relative humidity?

I'm in need of a 9mm 147gr load. What bullet? What charge TiteGr? DVC RobT

I have a Lyman tumbler very similar to the model pictured. I use it in conjunction with a Dillon separator. Emptying the media with the side plug just never seemed very practical. BTW, had it about 2 years and maybe 10K brass. The plug on the side has worked loose and is now duct taped on. The plastic wing nut holding the lid has broke and I'm down until I get a replacement nut (or tumbler). YMMV RobT

Thanks for the welcome Kevinc and thanks to all for your input. I suspected this topic had been discussed, but my search efforts usually result in 20 gazillion hits or none I did mention this problem to one of the shooters at our indoor league who has a masters in math. She recommended an experimental approach - record the standard deviation after every 5 rounds and when the SD "settles down" and approaches a limit, you have reached a practical sample size. Of course, it is yet to be determined if the SD will "settle down" in what I regard as a practical number of rounds to expend in trying to measure one load. Anyhow, based on the topic posts and my unscientific gut feel, I'll use 20-30 rounds per load at my next chrono session and may try the suggested experiment. DVC RobT

Hi Guys Just starting to use a chrono (Pact MK IV). Wondering what to use for a sample size working up data on a particular load. I know many people go with 5 round strings - but that seems to small given the variability of loads I've seen and measured so far. I could get out the old statistics texts - but only as a last resort. Any thoughts? - thanks in advance. RobT