PDA

View Full Version : LT32 Powder Throw Test



cpboomer
01-28-2013, 09:53 PM
Over the weekend, I ran a short test of my throwing ability using a Jones powder measure and the new lot of LT32 I just received from Powder Valley. My throwing motion consisted of slightly touching at the top of the throw and slightly bumping at the bottom. Since I was dropping the load into a pan, I didn't modulate the drop to simulate slowly filling a case. I threw ten consecutive loads from 50.0 clicks to 55.5 which ran from 27.65gr to about 30.6 gr. From early reports from the field, it would appear that window should cover normal load settings for the 6PPC. I used a full bottle of powder in the measure and the temp/humidity was 70 deg and 34%.

My reference scale is a Sartorius GD-503 that had been warmed up and calibrated prior to the test. The scale was zeroed between each new measure setting, although the usual error was on the order of 0.01gr or less. LT32 meters much more easily than N133 and there are fewer kernals cut in a loading session. There were usually 1 or 2 "light" kernal cuts per 10 loads, but the increase in force was minimal. I counted these loads in the spreadsheet and I couldn't see any statistical difference in the results. I plan to keep such loads at a match since they fall in the load window.

"Heavy" kernal cuts seemed to occur once every 20- 30 loads or so. These throws required significantly more force and I questioned the reliability of such throws. I weighed, but did not count any throw in which I judged to include a heavy cut. Most of those throws were still in the throw window, but a few were a couple of tenths out, so I would suggest that you test your own motion to decide whether to keep a heavy cut throw at a match. I will pour that powder back in my measure if I run into a heavy cut at a match.

As one can see from the data in the attachment, LT32 throws pretty well. Without fine tuning my throw for the new powder, it still threw an average of 0.205gr between the high and low load at each setting. The extrema were generally within .1gr of the 10 load average. I have been using a Chargemaster combo at the range to get that level of accuracy in my loads. It would appear that LT32 could provide that level of accuracy from a measure.

Using my fireformed brass, 29.0 gr (52.5 clicks) filled the cased to within about 3/16 of the mouth if dropped fast and was below the neck if dropped slowly. Lou's data suggests that one could expect to see 3450fps with Columns and 3400fps with Hottenstein 68's with this load. At the top end, 30.6gr (55.5 clicks) the powder was domed at the mouth in a fast drop and filled about half the neck if dropped slowly. There is easily enough case capacity to get to another node above 3400 if your rifle can safely use it.

If I get a few minutes next weekend, I plan to try the same test using a half full powder bottle to see if there is any variance in the average load or extrema.

alinwa
01-29-2013, 02:49 AM
Thank you Jeff!

Nicely done

al