rifletuner
Well-Known Member
Whilst I haven't had as much opportunity to use the "thing" as I would like, I thought Peter and other LRH folks might like some information on how I have found the ballistics spreadsheet to date.
The bulk of my testing has been with my light 1000yd bench gun, which is chambered in 6.5x57 improved. This round gives me good accuracy with a 140gn Amax at 2950 fps. When inputting all the data into the spreadsheet, I went to the Hornady web page to check the BC listed for the 140gn Amax. My recollection for this bullet was a BC of .660, but when I checked the web page, I found many of the BC's had been revised downwards on the Amax range. The new BC listed for the 140gn Amax was .618.
This left me in a bit of a quandary as to which BC to use, so I generated two charts, one with the "old" BC and one with the "new" BC. This was all done in preparation for a weekend of competition, day one at 500 meters, day two at 1000 yards. At the end of two days shooting, I checked the settings I had dialled into the scope turrets and found that the trajectory predicted by the "thing" when using the old (and higher) BC of .660 was within one "click" for the actual settings used each day. Admittedly, this was not a good use of the "thing", but it did serve as a good method of testing the predicted results from the program.
The issue with determining the correct BC is a bit of a red herring. The bottom line was that once I had accurate data to input, the "thing" proved to work well. I will be looking forward to other opportunities to use the "thing" for drop charts for other rifles.
Fergus
The bulk of my testing has been with my light 1000yd bench gun, which is chambered in 6.5x57 improved. This round gives me good accuracy with a 140gn Amax at 2950 fps. When inputting all the data into the spreadsheet, I went to the Hornady web page to check the BC listed for the 140gn Amax. My recollection for this bullet was a BC of .660, but when I checked the web page, I found many of the BC's had been revised downwards on the Amax range. The new BC listed for the 140gn Amax was .618.
This left me in a bit of a quandary as to which BC to use, so I generated two charts, one with the "old" BC and one with the "new" BC. This was all done in preparation for a weekend of competition, day one at 500 meters, day two at 1000 yards. At the end of two days shooting, I checked the settings I had dialled into the scope turrets and found that the trajectory predicted by the "thing" when using the old (and higher) BC of .660 was within one "click" for the actual settings used each day. Admittedly, this was not a good use of the "thing", but it did serve as a good method of testing the predicted results from the program.
The issue with determining the correct BC is a bit of a red herring. The bottom line was that once I had accurate data to input, the "thing" proved to work well. I will be looking forward to other opportunities to use the "thing" for drop charts for other rifles.
Fergus
