Here's my latest find when reloading and bullet groups not being consistent.
Over the last 3 months I have probably loaded 150 300 WM and I have been troubled by the results. Slowly, I have been trying to figure out what is wrong. Scope cant, fixed it... All rifle torques, rechecked. I have even taken my time to ensure that my powder weights are as close as human possibly, shy of cutting the h1000 grains. After months of wondering if old age was just getting to me I finally found the problem.
Originally, I developed my loads on the "tool shop" brand calipers, but when i found where my 10 year old Mitutoyo ones were stored I swapped over to them. The Mitutoyo always measured smoothly and always returned to zero. The tool shop ones were somewhat gritty and just didn't feel like perfection. Logically, this led me to think the Mitotoyo would be supremely more accurate. Well today I found out I was wrong.
For the longest time the Mitutoyo were supremely accurate and I never questioned them. After moving multiple times something happened. I loaded up 20 300 WM this morning following my same routine, and trying to get everything as accurate as possible. By this time i'd had enough and I was going to take as much time/care as needed to load these bullets. They were going to be my make or break rounds. After loading around 20 in 1-2 hours. I was measuring necks, then measured a bullet. The bullet measured .311-.312. I was astonished. Had berger always sent me large bullets? I measured some accubonds, same measurement.. The calipers returned to zero fine.
My father was a machinist for part of his life so I went into one of his old tool boxes and pulled out a standard gauge block. The block was marked with .127 on it.. The calipers read .131. That told me all i needed to know. Also, inside his tool box were some vernier calipers of higher grade. I took the gauge block and compared my newer "tool shop" to the Mitutoyo and the vernier. The vernier were on the dot. The tool shop were a little inaccurate and my "precious" Mitutoyo digitals were still off.
After that I decided to remeasure all my rounds. Every measurement I had made (Ogive OAL, Brass OAL, necks, etc) were all off from where i was aiming for.
I learned my lesson. Now I have ~50 total 300 WM to fire off before I get back to making accurate rounds..... Or so i hope.
Over the last 3 months I have probably loaded 150 300 WM and I have been troubled by the results. Slowly, I have been trying to figure out what is wrong. Scope cant, fixed it... All rifle torques, rechecked. I have even taken my time to ensure that my powder weights are as close as human possibly, shy of cutting the h1000 grains. After months of wondering if old age was just getting to me I finally found the problem.
Originally, I developed my loads on the "tool shop" brand calipers, but when i found where my 10 year old Mitutoyo ones were stored I swapped over to them. The Mitutoyo always measured smoothly and always returned to zero. The tool shop ones were somewhat gritty and just didn't feel like perfection. Logically, this led me to think the Mitotoyo would be supremely more accurate. Well today I found out I was wrong.
For the longest time the Mitutoyo were supremely accurate and I never questioned them. After moving multiple times something happened. I loaded up 20 300 WM this morning following my same routine, and trying to get everything as accurate as possible. By this time i'd had enough and I was going to take as much time/care as needed to load these bullets. They were going to be my make or break rounds. After loading around 20 in 1-2 hours. I was measuring necks, then measured a bullet. The bullet measured .311-.312. I was astonished. Had berger always sent me large bullets? I measured some accubonds, same measurement.. The calipers returned to zero fine.
My father was a machinist for part of his life so I went into one of his old tool boxes and pulled out a standard gauge block. The block was marked with .127 on it.. The calipers read .131. That told me all i needed to know. Also, inside his tool box were some vernier calipers of higher grade. I took the gauge block and compared my newer "tool shop" to the Mitutoyo and the vernier. The vernier were on the dot. The tool shop were a little inaccurate and my "precious" Mitutoyo digitals were still off.
After that I decided to remeasure all my rounds. Every measurement I had made (Ogive OAL, Brass OAL, necks, etc) were all off from where i was aiming for.
I learned my lesson. Now I have ~50 total 300 WM to fire off before I get back to making accurate rounds..... Or so i hope.
