I haven't built cartridges for maybe four years. I haven't actually shot a rifle for longer than that! But I recently found a test batch from a new recipe for a DMR that I never got out to the range to try. I decided enough was enough and took a trip to Deer Creek out west to shake down & check zeros on a couple rifles and put rounds through another I've not shot since I bought it. Here's the results of the test batch at 100 yds. Disclaimer: I haven't shot the DMR (or any rifle for that matter) in at least 5 years; it's a gas gun; there was a right to left wind.
Really, that's a decent 10 round group for me. The 10 ring is 3.25" in diameter and the group is 2.5" wide x 1.75" tall.
So, I got busy and over the course of about 5 days I built 111 examples of that recipe. Here's the OCD part: I trickled the powder charge and measured the OAL of every single cartridge. Sheesh! Powder charges are all spot on and the OAL is within 0.006" of the target number. Now, back years ago when I was competing, I would build 95 rounds every week the same way to use the following weekend. Didn't think twice about it. I forgot how much time it takes but also how therapeutic it is.
The 11 extra rounds are to validate the recipe, 1 sighter and the rest for group.
Now, if the validation works out, I intend to build another 100 just because everything is set up. Problem is I don't want to measure every cartridge again. The 1st 100 were built on a progressive press, so I could have banged those out in an evening if I wanted to.
(old pic)
OAL of 0.006" fixes itself when the round is chambered. While I was metering and measuring powder charges, about one in maybe 6 or 8 were off by about this much:
Is that enough to make a difference? Yes it is. The further the distance, the greater the difference. I may uses these out to 600 yds. Is it small enough of a difference that I can live with it?
I don't know...
Really, that's a decent 10 round group for me. The 10 ring is 3.25" in diameter and the group is 2.5" wide x 1.75" tall.
So, I got busy and over the course of about 5 days I built 111 examples of that recipe. Here's the OCD part: I trickled the powder charge and measured the OAL of every single cartridge. Sheesh! Powder charges are all spot on and the OAL is within 0.006" of the target number. Now, back years ago when I was competing, I would build 95 rounds every week the same way to use the following weekend. Didn't think twice about it. I forgot how much time it takes but also how therapeutic it is.
The 11 extra rounds are to validate the recipe, 1 sighter and the rest for group.
Now, if the validation works out, I intend to build another 100 just because everything is set up. Problem is I don't want to measure every cartridge again. The 1st 100 were built on a progressive press, so I could have banged those out in an evening if I wanted to.
(old pic)
OAL of 0.006" fixes itself when the round is chambered. While I was metering and measuring powder charges, about one in maybe 6 or 8 were off by about this much:
Is that enough to make a difference? Yes it is. The further the distance, the greater the difference. I may uses these out to 600 yds. Is it small enough of a difference that I can live with it?
I don't know...
