Neck Tension vs Accuracy

[dedeadeye]

Jim, my reamer is from JGS. Roger

 

[johara1]

We did some annealing to make shoulder bump in a couple of thick shouldered magnums more consistent, but we had to retain pretty much stock seating force and bullet hold, because these were accurate hunting rifles. To get the shoulder problem solved, and not soften the necks very much if at all, was very touchy as to annealing time, using a two torch rotary annealer that pauses cases in the flames. IMO if you are trying to keep bullet pull, and make it uniform by annealing (partial annealing, stress relieving?) the process becomes very critical. In short, it is very easy to miss your mark. We did our setup with 500 degree Templaq painted from the point of the shoulder down the body, and set the time to turn its color about where you see the annealing marks on a Lapua case.

Boyd, I use a rotary annealer with one torch i found it to be more accurate that way, as far as templaq, i have it and the thinner but i prefer the a dark room and use sight for the dim glow as it starts to turn and i even measure the pencil point length of the flame to try to get uniformity on the heat…….. jim

 

[johara1]

Jim, my reamer is from JGS. Roger

Roger i'm thinking it maybe the reamer mine on 12 different barrels does the same thing it leaves a circle with 4 land marks when hunting zero. The force it hold at the ogive over comes the little force of the seat with new BR. brass. So that takes the anneal BS. right out of the picture. What is your free bore diameter? i'm using .2438…..jim

 

[dedeadeye]

Jim, my JGS has a .2438 free bore diameter also. I notice, after polishing the seated bullet with a piece of white 3M scotch brite, I can see rifling marks easily. Much better then .0000 steel wool. I use a 40x magnifier also. The rifling marks are soft and naturally become longer as the seating depth is increased. With this reamer, a square fit (marks as long as wide) is about .024 in. .008 in is a nice soft defined mark. When closing the bolt without a firing pin, a very small resistance can be felt. Matt Kline is right on with this depth, about 1/3 square. Roger
PS. A few evenings ago my friend Chuck Loebsack shot a .214 group at 300 yards testing a lot of hybrids with this seating depth.

 

[johara1]

Roger, i just screw on my old barrel from last year and it was 4 clicks from the new one 1/2 ain't bad…….LOL. it shot like it had eyes my big group was .130…… i may leave it on for the national and worry about seating in latter. The hybrids shot well at .008 to .012 in with .001 neck tension …….. jim

 

[BoydAllen]

If it shoots, its right. We would use the same old case to calibrate with Templaq every time we set up, cooling it and repainting for each test. We did this because we felt that it was the best reference. Our final determiner was the shoulder bump of the cases. On the first batch we were a little too conservative, and did not get what we were looking for. Once we had that, and the neck tension that we wanted, we noted what we had done.

 

[johara1]

If it shoots, its right. We would use the same old case to calibrate with Templaq every time we set up, cooling it and repainting for each test. We did this because we felt that it was the best reference. Our final determiner was the shoulder bump of the cases. On the first batch we were a little too conservative, and did not get what we were looking for. Once we had that, and the neck tension that we wanted, we noted what we had done.

Boyd, I used the Hornaday set up first so i know where that came from and i did use that for years, I test with a small set of vice grips and squeeze the neck a little and see if it springs back. I found that seeing the faint glow start in dim light very reliable ……. jim

 

[BoydAllen]

With the rotary annealer, coincidentally, right when the case moved out of the flame, with the time right, there was a little something happening right at the case mouth. On the Hornady kit, I suggested that a friend get a cheap battery powered metronome and set it for 60 beats per minute, so that he could hear the seconds tick off while he was annealing. He said that that was a big help for the first couple of hundred cases, at which point he had learned to gauge the process by how the color was coming down the case body.