So I have developed a load for my 7mm Rem Mag that shoots really well. I am loading about 65.5 grains of IMR7828 and a 160 Accubond. Here is what is weird:
My load, during the late summer, showed no signs of pressure. Good primer, no extraction marks or difficulty etc.
I loaned the rifle to my brother to hunt elk with this fall and they did a lot of riding on ATVs etc. with loads of dust. After getting the rifle back, I wiped everything down and cleaned the barrel good. Didn't do a lot to the chamber area, but just wiped it out good with a couple of patches and a rag.
Anyway, a couple of weeks ago, I went to the range during a snowstorm with my boy and a buddy. We shot the 7mm-08 and my buddy's rifles and then I pulled out the 7mm Rem Mag to check and make sure all was good.
I fired the first shot and it hit right where it should. I noticed that the bolt was a bit stiff. Hmmmm. I noticed that there was a shiny spot on the case head where the extractor grinded into it. I shot a few more and they were all the same.
Any ideas? I was really surprised and have not had that issue in the past. I was really surprised as I knew that higher heat of the summer can cause higher pressures, so this seemed odd because of the colder temps.
Let me know your thoughts. It is a pretty new barrel with only about 100-150 rounds through it so far. It is a 26" Shilen Match grade barrel and this load was designed specifically for this rifle. Neck sized RP brass and CCI250 primers.
