OlympicViking
Member
- Joined
- May 23, 2017
- Messages
- 20
Today I took my 7mm-08 to the range to evaluate a hunting load I'm developing. The load involves Lapua brass, Barnes 120 gr TTSX, WLR primers, and Varget. Last weekend I fired 25 rounds in 5-shot groups ranging from 42.0 to 44.0 grains (first 25 casings starting from the left). I seated the bullets 0.060" off my lands to a COL of 2.850. The Barnes website lists 2.800" and a max charge of 43.9. My best group by far was 43.0 gr, and my second best was 42.5, so I decided to try 15 rounds at 42.8, 42.9, and 43.0 today. Well, two of my primers had a problem where a small hole on the side of the primer allowed gas to escape. One of them is pretty easy to see in the picture, and the other one is two to the right. There's also a small erosion mark on my bolt that I'm kinda pissed about, but from what I've read it shouldn't be a problem.
To be honest I'm scratching my head at this one. The charge weights I used today are all within the published range, and even when I previously loaded 1.0 gr hotter I did not have this problem. Unless I'm mistaken, none of the other 38 rounds I've fired have shown signs of overpressure. I realize my COL is different from the published load, but .05" longer shouldn't cause a pressure increase, right?
The brass has been fired twice, sized in a Redding body die, run through a Lee collet neck die, trimmed to 2.025", chamfered, and deburred. I also used a Lyman primer pocket uniforming tool and an RCBS case prep machine to clean out the primer pockets (they were already uniform when I got them, but the Lyman tool helps scrape out some of the carbon in the pocket). When I first got the brass the primer pockets were very tight (just like some new 9mm Lapua cases I loaded once before), but after the first firing they felt normal. Certainly not loose pockets. I left the remaining 10 cases unloaded & unprimed so that I could tweak seating depth slightly once I find the optimal charge weight and see if that will give me better accuracy.
To be honest I'm scratching my head at this one. The charge weights I used today are all within the published range, and even when I previously loaded 1.0 gr hotter I did not have this problem. Unless I'm mistaken, none of the other 38 rounds I've fired have shown signs of overpressure. I realize my COL is different from the published load, but .05" longer shouldn't cause a pressure increase, right?
The brass has been fired twice, sized in a Redding body die, run through a Lee collet neck die, trimmed to 2.025", chamfered, and deburred. I also used a Lyman primer pocket uniforming tool and an RCBS case prep machine to clean out the primer pockets (they were already uniform when I got them, but the Lyman tool helps scrape out some of the carbon in the pocket). When I first got the brass the primer pockets were very tight (just like some new 9mm Lapua cases I loaded once before), but after the first firing they felt normal. Certainly not loose pockets. I left the remaining 10 cases unloaded & unprimed so that I could tweak seating depth slightly once I find the optimal charge weight and see if that will give me better accuracy.