I'm making this thread because I want to see if I have enough tech savvy to actually post photos on CGN. So here goes...
Yesterday, I was at the range in Mission, playing with my "precision" rifle -- a .308 built on an old BSA action (with claw extractor) in a thumbhole stock, wearing a take-off Krieger palma barrel cut down to 26 inches. Until 2006, this was the rifle I used for iron-sight competitive shooting.
I always like to do my load testing at 200 metres because I find it gives me a better picture of the subtle differences between loads. Lots of loads look good at 100, but any problems become readily apparent at 200, in my experience.
Yesterday illustrated nicely the other side of the coin: the danger of relying upon 200 metres for load testing.
By the time you reach 200, the wind can have a noticeable effect.
Yesterday, I shot my "control load" at 200. This is my standard load for this rifle and barrel: 45.0 grains Varget, in a Federal case, ignited by a 210M, pushing a 155 AMAX, seated to 2.810". I was planning to experiment with some new bullets, as well as try some different charges of Vihtavuori N550. By the time I fired the control load, the wind was gusting a bit, but I shot through it without concern. I simply fired the string, bang, bang, bang, bang, bang, without looking through the spotting scope or making any windage corrections. I had a friend spot my target while I was shooting, and he noted about halfway through the string that the wind had dropped off.
Anyway, here is that 200 metre group, with the shots numbered in the order they were fired. The moment that the breeze let off is immediately apparent:
The breeze was mainly visible in the form of a light rustling of the leaves on the right side of the range. It was also apparent in the mirage through the spotting scope. As you can see, even this subtle breeze had a half-minute effect on the shots. If I didn't realize all this, I might conclude this was a mediocre load just by measuring the group size. The entire string measures a shade less than 1.5 inches, which translates into 3/4 moa -- pretty crappy for this rifle.
As a result of this lesson, I fired my N550 test loads at 100 metres. I guess there is a lot of wisdom in the standard practice of doing load testing at 100, and I stand humbled.
Yesterday, I was at the range in Mission, playing with my "precision" rifle -- a .308 built on an old BSA action (with claw extractor) in a thumbhole stock, wearing a take-off Krieger palma barrel cut down to 26 inches. Until 2006, this was the rifle I used for iron-sight competitive shooting.
I always like to do my load testing at 200 metres because I find it gives me a better picture of the subtle differences between loads. Lots of loads look good at 100, but any problems become readily apparent at 200, in my experience.
Yesterday illustrated nicely the other side of the coin: the danger of relying upon 200 metres for load testing.
By the time you reach 200, the wind can have a noticeable effect.
Yesterday, I shot my "control load" at 200. This is my standard load for this rifle and barrel: 45.0 grains Varget, in a Federal case, ignited by a 210M, pushing a 155 AMAX, seated to 2.810". I was planning to experiment with some new bullets, as well as try some different charges of Vihtavuori N550. By the time I fired the control load, the wind was gusting a bit, but I shot through it without concern. I simply fired the string, bang, bang, bang, bang, bang, without looking through the spotting scope or making any windage corrections. I had a friend spot my target while I was shooting, and he noted about halfway through the string that the wind had dropped off.
Anyway, here is that 200 metre group, with the shots numbered in the order they were fired. The moment that the breeze let off is immediately apparent:
The breeze was mainly visible in the form of a light rustling of the leaves on the right side of the range. It was also apparent in the mirage through the spotting scope. As you can see, even this subtle breeze had a half-minute effect on the shots. If I didn't realize all this, I might conclude this was a mediocre load just by measuring the group size. The entire string measures a shade less than 1.5 inches, which translates into 3/4 moa -- pretty crappy for this rifle.
As a result of this lesson, I fired my N550 test loads at 100 metres. I guess there is a lot of wisdom in the standard practice of doing load testing at 100, and I stand humbled.
LOL, anyway for what its worth , I find what a 22 rimfire does at 50-100 Meters, you can expect the same from some big game rigs at 200-300 meters. This can be quite a bit depending on the wind direction and speed. Another reason to use the fine little cal. as a training tool. 
