After nearly a year and a half of consistent irritation with
non-shooting bolt guns I finally got one that shoots, and decided to wring it out by taking it to a 1000 yard F-Class match last weekend. I was pretty happy with my scores since this was the first sanctioned match I'd shot in 7 years or so. I didn't intend this to be a match gun, but I'm afraid the bug has bitten me.
I am having a little trouble getting the 178gr AMAX to 2650 (to keep it supersonic at 1000) with accuracy and a respectable ES (to be competitive at 1000 the velocity ES needs to be under 10, and to be truly competitive it needs to be around 5-7). The load I wound up using turned out to be TERRIBLE on the chronograph in terms of ES, but I did
wind up with an X-count of 4, with three of those shot consecutively (you want to talk about a good feeling - put three rounds into a 5 inch circle at 1000 yards with a .308 in a constantly shifting wind and mirage. I was walking on air for the next couple of hours :-D). I didn't get to chrono the load until after the match, but it took me 12
mils of elevation to get to 1000 from 100 yards, which indicated 2550 - which proved to be right on the nose when I chronographed it.
According to Exbal (and my friend in the pit) it was going subsonic at about 975, but the bullet was still making nice round holes in the target and more or less hitting what I was shooting at. The problem is that the load I used was not safe (I kept the rounds in an MTM box inside a lunchbox cooler to keep them around 40 degrees instead of 92
after I saw the flattened and cratered primer when I shot three at 10 PM the night before) and though they seemed to shoot ok at 1000, the ES was truly horrible and the primer looks like it was licking its chops thinking about taking out my right eye. So I'm starting more or less over, and I had a couple of thoughts that I wanted to run by the
assembled multitude.
As you know, the general rule is that you need to have your bullet supersonic at the target, or you're out of range. However, some bullets do fly fairly true through the transonic zone, and it looks like the AMAX 178 might be one of them, at least at 92 degrees and 45% RH. Plus, I know some guys who are shooting essentially the same load out of 16" gas guns, which puts the MV at about 2450, and they're getting hits to 1200. So what I'm thinking is that maybe I should stop trying to push that bullet faster than 2550 and just work on the accuracy and ES, and just quit worrying about the supersonic burnout range unless or until I start seeing screwy behavior at the 1k line. Opinions are welcome here. My gun seems to really like 43.0 of Varget - groups are dramatically tighter than any other charge weight I've tried so far.
I know I'm mixing my metaphors here by talking about a "precision rifle" in the military sense and working on match shooting as well, but it would be nice to have a load that's usable in both arenas (I know it won't be optimized for F-class competition, but I'm just doing that for
fun, not trying to climb the ladder in that world).
For reference - the load was:
New Lapua brass, FL resized in Redding die
43.0 gr Varget
178gr AMAX
Federal Gold Medal Match Magnum primer (GM210M)*
COAL 2.800"
*I did this because of the 50fps ES I was getting with the standard primer. Preliminary tests indicated substituting the magnum primer brought the ES down to under 10 - but that's not what happened later that afternoon. When I chronographed the load after the match, the ES was 91!
I got some RL-15 and am interested in trying it to see if I can safely get a little more velocity, but it seems my rifle really wants to throw the 178s at about 2550 for best accuracy.
Thanks gents.
non-shooting bolt guns I finally got one that shoots, and decided to wring it out by taking it to a 1000 yard F-Class match last weekend. I was pretty happy with my scores since this was the first sanctioned match I'd shot in 7 years or so. I didn't intend this to be a match gun, but I'm afraid the bug has bitten me.
I am having a little trouble getting the 178gr AMAX to 2650 (to keep it supersonic at 1000) with accuracy and a respectable ES (to be competitive at 1000 the velocity ES needs to be under 10, and to be truly competitive it needs to be around 5-7). The load I wound up using turned out to be TERRIBLE on the chronograph in terms of ES, but I did
wind up with an X-count of 4, with three of those shot consecutively (you want to talk about a good feeling - put three rounds into a 5 inch circle at 1000 yards with a .308 in a constantly shifting wind and mirage. I was walking on air for the next couple of hours :-D). I didn't get to chrono the load until after the match, but it took me 12
mils of elevation to get to 1000 from 100 yards, which indicated 2550 - which proved to be right on the nose when I chronographed it.
According to Exbal (and my friend in the pit) it was going subsonic at about 975, but the bullet was still making nice round holes in the target and more or less hitting what I was shooting at. The problem is that the load I used was not safe (I kept the rounds in an MTM box inside a lunchbox cooler to keep them around 40 degrees instead of 92
after I saw the flattened and cratered primer when I shot three at 10 PM the night before) and though they seemed to shoot ok at 1000, the ES was truly horrible and the primer looks like it was licking its chops thinking about taking out my right eye. So I'm starting more or less over, and I had a couple of thoughts that I wanted to run by the
assembled multitude.
As you know, the general rule is that you need to have your bullet supersonic at the target, or you're out of range. However, some bullets do fly fairly true through the transonic zone, and it looks like the AMAX 178 might be one of them, at least at 92 degrees and 45% RH. Plus, I know some guys who are shooting essentially the same load out of 16" gas guns, which puts the MV at about 2450, and they're getting hits to 1200. So what I'm thinking is that maybe I should stop trying to push that bullet faster than 2550 and just work on the accuracy and ES, and just quit worrying about the supersonic burnout range unless or until I start seeing screwy behavior at the 1k line. Opinions are welcome here. My gun seems to really like 43.0 of Varget - groups are dramatically tighter than any other charge weight I've tried so far.
I know I'm mixing my metaphors here by talking about a "precision rifle" in the military sense and working on match shooting as well, but it would be nice to have a load that's usable in both arenas (I know it won't be optimized for F-class competition, but I'm just doing that for
fun, not trying to climb the ladder in that world).
For reference - the load was:
New Lapua brass, FL resized in Redding die
43.0 gr Varget
178gr AMAX
Federal Gold Medal Match Magnum primer (GM210M)*
COAL 2.800"
*I did this because of the 50fps ES I was getting with the standard primer. Preliminary tests indicated substituting the magnum primer brought the ES down to under 10 - but that's not what happened later that afternoon. When I chronographed the load after the match, the ES was 91!
I got some RL-15 and am interested in trying it to see if I can safely get a little more velocity, but it seems my rifle really wants to throw the 178s at about 2550 for best accuracy.
Thanks gents.
