Last day at the range for a while..........
Oct 20, 2009 20:18:12 GMT -5
Post by Richard on Oct 20, 2009 20:18:12 GMT -5
Well, Thursday I get the rotator cuff on the right shoulder repaired but that will curtail my shooting for probably a month or more. Anyway, I had a pretty good day at the range today and obtained some good information.
First let me say this, we (Herman and Bill) have started shooting from inside our range house as the morning temperature was 35*. Here we use an insert into the window that has a mini-slot to shoot from. We use heaters and this helps contain the heat rather than having the window wide open. Due to this set up, I have no place to attach my spring that retards recoil on the lead sled and also pulls the sled back forward "into battery". So, I just added and additional eight pounds to the sixteen pounds I was already using. OK, so here is what I am getting at. My rifle was sighted in some four inches high at 100 yards with a load similar to the one I was shooting today. My first shot at the upper left bull (about 6" from the top of my target board) was no where to be found on the target? (even walked up to the target) Velocity in line to where it should be, so no blown sabot!
Next shot I went to the center bull on my board and low and behold, the shot was 10" high?
For the life of me, I had no idea why it should have changed since last week............Then, the light came on in my head 
I was not using the Spring. So I fired three more shots and that groups formed a decent 1.188" cluster with an average velocity of 2934 fps.
Apparently that spring thing changed the vertical pattern from 4" + to 10" +! This also can occur with different degrees of shoulder pressure on the butt. So, if you are having problems with vertical stringing, this is an important area to examine.
I then made a scope adjustment based on that group and proceeded to shoot a different duplex. This was a slower load and went low and left but still produced a decent group.
Next I went back to the original duplex that I shot in group #1 (for which I had made the scope adjustment) and voila, a nice 1.027" right where I had adjusted the scope. (this was a 200 gr. XTP)
The fourth group (at 300 yards) I shot with the same duplex, but substituted a 200 gr. SST for the XTP. This produced five shots in 3.5" low and to the left. I should have shot the SST at 100 yards first so knew my point of impact. Anyway...............
Also note the group of four shots in the 3,000 fps range? I believe the sun may have caused those readings as the load was generally shooting in the 2930's. And yet, the readings were pretty consistent.
So the last group was the exact same load as the one at 300 only at 100 yards. Based on its location, it was obvious why I hit where I did at 300. This group is probably one of my best so far with four of the five shots so close together in one hole, we could not tell which shot was which!
I think 3,000 fps is definitely reachable, particularly with the longer barrels, but 2900 seems plenty fast enough and I don't think it worth overly pursuing it. This last group also seems to indicate that those 3,000fps shots were not real. 13 fps ES at 2938 is still cookin'!
Please excuse the picture quality as my good camera is out for repair
Richard
First let me say this, we (Herman and Bill) have started shooting from inside our range house as the morning temperature was 35*. Here we use an insert into the window that has a mini-slot to shoot from. We use heaters and this helps contain the heat rather than having the window wide open. Due to this set up, I have no place to attach my spring that retards recoil on the lead sled and also pulls the sled back forward "into battery". So, I just added and additional eight pounds to the sixteen pounds I was already using. OK, so here is what I am getting at. My rifle was sighted in some four inches high at 100 yards with a load similar to the one I was shooting today. My first shot at the upper left bull (about 6" from the top of my target board) was no where to be found on the target? (even walked up to the target) Velocity in line to where it should be, so no blown sabot!
Next shot I went to the center bull on my board and low and behold, the shot was 10" high?
For the life of me, I had no idea why it should have changed since last week............Then, the light came on in my head 
I was not using the Spring. So I fired three more shots and that groups formed a decent 1.188" cluster with an average velocity of 2934 fps.Apparently that spring thing changed the vertical pattern from 4" + to 10" +! This also can occur with different degrees of shoulder pressure on the butt. So, if you are having problems with vertical stringing, this is an important area to examine.
I then made a scope adjustment based on that group and proceeded to shoot a different duplex. This was a slower load and went low and left but still produced a decent group.
Next I went back to the original duplex that I shot in group #1 (for which I had made the scope adjustment) and voila, a nice 1.027" right where I had adjusted the scope. (this was a 200 gr. XTP)
The fourth group (at 300 yards) I shot with the same duplex, but substituted a 200 gr. SST for the XTP. This produced five shots in 3.5" low and to the left. I should have shot the SST at 100 yards first so knew my point of impact. Anyway...............
Also note the group of four shots in the 3,000 fps range? I believe the sun may have caused those readings as the load was generally shooting in the 2930's. And yet, the readings were pretty consistent.
So the last group was the exact same load as the one at 300 only at 100 yards. Based on its location, it was obvious why I hit where I did at 300. This group is probably one of my best so far with four of the five shots so close together in one hole, we could not tell which shot was which!
I think 3,000 fps is definitely reachable, particularly with the longer barrels, but 2900 seems plenty fast enough and I don't think it worth overly pursuing it. This last group also seems to indicate that those 3,000fps shots were not real. 13 fps ES at 2938 is still cookin'!
Please excuse the picture quality as my good camera is out for repair
Richard
