problem: shots are sporadic. not holding a "zero" @ 100yrds
story: buddy gave me his newly acquired AR15 to sight in that he got from a gun show. Plum crazy lower, ??? upper and Bushmaster 16" fluted barrel, 1-9 twist. everything is used but he was told that everything was in great shape; not shot a lot etc... he mounted a new scope "Center Point" on the rifle and it was handed to me.
1st trial run. shooting @100yrd, off my bench, with led sled. zeroing for 100yrd. factory ammo 55grain:
1st shot 6" high of bulls-eye
adjusted
2nd shot 0 but 1/2" left of bulls-eye
adjusted
3rd shot touched 2nd shot
4th shot 3" right? of bulls-eye
5th shot 2" high and 3" right of bulls-eye
cleaned barrel
6th shot 3" LEFT 1/2" high of bulls-eye
check tightness of ALL scope mounts, rings etc... everything was solid
7th shot 1 1/2" high from bulls-eye
8th shot 1" low to the left of bulls-eye
9th shot 1 1/2" low to the right of bulls-eye
10th shot 1/2" lower than shot #9
cleaned barrel
adjusted
10th shot 1" high and 1" right of bulls-eye
11th shot 1/2" lower than #10 of bulls-eye
12th shot 2" right 1/2" high of bulls-eye
thinking it was the scope. I cleaned the gun and checked the rings etc..and put on my Bushnell which I know is good. once I got it to hit paper:
1st shot 3" high 1/2" right of bulls-eye
2nd shot 2" high 1/2" right of bulls-eye
adjusted
3rd shot 1/4" left of bulls-eye
4th shot 1/2" left of bulls-eye
5th shot 1" left of bulls-eye
thinking all is good I clean barrel
6th shot 1" low and 3" RIGHT of bulls-eye!?
7th shot 1.5" low 2" right of bulls-eye
adjusted
8th shot 1" below bulls-eye
9th shot 2" right of bulls-eye?
10th shot 1" low and 1/2" right.
cleaned gun
11th and 12th shot, I aimed at bulls-eye target in upper right hand corner and was 1/2" left, then 1/2" right...figured I was good but was still skeptical
told him what was going on and we both assumed the cheaper scope could be the problem but I was still a little skeptical. he said fine no problem and was going to use a Nikon in the future anyways, so he shows up today with a new in box Nikon pro staff BDC 4-12x44
same shooting setup as before.
1st shot 3" high of bulls-eye
adjusted
2nd shot 1.5" left of bulls-eye
3rd shot touched 2nd shot
adjusted
4th shot 3" low and 4" RIGHT of bulls-eye?
5th shot 3" high and 2" left of bulls-eye?
checked mounts, screws, etc... and all was tight.
6th shot 3" low of bulls-eye?
basically from here on out we fired 5 more rounds and no adjustments were made and the shots were all over the place. basically a 4"-6" group.
I will admit that with my Bushnell the group was a little tighter but still I think it was about to become sporadic, I think I just quit while I was in the lead with it.
so he and I are assuming the barrel and if it was wore out from previous owner...bump stock shooter and or a lot of shots fired, bent??. I have helped sight in few rifles in my time, I'm no great sniper or great gun smith but I know enough on what I do. so am I correct in leaning towards the barrel and or maybe shooting a hotter load other than a 55grain.. maybe a 62 or 65grain?
thanks for your time and sorry for the long read...
story: buddy gave me his newly acquired AR15 to sight in that he got from a gun show. Plum crazy lower, ??? upper and Bushmaster 16" fluted barrel, 1-9 twist. everything is used but he was told that everything was in great shape; not shot a lot etc... he mounted a new scope "Center Point" on the rifle and it was handed to me.
1st trial run. shooting @100yrd, off my bench, with led sled. zeroing for 100yrd. factory ammo 55grain:
1st shot 6" high of bulls-eye
adjusted
2nd shot 0 but 1/2" left of bulls-eye
adjusted
3rd shot touched 2nd shot
4th shot 3" right? of bulls-eye
5th shot 2" high and 3" right of bulls-eye
cleaned barrel
6th shot 3" LEFT 1/2" high of bulls-eye
check tightness of ALL scope mounts, rings etc... everything was solid
7th shot 1 1/2" high from bulls-eye
8th shot 1" low to the left of bulls-eye
9th shot 1 1/2" low to the right of bulls-eye
10th shot 1/2" lower than shot #9
cleaned barrel
adjusted
10th shot 1" high and 1" right of bulls-eye
11th shot 1/2" lower than #10 of bulls-eye
12th shot 2" right 1/2" high of bulls-eye
thinking it was the scope. I cleaned the gun and checked the rings etc..and put on my Bushnell which I know is good. once I got it to hit paper:
1st shot 3" high 1/2" right of bulls-eye
2nd shot 2" high 1/2" right of bulls-eye
adjusted
3rd shot 1/4" left of bulls-eye
4th shot 1/2" left of bulls-eye
5th shot 1" left of bulls-eye
thinking all is good I clean barrel
6th shot 1" low and 3" RIGHT of bulls-eye!?
7th shot 1.5" low 2" right of bulls-eye
adjusted
8th shot 1" below bulls-eye
9th shot 2" right of bulls-eye?
10th shot 1" low and 1/2" right.
cleaned gun
11th and 12th shot, I aimed at bulls-eye target in upper right hand corner and was 1/2" left, then 1/2" right...figured I was good but was still skeptical
told him what was going on and we both assumed the cheaper scope could be the problem but I was still a little skeptical. he said fine no problem and was going to use a Nikon in the future anyways, so he shows up today with a new in box Nikon pro staff BDC 4-12x44
same shooting setup as before.
1st shot 3" high of bulls-eye
adjusted
2nd shot 1.5" left of bulls-eye
3rd shot touched 2nd shot
adjusted
4th shot 3" low and 4" RIGHT of bulls-eye?
5th shot 3" high and 2" left of bulls-eye?
checked mounts, screws, etc... and all was tight.
6th shot 3" low of bulls-eye?
basically from here on out we fired 5 more rounds and no adjustments were made and the shots were all over the place. basically a 4"-6" group.
I will admit that with my Bushnell the group was a little tighter but still I think it was about to become sporadic, I think I just quit while I was in the lead with it.
so he and I are assuming the barrel and if it was wore out from previous owner...bump stock shooter and or a lot of shots fired, bent??. I have helped sight in few rifles in my time, I'm no great sniper or great gun smith but I know enough on what I do. so am I correct in leaning towards the barrel and or maybe shooting a hotter load other than a 55grain.. maybe a 62 or 65grain?
thanks for your time and sorry for the long read...