uncle money bags
01-13-14, 16:10
I considered posting this in the terminal ballistic forum but thought i would get a better answer here. If it is in the wrong place please move with my apologies.
I have a slight conundrum. Well, more of an oddity to me, and would like some feedback.
Here is my data:
Ammo is the kick ass Markm 262-
77 SMK
21.6 gr H322
Wolf srm primer
O.a.l. 2.25, with a light crimp on the neck
Weapon is a DD mk18-
SSA trigger
Aimpoint m4 2 moa
Unsuppressed, a2 flash hider
2500 rds through the gun to date.
I have a run n gun coming up this weekend which will require shots from 25 yards to 500 yards. The furthest target will be 20x20 inch steel. Before i went to check my zero and hold overs this last week i ran numbers through hornady and another ballistic trajectory calculator to get a rough estimate of where i needed to be for the different ranges. I do not have a chrono, but was able to get a pretty fair estimate of about 2200 fps at the muzzle by comparing several load charts and formulas and making rough calculations from there. Like i said i just wanted to be in the neighborhood so i wasnt wasting time and ammo. I used the G7 drag profile and .190 for the ballistic coefficient. I also the data under G1 and .372 to compare, and it was very similar.
Long story slightly shorter both charts agreed that i should be approximately 6 inches low at 200, 24" at 300, 54" at 400 and 101" low at 500 with a zero for 100 yards.
After re affirming zero i took aim at the 200 holding about 6 inches over and smacked it. I couldnt see the 300 yard gong from where i was situated so i went to the 400. This is a steel plate 20" high by 18" wide. I held over the estimated 4 feet mol and my spotter reported no splash. So i raised the sight picture up another foot, again no splash. On a whim i dropped my dot down to about 2 feet over the target and smacked it twice in a row. They were both direct hits and not bouncing up into the target. I did not give the 500 yard target a shot as it was too small to see.
Additional info:
Wind was 10 mph gusting to 15 right to left, temp was 55, humidity was low and the shots were across a shallow dip with less than a 5 degree downward incline.
I expected some difference from the numbers but nothing like less than half my expected holdover. When i played with the ballistic calculator to see what fps would allow that drop at that distance i had to input over 2900 at the muzzle. Since i know there is no way this round is making that speed from my weapon what am i missing here?
I have a slight conundrum. Well, more of an oddity to me, and would like some feedback.
Here is my data:
Ammo is the kick ass Markm 262-
77 SMK
21.6 gr H322
Wolf srm primer
O.a.l. 2.25, with a light crimp on the neck
Weapon is a DD mk18-
SSA trigger
Aimpoint m4 2 moa
Unsuppressed, a2 flash hider
2500 rds through the gun to date.
I have a run n gun coming up this weekend which will require shots from 25 yards to 500 yards. The furthest target will be 20x20 inch steel. Before i went to check my zero and hold overs this last week i ran numbers through hornady and another ballistic trajectory calculator to get a rough estimate of where i needed to be for the different ranges. I do not have a chrono, but was able to get a pretty fair estimate of about 2200 fps at the muzzle by comparing several load charts and formulas and making rough calculations from there. Like i said i just wanted to be in the neighborhood so i wasnt wasting time and ammo. I used the G7 drag profile and .190 for the ballistic coefficient. I also the data under G1 and .372 to compare, and it was very similar.
Long story slightly shorter both charts agreed that i should be approximately 6 inches low at 200, 24" at 300, 54" at 400 and 101" low at 500 with a zero for 100 yards.
After re affirming zero i took aim at the 200 holding about 6 inches over and smacked it. I couldnt see the 300 yard gong from where i was situated so i went to the 400. This is a steel plate 20" high by 18" wide. I held over the estimated 4 feet mol and my spotter reported no splash. So i raised the sight picture up another foot, again no splash. On a whim i dropped my dot down to about 2 feet over the target and smacked it twice in a row. They were both direct hits and not bouncing up into the target. I did not give the 500 yard target a shot as it was too small to see.
Additional info:
Wind was 10 mph gusting to 15 right to left, temp was 55, humidity was low and the shots were across a shallow dip with less than a 5 degree downward incline.
I expected some difference from the numbers but nothing like less than half my expected holdover. When i played with the ballistic calculator to see what fps would allow that drop at that distance i had to input over 2900 at the muzzle. Since i know there is no way this round is making that speed from my weapon what am i missing here?