Bullet Drop at 25 & 50 Yards?

Guys - Save me some research time.  Where do you sight your pistols?  X ring at 50 or 25 yards, then compensate for one or the other?  Do you do it differently for 22, 38 & 45?

No sight adjustment "for me" from 50 to 25 yds. with the .22. Sight adjustment from 50 yds. to 25 yds. with the .45 is 5 clicks. This is with an UltraDot.

dsandula wrote:Guys - Save me some research time.  Where do you sight your pistols?  X ring at 50 or 25 yards, then compensate for one or the other?  Do you do it differently for 22, 38 & 45?

I sight my pistols .18607 above the x in the x ring at 50 and 25 for all calibers

Chris Miceli wrote:

dsandula wrote:Guys - Save me some research time.  Where do you sight your pistols?  X ring at 50 or 25 yards, then compensate for one or the other?  Do you do it differently for 22, 38 & 45?

I sight my pistols .18607 above the x in the x ring at 50 and 25 for all calibers

The secret to success is out.

Chris Miceli wrote:

dsandula wrote:Guys - Save me some research time.  Where do you sight your pistols?  X ring at 50 or 25 yards, then compensate for one or the other?  Do you do it differently for 22, 38 & 45?

I sight my pistols .18607 above the x in the x ring at 50 and 25 for all calibers

That's almost 3/16" .  

Why so much and not .0625' so your closer to the X in case of an errant shot?


Virgil

I sight at 25 (local range) but know that my 22's are good to 50 with no change. The 9/38 super need to go up 2 for 50 and the 45 needs to go up 4 for 50. I also have a Model 25-2 with powder puff loads that needs to go up 8 for 50. Then when the match starts I watch the scope to confirm or correct. All of the above adjustments were for Ultradots. Aimpoints just double those adjustments.

Lot of things will change sighting. Bullet velocity is one, now that different velocities are offered for the .22 that has to be considered too. Another is the height of the scope above the bore. Plus another issue is the height the targets are mounted at 25 and 50 yards when considering the difference between 25 and 50 yard impact

Froneck wrote:Lot of things will change sighting. Bullet velocity is one, now that different velocities are offered for the .22 that has to be considered too. Another is the height of the scope above the bore. Plus another issue is the height the targets are mounted at 25 and 50 yards when considering the difference between 25 and 50 yard impact

So this why my zeros are off from range to range? Not a lot but enough to make a few clicks with an aimpoint

Froneck wrote:Lot of things will change sighting. ... Plus another issue is the height the targets are mounted at 25 and 50 yards when considering the difference between 25 and 50 yard impact

What's the reasoning behind this? 

Are you suggesting that by changing the height of the target, and thus changing the angle at which you are holding the gun by +/- 2 degrees (1 degree is about 15 inches at 25 yards, and 30 inches at 50 yards) that you are changing the effect that gravity has on the path of the bullet?  And that it's enough to noticeably change the point of impact at 25 yards or 50 yards?

I couldn't get the Hornady Ballistics Calculator (use advanced mode to allow setting of the shooting angle) to show any such difference at +/- 2 degrees.  I tried a 40 grain bullet with a muzzle velocity of 1085 using a ballistic coefficient of 0.134 (this BC was chosen by trial-and-error to approximate Eley Club .22 specs of 1085fps at muzzle, 994fps at 50yds and 935fps at 100yds, but is reasonable, given that most 22LR rounds have a BC between 0.075 and 0.150).  All other settings of the ballistics calculator were left at their defaults.  I also tried a 200gr bullet with a muzzle velocity of 770 using ballistic coefficients of 0.127 or 0.070 (numbers given on the Hornady and Speer websites for 200gr LSWC 45 ACP).  But I'm no ballistics expert, so perhaps I'm doing something wrong.  

I had to change the angle to +/- 8 degrees for the 40 grain bullet and +/- 5 degrees for the 200gr bullet (both well beyond reasonable changes in target height), to a get 0.1 inch difference at 50 yards.

Don't forget to factor in temperature, air pressure, and humidity.  Also the Earth's gravitational pull is not the same every where.  I was in a Navy squadron that has a EC 121 Super Constellation that flew all over the Earth measuring the differences.