Sighting in your crossbow
“I have my scope sighted in at 20 yards but at 30 yards the next line down is way high. I adjusted it for 30 yards and now the 20 yard line is off.”
I see statements like that all the time on different forums. Furthermore there are statements on multiple websites that state the once you have the top line or dot of the scope at 20 yards each line or dot below is set at 10 yard increments. I believed that statement when I purchased my first crossbow, after all if it's on the internet it must be true.
If your scope does NOT have a speed ring adjustment the lines/dot will not always be exactly 10 yard increments. The two scopes that came on my crossbows were not exactly 10 yards. The slower bow the lines worked out to 5 yards each or thereabouts. The faster one the lines worked out to 10 yards apart for the first two lines and then things went way off, see the images below. When I purchased a new scope with a speed ring for my faster bow and moved the its old scope to the slower bow did things start to line up for the slower bow.
So what do you need to do if your scope does not have a speed ring?
Here is my suggestion:
- Using some type of rest to steady the crossbow, sight in at 20 yards with the top line.
- Step back to 30 yards and shot a minimum of 3 times using the next line down without making any adjustments to the scope. Go to Steps 3 or 4
- Shooting Low? Then step forward 1 yard (or what distance you think will get the arrow on target) and shot some arrows again without making any adjustments to the scope. Repeat this step as needed. If you start to shoot high then go to step 4.
- Shooting High? Then step back 1 yard (or what distance you think will get the arrow on target) and shot some arrows again without making any adjustments to the scope. Repeat this step as needed. If you start to shoot low then go to step 3.
- Document what yardage each line is and either carry it with you or as I did tape it to the stock of the crossbow.
- Make windage (right/left) adjustments as needed while at the farther distance that you would be comfortable shooting at. NOTE: you may have to make minor elevation (up/down) when making windage adjustments.
When you make changes to your setup e.g. different arrows, broadheads, age of the string, or just time, you should go through the process again just to make sure things are on target.