For those of you that have just brought a new crossbow or are upgrading your scope here are some tips and tricks to get it centered fast. The last thing we want is a fly away arrow.
I just purchased a new JUNXING Compound Crossbow M67 for my wife and to compare it with my Barnett Droptine. But I was having issues with the scope not being parallel to the Picatinny rail. I literally ran out of scope adjustment. Actually both Xbows have had issues with the scope not being level.
This was an issue from the manufacturer and I didn’t want to take it all the way back to the supplier for a quick fix.
Guess buying cheap is not always the best. So it was a quick tear down to work out why the arrows were low with no more adjustment on the crossbow scope.
The First shot of your new crossbow.
Now there is nothing wrong with quickly building your kit crossbow and going out for some target practice. But if you want the best out of your weapon then the correct set up is a must.
To quickly range test your new crossbow stand about 8-10 yards from your target. Place your crossbow on a stable surface or use a gun bipod. You can shoulder fire it as well but it won’t be as accurate as a bipod.
Load a bolt and fire into the center of the target. Make sure to have a backstop if the arrow misses the target. Hay bales, old car tires, thick rugs, or a dirt mount can work great for a backstop.
If the arrow/bolt flys low then adjust the up scope selector in the direction pointing to up anticlockwise. If your bolt is flying high then wind it the opposite way usually clockwise.
Each click on this 4-32 Bushnell scope is 1/4 inch at 100 yards.
Same for is the bolt is drifting left then screw the horizontal adjustment to pull it to the right. Scopes usually only have one letter stamped on the adjustment ring. For my Barnett scope, it says Up (U) and Left (L).
Problems can arise if you run out of scope adjustment. Usually, this means the scope is not parallel to the Picatinny rail.
|Bolt Direction||Top Adjustment (U)||Side Adjustment (L)|
Fire a group of three arrows or bolts to get an average grouping before adjusting your scope.
Center your crossbow scope reticle.
Work out the distance of where you would likely to be shooting from. I like to center my scope reticle at 20 yards. This gives me a good mange to shoot out to around 50 yards.
Any further and wind and bolt drop start to take a huge affect on acuracy.
Place a target out at 20 yards and adjust your compound scope to hit this target in the center.
Now depending on your scope brand, you may have Mil-Dot marks on the axis. A MIL–Dot reticle refers to a specific pattern of lines or dots placed along each axis of the scope.
Now depending on the power of your crossbow, you will have to move the target out to 30, 40, and 50 yards. Lift the Xbow slightly above the target center and line it up with a low Mil-Dot. Fire and check where the bolt lands. It will be trial and error, so make sure to have a good backstop.
Your crossbow scope sighting in is now complete. If you still have problems your scope rail could be out of alignment.
What to look for if your crossbow scope is not parallel.
Whenever I buy a new gun or crossbow the first thing to do is lap the scope rings and bore sight the scope. This takes out any error and defects in the scope rings from the manufacturer.
On my older Barnett crossbow, the 4×32 scope rings were out of alignment when sighting in. There was a slight bur on one of the rings. Lapping helps snug it all down tight and keep it all true.
On the Chinese Junxing Compound Xbow, the scope was lifted up slightly on the front which means that the bolt was drifting down from the center target.
To fix this I had to remove the Picatinny rail to see what the issue was. First, the crossbow scope needed to be removed and the 2x Picatinny rail bolts needed to be unscrewed.
The bolt tensioner device can then be unscrewed and removed. (Now is a good time to put some heat shrink on the bolt tensioning spring to quite it down.)
I did find two simple problems. A slight bur on one of the screw holes and the bolt tensioning device was not screwed down enough. This was causing the Picatinny rail to lift up on the front and arrows to fall low of the center target.
Once everything was put back together and lock tight back up. The scope was now parallel to the crossbow rail.
Don’t forget to re-sight in your scope whenever you take it on and off your xbow.
Crossbows are dangerous and should be treated with care whenever you are using them. Make sure to follow all the manufacturer’s instructions and maintenance tips.
Hopefully, you can get your crossbow scope sighted in fast and safely. I have yet to set up a gun or crossbow scope that didn’t need some adjustment and sighting in. Vertical compound bows are much the same just a different sight mechanism.
My survivalist compound bow SWA raptor has a 5 pin fiber optic sight and these are easy to use and adjust. Just no magnification.
Make sure to fire a group of arrows and then make an adjustment depending on the grouping direction. All the best in your hunting and target shooting.