Bushnell scope with DZ 22LR reticle- correcting for subsonic

madkiwi · May 4, 2022, 11:10 PM

Hi everyone!

I just purchased a Bushnell RR3940BS13 (3-9 x 40, illuminated BDC reticle) to be mounted on top of my CZ 452 "Varmint" 22LR rifle.

According to the scope manual it is supposed to be zeroed at 50 yards, and then the 3 BDC aiming points will be 75, 100 and 125 yards (using high velocity ammo).

I'm using Norma Match-22 which is subsonic (shoots very well out of my rifle and I have neighbors who appreciate me keeping it quiet while I slay ground squirrels). So I am trying to figure out what the range will be at those aiming points with this ammo, IOW what is my adjustment factor?

So tell me if I am doing this wrong. I used shooterscalculator.com to figure out my trajectory tables and matched the MOA drops on the aiming points (2.3, 5.3 and 8.7 MOA) in the table then read the distance for that amount of drop, which works out to 70, 90 and 111 yards (assuming G1 drag, 0.132 drag coefficient, 40g bullet and 1080 fps at the muzzle).

Is that how it should be done or am I making some fundamental error?

Thanks!

Scorch · May 5, 2022, 08:33 PM

Sounds like you're getting there. The big lesson to learn is that shooting it at those ranges is the only way to know for sure.

May 4, 2022, 11:10 PM	#1
madkiwi Senior Member Join Date: May 27, 2000 Location: Missoula, MT Posts: 227	Bushnell scope with DZ 22LR reticle- correcting for subsonic Hi everyone! I just purchased a Bushnell RR3940BS13 (3-9 x 40, illuminated BDC reticle) to be mounted on top of my CZ 452 "Varmint" 22LR rifle. According to the scope manual it is supposed to be zeroed at 50 yards, and then the 3 BDC aiming points will be 75, 100 and 125 yards (using high velocity ammo). I'm using Norma Match-22 which is subsonic (shoots very well out of my rifle and I have neighbors who appreciate me keeping it quiet while I slay ground squirrels). So I am trying to figure out what the range will be at those aiming points with this ammo, IOW what is my adjustment factor? So tell me if I am doing this wrong. I used shooterscalculator.com to figure out my trajectory tables and matched the MOA drops on the aiming points (2.3, 5.3 and 8.7 MOA) in the table then read the distance for that amount of drop, which works out to 70, 90 and 111 yards (assuming G1 drag, 0.132 drag coefficient, 40g bullet and 1080 fps at the muzzle). Is that how it should be done or am I making some fundamental error? Thanks!

May 5, 2022, 08:33 PM	#2
Scorch Senior Member Join Date: February 13, 2006 Location: Washington state Posts: 15,248	Sounds like you're getting there. The big lesson to learn is that shooting it at those ranges is the only way to know for sure. __________________ Never try to educate someone who resists knowledge at all costs. But what do I know? Summit Arms Services