Bob, I'm so glad you have all that time on your hands to go shooting...!
I'm a bit short on my supply of time — it seems like forever that I haven't had a range day. Maybe this Wednesday I get to hit it hard!
With time on hand, I recommend to dig into a
ballistic calculator.
For me this has been nothing short of "revelation" — to try different scenarios of power, weight, caliber, range, etc. etc. and make comparisons.
▪ One conclusion I drew was that at shorter ranges, out to say 30y, most sophisticated equipment and most nifty techniques don't make that much of a difference: Aim, shoot, done.
▪ Another conclusion was the ideal caliber for a PCP pistol for my particular application.
▪ Etc. etc.
About your question how projectile weight variations influence precision: Many ballistic calculators have a function that calculates "vertical stringing."
I'll run your weights and ranges:
▪Projectile: .22cal MRD "25.39gr"
▪Muzzle energy: 45.66FPE
▪Ranges: 50y and 100y
▪Muzzle energy: 46.0FPE (assumed)
▪BC: 0.040
▪Scope height: 2.50" (assumed)
▪Weight variation: 24.90—25.94gr = An extreme spread of
1.04gr ➠ Resulting in muzzle velocity variation: 912.2fps—893.7fps = An extreme spread of
18.5fps ▪Average MV: 903fps
RESULTS: 50y: The weight variation of 1.04gr
will cause a velocity variation of 18.5fps,
that will cause an impact variation of
0.22" (0.56cm) at 50y
(0.11" below and above your POA).
100y: These same weight and velocity variations will cause an impact variation of
0.94" (2.39cm) at 100y
(0.48" below and 0.46" above your POA).
Matthias
PS:
The app I used is the GPC Ballistics app — free — no advertising — no spying. ▪ for cellphones: Android, iPhone
▪ for computers: Windows, MacOS, Linux
Link:
https://gpc.fotosoft.co.uk/