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All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: josixpack on June 27, 2013, 06:00:26 PM

Title: Sights Zeroed in Distances
Post by: josixpack on June 27, 2013, 06:00:26 PM
If my .177 620fps bb/pellet gun is zeroed in with iron sights at 15 feet at what distance farther out will it be zeroed in at?

I tried using a calculator someone pointed me to but I didn’t know ¾ of the information it was asking for.

Thanks!
Title: Re: Sights Zeroed in Distances
Post by: sperho on June 27, 2013, 06:09:09 PM
What is the weight of your pellet that you are using?  How high is the front post above the center of the barrel muzzle?
Title: Re: Sights Zeroed in Distances
Post by: josixpack on June 27, 2013, 06:53:02 PM
7.9 grain and around 1.5 inches.
Title: Re: Sights Zeroed in Distances
Post by: sperho on June 27, 2013, 07:26:27 PM
According to Chairgun and assuming that you are using Crosman Premier Lites (BC comes into play, so if that's not your pellet, what is?) and that I handled the iron sights appropriately, your two zeros occur at 15 and 19.5 yds.  edit:  if you are using wadcutters, the two zeros will be at 15 and 17 yds.  Flat-faced pellets lose speed much faster than diabolos...


click to biggify:
(http://redboston.com/miscfora/josixpack_calc.JPG)
Title: Re: Sights Zeroed in Distances
Post by: UCChris on June 27, 2013, 08:13:22 PM
Oh Chairgun. What a wonderful program.
Title: Re: Sights Zeroed in Distances
Post by: josixpack on June 28, 2013, 12:13:31 PM
Quote from: sperho on June 27, 2013, 07:26:27 PM
According to Chairgun and assuming that you are using Crosman Premier Lites (BC comes into play, so if that's not your pellet, what is?) and that I handled the iron sights appropriately, your two zeros occur at 15 and 19.5 yds.  edit:  if you are using wadcutters, the two zeros will be at 15 and 17 yds.  Flat-faced pellets lose speed much faster than diabolos...


click to biggify:
(http://redboston.com/miscfora/josixpack_calc.JPG)

I just kept moving the target back and found that at around 45- 50 feet I was getting similar results as at 15 feet but was hitting high of the mark in-between those distances.  So at 30 feet I was aiming about an inch lower then the bulls eye and was getting good results.
Title: Re: Sights Zeroed in Distances
Post by: sperho on June 28, 2013, 12:17:54 PM
Oh, you said feet, not yards. Sorry.  In any case perhaps the picture will help you understand how to use CG.
Title: Re: Sights Zeroed in Distances
Post by: josixpack on June 28, 2013, 01:29:02 PM
Quote from: sperho on June 28, 2013, 12:17:54 PM
Oh, you said feet, not yards. Sorry.  In any case perhaps the picture will help you understand how to use CG.

No worries... I have an indoor range set to 5 meters (16 feet 4 3/4 inches) which is the NRA BB Gun Competition target distance.