Safety Ranges

[camies 1]

Got an interesting problem more directed to users of airguns though.

 

I'm going to help clear feral pigeon from a small wood that backs onto an industrial estate (both owned by same firm).

Problem is the industrial unit H&S wants a risk assessment about the dangers of air gun pellets crossing the boundary wire from the wood and falling into the compound.

Not a problem but my 'boss' was a bit confused (too much coffee / caffiene :crazy: :crazy: ) on how to approach it.

 

As we are shooting into trees (just a guess 45 degrees elevation), I put the figures into the JBM internets 'max range calculator' and came up with 420 yards! That seems a little excessive as a danger zone so I was wondering what you guys would quote (if at all).

 

Just found a shotgun association site quoting 275 metres in any direction, would that be a safe limit??

 

Cheers and

Edited October 29, 2009 by camies

[Guest RN-Rabbit-Control]

Just put down that your only going to take on shots that are absolutley vertical, and in the rare event of a miss, your mate has a butterfly net to catch the pellet in when it comes back down.

[camies 1]

Tee Hee Very funny! :clapper: :clapper:

[SEAN3513 7]

the only real issue as far as i can see is the velocity of the pellet at maximum range.

 

an airgun firing at 11.5 ft/lbs at the muzzle will have roughly 6 ft/lbs at 40 yds.

 

so.......at your quoted range (450 yds) the pellet will be at around 0.02 ft/lbs.....about the same as if you dropped from about 12 inches.

 

so i would quote for a h&s risk assesment the effective yardage of the said pellet......say around 100yds.

 

hope that makes sense ????

 

cheers

 

sean

[camies 1]

Hi sean 3513

Not sure about that distance as the jbm calculator gave me this

information.

 

Maximum Distance

Input Data

Ballistic Coefficient: 0.035 G1 Bullet Weight: 19.7 gr

Muzzle Velocity: 524.0 ft/s

Temperature: 59.0 °F Pressure: 29.92 in Hg

Humidity: 0.0 % Altitude: 0.0 ft

Std. Atmosphere at Altitude: No Pressure is Corrected: Yes

Output Data

Atmospheric Density: 0.07647 lb/ft³ Speed of Sound: 1116.5 ft/s

Initial Angle: 35.0 deg Terminal Angle: 70.2 deg

Terminal Range: 433.3 yd Terminal Velocity: 128.5 ft/s

Terminal Time: 10.1 s Terminal Energy: 0.7 ft•lbs

 

I then looked up the final figure as to what it would "do" so to speak and I found this:-

It's a breakdown of force needed to injure an eye. (Some american doctor's site)

 

Speed Power Injury

fps Ft lbs

42 0.02 Contusion

204 0.49 Retinal Tear

236 0.66 Globe Penetrated

407 1.95 Bone penetrated

 

You can see why The boss is a bit concerned although the likelihood of smacking an eye at that range must be pretty remote.

Edited October 30, 2009 by camies