GTA

All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: lockheed500 on July 06, 2015, 12:43:32 PM

Title: actual Coefficient tested ( crossman pre hollow point 14.3 )
Post by: lockheed500 on July 06, 2015, 12:43:32 PM

Decided to do a test to find out what the actual pellet coefficient is for the premier hollow point and these are the results. I first placed the chrony at 1 yard took five shots then moved it back 30 yards placed a guard in front of lcd screen ...

Crossman optimus .22

cphp 14.3 grain

average velocity at 1 yard =  738 fps

energy at 1 yard = 17.3

average velocity at 30 yards = 626 fps

energy at 30 yards = 12.3

advertised CPHP BC 0.019

actual  BC * 0.021 *

pretty close..

Title: Re: actual Coefficient tested ( crossman pre hollow point 14.3 )
Post by: K.O. on July 06, 2015, 07:06:20 PM

It would be informative to see the amout of variation from rifle to rifle...

tight or loose barrel and choked/unchoked...

Title: Re: actual Coefficient tested ( crossman pre hollow point 14.3 )
Post by: lockheed500 on July 06, 2015, 08:16:10 PM

you are right about that, I would like to try stoeger x20 next to see if it stays the same.

Title: Re: actual Coefficient tested ( crossman pre hollow point 14.3 )
Post by: rsterne on July 06, 2015, 08:27:06 PM

If you test at different velocities, you will get completely different results.... push the velocity supersonic and the BC will be about 0.010....

Bob