Different weight pellets--different POI???

Different weight pellets--different POI???

Joined: August 21st, 2009, 12:35 pm

January 26th, 2012, 9:15 pm #1

Shooting from a Benjamin Trail NP Hardwood, I've noticed that on a consistent basis, 14.3 grain Crosman Premiers shoot at POI, but when I switch to Beeman Kodiak extra heavies (21.10 grains), my point of impact is about 2 inches high and to the left (at about 40-50 ft). I'm shooting with the same technique for both, but can't figure out why this would happen.

Anyone experience this?
Last edited by pelletmeister on January 26th, 2012, 9:16 pm, edited 1 time in total.
Reply
Like
Share

Joined: March 1st, 2002, 12:22 am

January 26th, 2012, 9:16 pm #2


dupe nt
Last edited by dan_house on January 26th, 2012, 9:21 pm, edited 1 time in total.
Reply
Like
Share

Joined: March 1st, 2002, 12:22 am

January 26th, 2012, 9:21 pm #3

Shooting from a Benjamin Trail NP Hardwood, I've noticed that on a consistent basis, 14.3 grain Crosman Premiers shoot at POI, but when I switch to Beeman Kodiak extra heavies (21.10 grains), my point of impact is about 2 inches high and to the left (at about 40-50 ft). I'm shooting with the same technique for both, but can't figure out why this would happen.

Anyone experience this?
I'm surpised that the heavier ones hit higher, but any time you change pellett type or wieght, expect a change in POI.

different aerodynamics cause it to fly differently, the gun will trasnmit ienergy to different wights differntly, different shapes may interact with the barrel in many ways


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
Reply
Like
Share

Joined: August 21st, 2009, 12:35 pm

January 26th, 2012, 9:22 pm #4

dupe nt
Yeah, I guess if I go for the heavies I'll adjust specially for them. I do like how they hit like a brick! But I expected them to shoot lower as well!
Reply
Like
Share

Joined: November 28th, 2002, 6:26 pm

January 26th, 2012, 9:46 pm #5

Shooting from a Benjamin Trail NP Hardwood, I've noticed that on a consistent basis, 14.3 grain Crosman Premiers shoot at POI, but when I switch to Beeman Kodiak extra heavies (21.10 grains), my point of impact is about 2 inches high and to the left (at about 40-50 ft). I'm shooting with the same technique for both, but can't figure out why this would happen.

Anyone experience this?
...that particular peculiarity (heavier/slower pellets having a higher POI) happens.



http://www.arld1.com/rifledynamicssmaller.html

By the way - from now on when anyone claims gas spring springers ("rams") don't have regular springer recoil, I think I'll link them to this thread! Thanks for posting it.



Steve
Last edited by pneuguy on January 26th, 2012, 9:48 pm, edited 1 time in total.
Reply
Like
Share

Joined: March 1st, 2002, 12:22 am

January 26th, 2012, 9:51 pm #6


Intuitively (and Ive come tor ealize, a lot of what goes on in airguns IS NOT intuitive ) you would thin the piston coming forward would drive the muzzle DOWN.

 


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
Reply
Like
Share

Joined: August 21st, 2009, 12:35 pm

January 26th, 2012, 9:56 pm #7

...that particular peculiarity (heavier/slower pellets having a higher POI) happens.



http://www.arld1.com/rifledynamicssmaller.html

By the way - from now on when anyone claims gas spring springers ("rams") don't have regular springer recoil, I think I'll link them to this thread! Thanks for posting it.



Steve
Interesting, thanks for that! It makes sense, this gun does seem to want to shoot high.
Reply
Like
Share

Joined: March 25th, 2011, 2:35 am

January 26th, 2012, 10:12 pm #8

Shooting from a Benjamin Trail NP Hardwood, I've noticed that on a consistent basis, 14.3 grain Crosman Premiers shoot at POI, but when I switch to Beeman Kodiak extra heavies (21.10 grains), my point of impact is about 2 inches high and to the left (at about 40-50 ft). I'm shooting with the same technique for both, but can't figure out why this would happen.

Anyone experience this?
My Crosmod .177 was sighted in using RWS Super-H-Points (6.9 gr)at 25 yards.

When I use JSB Express (7.9 gr) they always hit (POI) 1.25" higher at same distance..

[/IMG]
Last edited by icufuzz on January 26th, 2012, 10:14 pm, edited 1 time in total.
Reply
Like
Share

Joined: August 29th, 2011, 4:50 pm

January 27th, 2012, 1:23 am #9

Shooting from a Benjamin Trail NP Hardwood, I've noticed that on a consistent basis, 14.3 grain Crosman Premiers shoot at POI, but when I switch to Beeman Kodiak extra heavies (21.10 grains), my point of impact is about 2 inches high and to the left (at about 40-50 ft). I'm shooting with the same technique for both, but can't figure out why this would happen.

Anyone experience this?
Okay folks, here it is, the reason the point of impact is higher with a heavier pellet is the same reason it is higher with powder burners, the gun will recoil more with a heavier projectiles, producing more muzzle rise, hence higher point of impact! recoil begins the micro sec. the charge is released, before the bullet exits the muzzle, heavier the projectile, higher the rise and therefore the higher point of impact. wondered about this on a 44 mag rifle I once owned, did the research and found out why!! Dave.
Reply
Like
Share

Joined: March 25th, 2011, 2:35 am

January 27th, 2012, 5:03 pm #10

that in my case,the JSB Express (7.9gr) was ballistically superior to the RWS Super-H-Point 6.9 gr.

Reply
Like
Share