GTA

Airguns by Make and Model => Benjamin Airguns => Topic started by: wll2506 on May 31, 2021, 02:33:40 PM

Title: Does 392 Change POI After 30 Minutes Aired and Sitting ?
Post by: wll2506 on May 31, 2021, 02:33:40 PM
I had a shot after letting the gun sit for about 30 minutes of pumping her up she shoot about 4 inches left and about 3 inches low. Shot was powerful and not a blooper for sure !

Anybody notice this ?

After pumping up and shooting within a few minutes, she was right on !

Just wondering !

She is holding air overnight and my chronograph test are pretty consistant and are in the parameters of what I expect.

Hummmm :-)

wll
Title: Re: Does 392 Change POI After 30 Minutes Aired and Sitting ?
Post by: 35 shooter on June 01, 2021, 01:06:38 AM
Maybe made a boo boo on the shot or follow through, or possibly a bad pellet?
If left in the bald sun and the air in the valve got extra hot, I suppose that could account for a bit higher or lower shot? Don’t see how it would affect the horizontal though.

Like you, I use a pistol scope on my 392. It’s a 2x7x32 non AO utg. If the field in the scope is clear, i can stack pellets with it, but if I see any black at all in the scope at the shot, I can easily be 2” off even at 20 yds. with it set on 6 or 7 power.
For me at least, parallax is worse with the non AO pistol scopes than with non AO rifle scopes.
As long as that field of view is clear through the scope though, it’s pretty much pellet on top of pellet.

FYI, the utg pistol scope has pretty thin crosshairs and 4 drop compensation marks on the bottom crosswire.
The first is a horizontal wire, then two diamonds(open in the center), then the tip of the thick bottom crosshair.
Title: Re: Does 392 Change POI After 30 Minutes Aired and Sitting ?
Post by: mrbulk on June 01, 2021, 01:42:01 AM
Maybe check those intermounts...?
Title: Re: Does 392 Change POI After 30 Minutes Aired and Sitting ?
Post by: triggerfest on June 01, 2021, 02:40:10 AM
This is normal...

Since it concerns physics. You have sighted your scope on the base that you've just pumped up your 392. But that air is warm because of the pumping. If you wait 30mins before you place your shot, the air inside the pressure tube air has cooled down, thus it has another density, thus will have another point of impact. Simple as that. That's why you also experience she is right on again once you pump her up again and take your shot close to the pumping moment.

Nothing to worry about, just simple physics  :D
Title: Re: Does 392 Change POI After 30 Minutes Aired and Sitting ?
Post by: triggerfest on June 01, 2021, 02:43:40 AM
This is normal...

Since it concerns physics. You have sighted your scope on the base that you've just pumped up your 392. But that air is warm because of the pumping. If you wait 30mins before you place your shot, the air inside the pressure tube air has cooled down, thus it has another density, thus will have another point of impact. Simple as that. That's why you also experience she is right on again once you pump her up and take your shot close to the pumping moment.

Nothing to worry about, just simple physics  :D
Oops double post
Title: Re: Does 392 Change POI After 30 Minutes Aired and Sitting ?
Post by: 35 shooter on June 01, 2021, 04:26:59 AM
Maybe pump it up, wait one hr. and shoot through your chrony just to be sure it has’nt developed a bad seal and a slow leak?
It’s a new rifle so I seriously doubt it, but it can happen.....still does’t explain 4” left though.

My bet is still on a bad pellet... bent skirt, head not fully formed, etc.
I’ve left my benji’s pumped for hours squirrel hunting and still hit right where it should according to the distance the shot was taken.
Title: Re: Does 392 Change POI After 30 Minutes Aired and Sitting ?
Post by: wll2506 on June 01, 2021, 10:44:13 AM
Maybe pump it up, wait one hr. and shoot through your chrony just to be sure it has’nt developed a bad seal and a slow leak?
It’s a new rifle so I seriously doubt it, but it can happen.....still does’t explain 4” left though.

My bet is still on a bad pellet... bent skirt, head not fully formed, etc.
I’ve left my benji’s pumped for hours squirrel hunting and still hit right where it should according to the distance the shot was taken.

Thanks for the info Buddy ?

wll