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bubblerboy64

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Jul 25, 2018
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Pa, United States
I was shooting my impact off a Caldwell bag this morning and I happen to get the bag forward enough to rest on the barrel shroud. This threw my POI way off. I realized what had happened and moved the bag back under the gun. However the POI was still off significantly ( meaning it did not return to my original zero) I had to re-zero

If you look you will see that the space between the bottle and the barrel can be opened and closed by rather light pressure on the barrel shroud 

THIS can not be beneficial to accuracy and maintaining a repeatable POI. 

The impact is not the only gun which this would happen to and I just got to thinking this could be a significant cause of at least some of the trouble I and others have experienced with air rifle accuracy. 

Seems as if heavier barrels and more secure attachments would be of help or at least awareness of the situation . No wonder we chase POI if these barrel are moving 

Thoughts and observations appreciated? 
 
I have a Benjamin Prod. With a moderator. When I was not shooting the gun I’d set it on a couch in my living room. Basically resting on the barrel and pistol grip. I started to get baffle strikes. Happened about three different times. Before I figured out what was the cause. So I’d unscrew the shroud then re install it and it would be back to normal.
So now I never rest the gun with any pressure on the barrel/shroud. I literally hang it buy the (Magpul CTR) buttstock on a coat hook. 
No more baffle strikes. 
 
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Yes this has been my biggest problem with airguns. Using them on the farm they get bumped and in and out of my truck. I need guns that arent going to have poi shifts when this happens. Tensioned barrel systems are my favorite. Guns like the R5M and EVOL are best being screwed into the receiver and then tension on the muzzle end. My Raptor is tensioned but held with 3 set screws in the receiver. Seems to hold poi this way still. Also the Edgun Leshiy with it's barrel completely hidden inside the frame so to speak also won't ever change poi from getting bumped which is why I have one. And have a EVOL on order. Other bullpups that have the barrel attached at the breech and then held by scope mounts farther down are good like the Taipans, Vulcans, Uragans and the Crickets. I HATE chasing poi.
 
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I have noticed the same thing. Whenever I do bump the barrel no matter how lightly there is always a lot of swearing 🤬 Then no confidence til I see where things are at. One tip I can offer with the Impact. Change the orings that the barrel slides through to install it. They are listed as nbr 70. I change them to nbr 90. They will wear a little if you are removing/replacing it frequently. They are for and aft of the cocking block. 4 in total. When I changed them I noticed straight away the barrel was tighter to install 

Ernest I noticed puts a set screw in the front guiding block. One on each side. 
 
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Why are you even resting the gun on its its shroud/barrel. Isn't it common sense that it will bend the barrel and affect accuracy? I would think that is just common sense. Always rest the gun on the airtube or bottle..never rest it on the barrel or shroud.
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2fast2furious to read the post properly. He didn’t do it on purpose. Sorry couldn’t help myself 😉
 
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Ernest I noticed puts a set screw in the front guiding block. One on each side.
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This is about the only way to make the Impact's repeatable in and out of the foam case. Reason being, there is "a lot" of movement in the o-rings, and a .001" movement (right above the scope) is a lot of miss down range. That said, they are awesomely accurate bench guns and work well for hunting, so long as you can take a few sighter shots before going into the field to ensure the scope is still zeroed.
 
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Robust barrels, secure anchoring of barrel attachment to receiver and well designed shrouds don't more POI when rested upon or bumped ..... If your argument is to say other wise ? read the first part again ... because if yours does you have issues with one or more of the stated requirements.



So YES .. many many guns suffer from this and you need to not be leaning the barrel against stuff, bumping them etc ....


 
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Why are you even resting the gun on its its shroud/barrel. Isn't it common sense that it will bend the barrel and affect accuracy? I would think that is just common sense. Always rest the gun on the airtube or bottle..never rest it on the barrel or shroud.
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2fast2furious to read the post properly. He didn’t do it on purpose. Sorry couldn’t help myself
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Ok I guess I read it wrong. I thought he was shooting his impact by resting the shroud on the bag and don't expect it to change poi. Cause pretty common sense to know resting any airgun by the barrel with have an impact on poi. Some gun more than others.
 
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I don’t mind being accused of not having common sense. I’ve proven that to others and to myself so often there is no possible debate. It might be poor judgment more then common sense. To many air rifles HOWEVER this thread is only meant to suggest that there are external design factors with these air rifles that differ from powder burners which I and apparently at least some others may not have been immediately aware of. 

The suggestion of confirming POI is a good one as is being careful not to “disturb “ the barrel . Both of these are sometimes difficult to do at times .

I was just seeing what others experienced might have been while also making others aware of mine. 

The idea of a set screw or two? That was worth the post. While having no common sense I at least still can recognize it when I see it . Thanks 😀

Common sense and wisdom and regards to all who have posted . Other solutions out there? 
 
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My first PCP was a Benjamin Marauder, and I frequently noticed that while hunting if I bumped the barrel ever so slightly on vines, small trees etc. while hunting I would have a POI shift and start missing shots. Even though I had a barrel band this would still happen. Since I use my Ag’s for small game hunting I switched to Bullpups as they seem to be designed for rugged play. I don’t experience POI shift with my Taipan Short or my Vulcan. In fact I haven’t re-sighted either in two years lol.
 
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Wrap some duct tape around that floppy thing haha I have always wondered how people get along with those 700mm barrels, those things really move and shift. I guess most are used from the bench so may not have same issue as in a rugged hunting trip. Wonder if a barrel band of some sort would solve poi issues with these guns? It may not look pretty but may work.
 
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Yeah the frailty that most PCP's are built with is stupid! 

Though depending on various factors, like weight. or how far down the firearm barrel is placed on a bag or whatever object, the result will be a POI shift.

It was funny one time, during one stage in a 22rf tactical match we had to shoot our 22rf's through a very small port in a barricade. Basically I had little choice but to lean the barrel on the wood at the bottom of the port. I missed over the spinner every shot until I figured out what was going on, and it was a hard lesson because I went from leading the pack to placing down the roster a bit.
 
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Wrap some duct tape around that floppy thing haha I have always wondered how people get along with those 700mm barrels, those things really move and shift. I guess most are used from the bench so may not have same issue as in a rugged hunting trip. Wonder if a barrel band of some sort would solve poi issues with these guns? It may not look pretty but may work.
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The worst POI shifting I've ever had with a PCP was with my Steyr LG100 because the part of the frame which holds the barrel, basically the guns barrel band, is aluminum and the barrel is steel, so as the day heated up the POI shifts got a bit crazy. There wasn't much tolerance between the barrels OD and the frames ID so I sent it back to AZ who reamed out the frame right there, to free float the barrel, and that problem was solved. 
 
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