Have you noticed?

Forums PCP Airguns Have you noticed?

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    orion
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    I'm releasing a video where I was expecting to use an FX Dreamline and after I arrived to the location I noticed the gun lost completely the zero, I was thinking was the scope but now I realize is the floating barrel that might be lean on my car and moved… boomer! I'll need to pay attention to that next time, or rezero the rifle in place… not a good experience for my hunt. These are the little things that I never had to deal when I was hunting with my Taipan.

    I really hope I don't have this with the Raptor because if so, this is a big NO NO to me, and it will be sold after the first hunting just because of that.

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    bucketboy
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    bubblerboy64

    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 noticed the same thing, and this is the reason, barrel sleeve is 14.0mm front block isn’t 

     

     

     

    there are a few way to rectify, wrap some tape around the sleeve to increase the Dia closer to the bore (4 complete wraps of sellotape). Change the o rings from 1.5mm  to 1.68mm, install grubscrews  in the block to secure the sleeve or fit a more rigid LW barrel.

     

    I started to machine this barrel for my impact today, just need to make a brass breech bush with the transfer port.

     


     

    spysir

    Can be a design feature in many  airguns.  Want zero shift after leaning your barrel against a tree and then using it as a crutch to get up off the ground 20 times in a day try the well designed theoben MFR.       No such issues ever, but not the latest greatest design.    

     

    John

    Agreed,  my impact needs re-zeroing every time I take it out of the case, it’s accurate enough but can’t compete with any of my theobens (I have 5, the oldest is over 20years)  I am slowly going through the impact slowly making the tolerances between parts better. 
     

    I have had my impact for a few months now but have yet to take it hunting as I still not confident enough with it, not just the gun but also my ability to shoot it well.

    Bb

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    bubblerboy64
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    Here is something I tried.  None of it alters the gun and it’s all removable.  

    I took the scope rail off and noticed clearance (space) between the barrel and the rail which also goes around the barrel.   I had some sheet rubber in the right thickness and I placed it between the barrel and the rail component ( not visible once the scope  rail is tightened back on to the gun.  Using the same rubber I forced a couple pieces between the extend picatinny rail on the bottom of the gun and the air bottle and also on top of the bottle and the barrel. I then tightened a large cable tie around the barrel, bottle and pic rail.  This completely eliminated the barrel flex.   Now how much this helps the cause is yet to be determined.  There are certainly more elegant ways to accomplish this but at least this will tell me if I’m heading in the right direction. 

    Hope the picture clarifies my efforts.  The goal was to stabilize the barrel with out stressing it in one direction or the other  The down side is it will all have to be removed to clean the barrel so it’s not a final solution.  

    I would think some set screws place appropriately might be a better approach and if this works I may go that way.  

    I think stabilizing the barrel is critical.  This barrel and liner interchangeability comes at a cost.   Other guns 

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    bucketboy
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    I am not sure that is going to cure the problem, if your fx shroud is anything like mine then it rattles, so something on the inside is not as good as it can be, I have removed mine, replaced it with a shorter, lighter mod to see if that helps with zero shift.

     

    Bb

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    bubblerboy64
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    I had previously tightened up the barrel to liner tolerances.   Tape O rings etc.   Nothing moving that I am aware of.  Time will tell.  Weather sucks in Pa right now .  I have lots of testing that I’d like to do.  

    May least the gun should be less sensitive to handling.  

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    pmg
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    After watching Ed’s video I reckon there is tacticool and a lot of others are fragicool. I don’t think I could deal with having to sight in again after leaning my rifle barrel up against a tree while taking a leak out in the woods squirrel hunting. The does look like there’s some creative solutions though. Hope you come up with a fix.

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    Corvid_hunter
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    I haven't had one of these apart yet. Does the barrel/liner float inside the shroud, or is it attached to the shroud at the end cap? Isn't the shroud threaded into the receiver? What is the weak point that leads to inaccuracy? I like to store my guns in a locking cabinet so the barrel usually bears some weight when the rifle is upright.

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    P_Bachman
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    EDgun

    Sorry guys for pouring some salt on your wounds…. 🙂

     

     

     

    One of several reasons I bought a Leshiy.  POI shift?  Huh?

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    orion
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    My video is out, you can see what happened to me while trying to shoot the first 2 iguanas. Do not need to see the entire video:

    I tested the rifle before going hunting and the zero was perfect but after I arrived the rifle was shooting really bad. I'm guessing this was what happened while on my trip and the rifle was lean on my back seat outside of the case.

    I'll talk about that on my next video with the rifle and mention this post! Thanks for bringing this up

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    Bigragu
    Participant
    Member

    Just my measly input- anytime I decide to buy a pcp(very rare, in fact, I’m done, lol) I research if any type of barrel shroud clamp is available for that make and model, weather in machined aluminum or 3D print. Having said that, Tim Hill of hillairguns.com makes one for the Marauder platform and JSAR had made one for the FX Wildcat. 

    It was the positive results I had gotten off of Hills barrel shroud clamp that made me understand the effectiveness of shroud support. I could lean my Marauder up against a wall or tree and my POI would stay put.

    same with the Wildcat. It’s unfortunate the wildcat barrel shroud clamp isn’t manufactured anymore(hopefully temporary) but an alternative is to contact Pappy_Yosh on here by PM, as he makes a 3D printed version. 

    On top of all of these add ons, I make it a habit to add an o ring that exceeds the gap in between barrel shroud and air tube by just a hair, slipping it onto the air tube, to create a separation buffer so there is no possible way for the shroud to push downwards towards the tube should one decided to lean a rifle against a wall or have any form of barrel shroud droop due to installing an oversized moderator.

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    oldsparky
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    2fast2furious

    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.

    Ok Im stupid. I didn't know any PCP was this fragile. If you go into AOA and other air gun shops they have their rifles in a upright rack where weight is on the barrel. I for one do not want any part of a rifle that fragile. To me that is not worth bringing home.

     

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    JungleShooter
    Participant
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    I think this barrel-bump-POI quirk (BBP quirk) should be mentioned to all new PCP buyers when they ask for buying advice on our forums….

     

    I remember being super excited when I began shopping for my first PCP and discovered the Gauntlet — a gun with great aftermarket parts and modding potential — and super low price.

    Then, in one post I read in a short comment about the BBP quirk — and that immediately put the gun off my list…. 😟 

    Because the BBPS quirk is both a very serious problem (change to POI = miss the shot) — and very common problem (transporting the gun, "parking" the gun, bumping the gun during walking or hunting).

     

    Then the Dreamline jumped to the top of my list. Until…, you guessed, a kind forum poster advised me of flopping barrels.

    Off the list, again. Now we're up from $300 to $1000. And still this serious and common problem of the BBP quirk.

     

     

    ⚠️ Now, I never would have dreamt that a $2000 gun would have this same very serious and very common problem!  

    Maybe I'd expect that in a specialized benchrest gun, but not in a "tacticool bullpup" (= "rough tactical action, to be taken everywhere due to its compact size")…. 

    Simply…

    ¡¡UNTHINKABLE!! 😲

     

     

    Now, again, this is my personal opinion here, your dream gun might very well be different. So, here it goes:

    The Impact was always my (unattainable) dream gun.

    Was.

    Not anymore.

    I need something much less fragile, much less delicate.

     

    🔶 Might it be that the F in FX stands for FRAGILE?

    🔶 And the ED in EDgun stands for ENDLESSLY DURABLE?

     

    I don't own either brands, but from seeing the video, and reading many posts, my personal conclusion is:

    An FX can be great and very precise gun — if I treat it like fragile goods.

    An EDgun is made to endure the rough & tough of my hunting adventures.

     

    Just my opinion. 😊 You have the right to yours. 👍🏼

     

     

     

     

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    Bigragu
    Participant
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    Hopefully in time this problem will all get FXED…..man, I’m killin’ myself here

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    bucketboy
    Participant
    Member

    All guns will have zero shift if handled roughly but amount of shift and the ability to withstand rough handling varies greatly. Generally,  less part, thicker Dia barrel will do much better than more parts with a thin barrel. I have guns at both ends of the durability spectrum, Rapids and an impact, while I will happily shoot both at the range, only one of these will ever go out hunting with me, the other is just not strong enough.  (Resting guns on the hood of a truck and blasting away at pigeons @100 yards it not hunting, it’s urban pest control)

    I bought an impact because I wanted to see what all the fuss was about, in many ways it has exceeded my expectations, others it has confirmed my doubts and there are a couple of disappointments. I don’t regret buying mine for one second but I am not going to try and justify me spending $2k by saying it’s fantastic when it’s not. IMO it’s just Ok.  This might upset a few other impact owners but it’s not more accurate than my other guns, it’s not more consistent than my other guns, it’s not quieter than my other guns, what it is, is different to my other guns and that is the all justification I need .

    Agree or disagree it doesn’t matter as obviously we all have different needs and expectations from our airguns, for every thread like this, there is another saying the opposite.

     

    Bb

    • This reply was modified 1 month ago by bucketboy.
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    wimpanzee
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    The only time my dreamline shifts poi is when i put the fx radar on, it drops about an inch at 25 yards.

    My mutant, despite seeming more rigid, still drops about .5 inches at 25 yards with the radar on it too.

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    Joekrooz
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    EDgun

    Sorry guys for pouring some salt on your wounds…. 🙂

     

     

     

    I would love to see another manufacturer run over their gun with an suv😏

     

     

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    Arzrover
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    BB

    This might upset a few other impact owners but it’s not more accurate than my other guns, it’s not more consistent than my other guns, it’s not quieter than my other guns, what it is, is different to my other guns and that is the all justification I need .

     

    Well said BB.

    A LOT of my collection was purchased out of curiosity. That's all I needed for justification because I could afford it at the time. There are many I'm still curious about but I've actually been able to curb that buying a bit for the same reasons…… what I'm curious about is NOT going to be actually better.

    Those old Theobens are pretty hard to beat. I've looked through my collection many times with the "if you could have one one" idea and it always is a front runner.

    Bob

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    Corvid_hunter
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    Member

    Someone needs to build a 2 piece clamp that mounts to the Picatinny rails on either side of the receiver and clamps on to the shroud just forward of the receiver. It will add a little weight, but would definitely be worth it.

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    Airgun-hobbyist
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    Corvid_hunter

    Someone needs to build a 2 piece clamp that mounts to the Picatinny rails on either side of the receiver and clamps on to the shroud just forward of the receiver. It will add a little weight, but would definitely be worth it.

    I was designing this same principle you suggested all morning, and then came up with a simple and rock solid solution that won't cost more than $10.00. I'll  post it later today when I have all the measurements compiled.

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    frank320
    Participant
    Member

    From my experience, the best accuracy and tightest groups on the FX Impact comes with leaving the barrel/shroud free floating. It was designed to be free floating.

    A year ago, i made the mistake of wrapping a foam sleeve over my Impact's carbon bottle as protection. The thickness of the foam sleeve caused it to barely touch and exert just that small amount of pressure on the barrel shroud. This immediately resulted in a POI shift of 2.5 inches higher at 30 yards and caused the groups to open up significantly. I couldn't believe it because the foam protector sleeve was "barely" touching the shroud, if even. But if you consider barrel whip during a shot cycle, the foam sleeve definitely messed with the harmonics and exerted unpredictable external forces on the barrel/shroud.

    I removed the foam sleeve and the POI and more importantly, tight groups came right back. From personal experience, I doubt some of the above solutions trying to lock down the Impact's barrel/shroud would work in the long run because while it might reduce some POI shift initially, it could cause group sizes to open up and subject the POI changes to other external forces(like temperature change, etc…) since it is no longer free floating. 

    One just has to be extra careful with a free floated barrel rifle and avoid leaning or knocking or allowing anything external to affect the harmonics of the barrel. 

    This also happens even in long range precision rifles in the powder burner world(start from 4min mark):

     

    • This reply was modified 1 month ago by frank320.
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