FX Dreamline POI shifts -HELP
- Thread starter bsahogger
- Start date
You could probably " stack " several CF pipes to fill the dreamline shroud just like the single CF liner sleeve would do in a barre like Impact or Maverick.
Actually when i changed from 600 mm barrel to 700 on my Maverick i did just that as the price for a FX shroud that would fit a 700 mm barrel and the additional barrel pipe to support a 700 mm barrel was too expensive.
So i got 3 CF pipes, each fitting inside the other ( with a little sanding ) and then of course on my barrel pipe which was extended 100 mm with a cheap adapter.
And my Maverick shot just fine and had a barrel the same size / thickness as it would have with the factory shroud.
Mind you the 3 pipes when assembled and installed on the rifle was a bit " bent " so you had to be weary of the clocking of the sleeve CUZ otherwise if off MAX you would be a foot or two off at 50 M.
I made a slight mark on my CF " shroud" but i did not have it off very often, when cleaning the barrel i just fished out barrel itself out the front so the CF " shroud" could remain in place.
Mind you POI on my Maverick still shifted, but i was okay with that as i anyway was tweaking on it all the time.
In my case it was more a problem of getting to a +100 mm longer barrel and still have the rifle look OK / stock.
Actually when i changed from 600 mm barrel to 700 on my Maverick i did just that as the price for a FX shroud that would fit a 700 mm barrel and the additional barrel pipe to support a 700 mm barrel was too expensive.
So i got 3 CF pipes, each fitting inside the other ( with a little sanding ) and then of course on my barrel pipe which was extended 100 mm with a cheap adapter.
And my Maverick shot just fine and had a barrel the same size / thickness as it would have with the factory shroud.
Mind you the 3 pipes when assembled and installed on the rifle was a bit " bent " so you had to be weary of the clocking of the sleeve CUZ otherwise if off MAX you would be a foot or two off at 50 M.
I made a slight mark on my CF " shroud" but i did not have it off very often, when cleaning the barrel i just fished out barrel itself out the front so the CF " shroud" could remain in place.
Mind you POI on my Maverick still shifted, but i was okay with that as i anyway was tweaking on it all the time.
In my case it was more a problem of getting to a +100 mm longer barrel and still have the rifle look OK / stock.
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I've got a .177 500mm Dreamtac with a carbon fiber sleeve on the barrel liner. I put one shroud spacer up against the action, then the sleeve, then the front (muzzle end) spacer. I secured the front muzzle spacer with a few wraps of gaffer's tape to keep the spacer in place when I remove the shroud. No spacer movement, no barrel band and no POI shift on mine. I'm not entirely convinced the CF sleeve is doing anything more than keeping those spacers in place, but whatever. It works for me.
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I never paid much attention to the full size Dreamline barrels. But this topic caught my attention and I’m a little shocked at the pictures. That thing is begging to POI shift. If you know you have a good liner because it shoots tiny groups, I would commit to fixing it. But it will be permanent. That is a nice setup you have there @bsahogger. Time to buy JB Weld, a carbon tube for your caliber and length then get to work. Lay out your work and cut the tube into sections accounting for those goofy discs. If you want to really commit then I would start my bonding process on the liner, then install the nut. Then work my way out to the end of the liner bonding everything tight up against each other.
My Dreamline Compact had a short version of “liner in the wind”. So accurate but it just shot tiny groups wherever it wanted from day to day. I thought about trying to fix it but wound up just making a barrel for it. If the little tiny barrel in this picture gave me fits, I can’t imagine how frustrating a long one would be.
My Dreamline Compact had a short version of “liner in the wind”. So accurate but it just shot tiny groups wherever it wanted from day to day. I thought about trying to fix it but wound up just making a barrel for it. If the little tiny barrel in this picture gave me fits, I can’t imagine how frustrating a long one would be.
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I was also shocked when I saw those flimsy spacers, not what I expected from FX, very reminiscent of my days chasing POI shifts on Marauder, very much the same sad set up. Anyways, right now I have the pieces of tape either side of the spacers, I've cleaned the barrel & put the barrel band back on. Dime size groups but only at 19yds, hopefully time allows this weekend for me to shoot longer distances & a whole bunch of strings so that I can check for shifts. If it shifts again I'm either going to make a full length aluminum sleeve with about 5/8" OD & set screws so that I can jam it hard up against the nut, then secure it to the liner; or epoxy a CF tube onto the liner. At this stage I don't believe that a CF tube by itself without epoxy does anything but keep the spacers in place, the barrel will still droop & the fulcrum will be very close to the nut... so POI shifts will occur.
Watch this space!
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Still no joy here folks. Shot the gun at 45yds yesterday, best group I could get was 1.5" with 10.3gr Premiers. Also tried 8.3gr JSB, grouped slightly worse than the Premiers. I thought that the POI shift thing may have been cured, just to discover on my last group (after once again filling up), gun shot 1" high. Tried adjusting the hammer tension, all that happens above the 7 mark is the gun hogs more air.
Any ideas? Getting despondent with this thing.
Any ideas? Getting despondent with this thing.
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Cutting the carbon fiber tube reduces its rigidity IMO
And there is no need to do it
Instead, you can get a CF tube with spacers that fit over it
I got mine from Cape Fear Airguns
Other vendors may have them as well
Sorry, but posting a link from my phone is beyond my skill range
Edward
And there is no need to do it
Instead, you can get a CF tube with spacers that fit over it
I got mine from Cape Fear Airguns
Other vendors may have them as well
Sorry, but posting a link from my phone is beyond my skill range
Edward
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I am a bit confused. Does FX recommend using the liner without the spacers? I have gotten that impression from watching a few videos. Is it just some models that use the spacers? I have a Dreampup and haven’t noticed any POI shift but like the idea of the carbon fiber liner. Does the Dreampup use o-rings rather than spacers? I am guessing I would leave out the o-rings as their thickness would be close to the liners thickness.
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I have noticed the following on my FX airguns with shrouds:
The FX spacers are "friction fit" pieces of plastic with o-rings "connecting" the liner to the shroud(at various points) down the length out to the muzzle. The air(and lead particles) from inside the liner is re-directed backward(toward the action) into the shroud from the muzzle end. There is a tiny hole near the action end of the shroud which vents some of the air(and lead particles).
The more air that is forced backward into the shroud(i.e- the faster/more power you shoot), the more(and higher pressure) air(and lead particles) is forced backward into the shroud. This redirected, high pressure air "blasts" into the shroud, impacting the spacers. Over time, this increases the likelyhood that the "friction fit" on the spacers will give way, and they will move to a different point of contact on the liner/shroud. This new contact point can potentially change harmonics, POI, etc...
At lower power, this system seems to stay in place well. When the power is increased to near max settings, no so much. The solution that has yielded the most consistency for me is using the carbon fiber sleeve over the liner. This serves help to stiffen the liner/shroud and anchors a single front spacer near the muzzle. It also makes it easier to remove the shroud for cleaning the barrel and cleaning the lead dust out of the shroud/liner system(which should be done on a regular basis because it actually does improve performance).
The FX spacers are "friction fit" pieces of plastic with o-rings "connecting" the liner to the shroud(at various points) down the length out to the muzzle. The air(and lead particles) from inside the liner is re-directed backward(toward the action) into the shroud from the muzzle end. There is a tiny hole near the action end of the shroud which vents some of the air(and lead particles).
The more air that is forced backward into the shroud(i.e- the faster/more power you shoot), the more(and higher pressure) air(and lead particles) is forced backward into the shroud. This redirected, high pressure air "blasts" into the shroud, impacting the spacers. Over time, this increases the likelyhood that the "friction fit" on the spacers will give way, and they will move to a different point of contact on the liner/shroud. This new contact point can potentially change harmonics, POI, etc...
At lower power, this system seems to stay in place well. When the power is increased to near max settings, no so much. The solution that has yielded the most consistency for me is using the carbon fiber sleeve over the liner. This serves help to stiffen the liner/shroud and anchors a single front spacer near the muzzle. It also makes it easier to remove the shroud for cleaning the barrel and cleaning the lead dust out of the shroud/liner system(which should be done on a regular basis because it actually does improve performance).
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If you use the liner without spacers on the Dreamline the pellets will for sure clip the front of the shroud.
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Fully agree, I have subsequently come across other threads that explain the issue exactly like this. I have come to the conclusion that this is a design problem, the spacers are a very cheap, ineffective way of spacing the liner aweay from the shroud. Even a Marauder has a better engineered set up. I finally got hold of someone at UA, they apologized for missing my emails/texts & hence gracefully offered to ship the gun back to them for warranty repairs. That's great customer service but I doubt whether they would be able to fix FX's design problem though, unless they maybe do the CF tube deal on the gun.
Think it's time to maybe go back to Air Arms or perhaps let the Impact M4 bug bite.
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I have a DreamTac compact in .177. Shot like a laser. Put on a barrel band and it shot like a shotgun. Took it off, shoots like a laser again. Sometimes a barrel band helps accuracy, sometimes it hurts, sometimes no change but barrel is better supported. You have to experiment; there is not one answer fits all.
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Tried wid & widout, no diff's. Gun's off to UA this morning, they promised me they'll make the gun shoot, even if it means 'gluing' the flimsy spacers in place. I'll post the results when the gun comes back home.
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I would say that the system's design is good for some things( light-weight, lower power shooting, interchangeability of calibers/lengths, etc..), but not so much for others( extreme accuracy, esp at higher power levels, resistance to bumping, etc ...)
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I only have one 177 and it is not a FX. You comment that it changes POI during a shooting session. But I do not see a mention of wind. I can see my POI move an inch at 30 yards during a shooting session just because of wind. With a 22 shooting 18s at around 900 fps. I've pretty much given up shooting 30 yard challenge targets with my 177 unless there is essentially no wind. When I am shooting any of my PCPs at these targets I normally have to make slight wind hold adjustments during the target. The further away your target the more wind is going to affect your POI. 50 yards is a long ways for a 177 IMHO.
You and your gun seem to like Crosmans. I had a "good" tin of Crosman 10.5s once. But even it was worse than H&N Baracuda Match. I had two bad tins of Crosmans too which had wildly varying head sizes. I think Crosmans (I'm talking about older mixed dies Crosman, not the new single die ones which I have not tried) are decent plinking pellets but I prefer to spend a bit more for H&Ns or JSBs if that is what shoot best in a gun. I have two guns that need JSBs to do their best. But most actually shoot better with H&Ns. H&Ns will not make up for shifting winds but they could help with the occasional flier from an inconsistent pellet. H&Ns are closer to Crosmans in cost. Baracudas more so than Baracuda Match. But head size consistency is better on the Match ones so that or the FTs (even more cost) are normally what I get. Long way of saying I think you should try a tin of H&N Baracuda Match and a tin of H&N Baracuda FTs. For little one tin orders I like to wait until Amazon drops the price to close to what the better retailers offer without shipping. They do not pack well but the last several times I've done it the pellets have been OK.
I'm pretty sure you can find a pellet that will shoot better in your FX and I am completely confident your gun will shoot better in low wind. If it is windy, I prefer to shoot shorter distance so I do not get frustrated.
You and your gun seem to like Crosmans. I had a "good" tin of Crosman 10.5s once. But even it was worse than H&N Baracuda Match. I had two bad tins of Crosmans too which had wildly varying head sizes. I think Crosmans (I'm talking about older mixed dies Crosman, not the new single die ones which I have not tried) are decent plinking pellets but I prefer to spend a bit more for H&Ns or JSBs if that is what shoot best in a gun. I have two guns that need JSBs to do their best. But most actually shoot better with H&Ns. H&Ns will not make up for shifting winds but they could help with the occasional flier from an inconsistent pellet. H&Ns are closer to Crosmans in cost. Baracudas more so than Baracuda Match. But head size consistency is better on the Match ones so that or the FTs (even more cost) are normally what I get. Long way of saying I think you should try a tin of H&N Baracuda Match and a tin of H&N Baracuda FTs. For little one tin orders I like to wait until Amazon drops the price to close to what the better retailers offer without shipping. They do not pack well but the last several times I've done it the pellets have been OK.
I'm pretty sure you can find a pellet that will shoot better in your FX and I am completely confident your gun will shoot better in low wind. If it is windy, I prefer to shoot shorter distance so I do not get frustrated.
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Fully agree, again! For folk who shoot off a bench & who don't mind making adjustments to their turrets now & then, the system works. For folk who want to for instance want to shoot HFT, not so much, POI shifts will ruin your day totally.
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A few years back I had a POI shift with my Dreamline and a friend told me to add a barrel band. If that didn't work add another barrel band and if that didn't work add another barrel band. Mine only needed 2 barrel bands. Fixed it well enough for me to take 5th at AZ state FT match a few years back. Mine is a .177 in the Aeron CZ chassis.
Thx
Dan
Thx
Dan
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You can fully discount wind from my complaint, I've been shooting .177 for many decades. Before I cry "POI shift" I make sure that I shoot the gun in a no wind environment, ie. indoors.
You can leave the different brand of ammo out of the equation as well: I have tried 10.3gr Premiers, 8.3gr JSB's & AA, all with 4.51, 4.52 & 4.53mm diameters.
Assume for the exercise that I am very methodical in my techniques, I am an experienced shooter, both air, rimfire & center fire. I have loaded for & hunted with more calibers than most folk know exist. I have hunted extensively on two continents with ammo that I have loaded & guns that I have tuned.
Read Ghostranger169's last post thread, the man hits the nail on the head. This light liner/shroud set up is the issue, it's not made for accuracy or consistent grouping. UA said they'd glue the spacers in, let's see!
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