IR hop tuning

Discussion in 'Sniper Rifles' started by kloit, Dec 16, 2012.

  1. kloit

    kloit New Member

    187
    0
    Greensboro
    So I've got the ir hop all set, but 1 out of every 10 shots the bb curves drastically to the side (flier), but every other shot besides the flier is perfectly on line.

    Setup:
    JG BAR 10
    PDI VSR 10 Hop up Chamber
    Prometheus 6.03
    Lonex 70 Degree Bucking
    IR Hop Z Kit

    I think this may be the due to the ir hop moving around since it's not permanently fixed with CA glue on the window, but I don't want to do that yet before figuring out exactly what the problem is.

    Also, although my shots are flatter and more consistent, I'm not getting as much over-hop range as I did with a regular bucking. the PDI chamber uses 2 o rings to press down both arms, and since the ir hop is significantly harder to press, the arms don't go down all the way, resulting in less maximum hop. Right now I'm thinking about a thicker nub, but not quite sure what to use for it.

    I should also mention that it appears my FPS has decreased.

    Max range with ir hop: 230 ft, 9/10 consistency. Max range without ir hop: 260 ft, 5/10 consistency.

    Any solutions to some of these problems are greatly appreciated.
     
  2. Archer627

    Archer627 New Member

    6,174
    5
    Figgington
    It sounds to me like the IR hop wasn't installed right. It's not supposed to move within the hop window. A little gap is acceptable to help prevent pinch type jams.

    The flier is probably from a lack of barrel stabilization.

    Your FPS decrease is probably from air seal problems. Check that first. If your seal is perfect, your IR hop is protruding too far into the barrel.
     

  3. kloit

    kloit New Member

    187
    0
    Greensboro
    The problem was barrel stabilization as I suspected and you alluded to. After making 3 spacers from 3 strands of electrical tape, 20/20 were right on target.

    The problem that I have now is most definitely air seal, since I've adjusted the nub, which produces varying amounts of hop (meaning working properly). However, the FPS is so low that there's simply not enough force from the bb pushing against the ir hop to create a greater spin, causing the max range to be only around 230 ft. (Btw, I'm using Madbull .4s with an M170)

    Despite that I know it's an air seal problem, I don't know where the leak is. Since I'm using the PDI chamber, the barrel with the bucking attached must be "shoved" in from the other side of the chamber. This makes it very difficult to apply any sort of teflon or fishing line wrap around the end of the bucking. I'm also having trouble getting the sleeve onto the bucking.
     
  4. kloit

    kloit New Member

    187
    0
    Greensboro
    So I wrapped some teflon around the bucking, giving it a good air seal and dramatically increasing FPS+hop, but it seems that I am getting a pinch-type jam despite having a small space between the r hop and end of the barrel.

    When I load a bb in individually, the gun shoots fine, but when I try to use a magazine, the pinch type jam occurs. I know it isn't a double feed, because I take the magazine out to find only 1 bb stuck in the bucking.

    Any ideas on fixing this problem?


    EDIT: I did a little investigation to figure out the problem. It has nothing to with the ir hop. So I purposely jammed a bb in to the bucking and disassembled the gun. When I took the barrel out of my PDI chamber, the bottom of the bucking lip was folded in with the stuck bb! I'm wondering how this could have happened? Not only that, but this only happens when I put the magazine in - it feeds fine one by one.
     
    Last edited: Dec 18, 2012
  5. kloit

    kloit New Member

    187
    0
    Greensboro
    NOTE: Title should now be PDI Chamber VII issues

    I kind of put this issue to the side for a while and used the Angel custom chamber with a good air seal (which has a modified nub system for my ir hop). But now I have a $90 chamber sitting on the side with no use. The problem is clear that it simply doesn't work well with the stock cylinder (even though it fits) and results in a great amount of air leak between the cylinder head and bucking (with PDI W hold and 380%, i'm getting about 70 ft of flat trajectory). Electrical tape on the tip improved performance for a while before it ripped off after 5 shots.

    So, I guess it's taper cylinder head time?
    Pretty sure PDI V2 "stock compatible" still forces you to buy their bucking and cylinder head, lol.
     
  6. dylan484

    dylan484 New Member

    441
    0
    Tifton
    Tell me how that works, I've got the same set up minus the ir hop, I've got the pdi chamber, w hold. I haven't put the rubber in yet I will tomorrow.
     
  7. kloit

    kloit New Member

    187
    0
    Greensboro
    Alright so I just got everything fixed and the cylinder head now works perfectly fine. It turned out that the two little inserts in the feeding system were a bit loose (never tightened them to begin with), so I tightened both sides, resulting in a tight grip with the cylinder head, preventing it from slipping out. It is up for sale with the W hold since I currently have no use for them (due to already having r hopped and modded the Angel custom chamber). You will see in the classified pics that the cylinder head fits perfectly fine with chamber. It takes a bit of shaking force for it to come off now.