|03-05-2016, 05:27 AM||#2|
Join Date: Jan 2016
Location: Vancouver, WA
My recommendation, pdi internals and pdi hop up chamber
KJW M700 HPA
CA M24 Civilian
Tippmann M4 (short and DMR uppers)
TKNW M4 SPR Custom
Lancer Tac FAL DMR
VFC FNX 45
|03-09-2016, 10:14 PM||#3|
Join Date: Feb 2016
Out of the box, my hopup was not properly installed -- the set screws on the side were completely loose, meaning that the hopup is not always applied vertically, and the chamber was loose and had no airseal. In addition, there was no hopup nub under the arm...so bb's would just fall out of the barrel, and didn't have any hopup.
I was able to fabricate a new nub out of eraser material. However, the stock hopup chamber has some serious design flaws that need to be corrected.
The hopup arm has a ton of play in it-- so it cannot be trusted to apply directly downward force or consistent hopup. I mostly resolved this issue by cutting some plastic shims and drilling a hole to thread them on either side of the hopup arm. Getting these on were very difficult though. Most of the slop is now gone.
The PDI hopup chamber looks like a complete gimmick. It has two hopup arms instead of one, which is a bad idea -- it only introduces the possibility of having inconsistent hop that results in left/right spin of the BB. Presumably this design is intented to give you ability to compensate for an existing spin, but more likely than not it would be the source of spin. In addition it would be much harder to TDC mod that I think, and it doesn't appear to resolve any of the fundamental problems with this hopup design.
The big problem with this chamber is that the hopup arm is adjusted by pushing up from a set screw that's in the barrel chamber. Backing the screw out permits more hopup in theory. The problem is that the screw is only about 3mm long so doesn't have much range of adjustment, especially considering that it's at the extra end of the hopup arm fulcrum, so in reality it can only adjust the hopup nub a fraction of a millimeter if that. If you back the screw out any more than is flush with the chamber, then the air nozzle will get stuck on it -- so there's no way to dial up the hop. Even if you were to completely remove the screw, the amount of hop applied is limited by the tension of the rubber o-ring which is wrapped around the chamber pushing the arm down -- which isn't much. This means it's pretty much impossible to adjust for different BB weights without changing the hopup nub. In other words, to adjust the hopup, you need to get a different sized nub.
I really think the only possible fix for this is the TDC mod. I don't want it to be ugly, though with a giant dial sticking out. I've just ordered some 2.5mm metric set screws and a 2.5mm tap, so hopefully that solves this problem and gives a good range of adjustable hop. The only real problem with this mod is that you cannot maintain your hopup setting when removing the inner barrel, as it will be necessary to back the hop screw all the way out.
It looks like there's nothing stopping me from doing R-hop on this, so that's what I'm going to try eventually.
Another really annoying problem with the hopup is that the overall chamber orientation is controlled by a third set screw in the bottom which merely provides pressure to prevent it from rotating. There is nothing to actually force the hopup to be vertical -- you have to align it approximately and just tighten the screw. In addition, the chamber has these sharp edges which grasp the top of the magazine well, and if the orientation is even a hare off, it will cause the magazine to get stuck, which makes it EXTREMELY difficult to remove the magazine, and almost always results in the magazine feed tube being pulled out, spraying BB's everywhere. This is an atrocious design.
I've come up with a solution to make removing the magazine easier, when it sometimes gets stuck, simply put a piece of cloth in there underneath it which protrudes on both sides, so you have something to grab with an pull it out, but this doesn't relieve the tension on the top of the mag well.
I may try filing down the edges of the hopup chamber so that it is more forgiving and less prone to get stuck around the magazine feeder.
|10-13-2016, 09:01 AM||#4|
Join Date: Oct 2016
I've had a CAM24 in my arsenal for a number of years now and nearly every problem I've had with it has been related to the shockingly bad hopup chamber. Jungley did you get anywhere with the TDC mod? I'm thinking that is the only way I'm going to get this otherwise brilliant weapon skirmishable.
How do you handle the hop moving back and forth or rotating? Eventually the set screw in the bottom of my hop deformed the brass chamber enough that it has a ridiculous amount of play. I'm wondering if I can TDC the arm at the top and also tap the bottom to keep the chamber in the right position.
I will worry about the magazines later, I had shaved a good amount of material from inside the magwell so that I can get my fingers in and pull it out, but that doesn't help the BB follower getting jammed in the chamber.
Is there any other sniper hop that would fit? I know a VSR one wouldn't but I'm wondering if it would be easier to convert the chamber+mags to an APS2 system?
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