Airsoft Sniper Forum banner

PDI Hop Up chamber.. Not hopping?

5493 Views 17 Replies 5 Participants Last post by  Cheese Man
I apologize if this thread is in the wrong spot. Trying to get a wider audience as this hop chamber is used for a vast majority of rifles. I've also done a lot of search on this topic and have come up with nothing. Most threads on this subject died off, are no longer visible or were never answered...

Anyway, here is my issue:

Just bought the PDI Hop-Up chamber for my BAR10 off of X-Fire and I'm having a hard time getting it to work. I'm not getting any hop, or, I'm jamming my gun.. This is the Version II chamber, so its a bit different then most I've seen. I have 2x 20mm O-rings to hold the arms down and no spring to aid in adjustments.

Gun is fully upgraded, pulling back the PDI SPR 300% spring. Shooting .40 BB's. Bought with the PDI Chamber was a PDI barrel as well as the PDI W-Hold bucking.

First thing, I installed everything I should have properly. I shoot the rifle, no hop.. Ok, so I back out the grub screws thinking I wasn't putting enough pressure on the bucking.. Shoot, same thing, no hop.. So I back it ALL the way out, almost to the point of the nozzle not being able to pass through. Still no hop.

So I swap one of the O-rings that holds the arms down with a rubber band; I wrap it around super tight. Try shooting again.. BB is now getting stuck on the bucking and can't pass through, even when the hop up is turned all the way off.. So scrap that idea.

My next idea was to make small shims out of aluminum foil and place them between the hop adjustment tube and the bucking. It either didn't work and I wasn't getting any hop or my shims were applying too much pressure on the nub, stopping the BB just like the rubber band did....

So what the hell is going on? Any ideas for me? I can't seem to find ANY of the "long arms" for this chamber, as I was sent the short arms. So I've got to work with what I have.

Do I need to grind down the grub screws that adjust the hop? They almost seem a bit too long.. Do I need to keep working with my shim idea? Maybe make my own hop adjustment tube?

Pretty disappointed after the money dropped into this product. I figured it would be plug and play, minus a few adjustments to the hopup itself. Though, when the gun is shooting with no hop, all the BBs went in the same place.. Which is more then I can say for the stock hop up.. Forever an optimist!

Shane
See less See more
1 - 18 of 18 Posts
Any ideas for me on how to make one? I was thinking the end of a pen tube, but that might be the same size as what I have now.. Maybe a piece of solder? Thicker piece of wire?
Solder is to soft to make a consistent cylinder. I tried it using solder and couldn't get a consistent cylinder. A pen tube end sounds promising though.
Alright so I made my own nub and it was working just fine for awhile. It was throwing a few BB's a little odd, but that was probably from a little lubricant or something as I just washed my bucking and lubed my gun.

I took everything back apart and made 100% sure everything was installed correctly.

I left the gun for a day to sit. Went to shoot it again today and it jammed every single shot. I left it at the same settings as before and it was working just fine. Even when I turned the hop "off" with my new nub, it jammed.. So I installed my stock nub, again.

It is shooting now, still with little or no hop and will throw BB's right at the ground or sling them far right. I seem to have found a spot where it will actually shoot the BB's straight, but every other shot jams without fail. Load the gun, shoot it, works fine. Rack another round in, jam.. Unjam it, load another BB, it shoots, rack another, jam.. Every. Single. Time.

So what can be the issue? Is this W-Hold bucking junk? Should I get something else? Maybe a hard bucking? I am shooting well over 500fps with .20's.
See less See more
Clean the chamber out, that could be an issue. Or, alternatively, make use of a TDC system to eliminate some of the screwiness with the nub/arm relationship.
Could you explain a little more in detail about making best use of the TDC?

I'm willing to try anything.. This gun has been an absolute nightmare because of hopup issues.. Its been basically useless.
I had the W-hold in my l96, it worked good, but I recently bought a scs nub and systema bucking and it's working good on my 550 fps shooting .4s, shoots straight, try adding that spring to the hop up on top of the levers just incase you havn't already. Make sure all your skrews for the barrel lock are tight, I was missing one, and my spring was off and I was shooting all over the place.
I'll try the little spring thing.. I just don't see how that is going to help though; Can someone explain?.. My BB's are getting stuck on the hop up and jamming.

Its like, too less hop and I obviously don't get ANY hop. Trying to get hop, just results in me jamming the gun..
Just use it instead of the dinky little screws provided by PDI.
I feel ignorant.. I'm still not getting what you mean lol.. Its been a long day man.. :cheers:

Shane
Ah, okay. Top Dead Center allows for external adjustment of the hopup via a screw through the outer barrel.
Ohh... Duhhh... I knew that..

Well, I have access to every tool imaginable. How would I go about turning this into a TDC hop up?
Still no luck today..

Something is clearly not right and its got to be something stupid.

I'm jamming at the hopup mound. Jams every other shot.

I'm at both extremes. No hop or jams. Nothing in between.
  1. What distance are you looking at when you say no hop up is occurring?
  2. If you can chrono your gun w/ 0.20g when it is able to shoot, what is the FPS?

Btw, the spring PDI includes is nearly essential when shooting higher FPS. Without it the hop up arms become too flimsy and therefore hardly applies any hop up.

I suggest cleaning your bucking + hop up chamber to potentially fix the problem and it will help your accuracy regardless. But first, it seems like the nub is primarily the issue. So...

3. Could you please go into detail explaining the nub you made?
  1. What distance are you looking at when you say no hop up is occurring?
  2. If you can chrono your gun w/ 0.20g when it is able to shoot, what is the FPS?

Btw, the spring PDI includes is nearly essential when shooting higher FPS. Without it the hop up arms become too flimsy and therefore hardly applies any hop up.

I suggest cleaning your bucking + hop up chamber to potentially fix the problem and it will help your accuracy regardless. But first, it seems like the nub is primarily the issue. So...

3. Could you please go into detail explaining the nub you made?
With .20's I bet I'm around or over 600 honestly. Using the "poor mans chrono" on a coke can, I can easily blow through the bottom end and severely dent the top end of the can..... with .40's.

As far as distances (If it will fire) it hardly makes it to 50-60 yards. Half the time the BB appears to have top spin and will go straight towards the ground. Hard.

The PDI Chamber I bought is the Version II chamber and did not come with any sort of spring.

The nub I had made that actually produced results was nothing more then a thick piece of wire that fit in perfectly. I was seeing results with it and was happy I had finally found a solution. But the next day, I went to fire the gun and I was jamming every shot, no matter what I adjusted.

The BB's are jamming on the hop up mound. I can tell its going to jam even before I fire due to that when I rack the gun back and go to slide it forward, I have to force it to go into place. End result is the BB being stuck on the hopup mound. I then clear the barrel, rack a round back.. and it will fire.. But when I go to take a 2nd shot.. Jam..
See less See more
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top