Tips for Centering Packing & Nub in the Hop Up?

203 Views 19 Replies 3 Participants Last post by Guges Mk3, 15 d ago

Sw1tch

Discussion Starter · 15 d ago

Hi Guys,

As the title says I've built a couple airsoft guns and I always struggle getting the hop up packing perfectly centered in the hop up unit. I was wondering if anyone has any tips. I usually don't add any lubricant and that could be part of my problem but I try to twist it lightly at first but not enough to make the packing twist in place on the barrel, and then I push straight (which could cause the packing to push too far out potentially.) I try to line up the seam of the bottom of the hop up unit with the barrel cut out that aligns the packing (Although that's not always dead on the center). I try adjusting the hop up, up and down and look down the barrel while assembled on the barrel to see if its centered but it can be hard to really tell if its truly centered. Any ideas or tips or tricks to make it as close as possible to center?

Thanks Joe

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Leo Greer

· #2 · 15 d ago

Are you struggling with curving groupings? I do about the same thing as you, and just fiddle until I get it perfect. Certain rubbers are more sensitive tor curve, though, so it'll be harder depending on what packing you're using.

Sw1tch

Discussion Starter · #3 · 15 d ago

I tend to use MapleLeaf MR 2019 (Non silicone) 60 durometer with the omega nub. With a VFC Rotary hop up (Its super tight, good air seal but the C-Clip is a pita to seat/reseat). Yeah generally curved groupings I was surprised at how straight the stock CYMA Platinum hop up unit/barrel shot. It just didn't have as much range with the stock packing.

Sw1tch

Discussion Starter · #4 · 15 d ago

Getting the C-Clip out of that thing is the definition of pain. It's awkward getting two flat head mini screw drivers onto each side to pop it off. I also don't want to bend the hop up or break the clips. So having to take it off each time is painful. Anyone tried just shooting it without clipping it for faster adjustments? Or do you think it'd move without the C-Clip.

Leo Greer

· #5 · 15 d ago

What BBs are you using?

Maple Leaf rubbers are thicker on the front than most, which makes it difficult or impossible to fit the c-clip without pushing the rubber into positions and places it shouldn't go, on some hop units. VFC may very well be one of these.

First off, you should try shooting without the clip. However, put a thick band of electrical or teflon tape around the barrel, so the hop unit stays tight and in-position and see if that fixes your issue.

I've done this process before when using a hop unit that wasn't the correct spec to fit the ML rubber.

If not, I'd take the Omega nub out of the equation. Make your own wide flat nub out of some scrap plastic or even 8mm vinyl tubing. Glue it to your hop arm.

Those are all the free options I can think of, assuming you've stabilized your hop arm, inner barrel, and outer barrel.

An Alternate option is to purchase a $7.50 PDI W-hold and try it out, as they are basically identical to original TM spec, and will be much thinner than ML.

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Sw1tch

Discussion Starter · #6 · 15 d ago

Leo Greer said:
What BBs are you using?

Maple Leaf rubbers are thicker on the front than most, which makes it difficult or impossible to fit the c-clip without pushing the rubber into positions and places it shouldn't go, on some hop units. VFC may very well be one of these.

First off, you should try shooting without the clip. However, put a thick band of electrical or teflon tape around the barrel, so the hop unit stays tight and in-position and see if that fixes your issue.

I've done this process before when using a hop unit that wasn't the correct spec to fit the ML rubber.

If not, I'd take the Omega nub out of the equation. Make your own wide flat nub out of some scrap plastic or even 8mm vinyl tubing. Glue it to your hop arm.

Those are all the free options I can think of, assuming you've stabilized your hop arm, inner barrel, and outer barrel.

An Alternate option is to purchase a $7.50 PDI W-hold and try it out, as they are basically identical to original TM spec, and will be much thinner than ML.

Interesting, I can try it without the C-Clip. I do have it teflon taped near the back for air seal. I only did 1.5 wraps around and it tends to push the tape protruding just barely into the C-clip "claw" part of the clip by maybe an 1/8" I tried pushing it away with tweezers but I think that's because I assembled it without any oil to make it go in smoother so it forced it back.

I did stabilize the inner barrel with tape around it to the outer barrel.

Do you think the Omega nub would be causing issues? I didn't seem to need to shim the hop arm it's pretty tight left to right.

I use Bushido .30g bb's.

Leo Greer

· #7 · 15 d ago

So it's not your BBs.

Omega nubs have been known to have tolerance issues over the years, and most of the Omega variants are made of rubber, which is inherently less stable than plastic. I have no guarantees that that's the issue--the omega may be working great--but it's just something to try that doesn't cost any money.

Sw1tch

Discussion Starter · #8 · 15 d ago

Leo Greer said:
So it's not your BBs.

Omega nubs have been known to have tolerance issues over the years, and most of the Omega variants are made of rubber, which is inherently less stable than plastic. I have no guarantees that that's the issue--the omega may be working great--but it's just something to try that doesn't cost any money.

haha for sure! I'm actually reading your accuracy guide. What'd you think of the Bushidos vs G&G? Did you try the Non Bios or the Bios and what weight?

Leo Greer

· #9 · 15 d ago

I tried .25g and .30g non bio. Both performed excellently in my opinion, better than G&G. It wasn't a huge difference, but enough to be noticeable when making some tighter shots. I actually used about 60% of both bags, and then stashed the rest for the games when I just need to try and win harder.

Sw1tch

Discussion Starter · #10 · 15 d ago

Leo Greer said:
I tried .25g and .30g non bio. Both performed excellently in my opinion, better than G&G. It wasn't a huge difference, but enough to be noticeable when making some tighter shots. I actually used about 60% of both bags, and then stashed the rest for the games when I just need to try and win harder.

Awesome haha, I've had great results with my .30gs. Definitely my go-to!

Your pictures on that thread don't work. Do you happen to have a picture explaining the MR hop not fitting properly and pushing it back? I'm not quite sure I know what you mean. I'm using an EDGI Paragon Armory 6.05 barrel (paid more than I'd like to admit) but I wanted to try a top notch barrel as my others are ZCI. I have the identical hop up assembly in my other gun and I'm wondering if I should run a vinyl flat nub instead of the omega. That's 420mm I believe with a SP 120 spring it's shooting at about 345 FPS with .30gs so pretty hot.

The current gun Is a CYMA PCC SBR Rapid Strike that's using a 275mm EDGI barrel and stock spring it's shooting about 325 FPS with that hop up unit and teflon seal with ~2.5 FPS variation. compared to the stock as it came it was 300 FPS with +- 8 FPS

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Leo Greer

· #11 · 15 d ago

Sw1tch said:
Awesome haha, I've had great results with my .30gs. Definitely my go-to!

Your pictures on that thread don't work. Do you happen to have a picture explaining the MR hop not fitting properly and pushing it back? I'm not quite sure I know what you mean. I'm using an EDGI Paragon Armory 6.05 barrel (paid more than I'd like to admit) but I wanted to try a top notch barrel as my others are ZCI. I have the identical hop up assembly in my other gun and I'm wondering if I should run a vinyl flat nub instead of the omega. That's 420mm I believe with a SP 120 spring it's shooting at about 345 FPS with .30gs so pretty hot.

The current gun Is a CYMA PCC SBR Rapid Strike that's using a 275mm EDGI barrel and stock spring it's shooting about 325 FPS with that hop up unit and teflon seal with ~2.5 FPS variation. compared to the stock as it came it was 300 FPS with +- 8 FPS

Darn my pictures! Let me see if internet will cooperate and let me share a pic...

Aha! I think it worked. See how much thicker the "shoulders" of the packing are? It basically places more space between the end of the barrel and the feed tube, which is what causes clips to not fit. This isn't always the case--hop units are different sizes and thus fit differently. I was just guessing that it may be part of the problem.

Try out the vinyl--it works quite well with MR.Hops in my experience. And it costs basically nothing.

Sounds like you're doing pretty well--Never tried an EDGI barrel, but I may start doing my own lapping soon. If only AliExpress had delivered me the right product.

A top notch barrel needs a top notch hop setup to go with it. Keep on tuning and trying!

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Sw1tch

Discussion Starter · #12 · 15 d ago

Leo Greer said:
Darn my pictures! Let me see if internet will cooperate and let me share a pic...

Aha! I think it worked. See how much thicker the "shoulders" of the packing are? It basically places more space between the end of the barrel and the feed tube, which is what causes clips to not fit. This isn't always the case--hop units are different sizes and thus fit differently. I was just guessing that it may be part of the problem.

View attachment 283662

Try out the vinyl--it works quite well with MR.Hops in my experience. And it costs basically nothing.

Sounds like you're doing pretty well--Never tried an EDGI barrel, but I may start doing my own lapping soon. If only AliExpress had delivered me the right product. A top notch barrel needs a top notch hop setup to go with it. Keep on tuning and trying!

Thanks! Any suggestions on getting C-Clips out on the VFC Rotary's? They have extra "Claws" on the edge that make it a pain in the butt to remove. It really stays in there hard to twist and even 2 screw drivers getting on each side and trying to pop it out doesn't work well. I feel like the amount of force required I can only re-fit it a couple times before I warp the hop up unit.

Leo Greer

· #13 · 15 d ago

Sw1tch said:
Thanks! Any suggestions on getting C-Clips out on the VFC Rotary's? They have extra "Claws" on the edge that make it a pain in the butt to remove. It really stays in there hard to twist and even 2 screw drivers getting on each side and trying to pop it out doesn't work well. I feel like the amount of force required I can only re-fit it a couple times before I warp the hop up unit.

Never worked on a VFC rotary--someone else here probably has though.

Sw1tch

Discussion Starter · #14 · 15 d ago

Leo Greer said:
Never worked on a VFC rotary--someone else here probably has though.

You got any more G&G Rotary's? I'd buy one off you. I can't find them

Guges Mk3

· #15 · 15 d ago (Edited)

To get a barrel unlocked from a C-Clip...all you do is with the hop-up off...give the barrel a twist to unlock the clip. No prying what so ever.

If your mound isn't centering it may be the barrel walls...IMHO...it can be out of tolerance and not allow the large MR patch to seat in the center.

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Leo Greer

· #16 · 15 d ago

Sw1tch said:
You got any more G&G Rotary's? I'd buy one off you. I can't find them

Unfortunately I do not. I'm making use of the two I purchased--I should've got more at $9 a pop...

Sw1tch

Discussion Starter · #17 · 15 d ago

Guges Mk3 said:
To get a barrel unlocked from a C-Clip...all you do is with the hop-up off...give the barrel a twist to unlock the clip. No prying what so ever.

If your mound isn't centering it may be the barrel walls...IMHO...it can be out of tolerance and not allow the large MR patch to seat in the center.

I tried that with the VFC Rotary Hop Up unit it has little "claws" that don't twist out like a normal C clip does.

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Guges Mk3

· #18 · 15 d ago

Those are alignment tabs and also helps to serve as a lock.

One can substitute a regular C-Clip in lieu of the tabbed ones if you have spares.

Depending on tightness...you can still give the barrel a twist to unlock the tab...maybe.

Sw1tch

Discussion Starter · #19 · 15 d ago

Guges Mk3 said:
Those are alignment tabs and also helps to serve as a lock.

One can substitute a regular C-Clip in lieu of the tabbed ones if you have spares.

Good to know, yeah it snaps in with some difficulty but getting it off is a real struggle, what about not using the C clip? I think Leo mentioned the C clip could be causing the MR packing to be pushed out of place?

Guges Mk3

· #20 · 15 d ago

Absolutely not...you need barrel retention and that clip provides it on 2 levels:

Rotation
Front and Back positioning.

It's not the clip...it the barrel window...

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