Advice on seating Hop Up Nub straight

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L3wisD

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Morning,

I need a bit of advice with seating my hop up nub on the straight and narrow.

Before we get started, I've got a ProWin M4 chamber with a Prometheus Purple rubber and nub just so you know what I'm working with.

Last night at the mall I noticed by shots were going well to the right. 

If you imagine aiming at a clock face, BBs were going straight towards 1 o'Clock position It wasn't a gradual curve, it was a pretty noticeable angle straight from the end of the gun.

I wound off the hop all the way in case it was me having too much wound on. But it didn't help.

So between games I disassembled the gun and had a look at the rubber etc

The barrel was clean and free from obstructions but it looks like the nub isn't sat straight down.

The mound from the nub isn't quite sitting at 12 o'clock in the barrel window.

So I took the Prowin apart and re-seated the nub in the arm but I just could not for the life of me get it to sit straight.

So for the rest of the night I had to aim slightly left at everyone - I still had a good night mind you!

Is there anything I can do to help re-seat the nub a bit more centrally? Any advice or wisdom is appreciated!

Duck? Trigger? PT?

Cheers,

Lewis

 
Just turn the barrel inside the hopup back and forth a bit util it sits in the middle.

 
The bottom of the barrel should have a guide rail that the bucking slides into to put the mound directly over the barrel window..

DSC00865.jpg


So when you slide the bucking onto the barrel it lines up right? Well on the bottom of the hop up near the C-clip there is usually a faint line that you line the guide rail up with. Simply line the line on the barrel up with the faint line on the bottom of the hop up.

 
The Prowin C clip is pretty useless at clocking the barrel to the hop. I've taken to drilling and tapping a couple of M4 holes in the underside of the outer barrel. Couple of cup end grub screws and you can lock everything down once it's sitting right.

 
Yeah it's not the rubber that off kilter. That is sitting straight on the inner barrel and the window is where it should be in the hop unit.

It's the nub in the hop up arm that is sitting wonky. Like it's slanted in the arm.

I'm going to try the Samurai wiggle technique anyway to see if I can jiggle the nub to sit flat.

Failing that I'll flat hop it.

 
Lose the prommy purple. While I normally rate the prommy the prowin doesn't like it sometimes, try the lonex 50 degree bucking. The prommy is quite thick and firm (that wasn't an innuendo for all you that jump on everything) and a few hop ups and arms dont fair too well it. That can be the reason your nubs tilting. If you want to stick with the prommy either use the bar in your nub or use a solid nub like the eraser mod.

 
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Could always glue it to the hop up arm but the eraser mod is a very good, cost effective mod that is piss easy to do.

 
Still can't get the nub/arm to sit dead on. God knows why.

Going to order a couple of the Lonex 50 rubbers and have a go at flat hopping them.

 
Cheers Trigg, appreciate that.

I'll let you know how I get on...

 
Flat hop done!

Just can't test fire it in my 6ft garden, so I'll have to report back!

I had to trim the ends off my flat nub to get it to sit in the ProWin's window, but that was easy enough.

And I must confess I opted for a laylax straight rubber (in a couple of different hardnesses) instead of the Lonex 50.

I'll see how I do with these and change them again if need be.

Thanks for the advice everyone!

 
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