Walkthrough needed - M4A1 hop tighten

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AshOnSnow

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Hi folks, a couple of you might have seen my posts earlier about tightening the hop dial on my M4.

I've not stripped down an AEG before so I would be really grateful for a talk through as I go.

I need to adjust the hop dial so it doesn't move so freely - at the moment it's so loose, that any automatic fire pushes the dial around and I lose the setting.

 
Is it the old style dial on the side or the new, big ring around the nozzle area?

For both, you'll need to remove the barrel assy. Remove the front pin and slide the upper forward from the lower until separated. If the gun is rear wired, you'll have to fiddle with the wire in the stock. Pull out the barrel + hopup.

If the hopup is the old style, unscrew the screw holding the dial, and shave a little off of the shaft it was on. When you put it back, the screw will hold the dial tighter if the shaft is shorter than the dial.

If it has the big adjustment ring, you'll need a thicker O ring under it.

 
Samurai said:
Is it the old style dial on the side or the new, big ring around the nozzle area?

For both, you'll need to remove the barrel assy. Remove the front pin and slide the upper forward from the lower until separated. If the gun is rear wired, you'll have to fiddle with the wire in the stock. Pull out the barrel + hopup.

If the hopup is the old style, unscrew the screw holding the dial, and shave a little off of the shaft it was on. When you put it back, the screw will hold the dial tighter if the shaft is shorter than the dial.

If it has the big adjustment ring, you'll need a thicker O ring under it.
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Off to a good start. Can't get the upper receiver off. Taken out all the pins, it slides forward a little then locks up. 

 
Yep tried that, there seems to be something stopping it further forward

 
Yep, slide the upper forward about an inch, then ease the cocking handle back as you push the upper forward. There will be a point when the cocking handle clears a little lump in the top of the gearbox and you should be able to pull the upper straight forward until it clears everything.

Then turn it upside down and you can ease the hop and barrel backwards out of the inner barrel. There may be some more cocking handle jiggling as the hop sometimes catches on the bolt cover release, but once it's clear of that it should pull straight out. Be aware there is a small spring on the front of the hop above the barrel. This should come out with the hop, but it's easy to knock it off as you're taking things apart. It will sometimes stick in the 'breech' of the outer barrel and you have to go fishing for it.

 
Hangtight said:
Yep, slide the upper forward about an inch, then ease the cocking handle back as you push the upper forward. There will be a point when the cocking handle clears a little lump in the top of the gearbox and you should be able to pull the upper straight forward until it clears everything.

Then turn it upside down and you can ease the hop and barrel backwards out of the inner barrel. There may be some more cocking handle jiggling as the hop sometimes catches on the bolt cover release, but once it's clear of that it should pull straight out. Be aware there is a small spring on the front of the hop above the barrel. This should come out with the hop, but it's easy to knock it off as you're taking things apart. It will sometimes stick in the 'breech' of the outer barrel and you have to go fishing for it.
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Will give it another go when I get home 

 
Managed to get it fixed and back together again. Put some electrical tape under the hop dial to make it sit higher against the screw - the screw was too long and wasn't able to come down all the way. Still enough gear contact to make sure it doesn't slip, but there is a fair amount of leeway with the thin plastic teeth anyway, so I will probably install a decent mad bull complete unit with new bucking later down the line. 

Thanks for for the help guys.

 
I'd heard good things about it. What would you recommend?

 
The red Element, but I'm old. They might not even make that any more. :)

 
Samurai said:
The red Element, but I'm old. They might not even make that any more. :)
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yup still make it and its a nice unit for the price...

Element Accurate M4 Hop Up Chamber IN0804

013889910451_zpsa648c7fc.jpg


worth a shot, lot easy to work on than ye ol' tiny circlips & cogs type

Pete - ak2m4 has got some of the SHS ones in just recently

You are best off leaving your hop/barrel/bucking as is if possible

then build a new barrel/hop up, some hop units work great/crap on certain guns

stuff like squished bucking lips can cause feed issues, some buckings work better/worse etc.....

ProWin's can be great for some but quite a few people find they might get feed issues on certain builds....

Hence - keep old barrel combo to hand - if you have grief then at least you can still use your gun until you suss the other hop

& Madbull - just overhyped - overpriced & bloody over-rated imho

these pro-win types are a lot easy to strip/mess around with than lose a tiny cog/circlip spending hours on your knees looking for it in the carpet. May not work flawlessly for everybody straight away but work a look as an alternative to some cheap nasty hop unit found in some guns that fail to hold the setting etc....

Soz - not crashing thread, just saying these Element or maybe plastic SHS ones are worth a look perhaps

 
My current favourite is the ASG/Lonex conventional hop. I've also got a Prowin that works well with a Prometheus barrel, Maple Leaf and R hop. I'm tempted to grab one of the ZCI Prowin clones while AK2M4 have got them in stock. Has anyone tried the plastic ones?

 
Hangtight said:
I'm tempted to grab one of the ZCI Prowin clones while AK2M4 have got them in stock. Has anyone tried the plastic ones?
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Gotta be worth a go for about £8, can't be no worse than your battery project

I have a couple of Element ones, though fine hop tuning is not my forte

But they are a lot easy to experiment and assemble etc....

worth a shot

 
+1 again for the lonex hop up. I always rate it but it's just one of the only good standard hop ups that dont have the newer wheel but are just good. Stiff to turn out of the box and a deeper feed lip to help with feeding and it does when it comes to those mags that didn't work before like my EPM's. 

If you can get a rotary style hop up working like the prowin though, it is more rewarding as it's easier to change hop setting and easier to work on.

 
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