My First Flat Hop

[AndyDynamic]

Hi all,

 

As the title suggests, I've begun to move into the dark arts of hop unit tampering, starting with what has been called the easiest modification, installing a flat hop.

 

After much Googling and trying to figure out what the difference is between a flat hop, r-hop, z-hop, g-hop, cookiemonster-hop (that last one possibly isn't real) I made the plunge.

 

1. I started by taking my standard hop bucking which had seen some use. Turning it inside out with the help of a pair of needle nosed pliers (it can be tricky) I then used a hand held Dremel to gently sand away both the bucking mound, and the raised line. Once done and cleaned up, I rolled it back the right way. I would recommend using a permanent marker to show where the mound and raised part were before you sand off. This is helpful for the next part.
2. Placing it back on the barrel, you need to rotate the bucking 90degrees, basically so that a clean part of the bucking is over the hole in the barrel. Hence the drawn on line.
   1. I use a MadBull 6.03 barrel and bucking, so the fit is pretty tight.
3. Next you want to remove the hop arm from your hop unit, and the nub. The nub will become obsolete shortly.
   1. At this point you have 2 options.
   2. You can either buy a pre-made flat nub (Prometheus make one)
   3. Or you can modify the hop arm to remove the "claw" from it, and make up your own square nub
4. I went with option 2, for 2 reasons. I didn't have a flat nub, and also I wanted to make sure the nub was perfectly sized for the window on the barrel and the area on the hop unit for maximum snugness.
   1. This does mean there's no turning back, you have to grind off the "claw" from the hop arm, so if you don't have a dremel, or don't want to risk it, just get a flat nub from Prometheus : Example on Pro Airsoft
5. Once the "claw" is removed, you now need to make your own flat nub. All the guides online say you should use the old pink erasers you got in school - that just smudged pencil instead of y'know, erasing it. I couldn't find these for love nor money, but what I did find is carving blocks of rubber on Amazon. These are perfect, cheap, and you get LOADS so you can cock up enough, which I did many times - This is the stuff I got - it's got great consistency, is semi-hard (oo-er) so it won't squash under the hop arm too much.
6. You then need to carefully cutout a square which will not only fit into your hop unit, but also fit into the window on the barrel. This is much smaller than you think. And something that caught me out is how short it needs to be in terms of height. Basically at the end of it, your nub wants to be tall enough so that at zero hop on your unit, you are only just applying pressure, so it doesn't fall out. A tiny bit of default hop will be fine.
   1. I would recommend a set of modelling knives, preferably one that has a straight edge, as that means you'll get a cleaner, straighter cut. Number 18 from here
   2. When cutting you want the top and bottom to be perfectly level, otherwise when you apply hop, you end up with an angle on the hop rubber which will send your BBs off left or right.
7. Slot it into the hopunit, get the arm on there and check through the barrel  that your hop is applied evenly. 
8. The flat hop will apply a LOT more hop than usual, so be careful, you will not need a lot. If you crank it on, you could split the rubber (steady lads) or, in the case of my MadBull hop unit, the strain on the hop arm can pop the adjustment wheel off of its rubber o-ring. But you really don't need a lot.

 

Testing

I got to field this for the first time on Sunday and I was anxious - my hop didn't look quite level in the barrel so I expected it to be crap and off to one side.

I started to dial in the hop very slowly, bit by bit, and it was rubbish - BBs were dropping very low, then I gave it another turn a bit further and suddenly they're going much further! A little tweak back down - I'm talking 1mm of turn - and the shots are lovely and straight with only a tiny bit of lift towards the end to extend the range, just what you want.

I wasn't seeing any side deviation, and if I was it was minimal.

 

I would say I was getting perhaps 5-10 metres more effective range out of the RIF but more importantly, the spread of BBs had narrowed - this is key. On full auto, previously the BBs would have a grouping that was quite wide after about 15 metres. In the old hop, this is caused by the hop arm moving, the contact patch on the BB being small which in turn rattles the BB down the barrel.

 

With the flat hop, not only does the contact patch extend by an extra 1-2mm but the affect of the larger nub on the hop arm stops most if not all of the lateral movement of the arm. The effect of this is that a burst on full auto lands the group of BBs in a much tighter pattern, so there's more chance of scoring multiple hits on a target and the targetee acknowledging them.

 

Where to go from here

I have some of the fabled R-Hop patches to try next. These are apparently even more black magic and can be a pain to setup, but the effects are even tighter grouping and possibly a little more range, but more importantly, better hop of heavier BBs, so moving up to 0.28 would mean the RIF would be much more consistent at range.

 

Hope you've enjoyed reading this wall of text - I can add images if people would like.

 

Cheers

 

Andy

[Adolf Hamster]

well written mate.

 

i'd add from my own experience that if you do go for a pre-made flat nub, and you're having problems with very finnicky adjustment (mine was so sensitive the difference between a full and near empty mag resulted in massive hop changes) then filing away a bit on the arm to give the nub a bit less compression can help a lot.

 

i've noticed prometheus have also got a pre-made nub that will give somewhat of an Rhop effect to it as well, although i haven't personally tried it out.

[Monkman]

Nice write up....did my own flathops last month to my two rifles...at first wasn't to impressed with what I did, then switched to a heavier BB (.28) and a some tiny hop adjustments...and yes I was quite impressed.    (I destroyed one prommy purple bucking when attempting the 2nd rif, so used an ICS bucking instead..seems to do the job)

[AndyDynamic]

On 03/08/2018 at 21:06, Monkman said:

Nice write up....did my own flathops last month to my two rifles...at first wasn't to impressed with what I did, then switched to a heavier BB (.28) and a some tiny hop adjustments...and yes I was quite impressed.    (I destroyed one prommy purple bucking when attempting the 2nd rif, so used an ICS bucking instead..seems to do the job)

 

Yeah I think all the types of custom hops will damage softer buckings quickly, definitely something to watch out for

 

Also yes I agree, I think these hops are all better suited to heavier weight ammo, it grips the bucking more so you get more back spin