Hi guys, wanted to do the hop mod on my vsr, where you file the "bump" off the rubber. Is it necessary afterwards to mod the hop arms too, if so whats the best materials or "thing" to use doing so. thanks joe
Yes, you'll need to fill the gap between the prongs, plus add a little bit of length to the prongs to recover some of the lost depth you get when you remove the inner nub. You also need to do it if you want to use heavier ammo.
I use car body filler and file it roughly to shape, then cover it in mitre bond, thats a builders super glue that 'really does' go hard in 10 seconds, to make it harder, I then file my shape into my arm nub more accurately.
You might find you have to have several goes at this before you get it right, so don't be despondant when it doesn't shoot straight on the first attempt
went to do it and for the life of me couldnt turn the bloody rubber inside out lol, what a fail, in turn i managed to kill the accuracy i had by "trying" new mods which popped into my head. Back to basics for me and start over.
I sorta fold the less stiff end in on itself, then fold it over so it looks like its rolling down the outside of itself, if that makes any sense, then I fold the stiffer end in on itself to, and then force/push it into the folded over end, I then use surgical clamps to pull the stiffer end through so its pulled inside out, job done. I more or less reverse this to turn it back the right way.
I just read that back and it still makes more sense in my head than it does written down :-/
awell i did all the mods etc, getting right side fliers but alot more range, i want to rethink my hop arm strategy, maybe make the nub (attached to the arm) out of rubber instead of the body filler stuff i used, i can see it beibg a pain in the arse getting the body filler dead level to rule out the risk of left or right hookers, so ive found some hardish rubber that i am going to glue to the arm to see if it has more forgiveness on the bb leaving the hop. what dya think? Also while im here im looking for a vsr trigger guard and bipod/sling stud if anyone wants to flog me them (uk plz)
Re your hop arm.... Dont use solid rubber.... far to much play and give.
What I did to mine.....
Extend the barrel window as far as the stock rubber will safely allow, both forward and towards the open end, making sure to maintain the support loop to hold the rubber in shape.
Increase the width of the window, so that the stock prongs actualy go into the window without fouling on the barrel.
Remove the nub from the rubber
Go to hobby-craft, or your prefered hobby store, and get some ever-green plastic card in various thicknesses.
Cut the plastic card to slightly smaller in length, about 1.5mm, but the same width as the barrel window. You'll need several 'patches' in different thickness' as the depth needs to be adjusted, but its better to get it so that only 2 maybe 3 patches are used in the finished article, you dont really need to remove the prongs from the arm if you haven't.
Lastly cut a small patch of ordinary AEG hop rubber the same size as your plastic card patches, place this between the card and your hop rubber. This takes into account any variation in bb size and helps to mould to the top of the bb to give it more grip. Don't worry about forming a curved profile, the length of nub will help to stabalise the shot, plus as you've discovered its an arse to get right :-/
Sadly the only real way to prevent right curve is to make/buy a 'over centre' adjuster
Using this system in my 350fps VSR I have the hop set to only just barely hold a bb in place and it will send a .2 north straight out the end of the barrel and a .28 flat and level for a good 80/90 metres ND its lazer beam straight.... every time!!
so you think my main problem in essence is the crap design of the slider that adjust the hop unevenly. As you and i said all of my shots are righties. Would you reccomend making a TDC adjuster or extending the barrel window first? im a bit stuck now as both tasks are easy to screw up lol. TDC is the more appealing if i had to go for one.
Sadly, yes, crap design/materials is the issue and yet noone seems willing to make a more solid replacement, probably due to the fact it'd be an arse to machine and to complicated to cast in metal :-/
I'd go TDC first, then do the long hop mod if your feeling confident, as the TDC will straighten out the shot, the long hop will add range and accuracy at range
I did mine using an M4 nut and bolt, a tension spring (to stop the bolt un-winding).
Measure the exact centre of the outter barrel, and the point that is over the centre of the hop window of the barrel. Make sure you do the measuring bit a good couple of times as accuracy hear is paramount ( I f**ked up my first attempt by hold ing the outer one way and the hop chamber I was using to find lengths from the other, only realising when it came to re-assembly
I then drilled and tapped for an M4 bolt, you must make sure you get this absalutely spot on upright or it makes the next part a bit of a ball ache and it looks horrible on the finished job though I dowt it affects the out-come to drasticaly so long as its not to far out, then take the bolt with the spring and nut assembled together and fit into the threaded hole, I then glued the nut into place to increase the effective length of the thread depth.
Re-assemble the hop/barrel and fit it in the outer after backing of the adjuster bolt until the hop chamber slides past easily.
Before re-fitting the bolt/reciever adjust the bolt to the point you can just see the hop rubber coming into the barrel opening, dont forget to push the bb holder up while you do this , enough to hold the bb with-out it falling right through. Mark the bolt head so you know where your start point is, re-assemble your gun and go try it out..... adjust bolt to suit your ammo..... job done
Being having a play with all these ideas and found a sort of sweet medium now, ive done the TDC adjuster, shots are now one hell of alot straighter, its now just getting the hop arm done to perfection, If im not happy in the next couple of days with the shots up my garden (big garden) Ill rethink and do the extended window, thing is with this PDI barrel there really isnt much material to play with. Anyhow, thanks to vindi for the help, anymore suggestions are very much welcomed.
Yeah i get what your saying, in essence its probably not worth me extending it any further (1-3mm left) as it wont reap too many rewards for the work involved, im only running 400fps, when im braver i may look into th r-hop or a varient of it, but for now ill just improve on what i have.
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