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R-Hop Installation Manual

posted May 31, 2012, 1:54 PM by spike HSA   [ updated Mar 23, 2014, 5:04 PM ]

The alternate installation technique SPECIFICALLY for the Z-kit covered here:

Standard R-hop Installation:

Installation of an R-hop, particularly the Z-kit, is not particularly difficult but can be a little time consuming. I highly recommend new installers take their time, do not try to rush the process, and DO NOT ATTEMPT TO USE A ROTARY TOOL. A rotary tool (dremel) is an excellent way to remove material quickly, but often times can do so too quickly and/or launch your R-hop into low orbit. The instructions can seem a little confusing and long winded, but thats simply because there are so many ways to go about doing it.

Step 1:

Get a grip on your R-hop. If you are using one of the installation aids this isn't too difficult, although a thin splinter can aid in pinning it particularly if you have large fingers. If you don't have an installation aid a drop of hot glue will secure it firmly to a surface for easier manipulation. Careful manipulation is key to a quality install.

Step 2:

Adjust the length. This is best done with a VERY sharp blade and in a single clean cut. Measure twice, cut once. While previous iterations of this manual suggested leaving a gap at the front of the R-hop, it is now recommended for optimal performance you aim for a snug fit in the window, and radius the leading and trailing edges of the R-hop to prevent pinch-type jams. Mark the R-hop carefully, and cut it against a hard surface.

Step 3:

The key to a good install starts with an R-hop that fits flush with the outside of the barrel. The R-hop itself is pliable so the best way to achieve this flush fit is with adjustment of the so called “legs.”
If you are using an installation aid, look in the “Concepts” section of the site, you can combine the rod and U to pinch the R-hop for leg adjustments like so:

Gentle application of sandpaper (finishing with 600 grit or higher) can then be used to remove material from the legs or a very sharp high angle blade. Again this gets back to step 1, where you need to be able to firmly grip and thus manipulate your R-hop in order to work on it. The Z-kit eliminates this step. 

If you go a little too far, you can use RTV paired with the V.6 installation aid to do a Z-kit type install. If you go a lot too far, or your window is simply far too deep, an easy trick is to build up the side of your barrel window either with pieces of paper CA glued together in situ or, again pairing with the V.6 installation aid and mold release, epoxy putty. Cut strips longer than necessary, square them at the ends, and make sure they sit shy of flush with the bore. Excess outside the bore can be trimmed off easily later. Using CA and paper is essentially creating a composite in situ, and can actually be easier than adjusting the legs shorter. Its not a hack at all, and is a very effective solution. This technique can also be used to rescue barrels which have been otherwise ruined by modified excessively deep windows.

Further improvement of the fit with the barrel on the outside can be accomplished with a thin strip of sandpaper. Credit goes to Maekii for this clever trick:

EngelMacher has used a shaving razor to accomplish the same thing. (again done to an R-hop on the barrel) People's response to this however has been mixed.

Step 4:

Adjust the channel. This is the part of the R-hop that contacts the bb. You would be amazed at how gentle a touch is required to spin a bb. Again credit goes to Maekii for coming up with the original version of the installation aid. I added a few touches and worked up a pre-made version people can easily acquire, but the original concept is his. Feel free to experiment, this is why the R-hop is kept open source.



Please note the Z-kit and associated installation technique eliminates this step as well. 

Step 5:

Test. You're primarily testing channel adjustment here. With a bucking (mound and alignment ridge removed) and hop unit installed use a small rod to gently press a bb through the chamber. If the bb doesn't go through with just the slightest push, or feels like its catching somewhere rather than pushing through smoothly, you need to adjust the channel further. If you can't press your lips against it and blow the bb past the R-hop chances are you have too much. (credit KJerry) Once the bb does this, you can move to actually firing rounds through the R-hop to test. If you have under-hop its no problem, just use a nice nub like the M-nub or Firefly nub to apply soft deformable pressure to the top of the R-hop, over-hop means a little more has to go from the channel.

Step 6:

Secure your R-hop. Using CA “permanently” bond your R-hop in place. Be careful not to allow CA to enter the barrel, apply around the outside edges only. You can also flip your bucking inside out, put a drop of CA on top of your R-hop, and then unroll your bucking onto the R-hop. To undo this gently reach inside your barrel with a plastic or wood instrument and press upward on the R-hop around the edges to break the glue bond. (you'll hear a soft cracking sound)

You're Finished. See wasn't that easy?

The Z-kit. Whats different, and whats the same?

The Z-kit is a series of different size R-hops. It effectively removes steps three and four, which are the hardest steps, and uses a slightly different installation technique while being paired with the V.6 Installation Aid to significantly ease and speed installation. 

Common Problems

I still occasionally get questions/complaints about low accuracy/performance for "no apparent reason." The four most common causes of this are:
Grossly incompetent install -- Issues are usually visually apparent. Show it to one of your friends and then duck before they hit you for being a moron.
Pinch type jam -- The R-hop pinches between the front of the barrel window and the bb. Radius the trailing edge of the R-hop and keep it off the front edge of the window.
Low grit finish -- in the guide I recommend a 600 grit finish. Consider this a MINIMUM. The hops prefer even higher surface finishes when possible. They can and do break in with time, so lots of shooting can and will improve the consistency of your R-hop should you start with a low finish. Maekii adds a drop of silicone to his sandpaper to further improve surface finish.
Hooking of shots -- severe hooking is the result of an asymmetric install, or one of the aforementioned factors existing only on part of the R-hop. It can also be caused by an uneven removal of the bucking mound resulting in uneven pressure on the R-hop. Less severe hooking can be corrected by rotating your inner barrel within the hop unit. After all your gun's vertical is defined by your hop's vertical. 

The R-hop Q&A thread for users who require extra help:


Here are alternate manuals NOT written by Hunterseeker Armory which may also be helpful, some of which are not in English:


Video Pt. 3



Video (English, somewhat exhaustive)

If you still find yourself stymied, or just want to see other people's complaints/issues/solutions, there are two old installation manuals on public forums: