Metal spring guide v2

I have a question for owners of the MK v2 box. What spring guide are you using and where can I get it please> Have bought one but it was too wide. I also have a plastic v2 but it moves alot with the M120 spring. I saw some company selling the MK box with the spring guide but can’t find it again. A point in the right direction will save me some money on an already expensive build

This is the one I am using.
I don’t like the way the retainer sits in the MK boxes :frowning:


does that move about or sit skewiff

Yep everything does thats why I hate the way it’s done

1 Like

think I may just file my current one down to fit snug in the end then, thanks baby yoda

1 Like

No problem baby pig dog :rofl:


I bolt mine through the back

Sometimes with the buffer tube bolt, sometimes with a washer and shorter bolt


Yes that is a must with the MK box but it still doesn’t fix that the retainer lugs just don’t sit nice and square in the seat.
There are also other issues that most people just would not notice without very careful inspection when building :frowning:

I’ve got an fb retainer I’ll check fit tonight

1 Like

Sounds painful icon_e_ugeek being bolted thru the back eek

The buffett tube sounds ok tho… all you can eat I hope? laughing (1) pop

alas no…there comes a point where it impacts on your spring and retainer integrity :stuck_out_tongue: leading to all sorts of weird positioning under load


1 Like

Ohhhhh Hammie… I love it when you talk dirty goofy koolaid


So what’s the work around? Got a mk 92 box and having similar issues. Spring retainer just doesn’t want to play ball

What is the exact issue your having ?

The spring retainer doesn’t sit nicely and it wobbles up and down. I just realised the thread on the back of it (metal retainer for gen 9) so gonna chuck a long buffer tube bolt in tomorrow morning and see if it straightens it up

1 Like

Yes that will do it, I don’t like the way it’s done on these MK boxes

Would’ve been the ‘dream’ box had it just sat flush. Was good fun to shim though, everything is so smooth

There are a few things to watch for, when rotating the gears through a full cycle with no spring the piston seemed to hit the back of the box before the last tooth was fully released but after close inspection the back of the piston head was contacting the cutout window in the box so I had to file it out a bit for clearance, I use the SHS 14t piston’s so I tried 3 other brands and every one did the same. Also with everthing together and no spring I pushed the piston slowly all the way home but there was a tight spot which was the top of the pickup tooth contacting the main body of the sector gear, this also happened with every piston I used so I had to file the height of the pick up tooth slightly.
Also check the fit of your cylinder head in the front of the box with no cylinder in it, most cylinder heads were a very loose fit which can allow the head to tilt giving a misaligned nozzle. Once I sorted everthing perfectly the boxes run super sweet.


Cheers for all the heads up. When I have every thing assembled and pull the trigger I just get a whirring noise and the nozzle moves slightly. I thought this had to do with the spring guide issue but do you have any other thoughts? Thanks in advance

Are you sure the motor is not running in reverse ?