How to fit a G&P crane stock

[colonel_kipper]

Hi,

 

More people seem to be using crane stocks these days as opposed to the awful PEQ boxes that can alter the look, feel and balance of a rifle (for the worse!).

So, I thought that I'd show you how to fit one of the G&P variants, but this guide can apply to (I suspect) other brands such as Zenith, STAR and CA.

 

1) Purchase new gun. (Optional )

 

 

2) Disassemble your current stock

 

3) Burn the instructions

 

http://img295.imageshack.us/img295/7691/upload1ct0.jpg

 

4) Preferably using a hacksaw or dremel (have a good supply of cutting bits because the soft zinc alloy of the receiver "jams" in the cutting bits and breaks them 14 to the dozen), or even a nice cnc mill, cut the stock tube down so that it's 3cm long from the joint of the receiver or less. I prefer to leave it dead on 3cm just in case I decide to put a normal stock back on.

 

 

5) The mechbox in this case is rear wired and is a systema high speed unit. Note the red positive marker on the wire - before you start work ALWAYS make a similar mark to discern between each wire if they aren't colour coded like most v2 units. This particular method is called the "wire splice" method. It is not the best way that you can approach this, as if the wires are not well insulated, a sharp corner can short out the motor or even the battery, causing a real scene. If you're more condfident with soldering and gearboxes (The only reason I used this method today is because I ran out of silicone wire) then I reccomend that you desolder the two wires coming from the trigger unit to the back of the gun, keep them in the bits box, and replace them with suitable lengths of 18/16 awg silicone wire, with a fresh Deans connector. This ensures that the chance of shorts or intermittent connections is kept to a minimum.

 

 

6) Cut off the tamiya plug if necessary

 

7) You now need two thicknesses of heatshrink wire - one must fit snugly over 18 awg wire, and the other must fit easily over 2 18 awg wires in parallel. Slide the large one (in this case black) over BOTH wires until it's just behind the Deans connector. Take the two smaller pieces (Red) and place well away from the end of the wire, close to the Deans connector (This ensures that the heatshrink won't contract during the soldering due to the transfer of heat along the wire, as that's a real *badgeress* to deal with)

 

8) Strip the ends of both wires (The G&P battery wire comes with pre soldered ends for the lazy among us; I

prefer to cut them off and re-strip the wire, and use good quality rosin core solder.

 

9) Place together and solder nicely.

 

http://img295.imageshack.us/img295/5643/upload4xf8.jpg

 

 

10) ALLOW TO COOL SUFFICIENTLY - then slide the red heatshrink along the wire and shrink it with a

lighter/hair dryer/cat

 

 

 

11) Repeat to other wire

 

11b) Slide main piece (in this case black) of heatshrink over the smaller two and seal as below :

 

 

12) Nearly there! Most crane stock kits come with a new plate which bridges the stock pipe to the receiver, which has an indent for the wires to run through. Don't forget to make sure that its edges aren't sharp otherwise you might end up with the whole thing going up in flames! If you don't have one, just file your stock one so that there's an indent wide enough for the wires to slide through unobstructed parallel with the stock tube when assembled. (You can see how I did this to my one in the picture below instruction number 4)

 

 

13) This particular gun has a channel built into the receiver tube to further aid routing of the wires. You can dremel a normal receiver like this or use a hacksaw to make a straight cut down it. Either way, it's not mandatory but does help and greatly reduces the chance of a wire being damaged.

 

 

14) Tuck it all in and assemble like a normal stock.

 

 

[colonel_kipper]

15) Enjoy!

 

[TriChrome]

Great guide and all, I can see you took your time to post it, but the traditional and correct method for most guns is to cut a whole in the tube that sticks off the rear of the metal body, not cut a channel through the bottom of it to run the wires. --in those cases you also don't want to cut any length off that tube either.

 

Your HK416 already had that tube there (with the groove for the wires) because it came with a battery stock initially.

[RaboonTheBaboon]

Nice one, there's a ready made guide on the G&P website that you may have skimmed over too.

 

http://www.gp-web.com/en/photo/m4battstock_copy3.zip

 

Fortunately yours has no Engrish!

 

Forgot the link...