How To: RVA for Collapsible Car Stock

Boyd4447 · #1 (**permalink**) 03-12-2008, 01:19 PM

Ok, I didn't take any pictures of this, but I will see if I can retrace the steps and show some.
Here is a little tip for you all that has a car stock, but wants the flexibility of an RVA with out the price tag.

Items needed:
Dremel tool or other drill
SAE #6 washer
typical 4.5mm BBs
large O-ring

Ok, my stock spring is a little on the tight side and I have to crank my FVA pretty much all the way in to get to the field safe 280fps with HPA. I also love my Car stock set up, so I didn't want to have to buy another stock with an RVA from JCS, nor did I want to shell out the extra money for a spring kit, and finally I didn't want to clip the spring just in case it starts to get more compact, I can just adjust with this mod.

Here it goes. I want to add a disclaimer. I don't know if all car stocks are designed this way, and I am unsure to the brand of mine. Attempt this mod at your own risk. I will not be held liable if this doesn't work for you.

In the hole where the recoil spring and guide enters the sotck, drill into it using a 3/8" drill bit. BE CAREFUL!!!! IT MUST BE STRAIGHT DOWN!!!! It must be that size since there is a smaller hole that travels the length of the stock, and that is also the outer diameter of the #6 washer. I drilled about 1/2 to 3/4" into it.

Once you have a small hole drilled, here comes the tricky part. You need to get the washer to sit at the back end of the hole. It will be a tight fit, I used the ink refil to a ball point pen as a make shift shive to push it down all the way.

Once the washer is seated against the back on the hole, drop in a couple BBs. These will now become your RVA. They are small enough to fall easily through the hole, but big enough to be stopped by the washer. You are going to have to play with it some by adding or removing some BBs over a chrono to get the FPS right. I slightly glued the O-Ring to the back of the stock to act as a little buffer since the hammer might slam into the stock now. I hope it doesn't, but it will add just a little extra protection.

Personnaly, three BBs did it for me after drilling. I now have my FVA flush with the powertube so I don't get as much fluctuation with the fps. Before I was +/- 10 fps, now I am down to around +/-4 with HPA and no second reg!

Like I said before, I will add some pics later, but I just couldn't wait to share this. Good luck! Here is the finished marker!

FONZ · #2 (**permalink**) 03-12-2008, 01:23 PM

wow, sounds great! would like to see some pics of this baby

Papiriqui · #3 (**permalink**) 03-12-2008, 01:39 PM

Sounds very very good. Definetly would like to see some photos.

SilentDeath12886 · #4 (**permalink**) 03-13-2008, 05:32 PM

Sounds interesting. Clever way of going about it.

Boyd4447 · #5 (**permalink**) 03-13-2008, 07:50 PM

Pictures have been added!

DUFF MUFFIN · #6 (**permalink**) 03-13-2008, 09:42 PM

how do you adjust the velocity? take off the stock?

Boyd4447 · #7 (**permalink**) 03-13-2008, 09:58 PM

Quote:

Originally Posted by DUFF MUFFIN

how do you adjust the velocity? take off the stock?

I have a hand held chrono. I messed around with the amount of BBs I placed in while I had my FVA flush with the powertube. I got it to hit 285 with three BBs, then I fine tuned it with the FVA from there. Now I am hitting 275 +/-4.

SSgt.R-Ichikisu · #8 (**permalink**) 03-13-2008, 10:31 PM

I have to admit, that is one heck of a project you did mate. I might just do this myself!!

Boyd4447 · #9 (**permalink**) 03-13-2008, 10:37 PM

The only thing I would change is instead of using the washer and BBs, is finding some sort of plastic ring that has the same inner diameter as the recoil spring to help guide it when it is compressed, and larger diameter ball bearings that fit the hole better.

SilentDeath12886 · #10 (**permalink**) 03-14-2008, 01:40 AM

Im kind of confused to what the washer does. How is it held in place?

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