40 replies to this topic

[WratH]

I'm not sure if anyone else has tried to say this, if they had it was pretty fuzzy. Trogdorian Grey seemed to get it, but perhaps if you add a spacer so that you get the full (or almost full) compression of the AR spring you would get more power, no? And another question, does this breech seem easy to add a tigher barrel (say PETG) to, or is gonna be a bitch like the longshot?

[xNFx 37]

I just got a Recon today (6 on the shelves). And I'm gonna do this mod and AR removal (if i can).

And I just accquired a BBB spring...

I'll be using that for the replacement, implying the plunger won't snap

[Diablo]

What I was about to post many of you already stated. A more compressed spring would warrant better results. By shortening the space the spring has to compress, more compression will occur, and thus a greater force will be exerted upon firing.

I also think that a bigger gauge spring would work better, if the Recon can handle that much extra force. If it can't, I'm sure some reinforcement would do the trick.


Great initial idea though! I never would have thought of this myself, and I'm really glad that many of us are finding ways to improve upon it.

[rokor]

[quote name='Diablo' date='Jan 3 2008, 11:31 PM' post='134913']
A more compressed spring would warrant better results. By shortening the space the spring has to compress, more compression will occur, and thus a greater force will be exerted upon firing.

I would say the easier way and maybe even better way would be to put in a smaller spring like a maverick spring on the dead space in the plunger and keep the center peice of the stock. With a DGK breech(CPVC breech that I made, felt like giving it a name, stands for Dirty Ghetto Kids) And the mav spring on I can get a pretty fast 80 ft or more out of this gun.

[M30]

First off, I'm not sure some of the assumptions being put forth here are true.
A "more compressed" spring is not better than a "partially compressed" spring if it's the same spring. You're going to get about three inches of displacement for any spring, just because that's how long the "ARMED" thing is.

Hooke's law tells us that Force = SpringConstant * Displacement.

As I said before, we know Displacement is always three inches. So if you take the original setup, with that super-long spring that extends to the rear, and assign the spring a constant of K, then your force is 3K.

I believe it was suggested to use a shorter spring that fully compresses. However, this is still only going to have three inches of compression, so unless its spring constant is greater than K, it will have the EXACT same effect. Seeing as how the OP was using the AR-15 spring, I doubt anyone was suggesting sticking anything much stronger in there.

I guess what I'm trying to say is that "compression" yields a linear increase in force. Compressing it the first inch gets just as big of a jump in force as the last inch does.

So the original setup really can't be improved on much.
That said, I did the same mod a little differently.


The first thing I did was fashion the above items. First, crack open that middle piece of the stock. Find a wooden shim and cut/file it down in the appropriate way such that it creates a "base" perpendicular to the direction of the compression of the spring. Glue the spring to it. In order to ensure the spring didn't mess up the plastic of the ARMED piece, I glued a washer to the other end of the spring.

The second piece is created by getting your pipe cut to a length such that it is flush with the black square end of the gun, AND the middle piece of the stock when the gun is connected to the stock. Finally, bore a hole (I used a dremel tool) in the middle stock piece with the same inner diameter as the tube. I used a sparing amount of hot glue to affix the tube to one half of the stock piece.

Connected, they appear as so:


Another angle, you can see the washer here:


Fully assembled:


Attached to the gun:


I'm sure the spring I used wasn't quite as strong as the AR-15 spring. In fact, I had to the clip it a little, because even fully compressed it was physically too large, and this made the cocking of the Recon impossible. However, even though I shortened it, I've seen noticeable range increases, and the gun can still be cocked almost as quickly as it could before.

I would be wary of sticking anything much stronger in there, as the mechanism that holds the stock on is what takes the entirety of the strain of the spring (at least it does the way I crafted it). I worry that anything much stronger will just snap the stock off, perhaps in an irreparable way.

Thoughts?

[xNFx 37]

What spring did you use?

I have a BBB spring I could use for the OP mod.

But I thought It would break anyway. Meh.

[M30]

I didn't use a specific spring (BBB, NF, etc.), as I don't have a ready supply of any of those. Instead, I just pick up an bunch of springs from the hardware store, and use the strongest one that will fit.

I believe this one is rated around 165 N/m. I've used a similar spring before in a LS spring addition, and achieved typical results, if that gives you an idea of how strong this spring is.

[chalywong]

Another thing you can do with your mod M30 with different springs is place different amounts of washers in front of the spring to get maximum compression. This will do just about the same thing as the penny mod for mavs and crossfires.

[Peter]

I didn't use a specific spring (BBB, NF, etc.), as I don't have a ready supply of any of those. Instead, I just pick up an bunch of springs from the hardware store, and use the strongest one that will fit.

I believe this one is rated around 165 N/m. I've used a similar spring before in a LS spring addition, and achieved typical results, if that gives you an idea of how strong this spring is.

Since most people aren't familiar with spring constants: 165 N/m means that it will take 165 Newtons of force (about 37 lbs) to displace the spring 1 meter. M30 said the displacement was 3 inches so the amount of force on the spring will add is 2.8 pounds when cocked.

Edited by Peter, 10 January 2008 - 05:59 PM.

[MavericK96]

*cool mod stuff*

Thoughts?

I really like this design, primarily because it seems like you could easily remove the stock if you wanted to use the gun without it. I also like the idea that adding the stock adds range, making it more beneficial to convert the gun to the "rifle" configuration. Makes sense that the "rifle" should have more range than the "pistol".

Anyway, nice work. I do see your concern with the stock's locking mechanism, though, since it's just a tiny piece of plastic, but maybe if it was replaced with metal or something it would be stronger.

[zaphodB]

This is another good idea that I jumped on and cleaned up (the other being the dtg/ longshot integration). I'll have a topic up as soon as my camera connects to the computer, but here's some goodies for everybody for now.

First of all: The plunger tube on the recon fits perfectly into the plunger tube of a night finder. And the nightfinder plunger tube can fit into the RC stock with only a little dremeling.

Second thing: Taking out the air restrictor is EASY. A drill will get it done in not time flat, and it adds a good amount of range.

All in all, even though it *only* gets nightfinder ranges, it's a solid gun. With an extended clip, you've got 12 rapid mid range shots from a compact and comfortable gun, with an extra 6 in the stock. Add a tactical light and stick the "laser" on (it's got a tight enough beam for indoors) and you've got a fantastic defensive weapon for a HvZ game. (I imagine, I can't drum up enough people for a good game). I'm more than happy with this gun.

[rokor]

Now his camera aint working either, what is this?! jk, but I wont be able to put up pictures for my breech mod since I was having too much trouble and ended up singleing it. I also made a crossbow style way of cocking it since I didnt want to have the bolt sled take up room(for a later SSPBx2 integration). The way I did it is found a peice of scrap CPVC in my room and glued it in the dead space(lets call it that) behind the plunger, then stuck a 1in peice of PVC ove it so it would cock esier. Althoug I did have too take the center peice of the stock out, I stuck a strip of thick vynal over the top to make it sturdier, then moved the center peice to the end of the stock with e-tape for a tighter fit(this reall does work btw). Hope that made sense. I think there will be tons of unique mods for this gun, just cant wait to see what everyone else is up to!

[Squishy]

hooke's law assumes small changes in length. In order to properly model a spring that reaches almost full compression, an integral must be used on an equation based on the k constant and it's elastic range. However, if you take a spring that is half compressed and compress it the last half, it usually takes more force to compress the last half of the spring. Most of the time, Hooke's law is close though. If you want to learn more about it, I suggest looking up information on Non-Hookean springs. For steel below it's elastic range (depends on the composition of that particular steel) it can be considered a Hookean elastic material, assuming that most other conditions are about normal.(Temperature, stresses are relatively small.)

Edited by Squishy, 16 January 2008 - 12:47 PM.

[smeagolsaur]

I just did something similar to this mod, but rather than remove the middle yellow block in the stock, I kept it there and am using it as the back bumper for a spring that I've put within the dead space in the back of the plunger tube--- just remove the circular back piece from the back of the plunger tube and sand down (or in my case, tear off with screwdriver) the four nubs so you can stick an extra spring in there (I used a double-shot spring).
This (plus air restrictor removal) actually gave my recon more shooting power than my modified longshot (which has 2 extra springs but no air restrictor removed).
I was extremely surprised, and pleased.

I have yet to get a small piece of pvc to encage the spring behind the plunger tube, or else the spring jumps out everytime you shoot.

In summation, there is hope for this gun. And potential to be more powerful than a longshot!

Edited by smeagolsaur, 17 January 2008 - 01:21 PM.

[PC III]

In summation, there is hope for this gun. And potential to be more powerful than a longshot!

A great nf can beat a crummy xbow...

[ShadowTank]

What is the wire size of the AR-15 Spring you are using for this Mod? I'm moding a Recon slightly different and I purchased a spring: #9637K26 from McMaster part, from another thread (Spring Criteria?) and this spring seems very stiff to do the job. I'm wondering if I should buy an AR-15 Spring instead of what I bought.

OR should I try finding a "lighter" spring. With the modification I am doing, I am increasing the distance the "breech block" (or what I am calling the breach block, the orange internal piece that slides back and forth) slides back, thereby increasing the amount of air in the chamber (which I am also replacing) so instead of the original 3.25" it slides back, it will slide back a total of about 5.5". So the spring needs to expand to push it forward that distance. I'm debating if the Spring I have now, or even an AR-15 Spring will be too difficult to compress that much and if I should try finding a smaller dia. wire size spring.

Does anyone know of a spring that would be say 6 or 7" when fully expanded to push a distance of 5.5" after being in its' compressed position?

Thanks very much!

ShadowTank.