11 replies to this topic

[MavericK96]

This is pretty easy to do, but I'll post a write-up just because I haven't seen anyone post it yet.

Tools needed:

-Small Philips screwdriver
-Power drill or drill press
-3/8" and/or 1/2" drill bit
-Time
-Patience

Here's a picture of the unsuspecting Stampede, along with the tools I used:




First off, we need to get the beast open. Remove the battery compartment first if you haven't already. Next, remove all the screws you see, which is a tedious and time-consuming process but necessary nonetheless.

After you get it open, be aware that there is a wire connecting the two halves together for the on/off "safety" switch. I simply rotated the half around to gain access to the plunger/bolt sled without having all the screws fall out and without damaging the wire:




After getting it open, you need to remove the large orange piece covering the plunger assembly. There are about 4-5 screws to remove and then this should pop off, leaving you with this:




Next, you want to remove the pieces circled in red here:




After those are gone, you should be able to slide the entire plunger/bolt sled assembly out easily.




There are two screws holding an end-cap on the rear of the plunger (sorry, no picture). Remove this to remove the spring and plunger from the plunger tube.

You will then see something like this when looking down the plunger tube from the rear:




...and the front:




Basically, this is no different from any other air restrictor that Nerf makes. All I did was take a 3/8" drill bit and drilled through the back, exposing the rear of the air restrictor:




Then, simply use a screwdriver or pliers or whatever you want to break out the dart post from the front of the bolt sled. This is crucial because the rest of the air restrictor will not come out otherwise. I tried drilling through the entire thing, but due to the structure of the air restrictor, the drill bit will get caught on it and it will simply spin around rather than drilling through it.

I then used a 1/2" drill bit through the back of the plunger tube again to clear out more of the air restrictor assembly, and eventually everything fell out and I was left with this:

Front:




Rear:




(And yes, I cleaned out the plastic particles on the inside before I re-assembled it)

And there you have it. Simple, clean, easy to do. The stock plunger O-ring does not make a great seal, but I didn't have anything to replace it with so I didn't bother with it. Replacing it might net you a bit more range, but it's hard to say how much.

With the air restrictor removal alone, I'd guesstimate that the blaster shoots about 5-10 feet further. It is also a bit more loud, but it's loud in the first place so it's not much of a difference, really.

Questions, comments, concerns? Post them below. Thanks for reading.

[meatballica]

From the looks of it, it looks similar to how a longshot is. By that I mean it has a real plunger rod/tube setup unlike a reverse plunger tube. Am I correct?

[MavericK96]

Correct. It is very similar to the Longshot. I believe SGNerf did some comparison side-by-sides with the Longshot plunger and they were practically identical.

It seems to me the way the mechanism works is by pulling the entire bolt sled/plunger tube forward over the dart, while holding the plunger rod back and compressing the spring. Then, when the maximum pull is reached, the plunger is released and forces the dart out of the chamber and the entire bolt sled assembly slides backwards again to load another dart. It's pretty ingenious in its simplicity and efficiency, really.

[Mills]

How strong is the spring compared to other stock nerf guns? Ranges?

[MavericK96]

I don't have any way of getting accurate ranges right now (no tape measure long enough), but with some quick testing I would say it's about on par with an AR-removed Alpha Trooper in terms of range. I tested it against an AR-removed, spring stretched Longshot and the Longshot is definitely more powerful.

Still, it has some pretty good potential. It may be possible to stretch the spring or put in a more powerful one, but the strain on the gears/motor might be considerably increased and could cause the blaster to fail.

The big draw of this blaster is that it is a clip-system, fully-automatic, compact (compared to the Vulcan, anyway) assault weapon.

The ultimate mod for this blaster would be the following:

1. AR removal/O-ring replacement/spring replacement (maybe)
2. Battery mod (rechargeable battery pack, possible greater voltage)
3. Brass breech
4. Machined steel/aluminum gears, maybe even high-quality plexi versus the nylon plastic ones that are stock
5. Motor replacement (if possible)

Everything except the gear replacements is probably doable with not a ton of effort or money.

Edited by MavericK96, 02 September 2010 - 07:02 PM.

[AbstractSociety]

Thanks for posting this much appreciated!

[MavericK96]

Not sure what you're thinking of, but there's no way plexiglass replacement gears could be even half as good as nylon.

Honestly I don't know much about plexi vs. nylon, but it seemed like plexi might be stronger, or rather some sort of acrylic sheet? I have no idea, just brainstorming. Metal would of course be the best, but most people don't have the facilities to cut metal that precisely.

[durka durka]

This is the first mod to uncover the stampede's potential.

Here SgNerf demonstrates how AA rechargable batteries can be used in the stock tray and still provide a rof increase. I this particular method a lot. it gives you all the advantages of a rechargeable battery pack without having to alter the stampede itself.

For most people, I think finding commercially available gears would be easier than manufacturing their own. This way, these improvements can be widespread, rather than just for those who have the right machining tools.

Edit: Maverick, it would be a very wise move to replace the motor if you plan to up the voltage. Chances are the motor won't be able to handle substantial increases in voltage for very long.

Edited by durka durka, 03 September 2010 - 12:42 PM.

[MavericK96]

Right now I'm just trying to figure out the best rechargeable solution. Honestly the ROF with the stock 9V or so seems decent enough to me, and I think I will wait and see what SGNerf reveals with further testing (that 22V ROF is killer ) I've been looking into rechargeable battery packs for Airsoft/RC, and also high-capacity, rechargeable D-cell batteries, but the cost of those is fairly high (~$7 per battery) and the weight would still be pretty significant (the gun seems rear-heavy with standard D-cells).

[MavericK96]

So, after some more experience with the Stampede, I have to say the accuracy leaves something to be desired. Using normal Streamlines, they can spin wildly off-center. Using my own shorter Stefans, it seems a lot more accurate and performs better as well. Sometimes with Streamlines I would get a few that would barely shoot 15 feet, and some that would shoot 30+. Not sure what the huge variance is, but it's a bit annoying. The ROF is second to none, though, for not having to prime anything at all.

[IronicTrout]

I know what you mean. It has horrible consistency with accuracy. If you can figure out an Angel Breach type system then please post it up. I'm too scared to try anything out on mine. It's too sweet.

[maseman 46]

Edit: Maverick, it would be a very wise move to replace the motor if you plan to up the voltage. Chances are the motor won't be able to handle substantial increases in voltage for very long.

You would be real surprised what those little motors can handle as far as voltage. However, if you want more power (bigger spring) you would need to replace the motor. Finding a stronger motor this size would be very easy. These are very common little motors. If your a DIY kind of person, you could always put stronger magnets in it, that would have nearly the same effect