24 replies to this topic

[GundamX67]

Hey folks,

I have a slight issue with my Stampede. I recently modded it by removing the air restrictor, increased the spring's strength in the tank, and replaced the O-ring for the plunger. As of right now, when I dry-fire it, it's fine, but when I put in one dart to test the firing, it doesn't complete.

I'll upload videos of what happens soon, but does anyone have any ideas as of right now?

*Edit: Video of problem uploaded:

Edited by GundamX67, 17 August 2011 - 05:37 PM.

[Wickbuddy]

ummm... change the batteries.

[ChaosPropel]

I'm not too familiar with Stampedes, but it seems that your plunger tube is moving very slowly when there is a dart in the breech .....could it be that your o-ring replacement created TOO tight of a seal?

[Zorns Lemma]

I would be extremely amused if your batteries had enough juice to advance the mechanism against the plunger return spring, the dart tooth, and the main plunger spring, but not enough to advance the mechanism against the above plus the friction of the dart in the plunger tube (and compressing against the dart tooth).

Try the following:

1) Replace the batteries
2) Check the bolt for any obstructions that prevent the dart from securing itself (unlikely issue since your darts don't seem torn or compressed)
3) Check for impediments in the dart tooth that would only come up if there was a dart in the way.

[GundamX67]

The batteries are all fresh from a new pack, so it's doubtful it's that. I'll check the O-ring again. Could be that, since when I put it in it was a tad tight.

[Aeromech]

Even with brand new batteries, the six D batteries in the stock electrical setup only yield 9 volts of potential to your motor. If you have replaced the stock spring with a stronger one, it may be a good idea to perform a voltage mod. Nothing too crazy, as it seems to be just short of functioning.

Also, re-greasing the O-ring couldn’t hurt. = )

[spencerak]

Have you tried different clips? It looks like the dart may be popping out of the breech line causing it to jam. Maybe. . .

[SgNerf]

From the looks of the speed of your bolt movement, the normal alkaline batteries you are using (i assume) are already at the limits of their voltage and current output.

So although it seems to be able to move while dry firing, when its under just abit more load (when chambering a foam dart), the motor stalls.

Use higher voltage and higher discharge rate batteries... note that if you are using a stronger aftermarket main spring you'll need to focus on using batteries with higher current discharge rates (not just voltage, they are different factors), so that the motor can get enough current feed to create the torque necessary to pull the stronger main spring.

[KaneTheMediocre]

From the looks of the speed of your bolt movement, the normal alkaline batteries you are using (i assume) are already at the limits of their voltage and current output.

So although it seems to be able to move while dry firing, when its under just abit more load (when chambering a foam dart), the motor stalls.

Use higher voltage and higher discharge rate batteries... note that if you are using a stronger aftermarket main spring you'll need to focus on using batteries with higher current discharge rates (not just voltage, they are different factors), so that the motor can get enough current feed to create the torque necessary to pull the stronger main spring.

If you want to know whether you need higher current discharge batteries, or just more cells for higher voltage, a multimeter (good-enough for this job should be $10 or less) should be used to check the voltage of the batteries with and without firing. If there's a big voltage drop while firing (ie, 9.3V to 6.7V), then your batteries cannot discharge fast enough, and you need more of them in parallel or larger cells. Otherwise, adding another D-cell or two in series should increase the voltage enough to fire.

[chavez guy]

I don't know if this is relevant, but I had a dream about this thread. And in my dream I found the solution. But in my dream stampedes were reverse plunger or some shit. But even still, in my dream you had to big of an O ring. If that isn't the problem, there isn't really much else I can say, haha.

Edited by chavez_guy, 18 August 2011 - 12:31 PM.

[Curly]

In addition to putting the stock O-ring on, upgrading the batteries, and other stuff, I would upgrade the dart tooth spring. I've heard that in some cases with modded stampedes the dart tooth's spring can cause jams. This might not be the case, but once you up the voltage that may happen as well.

[HasreadCoC]

Ok, Darth Vilna on NRev asked me to tell you that the back of your plunger tube might be on upside down, he said it happened to him and that it's an easy fix.

[GundamX67]

Thanks for the help, everyone. I'm taking a few options: 1) Buy some better batteries as per NgNerf's suggestion and 2) Checking if the plunger's in wrong (as this is a simple check) and 3) re-lubing the plunger itself.

I'll post more updates if any of this fixes it.

[jiauniverse96]

I am having this problem currently. I completed the same actions as you ar removal etc. I was wondering did you ever fix this problem? If so, by what solution?

[magnum]

maybe its just a bad dart. I know some times mine jammed with mushy darts

[Dragon]

I am also having a similar problem but no matter if it's dry firing or if there is a dart it stops moving just short fully moving forward. Any help would be greatly appreciated.

[hamoidar]

ignore

Edited by hamoidar, 16 March 2012 - 05:35 PM.

[hamoidar]

I am also having a similar problem but no matter if it's dry firing or if there is a dart it stops moving just short fully moving forward. Any help would be greatly appreciated.

Since it seems this thread is alive again, here goes. Have you done any mods to it? If so, what are they? If you can give me a little more information, I can most definitly help, having modded five stampedes.

[Dragon]

I removed the ARs, increased the seal, and added a crossfire spring. I'm going to increase the voltage as soon as I go to RadioShack. I also am going to minimize it in the front. Also on a similar topic do you think it would be possible to do a half brass mod to a stampede?

[hamoidar]

I removed the ARs, increased the seal, and added a crossfire spring. I'm going to increase the voltage as soon as I go to RadioShack. I also am going to minimize it in the front. Also on a similar topic do you think it would be possible to do a half brass mod to a stampede?

Your problem is most likely the voltage, as the stock batteries are not capable of compressing a stronger-than-stock spring. As for brassing the stampede; here is a step-by-step guide for a brass mod.http://nerfhaven.com...1&#entry310074' class='bbc_url' title='External link' rel='nofollow external'>Stampede brass mod If you only want to brass the dart tube, simply leave the barrel stock, and only complete the bolt/dart-tube brass conversion. Good luck!

[ThatBritishGuy]

Your seal may be too good to allow the plunger to move forward while there is a dart in the chamber as the dart is stopping off the end of the bolt as it is trapped by the dart tooth.

Low voltage batteries may exacerbate this as they dont provide enough torque to allow the motor to move the plunger against the increased resistance caused by compressing the air behind the dart.

[hamoidar]

Low voltage batteries may exacerbate this as they dont provide enough torque to allow the motor to move the plunger against the increased resistance caused by compressing the air behind the dart.

Don't quote me on this... wait...uh...nevermind. Anyway, I do belive the dart would not have any pressure behind it. One, the dart tube does not hold the dart tight enough to make a seal until the very end of it. Second, I think this gun also has a pin hole on the side of the dart tube, just like almost every newer nerf gun, which would release pressure as well.

Edited by hamoidar, 17 March 2012 - 09:03 AM.

[ThatBritishGuy]

Don't quote me on this... wait...uh...nevermind. Anyway, I do belive the dart would not have any pressure behind it. One, the dart tube does not hold the dart tight enough to make a seal until the very end of it. Second, I think this gun also has a pin hole on the side of the dart tube, just like almost every newer nerf gun, which would release pressure as well.

He said he had modded it do by that I'm guessing he plugged the air release hole. And the stampede has a rather firm grip on the dart in the bolt compared to most blasters, it was comparable to 17/32 brass in my stampede so the buildup of pressure is quite possible.

[hamoidar]

He said he had modded it do by that I'm guessing he plugged the air release hole. And the stampede has a rather firm grip on the dart in the bolt compared to most blasters, it was comparable to 17/32 brass in my stampede so the buildup of pressure is quite possible.

Even if pressure was building up, it would be negligble compared to the stronger spring. His problem is the voltage, with the combination of the tighter seal, stronger spring, and prehaps pressure behind the dart. The stock voltage is just too weak to operate the modded gun.

[ThatBritishGuy]

Touché

If you choose to replace the batteries with higher voltage rechargables, make sure they are UNPROTECTED as protected batteries wont move the bolt at all.