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Reverse Plunger Dead Space Killing Method


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#26 Jagiro

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Posted 17 February 2010 - 11:55 PM

Wouldn't it be easier to just cut off the end of a funnel and glue it on?
(and hot glue the rest of the dead space)

Edited by Jagiro, 18 February 2010 - 12:00 AM.

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#27 nihil413

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Posted 18 February 2010 - 12:37 AM

The idea behind this was to create an easy (it literally takes 15 seconds to hand drill through a piece of fbr), cheap (less than a dime for items used) and removable setup if it failed so I didn't want to use hot glue or anything that could be difficult to revert back to stock form. Because yes, I kind of expected it to fail but with the testing I have done it's only seemed positive for me.

This was also basically meant for stock barrels only. As usually, due to the loose dart fit, the dart is already out of the barrel before the full back pressure can get to it, resulting in just wasted air volume as opposed to an upgraded barrel setup where the blaster actually builds up the full pressure before the dart is pushed out of the barrel. This should give a stronger initial burst which, I would think, would give the dart a better range than a standard setup where most of the pressure is wasted anyways.

I decided to also test this in a raider (since I have two raiders I use as guest blasters with identical mods done to them (Basic AR removal, spacer to fully compress spring and increased plunger seals) I decided to put this in the one that tends to be the weaker of the two and tested them side by side in my house (distance wall to wall is limited to only 25 feet but unfortunately it's winter here with really bad winds so attempting to go outside would be useless). The raider that I did this too is now outfiring the one that seemed stronger before by a noticeable difference in the velocity the dart travelled at and the relative straightness of it's trajectory (using stefans, not streamlines) So I will have to wait until the weather breaks so I can actually test ranges outside to confirm for myself and I will use the same gun for both tests since this can be removed cleanly. And if, when I test it outside, it fails miserably I'll let you know.
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#28 TantumBull

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Posted 18 February 2010 - 04:04 AM

But Is the other raider bored out completely? Of course the deadspace removed one will perform better if flow is identical between the two.
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#29 Vinnie D

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Posted 18 February 2010 - 04:23 AM

I did something similar a while back though I used the shaft of a pen and hot glue instead. The results are about the same either way. More pressure with reduction of dead space but with reduced airflow due to higher resistance. It doesn't seem to change performance with the stock spring. If you powerstock it though you should see an improvement in performance.

This mod sounds easier though, and I'll probably use it next time I'm working on a reverse plunger.
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#30 nihil413

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Posted 18 February 2010 - 07:09 PM

But Is the other raider bored out completely?

I decided to also test this in a raider (since I have two raiders I use as guest blasters with identical mods done to them (Basic AR removal, spacer to fully compress spring and increased plunger seals) I decided to put this in the one that tends to be the weaker of the two and tested them side by side

I'm not sure if I'm understanding your question... I used two raiders with the exact same modifications done on each except one I put this filler in to see if it would make a difference. Which it did seem to help in both velocity and trajectory.

Of course the deadspace removed one will perform better if flow is identical between the two.

That's the point of this mod. I'm not sure if I'm misunderstanding something in your post?

Edited by nihil413, 18 February 2010 - 07:13 PM.

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#31 moosa

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Posted 20 February 2010 - 09:02 AM

That's not all.

The more flexible the material used for dead space reduction is, the more certain it is to absorb energy by flexing. Filling dead space with flexible foam is almost a complete waste of effort.


I don't follow you here. We're talking about air pressure, not direct kinetic energy. The foam may serve to absorb some vibration from the plunger action, but it's not going to absorb the pressure of the air, which is what is propelling the dart. The only way the flexible foam could reduce air pressure would be if it was allowed to be compressed under the pressure, widening the airway, which the plastic straw the air is passing through prevents from happening.

(To everyone:) If he says that this mod alone has improved the performance of his blaster, why argue that it doesn't work? He's said that he will do more actual tests on the range difference when he's able to. There's no reason to assume that he's lying or that he's incorrect in the actual observations he's reporting to us.

Edited by moosa, 20 February 2010 - 09:08 AM.

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Yes.

#32 TantumBull

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Posted 20 February 2010 - 05:46 PM

Nihil: We are at somewhat of a misunderstanding. I'm arguing tha a completely bored out recon/raider will perform better than a deadspace removed one limited to ~1/4" size hole of flow. You're arguing that a deadspaced removed recon performs better than one that has more deadspace, but is still limited to the same size hole, and thus flow. Both of our arguments are correct.

Edited by TantumBull, 20 February 2010 - 11:31 PM.

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#33 nihil413

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Posted 21 February 2010 - 01:47 PM

Nihil: We are at somewhat of a misunderstanding. I'm arguing tha a completely bored out recon/raider will perform better than a deadspace removed one limited to ~1/4" size hole of flow. You're arguing that a deadspaced removed recon performs better than one that has more deadspace, but is still limited to the same size hole, and thus flow. Both of our arguments are correct.

Ok, I now see what you are saying with the message. Yeah, these guns were all limited to 1/4" air holes because they were to be used more for indoors and just being loaner guns in very friendly games that don't need excess power.

Which your comment is making me think about looking into another setup to test with this using 1/2 inch aluminum tubing (13/32" ID) I accidentally ordered a couple months ago and had no use for... and another reverse plunger gun I have (I somehow have a lot of RP setup guns lately, thanks to Nerf) that has a 3/8" airflow hole and seeing if that's a help or hinderance to it as well. So when the weather does clear up I will test these.

@Moosa: Thanks.
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#34 foodstuffs

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Posted 13 March 2010 - 12:59 PM

could you use streamline darts instead of foam?
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#35 b00m13

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Posted 20 March 2010 - 01:23 PM

Hi guys, first, sorry for bumping an old thread but I had to.

I want to recommend to you guys to NOT preform this mod.
I'm sorry nihil413, I'm sure you were just trying to be of help, but TantumBull's right about this mod, and it just wont work. I can say for sure because I've tried this same mod with the Recons when they were first released, and I've tried it again this morning on my new Long Strike, based on your instructions exactly.

It's disappointing, I know, but like they say "less is more", "keep it simple", etc.

If you really want to get an enhanced performance out of your LS, then just follow Slug's Recon AR Removal Mod. It works just as well as it did for the Recon, I know because I tried it and got an instant 15+ feet from the streamline dart.

For those of you that don't have access to a wood-boring drill bit, then you could go "old-school" and use a simple tube cutter and cut the area where the AR+spring's located (shine it to the light to see through the plastic if you need). After you remove the AR+peg, make sure you seal up any leaks on the tube when you glue it back together (don't leave ANY LEAKS). Best way is to probably use those thick straws and wrap some E-tape around it until the straw is thick enough to tightly fit inside the 2 tubes (as a connector), and then glue the tubes with some Krazy glue. If you want to know where I made the cut, look at this pic.
Posted Image
You can use the dart clip as reference.

To nihil413, I'd like to suggest that perhaps you could change your thread; from killing dead-space to just an AR removal thread. Again, thanks for even trying to post a thread for the Long Strike, besides for yours, I couldn't even find another on the mod-directory.
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#36 TantumBull

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Posted 20 March 2010 - 10:29 PM

Gluing in a straw as a sort of internal coupler would then actually make reducing the deadspace worth doing, as the straw is now the "weakest link" so to speak as far as airflow goes. So yeah, if you cut the bolt open, use something like 17/32 brass whch fits in almost perfectly and is much wider than a straw.
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#37 b00m13

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Posted 20 March 2010 - 11:04 PM

Gluing in a straw as a sort of internal coupler would then actually make reducing the deadspace worth doing, as the straw is now the "weakest link" so to speak as far as airflow goes. So yeah, if you cut the bolt open, use something like 17/32 brass whch fits in almost perfectly and is much wider than a straw.


Actually I didn't say glue in a straw, I said the thick straws, like the ones you get from those bubble tea drinks which are about 17/32" (if it's a bit loose, then as I mentioned before, just use wrap some E-tape around it until it has a tight fit inside the tubing).
Posted Image

The length of the straw would be about 3/8" if you want to fill in as much of the space as possible.
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#38 TantumBull

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Posted 21 March 2010 - 01:07 AM

My apologies. I thought you just meant a normal diameter straw with thicker walls.
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#39 billyblue888

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Posted 21 March 2010 - 02:47 PM

This mod does work if you use a looser barrel material. For example if you did this mod there would be higher pressure but all of the air would take longer to release. So you would have to use a looser barrel material like PETG. Like it was a air gun.
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#40 Zorns Lemma

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Posted 22 March 2010 - 12:34 AM

I am in the process of testing my hypothesis that increasing spring force (force is required here, now just overall energy), increasing the initial static friction on the dart, and decreasing volume before the dart when the plunger is at stop will lead to better results.

However, I only have two available raiders for my own use, and they're both getting brass breeches and then I'm adding the "straw mod" and crowned 1/2" brass to one and comparing the two. It would be nice if someone else could test other variants so we can figure out which combination of factors will produce the optimal results.

Of course, the simplest way is just to replace the plunger setup, but that has very low ease of reproduction.
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#41 dmactheballer

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Posted 04 May 2010 - 05:47 PM

See, I never agreed with the whole "smaller air hole = no range change."

When I went to mod my friend's Recon, I hammered out the whole damn AR, peg ring and all.

So in simpler terms, my Recon had a probably 1/4 inch air hole and his had a 1/2 - 3/4 inch air hole.

His went 9 feet, mine went 47.


The thing is, the exact size of the hole doesn't make a huge difference as long as air is not escaping around the sides of the dart. Ideally, you want the hole to be the exact same size as the hole in the dart, but this is not always possible so smaller is generally better. If the hole is too small though, it will slow down the plunger.
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#42 KyleTehDevil

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Posted 05 December 2010 - 11:01 AM

can someone pls tell me what exactly is dead space and why is it so bad? Why do you need to remove it? and also, sometimes, other people just fill it up with hot glue.
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