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Marshmallow Mforcer

Fifteen shot, rear loading, semi auto pistol

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#1 nerkum

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Posted 27 May 2010 - 09:39 AM

A while back I seen these Marshmallow guns posted by Mr. BadWrench and decided to pick up a couple. It took me forever to get around to modding them, but finally… here are my results.

Start with this:

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Open it up to see the internals.

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First thing to do is glue this little hose down. It is weak and expands, so I super glued it down and coated it in plumber’s goop. Note: plumber’s goop does not stick to the hose plastic, so in the future I will be replacing this hose.

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Next I took the front piece off and boiled it in hot water until the glue gave way, this allowed me to not have to cut the pump handle. Do not cut the pump handle as it goes all the way into the pump housing only leaving the little piece that is glued sticking out.

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For my pump handle I used a piece of 3/4 PETG pipe and epoxy puttied it to the stock pump handle to extend it, then I added a foam rod butt cap (fishing rod building material) to the end to make it comfortable to pump.

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For the barrels I cut off 2 inch sections of OMC PETG and then used a 5/8” brass tube as the attaching sleeve. The original barrels have a nice funnel pinch point on them that holds the darts great and gives it a popping noise when shot.

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The turret uses magnets to align the rotation, but when pulling the trigger quickly these have a tendency to skip or not align up correctly. So I took some Foam sticker sheets and cut out two small pieces to create a friction point to slow down the barrel. This has cause that issue to disappear.

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Next, put it all back together and go crazy with your 15 shot semi auto rear-loading pistol.

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Ranges: 25-35 feet with 3/0 mod darts. I am sure I would get better range with single bb darts, but I don’t have any to test at the moment.

VIDEO
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#2 Ambience 327

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Posted 27 May 2010 - 10:19 AM

Man I need to get one of these things. They would so totally own anything else indoors! (~30 pumps for 15 semi-auto shots @ 25-35 feet is nearly the equal of an RF20 - in a much smaller and lighter package!)

Great mod & nice write-up.
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#3 nerkum

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Posted 27 May 2010 - 12:37 PM

Ambience 327: I think I can get a bit better range out of it with a few tweaks (lighter darts, stronger hose). Since this gun is so compact it is real easy to wield two of these.

Just Some Bob: That hose acts as an over pressure guage for the gun, since when it expands it pops off. So stock you can get about 20 pumps before it tries to pop off. I have gotten mine up to 35 pumps so far with no issue. I think with a solid pressure hose I can get up to 40-45 with no worries.
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#4 wardrive

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Posted 27 May 2010 - 01:52 PM

I think the piston would be the area you'd want to look into for your next mod, especially if your aiming to improve range.
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#5 Zack the Mack

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Posted 27 May 2010 - 02:20 PM

Nice mod! These things look really promising - semi-auto and awesome aesthetics. I'm really digging the fishing-pole pump handle.

Just curious, how many pumps does it take to fill this thing?
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#6 nerkum

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Posted 27 May 2010 - 03:05 PM

wardrive: I think if I can get that hose replaced I can put more pressure into the gun. That will help my ranges for sure.

Zack the Mack: Right now I pump it around 30 times. I could easily do more, but that hose will pop if I go too high.

Video of how the Mforcer works

Edited by nerkum, 27 May 2010 - 04:55 PM.

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#7 Buffdaddy

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Posted 27 May 2010 - 05:03 PM

It makes me happy that someone else is actually working on one of these things.

Mine is almost complete, except for one problem: somehow, the air meter is messed up. It leaks air EXCEPT when you pull the trigger. Then it stops. Not good, although I guess I could hold the trigger down and meter it myself. But that's a royal pain.

Any ideas on that one?
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#8 oh1134

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Posted 27 May 2010 - 05:19 PM

Someone should try replacing the semi auto valve with a regular one, then it might achieve titan ranges.
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#9 Aquinas

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Posted 27 May 2010 - 08:36 PM

Thank you! The Marshmallow Mforcer had by far been one of my most disappointing foam-flinging related purchases ever. This modification fulfills my original intent for this thinger: a high ROF, indoor / HvZ type blaster.

The black piece and the attached pump mechanism is definitely the weak link on this blaster. I guess it never occurred to me that I can simply get rid of it. Props for your creativity and execution.
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#10 nerkum

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Posted 01 June 2010 - 01:24 PM

Fixed the expandig hose with a hose from the SMDTG, the hose needs to hold pressure and still be flexable.

Ranges: 30-43' average 36'

Here is a video for your enjoyment:

Range Test
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#11 nerkum

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Posted 01 June 2010 - 02:43 PM

The slug darts have a real snug fit in the barrels, hence the popping up out of the barrel. I'm thinking of slightly extending the barrels and maybe trying brass to get that perfect fit. Thanks for the ideas. It is easy enough to swap the barrels out.
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#12 NerfNoob10

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Posted 31 May 2011 - 06:05 PM

Hi, I'm new to Nerf Haven so I hope this isn't considered necroing a dead post, but I just wanted some help on my mforser, and I thought I would start here rather than start a new post. So I did your exact mods, but with 4 inch petg barrels, and I extended the pump handle with PVC, and my mforser is barely shooting 10 feet. I thought I may be due to the barrel fit being too tight so I sanded them out to be a bit loser fit, but I am having trouble getting the blaster back together. My first issue is the screws holding the piston in place are behind the piston and very difficult to get to, is there an easier way to do this, or do I just have to be patient? My second issue is with the 4 inch barrels on the turret i cant fit my hand down to the center of the turret to screw on the red cap that holds the turret snug to the body, as well as holds the pump in. Without this i don't think the turret will work properly. Am I wrong?, can I leave this off/very lose, or is there a way to get this on that I'm not thinking of. Also as one more comment you said you glued and plumber's gooped the hose on(b4 you replaced it), well it is so close to the air tank I can't find a way to get the glue all the way around. How did you accomplish this? Thank you in advance for the help.
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#13 NerfNoob10

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Posted 01 June 2011 - 11:03 PM

Ahh so basically just be patient and it will be a bitch. I finally got the screws in, but something is wrong and the piston isn't lined up with the barrels, so I'm going to have to retry I guess. At least I don't have to worry about the hose. So do you have any advice for my second one. I was going to try cpvc barrels since I'm out of both PETG and 5/8 Brass? Thanks for the help.
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#14 nerkum

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Posted 03 June 2011 - 12:25 AM

To reattach the screw on turret cap I actually left a couple of barrels unattached, then screwed it on snug and reattached the barrels.

I never had to take those screws out, basically only the cover, front piece, and hose was modified. No need to play with the piston.

You do not need to worry about the hose unless you want to do more then 25ish pumps. Otherwise you will need to replace it.
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