Just finished my Marauder Bullpup!

All I can say is it’s been really fun doing this project. I’ve had a whole lota snags but I eventually overcame everything and created what I believe to be a really fine rifle. Bullpup conversions for air rifles really aren’t as easy as one might think, and oftentimes the solution for one problem leads you directly into another. On top of that I had to deal with the typical “Marauder problems”. If you want to stick with me then grab a drink and a bowl of popcorn because I’ll be explaining my journey in this single post.

Chapter I: Curing it’s “Marauderness”
I purchased my .22 Marauder about 6 months back from Pyramyd. When I received it I was a bit disappointed. My discovery was easily outshooting it and it couldn’t hold groupings of less than 2 inches. It seemed like I checked everything, it was not clipping, I went through nearly every pellet, and I even polished the crown with a brass screw – nothing would help. So I called up Crosman and they agreed to send me another .22 barrel. A few weeks later I got that barrel and it really started shooting well. One hole groups at 25 yards and <1” at 50. It was everything I could ask for. Because I had that old barrel that wouldn’t shoot for crap I decided to experiment on it…
I decided that I would cut it down in 1/4” increments then crown it and see how it did. I did this about 5 times in total and I ended up finding something that amazed me. After I cut to the point where I took off the choke the accuracy seemed to improve tenfold. Basically, I cut off the choke and it became accurate! I have since done this with a .177 Marauder barrel that wouldn’t shoot and it showed the same thing. I predict that there is something wrong with Crosman’s chokes in their barrels…
Anyway, I ended up cutting this barrel down to about 15” polished the inlead, upgraded the o-ring, plus all the other typical stuff and it currently sits this way – shooting one hole groups at 25 yards. This will lead us into chapter II.

**EDIT** I almost forgot. I wanted to ad in that I think I found another problem with the Marauder’s design that inhibits it’s accuracy. The shroud is propped up against the breech. The problem with this is that neither the breech or the end of the shroud are perfectly flat. When screwed down against each other it causes the shroud to kink forcing it to “bend” in one direction. Because the barrel is touching the shroud via the air stripper it makes the barrel bend slightly aswell. My solution is to move forward the piece where the shroud screws in the breech side. Basically make it so the shroud doesn’t tough the breech, this will make the barrel and shroud truly free floating.

Chapter II: Marauder Carbine.
From the second I opened the box I knew that it would be so much better if the shroud ended at the same place as the end of the airtube. Long before I decided to take on the challenge of turning it into a Bullpup I decided that I should make it a carbine. There are two problems. First off, I wanted to keep the gun very quiet – if I cut down the shroud but kept the stock length barrel in then I would have no room for baffles and the rifle would be loud. So, I took my cut down barrel from earlier and used this for the carbine configuration. I ordered a new shroud tube from Crosman and cut it down so that it would end at the same place as the airtube. The combination of the shorter barrel and shorter shroud still allowed for 4 baffles to be used, thus keeping it a quiet rifle – the only drawback was I lost about 50-60 fps in velocity. At this point I had one long barrel, one short barrel, one long shroud, and one short shroud. I had many combinations that I could do, I even named a few:
Mouse Fart: Short barrel, Long shroud, 8 baffles
Carbine: Short barrel, short shroud, 4 baffles
Get the earmuffs: Long barrel, short shroud, no baffles OR no shroud.
Stock: Long barrel, long shroud, 4 baffles.

I loved the carbine for what it was. I refinished the Marauder stock and skeletonized it a bit in the back. It kept in line with the traditional rifle platform but made it more compact. It is useful for when you’re lugging it around hunting and don’t want to snag the end of the shroud on anything. However, around this time I became aware of the Edgun Matador. I lusted over it – I really wanted a bullpup air rifle but couldn’t afford the $1,995 that people were charging. So I decided to take it into my won hands and turn my Marauder into a bullpup.

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Chapter III: Bullpup.
I knew that building this thing would take time, but I was willing to put in anything necessary to perfect my beloved ‘Raudy as I would call him. I did some research online and read some threads about how people converted their own rifles into bullpups. I ended up writing down about five pages of notes and ideas that I had that might make things a bit easier. I started emailing a really cool guy named Tom and he really helped me bring everything together. Anyways, lets get into the Bullpup building process…

So it seems like there are three main problems in building a bullup.

1. Moving the scope mount forward to allow for the head to rest on the breech.

In my first setup I drilled out a UTG weaver “riser mount” that was “see through” so that it slid over the barrel. It basically gave me an extended “breech” which has a weaver mount on it. The problem with this is that it doesn’t go over the shroud – therefore I have to push the shroud forward. If the mount were able to fit over the shroud then it would allow for more volume in the shroud thus making it quieter. The second problem with this is that it doesn’t push the scope mounting platform forward enough. With this I was resting my cheek on the back end of the bolt rather than in the middle of the breech where it’s ideal. I thought another idea but never put it into practice. Get about 2-3 airforce tri-rails. Use these to extend the stock dovetail mount on the Marauder forward by clamping each one forward of the other. The best way I can think of describing it is like a set of stairs… In the meantime I was communicating with Tom about him perhaps machining me a set of true Maruader Bullpup scope mounts that would attach around the shroud and airtube. Eventually I opted for this option for one reason and one reason only. I figured that if I was going to build a bullpup Marauder then I ought to do it right and professionally. So I put in the money to but these mounts. I do have to say though, that drilled out weaver riser was damn good and it only cost $10. If you want to make a bullpup yourself I strongly suggest you do that first.

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2. Pushing the trigger assembly forward.

As I see it there are two ways. One being mechanical with a rod to connect the two assemblies, and the second being electrical with a solenoid to push the back assembly. I chose electrical for two reasons. First, it would be easier to contour the wires to the stock rather than have to contour the stock to fit the mechanical rod. Second, it’s impossible for an electrical trigger to creep as it’s a switch and not a sear. It doesn’t look as nice as a traditional trigger but you can always replace it with an AR type paintball trigger to get some better aesthetics. The solenoid also works flawlessly to trip the sear on the Marauder. To end this part I will say one thing, I HAVE NOT YET HAD A MISFIRE.

3. Getting a stock.
I do not have any fancy machines, literally all i’ve got is a jig saw and a drill. Tom gave me an ingenious idea and I followed it. I took three boards of wood each about half an inch thick. I cut out three identical “stock figures” two of them I used for the “outside faces of the stock” and the third was further cut down because it was going to be in the middle. I then sandwiched all three together with glue. Because the middle board was cut to dimension it basically made it “pre inletted”. I had to cut that dome out of the back at the trigger assembly because the solenoid was too fat to fit in the “sandwich”. I was amazed at how well it turned out. If you don’t have to tools to carve a stock then I strongly suggest you look into this method. It works well, it’s user friendly, and it’s really not too complicated! At the beginning of this project I knew that the stock was going to be the biggest challenge for me but this method really helped with bringing down the difficulty level!

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Chapter IV: Final Thoughts

The bullpup conversion took about a month and a half to complete. If you want to create your own bullpup rifle then I suggest you go for it. It’s really not too hard and it’s a really fun learning experience. Anyway, I chose to go all out on my new Bullpup ‘Raudy so I purchased a regulator for it. Installation was a breeze and as it stands now I get a conservative 40 shots at 785 fps with 14.3 CPH’s with an extreme spread of 10 fps. I also purchased an adapter that converts the shroud endcap threads to a 1/2 UNF. I got a nice little LDC and the great thing about it being 1/2 UNF is that I can take it off if I want to make the rifle compact again (hunting) or put it on if I want it to be dead silent (backyard target shooting).

Overall, I feel accomplished. It’s a nice light, compact, quiet, accurate rifle with an insane shot count for it’s reservoir capacity. It’s look really “tactical” and it’s just a really fun rifle to use. I know everyone wants bullpup kits for the Marauder but I’ll never be able to do something like that. Even if I wanted to, I don’t have the tooling or the consistability. But hopefully you guys can take my ideas and adapt them for your needs.

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In the end it’s been a fun trip with my Marauder but I’m going to be giving it up for adoption. ‘Raudy simply down’t have anything else that I can do with him – and the main reason I’m in this sport is for the fun of modding our rifles, shooting them comes second to me. I purchased a Royale 200 and plan on making the first ever Royale 200 Bullpup. Wish me luck! 😀