Marauder G3, The Things I Do For Fun

[Pumacarl]

This was a long time coming for me and I started to think that it wasn't going to happen at all. Never been happier to be wrong. The third genereation of the Marauder is surprisingly here. I have been rather outspoken on many threads over the years about what this gun should be, to us as shooters, to Benjamin as a company, and the airgun community in general. Actually, a lot of us airgunners have. Has Benjamin listened? Well, that is not what this thread is about, but I will talk about that plenty along the way. This thread is just meant to be a long ramble on what I do to a gun, and why, and how things develop and actually turn out. I have already started down paths that I have abandoned and I didn't want to exclude why, so I thought that I had better start writing about it, or I'd forget, or I'd never want to start. I am not a writer, or a machinist, just a long time tinkerer who uses basic hand/power tools to accomplish things that they are not meant to do. Patience is key. I type slowly too. So this is going to take a while. I don't work for or represent anybody in the industry. If you enjoy following along, great, but honestly I catalog these exploits as a sort of cloud storage so that I don't have to keep re-explaining something to somebody, and for me to remember what I did. If it helps or inspires you, more so the better. On to the G3 mrod...


I had a rudimentary plan already in place when I heard this gun was coming. To drop significant weight, a carbon fiber bottle would be the first thing done without hesitation. This was not going to be a bench gun for me, and I didn't want the weight. Wanting at least twice the volume of my G2 mrod, I figured that a 360cc bottle plus the 80cc of plenum would cover that. I got the fattest, shortest, bottle that I could find because I knew it would look better on the gun, and keep the weight back. Long story short, the bottle didn't fit, until I came along. I'll explain later, here's some pictures:

Bottle comparison, check out the neck lengths and radius difference.


Using just the side edge radius of a WorkSharp belt sander to start the concaved radius needed.


Finished, after sanding and 100 checks for fit.


The fit just accepts a strip of paper w/o touching. The lines of this size bottle look really good.

 

[Chief55]

Nice job. It looks great. How much does it weigh now?

 

[Pumacarl]

Nice job. It looks great. How much does it weigh now?

I'll never know because things are still going to change. This bottle weighs 14.5oz less, and the cg for its weight is a couple of inches back so it feels like a bigger change than the numbers would indicate anyway. I have many things to do before this gun goes back together. I'm taking apart and going over everything. I've warned you, this ramble is going to be so long winded that you could sail around the world on it, lol.

 

[Billm]

I have to admit when I saw the first photo, I started to weep . Then by the last photo, I was darn, it really looks good. Nice job, keep going.

 

[Pumacarl]

So many people get turned off by the process of creation that they never proceed, hey, baby birds are ugly, and pruning looks like hell when you get done, but the results speak for themselves.

I said that I had abandoned some ideas already, one of those was to put on a full length Arca Swiss rail from just in front of the trigger guard to within an inch of the tip of the stock. Once I got done with this bottle several points finally hit home. This looks really good, better in person then in the pictures, almost like it's molded into the gun, and I don't want to screw that up. The other reason is big too, weight. The only really good rail to get for what I wanted to do was the 10.25" MDT, but it alone weighed 6oz. Add in the hardware and the JBWeld I was going to need to form it in, and how far out that weight would be, and I scrapped it. If I had wanted an Avenge-XL, I would have bought one.

Here is some more pics to show how fluid and melded in this bottle is to the look of the gun:




This is the way.

 

[BBGunn]

Reminds me of the look BSA has had with their PCP bottle guns for years.

 

[Pumacarl]

I'm still planning and working on putting a short Arca rail in front of the trigger guard. I like them too much not to use one. I'm trying to keep it low and as inconspicuous as possible, but it is what it is. It will be level and not match the angle there because I want to use my aluminum hamster that I made during the 250Z project. We'll see how that goes.

 

[Pumacarl]

Reminds me of the look BSA has had with their PCP bottle guns for years.

That was the inspiration! That is what I was begging for on the new Marauder, but they wanted to keep the price down. I'll tell you what, I like this gun, it's power, and it's internal design, w-a-y better than the R10/R12. I almost bought those guns on looks alone, until I watched sub12airgunners videos on how they were made internally, yeah, forget that. I care about what's inside and if I can't work on it myself then those guns are a no-go for me. The BSA barrel is top notch though, but I'm getting ahead of myself.

 

[rayroz]

Carl , killer job ! Custom work .
Quick question , i will be getting my carbon fiber bottle next week and i would like to remove the stock .
Do you have a link to remove it or can you spell it out to us watching your job .
Thanks and great job .
Ray

 

[wolfmangreg]

Looks great! Not good... Great!

What kind of projectile do you envision setting it up for?

 

[Pumacarl]

Looks great! Not good... Great!

What kind of projectile do you envision setting it up for?

Thanks Greg!

My favorite pellet, JSB 33.95gr MkII, of course! I might try a few slugs but I do need to keep the range down sometimes and these have worked for me everytime on woodchucks.

 

[wolfmangreg]

Out of the .25 game at the moment but have to agree- King Heavy MKII has always been an excellent pellet, & big medicine for chuck head shots.

 

[Pumacarl]

Carl , killer job ! Custom work .
Quick question , i will be getting my carbon fiber bottle next week and i would like to remove the stock .
Do you have a link to remove it or can you spell it out to us watching your job .
Thanks and great job .
Ray

I can explain the process but know upfront that it took me six hours to do this. I only had one shot at it so I was extremely careful. I purposely took a picture when it looked the ugliest because even I was worried about how it would turn out at that point. If you're going to try this go really slow. Also, I should point out, that all is not lost if you make a mistake. I was very prepared to use JB SteelStik to mold back in material and sand down to shape if I really messed up.

Start by twisting off the moderator and shroud, then take out the two screws that hold down the barrel. This gun uses Imperial sized allen wrenches, not metric. [ It pains me to have to mention the obvious but here it goes, air down your gun completely using the de-gas screw located just in front of the trigger guard under the stock. To me, anyone that needs to be told this should not be working on their own airgun. Yes, I said that, and stand by it. If anyone reading this needed to hear that, seriously reconsider working on your own airgun until you understand them, and HPA, better. Enough said about that.] It is easier to unscrew the factory bottle, at least for the first time, with the barrel off first. You'll need it off anyway as it gets in the way and you will be removing and replacing the gun from the stock many many times. Unscrew your factory bottle but leave the oring on the threads. You will be screwing the bottle on and off a lot at times and I keep the oring on for continuity. Remove the action screw at the front of the trigger guard and put it aside, you won't be needing it for a while. This gun has an extremely perfect fit for a synthetic stocked gun and the action is so secure that you can easily forget that the stock screw isn't in place, just an fyi. Get your bottle that you are switching to and screw it on until you just start to touch. Here is where you are just going to have to use your own judgement to get an idea of what and how much you need to do.

Let's go over materials and tools used at this point. Doing this kind of work is my thing so I already have the stuff to get it done but you might not. Just get what you need and what you're familiar with or just comfortable using. You don't have to use what I used or do it the way I did, but whatever you do, do it very slowly. A dremel could work, carving tools could work. You'll want a flat file, a half round, and a rasp. The half round and rasp can help with the forming of the concave bottle contour and cleaning out melted plastic, and the flat file is used laying flat across the new face that you will be creating, to keep it even. You'll need a sharpie to mark where you need to work. To figure out where you need to work in the beginning, use stiff paper like the shiny junk mail fliers cut into 3/16" wide strips, to push in like a feeler guage, and then mark the edge of the stock where you need to take down some material. You'll need to do that at the end too. In the middle of it you'll just be going after a compression mark that the bottle makes when screwed on.

I used a WorkSharp mini belt sander freehand and I only used the very edge of the radius, so no flat spots. I started with coarse grit which actually melted the plastic more than removing it. After I did what you saw in the picture above, I took a rounded file and scraped out the melted plastic and then hand sanded using my thumb firmly in the groove that I was trying to create. I also switched the WorkSharp sandpaper grit to medium. The key is the hand sanding. When you sand the plastic with coarse sandpaper it creates a rough raised finish that looks like a light grey (fur?). This finish, when touched, or rubbed on, by the bottle, gets squished down and looks like a pencil line because it gets darker like the plastic color of the stock. This line is what you remove material from, and I mean just a little, and then scrape and sand the plastic again, put your gunback in the stock, screw the bottle back to touching the new surface again, just enough to leave a mark and show you where to work again. Repeat. Repeat. Repeat..., until you can screw on the bottle without touching anything, and can slide a piece of paper around it everywhere. It is a long process but looks awesome when you're done.

 

[Florida_Man]

Great work. Looks like it has been and will continue to be a fun project.
This new one uses the same magazines right?
Anyone else feel like I do and are surprised you’ve never owned a Marauder?

 

[Pumacarl]

Great work. Looks like it has been and will continue to be a fun project.
This new one uses the same magazines right?
Anyone else feel like I do and are surprised you’ve never owned a Marauder?

Wow! I guess I never did a thread on this forum about my Gen 2 Marauder but I did some work on that one too. The special things that I did to that gun was to put on the aluminum air tube from JSAR, the Huma end piece and regulator, I completely bedded the gun and the barrel piece so that they could not move and you can pick the gun up by the end of the barrel with no poi shift, that gun has never even been in a case and has never lost zero. The real biggie though was making it so that it could never loosen up and go out of tune. I backed out the adjustment screws all the way for the hammer springs, used a twin spring setup and I cut the springs little by little, putting the gun back together after each change until I got it to shoot 875fps. THAT took a while! The gun basically can't be bumped out of adjustment and the settings are always correct, even after takedown and re-assembly. With the light weight tube it is the best balanced airgun that I have ever held for off hand shooting, in zero wind it is close to an moa gun (I'm not), and I have brained many woodchucks with it. The only complaint that I have with it is it is a chore to cock back, but it's where it needs to be so I put up with it, and I only get about 7 perfect shots a fill. I did throat the valve too, and opened the port doing the angled in drilling thing too, to avoid hitting the valve seat. Yeah, I have a Marauder already, thats why I have really been wanting them to do a Gen 3. This gun certainly solves the power, shot count, and cocking effort problems, without having to do anything, a big step up.

The magazine is totally new and huge. It will accept any ammo I'm sure, just by looking at it. Long polymags, no problem. It might be an issue with some of my scopes but I haven't checked yet and I've got plenty of mounting options anyway.

 

[jps2486]

Now, we need someone to make a decent looking wood stock for this. Hey, wait a minute. Adding a $300 CF bottle and a $200 stock is pushing this project into the range of off-the-shelf guns that already have these features. But, Pumacarl, you are doing a great job on this project and have a great basic rifle to start with.