Marauder Pistol long barrel carbine.

 I picked up another PRod and am working up a carbine configuration I've been wanting to try for years. I'm one of those guys that gets excited about an idea, buys the parts and then takes years to "get around to it".

 I was discussing the idea with a forum member in an unrelated email conversation and was told the .22 rifle barrel was a direct bolt-up. I purchased a .22 Marauder rifle barrel with the intention of putting it on my PRod but was enjoying it so much as a pistol I never wanted to take the little hammer offline to make a carbine. The new PRod allows both.

 The barrel bolted right up with no modification. I just test fired it and the magazine seemed to function fine. I didn't measure the barrel protrusion into the magazine well so I'm not sure if there is difference but the bolt probe feels like it passes the Oring seating the pellet properly.

 Anyone have any experience with this mod?

Nope, but I'm sure as he** interested in hearing what you think about your results, so far -

I've a P-Rod with a extended airtube & shroud set up, it's really sweet, but never new a M-Rod barrel was a drop in fit, but can't say I'm suprised, in retrospect, and everythang -

Gosh Steve, I though you were responding with the barrel protrusion measurement(I'll check my other gun). ? 

I can't believe I've waited so long to try it; It may be another Crosman homerun in the backpacker class IMO.

 Unless I encounter any problems, I'll start building it up with a small scope and possibly the shroud on the end if it doesn't screw up the harmonics, cheek piece, etc . Chrony and tuning to follow. I even have an HHD that has been sitting next to the barrel for about 3 years that I can throw into the mix.

 It should be interesting to see what performance gains are had. I have plenty of pistol data to compare it to.

 I wish I could remember who told me about it and credit him. Guy was a regular and was into the Mrods when they came out. He participated in most of the good threads.

PS Part # 2263-001.

PPS The barrel protrusion looks to be the same, ~.05 in both.

 The gun weighs 3.7 lbs; the scope I have is 1 lb. The total weight should be about 5 lbs with rings and a full magazine.

 I mounted a Simmons 3-9X32mm A/O using the only half decent mount I had on hand.  I get these scopes when they go on sale for ~$35 shipped and think they are a real value.  I love the size, the glass is surprisingly good for these applications IMO and of course, AO. I have BKL's on order but was surprised to see nobody had the 257s I wanted in stock so this will have to do until they fill the backorder. The gun tipped the scales at 5.15 lbs as expected.

 This is a completely stock gun except for the barrel. When I was sifting through my notes, I discovered that I didn't do a perfect job of recording port sizes. The consensus back when was the gun requires a larger port and IIRC, I settled on .116 and was running that for the most part, so it was difficult to compare these velocities. There is a plethora of data on the Internet so I'll sort through it and do additional testing as time and desire dictate. Right now I was hot to get it up and going!

 I really like the handling and suspect it has a lot more performance to give. I'll port it and maybe test it with a Disco spring.

 I rushed to get some numbers and was really sloppy with the chrony setup so I got a lot of errors. The gun was remarkably consistent shot to shot:

 Hammer preload 3 turns CW, Stroke 0 turns. Starting fill pressure was ~2600+. 20" barrel  .08 port.      Pellet FTT

Mag 1          Mag2          Mag3

663              658             657

Error          665              670

Error          Error           Error

Error          Error           Error

664             Error           Error

661              664             Error

661              675             653

                    Error          653

EFP 2300 EFP2000  EFP1600

 I've tried searching and can't find the OD for the Marauder rifle shroud in .22. I may want to put one on and need to know if it will fit through the forearm loop.

 Help please?

Very nice....   I have a PRod with an extended air tube and collapsible stock. This seems to be the next logical step.   I think it looks sharp

Posted by: Rob in NC

Very nice....   I have a PRod with an extended air tube and collapsible stock. This seems to be the next logical step.   I think it looks sharp

 Thanks, I haven't been this excited about an air gun in a while.

I've always thought the Marauder platform was a homerun and the pistol is the Holy Grail that I pursued as a 22XX fanboy. Think back to all the aftermarket breeches we bought chasing the configuration Crosman delivers with the PRod - magazine fed, shroud capable, rock solid scope mount, ambidextrous , power adjustable. The perfect carbine conversion using OEM parts seems to be within reach. 

 I'm going to start dialing it up soon but I'm stressing over the fact that I only have a .125 port and I'm thinking .1 is the most power without getting too sloppy about dumping air. I'm revisiting "Airgun Enthusiast's" work and am appreciating his contribution to this platform all over again. The stock performance with a minimal power setting looked promising from my review of data. 12+FPE without breathing hard. Shot to shot looked good too. Hope it ramps linearly.

PS Another thing to note. The early versions of the PRod were pellet fussy - IDK if that changed, this moves the pellet selection over to the rifle platform.

My Prod has the stock length barrel. I installed a Marmot Militia barrel and that made it a different gun. If you are worried about yours being  pellet  picky you might want to look into one.

Stock

Marmot barrel.

Posted by: pluric

 If you are worried about yours being  pellet  picky you might want to look into one.

 I want to see if there are any power gains to be had with a longer barrel, shooting a larger selection of pellets will hopefully be an added benefit. 

Posted by: Bigbore

 I've tried searching and can't find the OD for the Marauder rifle shroud in .22. I may want to put one on and need to know if it will fit through the forearm loop.

 Help please?

http://www.marauderairrifle.com/forum/viewtopic.php?f=28&t=4512

Posted by: Domer_Pyle

http://www.marauderairrifle.com/forum/viewtopic.php?f=28&t=4512

 Thanks, I saw that thread when searching. They are discussing a .25, I couldn't be sure the shroud was the same for a .22.

 I did end up looking at the MRod rifle part #'s and the shroud part # is the same for the .22 & .177. I have a .177 so I measured it and it is larger than the PRod, although it still may go through the forearm hoop.

 As you probably saw, I received a new chronograph so I finished collecting the baseline data for the stock carbine. My Crosman parts came in too so I have ports to ream. I'll start @ 7/64ths(.109)

.110 Port numba's:

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 I wasn't happy with the .110 port results and I knew it right away. I was lazy about collecting chrono data, but we know a lot about reservoir volume and shot string curves for this gun so I assumed anybody interested could extrapolate the data and arrive at whatever conclusion they thought relevant.

 I reamed another port to .093 and installed it last night, the .110 port results not giving what I had hoped for. The numbers seem to show better efficiency with little loss in power. I didn't test 7 turns because I'm just not into standing on valves right now, especially for this gun. As is typical, this gun starts to develop power at ~ 2500 psi.

 I'll enjoy it for a while as is and may throw in some pellet accuracy testing but it is a MRod barrel so what ever works in your rifle should apply here. Next(A month or so) we put N. Carolina Steve on the spot and install the sprag HDD and see if we can pick up even more efficiency.

.093 numba's:

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I love mine. I have it suppressed to allow use in the neighborhood, and a ar15 collapsible stock. What I'd like to know is can the rifle reservoir fit on the pistol?

Posted by: Arizona Bushman. What I'd like to know is can the rifle reservoir fit on the pistol?

No, the rifle reservoir has a MUCH larger diameter. A few posts up Rob in NC mentions a reservoir extension. 

 This is the final configuration for this carbine. I picked up a set of mounts, which I wish were a little lower but 3/8" wouldn't make that much difference and these allow for better magazine and bolt access. I also shimmed the trigger to take out some slop, its really dialed in perfect now. I'm VERY happy with the final result.

 I installed the early version of the Steve in NC cam style HDD. I tightened down the breech too much and the bolt action was stiff and the gun actually failed to fire. Loosening the breech screws a little allows for a smooth bolt cycle now. I put four magazines through it to function check and set it for 6 turns of hammer preload. I kept the .093 port. I reposted the results I got before HDD installation so we'll see how it compares. The JSB Exacts seem to be my most efficient pellet.

 Shots 4 - 24 are the curve I'm hoping for. The HDD should make 3 full magazines at these velocities possible yielding 18+ ft lbs.

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Been a few months now.

Any further info on this ?

Posted by: TomR_here

Been a few months now.

Any further info on this ?

 Nothing new yet. The last few months have bee a blur. I have been crushed with work, holidays and I've been running some other hobby projects simultaneously.

I bought some steel rod and I'm going to attempt a heavy hammer. I want to give the numbers I have another look also, my pistol seems to be shooting stronger with a shorter barrel. If this is in fact the case, I want to figure out why before moving forward. Maybe by March if it doesn't get shelved for some reason.

It is on the front burner for the time being, sitting right here.

Thanks for update.

I can so relate to the work load, been pulling 50-60 weeks for a few months myself.

Makes this old man tired.