Tale of THREE BRods - .25, .30 and .357 Completed, Page 19 !

[rsterne]

I have a couple of other projects to finish up, but I wanted to give you a tease about a new project I am about to start.... I have been collecting the parts for nearly a year.... It all started when Travis at W.A.R. was moving his shop and decided to "clean house" and send me a big box of parts.... When I opened my "surprise package" I was pretty enthused with the contents, and could see a lot of the parts required to build two Bottled Marauders.... I scraped together enough money to buy the remaining parts I didn't plan on making myself, and the results of this collecting of bits and pieces is shown below....



Above are the parts for a Traditional rifle, using the beautiful stock that Travis supplied.... He also sent me two main tubes, a drop down, and a ton of other parts, including a bunch of valves, one of which (shown) I modded by moving the seat forward and increasing the ports to 7/32" (0.219").... I purchased two receivers from Crosman (through Lloyd Sikes), along with the Gen 1 MRod trigger group.... Below are the parts for the Tactical version.... I purchased another drop down from Travis, the PRod trigger group through Lloyd, and he graciously supplied me with the AR style Buttstock to help this project along.... The valve is a Cothran Powerhouse, which will be used in one of the builds....



Below is a photo of the tank options I have available.... At the rear is a 500 cc, 250 bar (3625 psi) tank from England, next a regulated 3000 psi 500 cc from Travis, and in the front another 500 cc 3000 psi, but with an adapter to fit directly to the drop down, so that it can be used unregulated.... Travis also supplied me with an adapter for the Metric 250 bar tank as well....



I haven't completely decided on the calibers yet, I have several barrels to choose from.... I have a .25 cal LW Polygonal, a .30 cal TJ's, a .308 PB barrel, and a .357 cal TJ's.... I have obtained some 1/2" ID high-modulas Carbon Fibre tubing with a 0.64" OD.... Sleeving the TJ's liners with that would increase the stiffness to at least equal to a steel barrel with a 5/8" OD (the diameter of my other barrels).... and I have determined that I can bore the front of the MRod receivers out to that size forward of the two 4/40 mounting screws.... which will allow me at least 2 diameters of support for the larger barrel inside the receiver for a very rigid, free-floated barrel installation....

All the parts will be interchangeable.... I plan to end up with two receiver/barrel assemblies, which can mount on either main tube.... One tube will contain my modded MRod valve, with suitable hammer, spring, and SSG.... while the other will contain the Cothran valve, with the optimum parts for that.... and both will have their own drop down, a complete, ready to go, pressure assembly, minus tank.... Any of the three tanks can be used on either main tube.... Onto each main tube, I will be able to attach whichever trigger assembly and stock I wish.... I will be making a rear mount for the AR stock that will contain the SSG, of course....

Anyway, that's what my next major project is.... I hope you enjoy following along as it progresses.... My thanks to Travis, Lloyd, and Don for their assistance and generosity....

Bob

[oneshot61]

Wow... looks good already. I'll definitely be following your build on these. I've been eyeing the tactical look with a front tank lately.

[Motorhead]

Bob with an M-rod based bottle gun (2) .... His disco stuff may be getting dusty
Be watching this one too !

[Hobbyman2007]

Nice looking collection of parts Bob. Any idea where Travis got that wood stock from ?

[rsterne]

Nope, no idea.... I think it's a Bullpup stock, but I'll be using it conventionally, since BP stocks are prohibited in Canada.... I've already inletted it for the MRod trigger in a conventional (rifle) setup....

Bob

[KnifeMaker]

Bob, I have been interested in Bottle Rod Mod's for quite some time as a big fan of the Rapid and AirWolf AG's.  Yet is seem the idea comes and goes rapidly often. Wish it would become an easier option

As one poster on another form used as his sig.
I'd rather have a bottle in front of me, than a frontal lobotomy. LOL 

Wishing you very good fitting and finishing on your project Bob!

Knife   

[rsterne]

I think the big problem is that guys don't want to pay for the time necessary to make the drop down tank block.... I've been making my own for years for my 22XX/Disco conversions, and have given the drawings to several machinists.... They inevitably would have to charge too much for what people perceive them to be worth to make any money.... The only one currently available (that I am aware of) is from JDS, and I would not use it because of the way it mounts into the MRod tube.... Travis has stated he will do another run of them if he gets 5 orders, but even that doesn't seem to be happening....

http://airgunguild.com/pcp-c02-and-helium-powered-airguns/bottled-mrod-kits-buyers-list-order!-deadline-is-january-9-2017/

You would need the drop down and tube, as they thread together.... and that comes to $235 just for those two parts.... bottle, and regulator or adapter, extra....

Bob

[Buldawg76]

Bob
I have a bottled kit from Travis that I have been following Lloyd build of the 30 cal Mrod for Don and just paid for my plenum for the huma reg so I can start the build as soon as I get it and the TSS from Travis.  Its in a RAI stock with the AR butt stock with Daves adjustable adapter. I will be following this build as well very closely as I get the parts to start my build. I am hoping to be able to shoot the JSB 33.95 pellets at 950fps or so to be good an accurate 100 yard gun. I also have a Jim Gaska MM barrel in the breech now so the plenum and TSS are the last two parts I need to proceeded with a finished gun. 

Mike

[rsterne]

Sounds like you have a pretty good handle on it, Mike.... I haven't even calculated the plenum volume in Travis' BRod kit yet.... *LOL*.... but having the regulator on the bottle will at least make all of the tube volume into plenum.... I sure wish the Cothran valve would produce a bell-curve.... I'm not crazy about setting it up unregulated in a "first shot fastest" scenario.... so that may restrict its use to a regulated gun.... The plenum volume will then dictate the most suitable caliber.... So far it's just a collection of parts without a clear direction to pursue....

Bob

[Buldawg76]

Mine is going to be pretty close to the one Lloyd is building for Don except it will be 25 cal and have a 500cc bottle instead of the tube extension. So if Lloyds calculations for the total plenum volume is correct it should be close to 44ccs. I am using the cothran valve with a Hill gauge block that is much more open than a stock one and likely close to the hogged out one Lloyd is using with the BT65 30 cal plenum on the huma reg. I wish the drop down block was threaded to accept a paintball reg but its not and use the same bushing as the bottom bottle in your pictures so I plan to drill out the small pass thru hole in the bushing out to 5/16 or 3/8" for a better flow into the tube. I am hoping the larger plenum will clear the threaded bushing once assembled into the drop down block since with the stock 25 cal huma reg its real close to the end of the drop down when its fully threaded into the short tube.

I will know soon since the last two pieces will be here this next week.

Mike

[rsterne]

The drop down block Travis makes DOES fit paintball regs.... The adapters he sells are exactly the same thread (1/2"-NPS).... What is different is that the regulator doesn't seal down inside the threads in a smoothly bored hole.... You use an O-ring between the bonnet OD and the drop down.... outboard of the thread, just like with the adapter.... REALLY a slick arrangement.... and much easier to machine.... 

Bob

[oldpro]

The drop down block Travis makes DOES fit paintball regs.... The adapters he sells are exactly the same thread (1/2"-NPS).... What is different is that the regulator doesn't seal down inside the threads in a smoothly bored hole.... You use an O-ring between the bonnet OD and the drop down.... outboard of the thread, just like with the adapter.... REALLY a slick arrangement.... and much easier to machine.... 

Bob

Thanks Buddy, if you need anything just PM me and Ill look threw boxes.

[rsterne]

Thanks, Travis, but you've cost me enough done enough for me already.... 

Bob

[oldpro]

Thanks, Travis, but you've cost me enough done enough for me already.... 

Bob

LOL

[rsterne]

I got around to measuring the plenum volume in the tubes today.... There is 69 cc between the back of the tank block and the front of the valve.... However, in my drilled out MRod valve there is another 4 cc (even more in the Cothran), and in the tank block, which has large passages, there is about another 8 cc.... so the total is over 80 cc.... That means the plenum is large enough for any .25 cal or for a .30 cal pellet shooter for sure.... and for a .257 cal or .30 cal bullet shooter, or .35 cal pellet shooter it is large enough that it would only take about another 100 psi bump in the setpoint to make up for any lack in plenum volume.... It is, however, on the small side for a .308 or .357 bullet shooter, or anything over about 160 FPE, so for those an unregulated setup would be indicated.... The good news is that the passages through the tank block, and the brass tank adapters, are large enough that without the regulator in between, the entire 500cc tank becomes part of the reservoir, able to keep the pressure up during the shot.... This means the effective reservoir is about 580 cc (35 CI) when unregulated....

Bob

[Dairyboy]

Dang I need to regulate my .30 Brod. Definitely going to bottle my .25 now as well.

[Buldawg76]

The drop down block Travis makes DOES fit paintball regs.... The adapters he sells are exactly the same thread (1/2"-NPS).... What is different is that the regulator doesn't seal down inside the threads in a smoothly bored hole.... You use an O-ring between the bonnet OD and the drop down.... outboard of the thread, just like with the adapter.... REALLY a slick arrangement.... and much easier to machine.... 

Bob

Bob
I just checked the threads and you are correct that they do fit the ninja regs threads and the bottle accepts the regs threaded end as well. I never even thought to check the fit so thank you very much since I now don't need the huma reg and bigger plenum if I choose to go with the reg on the bottle instead. It just never occurred to me to check the threads. So I see you use the o ring between the adapter block and ninja regs bonnet but I assume then you need to remove the check ball or pin in the top of the bonnet since there is no pin in the end of the adapter to depress the check ball or pin in the bonnet. I agree its a slick trick that in much easier to machine and will give the added plenum size to achieve the power level and fps I want out of my Brod.

Also in using the cothran valve I will be using a 26 gram MDS with aluminum insert form Motorhead in place of the stock hammer to help lessen the hammer strike on the cothran valve. I believe its going to turn out very nice now and better and easier than I first anticipated. Again thank you for letting me know that the block will accept the ninja regs so easy.

Mike

[rsterne]

Yes you have to remove the check valve inside the bonnet of the regulator.... It's nice that Travis made the passages through the drop down so large so that if you use it unregulated the bottle can flow fully into the plenum.... that adds a touch of volume to the plenum, too....

Bob

[Buldawg76]

Well the bushing I have has a 1/8" hole thru it so it will need opened up to 5/16 or 3/8" to match the passage thru the tank block which is no big deal. This opens up a bunch of new possibilities for the build with the different combinations possible with the bottle and regs. I am now thinking of getting a CF 4500 psi bottle to have even more air to gain more shots per fill and reduce some weight as well.

Mike 

[rsterne]

You wouldn't want to use 4500 psi in the tube,, but with a regulator between you are probably OK.... It's too bad we can't get burst discs at around 3800 psi, but they jump from 3K to 5K.... although from England you can sometimes get 4.5K ones.... It you had a regulator failure on a full, 4500 psi bottle, you could end up with that in the main tube.... The safety margin is probably high enough to not cause you injury, but you should degas and disassemble the gun and replace the valve mounting screws as they will have been overstressed.... I don't know what the limit if for pressure on a MRod setup, it's almost impossible to calculate the failure point of the valve screws (which is likely the weakest point) because the heads of the screws are supposed to be in shear, not the shank.... I don't know of anyone who has tested an MRod tube, with valve and fill fitting, to failure, perhaps Lloyd will do that now that he has his new 30,000 psi test rig built.... I think Lloyd uses up to 3500, and I'm pretty sure Travis uses a 250 bar tank unregulated on the FLEX.... so maybe they will chime in....

Bob