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Author Topic: Tale of Two BRods  (Read 8028 times)

rsterne

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Tale of Two BRods
« on: January 07, 2017, 11:09:30 AM »
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
« Last Edit: January 07, 2017, 08:10:53 PM by rsterne »


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Dairyboy

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Re: Tale of Two BRods
« Reply #1 on: January 07, 2017, 12:00:17 PM »
I can't wait to see these get done!
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John 3:16

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Monkeydad1969

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Re: Tale of Two BRods
« Reply #2 on: January 07, 2017, 09:40:18 PM »
Looking forward to the progress... ;D
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Joe the P-Dawg Slayer!!!!!

oldpro

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Re: Tale of Two BRods
« Reply #3 on: January 07, 2017, 11:32:07 PM »
me also. get to it Bob.
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grumpy

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Re: Tale of Two BRods
« Reply #4 on: January 08, 2017, 05:56:55 AM »
Another looking forward to following along on your new project Sir.

Dave
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bnowlin

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Re: Tale of Two BRods
« Reply #5 on: January 08, 2017, 06:29:57 AM »
Bob,
I love my polygons on my 22 and 25 MRods I got the long ones from Jim G a long time ago and very accurate. one at 22 and one at 25.   Probably can't compare them with prod. but good luck.
Bobn

rsterne

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Re: Tale of Two BRods
« Reply #6 on: January 08, 2017, 11:06:39 AM »
The one barrel I really wanted to try was a 14" twist TJs in .257 cal.... but alas I have none left.... and getting barrels (or scopes) out of the US is nearly impossible any more....  ::) .... The aftermath of 9-11 sure screwed things up for legitimate airgunners....  >:(

Bob
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bnowlin

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Re: Tale of Two BRods
« Reply #7 on: January 08, 2017, 01:04:22 PM »
I know what you are talking about.  I had to box up a shoebox and send it to NY and the guy had to come over to a UPS store in NY and pick it up and pay duty on it and they almost didn't let it across.  Just because the  guy that day new it was used for air guns.  Go figure.
Bob
« Last Edit: January 08, 2017, 01:06:59 PM by bnowlin »

rsterne

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Re: Tale of Two BRods
« Reply #8 on: January 08, 2017, 01:23:16 PM »
Getting stuff into Canada is NOT the problem.... it's getting it OUT of the USA.... Optics and barrels are on the ITAR list, just like Nukes....   :o .... Export permits (last time I checked) are $380 US per shipment.... I heard recently that Canada Customs are now giving their US counterparts a heads-up when anything on the ITAR list shows up in Canada.... even though Importation is legal....  ::) .... I better stop, or I will be dragging my own thread of course....  ;D

Bob
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bnowlin

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Re: Tale of Two BRods
« Reply #9 on: January 08, 2017, 01:34:29 PM »
IK ttyl good luck
Bob

rsterne

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Re: Tale of Two BRods
« Reply #10 on: January 08, 2017, 05:00:48 PM »
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
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rsterne

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Re: Tale of Two BRods
« Reply #11 on: January 10, 2017, 07:12:21 PM »
I worked on the tubes today.... The tubes that Travis sent me are intended for Gen 2 MRod parts.... I have two Gen 2 receivers, but I wanted to be able to interchange the tubes from traditional wood stocked rifle to a tactical setup with pistol grip.... Since that needed a PRod trigger group, and it is the same bolt pattern as the Gen 1 trigger, I had to redrill the tubes to accept the Gen 1 and PRod triggers.... In addition, the transfer port hole in the top of the tube had to be drilled out to 3/8" to accept the larger transfer ports.... Here are the redrilled tubes, with the new holes circled....



The front two holes on the bottom are drilled and tapped with 8-32 threads, while the rear hole on the bottom is the clearance size for an 8-32 (11/64"), because the rear trigger screw threads into the rear tube plug.... A custom rear plug will be required because the bolt pattern is Gen 1 on the bottom and Gen 2 on the top, to accept the two rear 4-40 screws that hold down the receiver.... The only change on the top was drilling the original TP hole out to 3/8" in the same location....

I installed the male Foster and gauge in the tank blocks (drop downs), along with a 1/4"-NPT flush plug on the bottom.... I want to be able to tether the guns without having to waste all the air to fill the 500 cc bottles during development, so I made a blanking plug for the tank/regulator mount in the drop down from an old regulator bonnet....



I simply removed the pin valve and drilled and tapped the bonnet for a 1/8"-NPT flush plug to seal it.... I installed a couple of 5/8" long 10-32 SHCSs in the threaded holes in the bonnet and screwed them in until they touched each other in the middle.... This gives me something to grip better with my fingers to screw the blanking plug into the front of the tank block.... You can see the O-ring that seals the regulator bonnet to the tank block sitting on the bonnet.... It seals in the recess in the front of the tank block, instead of way down inside, so you don't use an O-ring in the normal location on the bonnet.... Travis is to complimented on this arrangement, it certainly is a lot easier to machine, and less prone to leaks, IMO.... I then installed the valves in the tubes, and threaded in the drop downs, stopping with them pointing downwards, lined up with the trigger group.... Once there is pressure inside, they won't have any tendency to rotate, and it isn't important for them to be screwed up tight against the end of the tube (and it you do, they won't line up with the trigger on the bottom of the tube.... You simply screw them in all the way and then back them out until they line up with the trigger.... I then installed my blanking plug and checked for leaks.... Here is the assembly, which I will leave overnight to make sure it holds pressure....



For the eagle-eyed amongst you, you will notice that the gauge is showing over 3000 psi.... I filled the tube to 3000 psi exactly with a known gauge, but this one shows 3500.... In fact, it was 500 psi high all the way from the start of the fill.... Does anyone know if that is an MRod gauge?.... Anyway, it's nice to get a start on this project, other than just collecting parts for it....

Bob
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bnowlin

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Re: Tale of Two BRods
« Reply #12 on: January 10, 2017, 07:56:32 PM »
Bob
It looks like a benji gauge and calibrates easy with known gauge by by squeezing the top of the gauge easily remove the plastic or glass and turn the back plate to correct psi or get one from Travis they are great. You probably already know all that.
Bob

rsterne

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Re: Tale of Two BRods
« Reply #13 on: January 10, 2017, 09:00:39 PM »
Thanks, I'll try that....  ::)

Bob
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oldpro

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Re: Tale of Two BRods
« Reply #14 on: January 10, 2017, 09:28:53 PM »
 bob wont drilling the forward hole put the front trigger screw into the high pressure area in front of oring on valve?
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