Just finished my B-Rod

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T3PRanch

T3PRanch

Member
Apr 22, 2016
2,939
111
Post TX, United States
www.t3pranchags.com
Specs:

.25 Marauder from Imold
New M-Rod Tube from Air Venturi cut to 17"
SS Valve from Jefferson State Air Rifles
Gauge Bypass by T3PRanchAGS
Bottle adapter by JDS Airman
500 CC 4500 PSI working pressure CF Bottle from AliExpress ... AceCare
Regulator set to 2400 PSI from Air Rifle Technology
Boyds Blaster Stock inleted by AGN member plinker
Hawke Airmax 30 6 - 24 X 50
FX No Limits Scope Mounts
DonnyFL M-Rod to 1/2" - 20 UNF Moderator adapter
Huggett Belita Moderator

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Thurmond



 
Thanks. Unfortunately I discovered a regulator issue. The output is apparently leaking up to bottle pressure. I tested it this evening from a full fill of 4500 psi and shot it down to 4000 psi. Brought it in the house and took the pictures. Not half an hour later the 3K burst disk on the regulated side blew dumping the bottle to zero psi in a very LOUD fashion. I have heard of this issue before. I can't remember where or the solution but it will not be brought in at over 3K psi bottle pressure until I can effect a repair.

Thurmond
 
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Not a fan of bottle guns personally but you knocked this one out of the park, one of the best ones I've seen.

2400 psi is very high for a regulator set point though, unless you're trying to make TONS of power ie: 70 fpe regulated in .25 cal.

I would set your regulator set point lower if you are only aiming for 50-60 fpe max (ideal levels for MKll's), would make the valve A LOT easier to open (20% easier) if you brought the set point down to 140 bar, provided you have adequate porting to push enough air in a short enough dwell time.

If you cut off 7" from the original air tube that leaves you roughly 100~ CC's of air tube for your plenum, if that is the case, you could easily make 100~ FPE in a .257/.30 cal build. 

-Matt

 
Upvote 0
"ackuric"Not a fan of bottle guns personally but you knocked this one out of the park, one of the best ones I've seen.
2400 psi is very high for a regulator set point though, unless you're trying to make TONS of power ie: 70 fpe regulated in .25 cal.
I would set your regulator set point lower if you are only aiming for 50-60 fpe max (ideal levels for MKll's), would make the valve A LOT easier to open (20% easier) if you brought the set point down to 140 bar, provided you have adequate porting to push enough air in a short enough dwell time.
If you cut off 7" from the original air tube that leaves you roughly 100~ CC's of air tube for your plenum, if that is the case, you could easily make 100~ FPE in a .257/.30 cal build. 
-Matt





Click to expand...
100~ FPE in a .257/.30 cal build

You have been peeking haven't you?

The SS Balanced Valve seems infinitely tuneable with 100ft/lb being reported at the GTA.

I am all about power and cast rounds. Coyotes and Pigs!

@kayaker Here are some pics....
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Currently shooting 25.4 JSB's at 950 fps and 34 grain JSB's at 850 fps. Hammer travel 4 turns from maximum, Spring preload only 1 full turn.
Regulator is definitely leaking up to bottle pressure since I pressurized to 3200 psi and the first shot was 400 fps with JSB 25.4's. I'll have to tear it down as I suspect that
the Chinese belville washers are the culprit. Have to order a new burst disk too since I am temporarily running a 5K just so I can use the gun (at no more than 3200 psi for now).
34 grain grouped 2" over 1 magazine at 75 yards with gusting 20 mph winds and only a bipod for a rest.

Thurmond
 
Upvote 0
"T3PRanch". I'll have to tear it down as I suspect that
the Chinese belville washers are the culprit.

Click to expand...

Could be the washers collapsing at the higher pressure but more likely it's the piston. Order a Ninja regulator rebuild kit and put the Ninja piston in it. They are usually under $15 on Amazon or Ebay. Those Chinese reg's creep like crazy due to the seal design. (Yeah I'm the guy that first started doing that when Travis sent me a junk Chinese regulator with the $1800 American made War rifle I bought)
If the bellevilles collapse then the regg'ed pressure would actually decrease as opposed to increasing. If the reg has the .032" washers get some of the .047" (IIRC) that's the ones the Ninja uses in the 3K output bottles.
 
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"Imold"I want my Marauder back hahaha I had a feeling it was going to be taken advantage of but anyway nice job.
Click to expand...
I hacked up a new tube and used a new valve. All your old parts are intact in case the gun needs to be restored to stock form.
Only parts used from your gun were breech, barrel, shroud, hammer and spring. :)

Did some more testing today over the chronograph. Shot 3 mags (24 JSB 34 grain) 855 fps average. Starting pressure 3800 psi, Ending pressure 3200 psi. Regulator at 2400 psi. 55.2 ft/lb average.

Thurmond
 
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