MarauderAirRifle.com

[pgala]

Travis is right on, I did this to my .25 and now it is a smooth as butter and I got exactly 20fps more with a better bell curve. I have bought several products from Travis and I had several questions and a couple of issues. He answered all my questions and accommodated all of my issues. He gives wonderful customer service and I look forward to buying more of his mods. Because of his mods my marauder shoots with energy that I never thought it could have.

[rupert3]

Same here Just need more money to do the other one.
Bob

[pgala]

Here is my last shot string. I have a 12.5 pound spring.
EUNJIN 43.2g
HT4 HS3.5
3500psi
1)854-69.6
2)859-70.4
3)875-73.1
4)881-74.1
5)881-74.1
6)888-75.3
7)889-75.5
8)893-76.1
9)893-76.1
10)888-75.3
11)885-74.8
12)883-74.4
13)876-73.3
14)868-71.9
15)860-70.6
16)855-69.8
2450psi

[RayK]

Dude! That is awesome!

Some may wince at the 3500 psi fill, but it is really awesome!

Ray

[pgala]

Thank you, Ray. I have put 1000+ shots through at 3400psi-3500psi and have had no issues...yet. I store my gun with that pressure as well. I figure the engineers have to take crazy people, like me, into account and build tolerances into the "max" pressure. I do think 3500psi is the max though. I do not feel comfortable going higher than that. I have noticed to get a good curve with Baracudas 31.02g I need to come off the HS by 1 turn. So, my adjustments for Baracudas 31.02g is HT4 HS2.5 and EUNJIN 43.2g HT4 HS3.5. Next, I need to test JSB 25.4g they seem to like lower velocities so it may be close to HT4 HS0.

[RayK]

Read USMCShooter's post about half-way down on this thread.

viewtopic.php?f=24&t=4449&p=26086

I think you're ok. It might be smart to replace the three valve allen bolts maybe every 10,000 pellets on any Marauder.

my buddy has been filling one to 4200psi, for over 25,000 shots, before the screws failed....it scared the bejesus out of both of us....and shredded the stock under the tube and trigger group.....however, nothing hit, or hurt anyone.....another reason I ALWAYS wear glasses of some sort when shooting....that being said, he's had his .25 running at over 110fpe at these pressures for quite some time.....WITH his highly modified valves. By his engineering knowledge, the valves are simply not capable of flowing enough air in the factory design...even with opening delivery ports....however, he was able to get 10, full power shots at over 100fpe....

A very renowned engineer, airgunsmith and tuner told me within 6 months of the Marauder's release, that the valve design preferred higher fill pressures, and recommended filling to 3200-3400psi....individual valve dependant....being the careful individual I am (sometimes), I have tuned all my guns to 3200psi....and I'm finding the Prod to be the same with valve design....while the PSI/air usage figures don't mathematically add up, the extra 200psi at the top of the string seems to deliver an extra mag of shots with the proper tune.....at least this has been my experience with around 30 .22 cal and 12, .25 cal's tuned now....and I've just started playing with the Prod....but it too, with stock spring, transfer port etc, delivers an extra mag, 32 shots, at 35yds, with no POI shift.....

Ray

[Doc]

Ray, I not saying it isnt true but how can the bolts fail when its the head of the bolt holding the valve?

[AlanMcD]

It would be a shear failure - the head of the bolt breaks off. That was what I forecast to be the weak link and fist point of failure in the system before I heard fo the failure a few years back . . . .

[Doc]

It would have to sheer the threaded portion and the head at the same time because the head is counter bored into the valve body. Plus it would have to sheer the two breach screws.

[Doc]

I think the pressure tube on the Mrod is 1" I.D. So the pressure on the valve body would be area times pressure = force.

.500x.500x3.14x3000 = 2355lbs
3500 psi = 2747lbs
4000 psi = 3140lbs

The 10/32 grade 8 bolts have a sheer force of around 4000lbs each. Add that the head is around .300" and would have a sheer force of around 11,000 lbs. The threaded portion of the bolt is not going to sheer unless the head of the bolt starts moving through the counter bore area of the aluminum valve body that the bolt head sits in. I would be far more concerned about the fill plug and thinner pressure tube wall because of the threads cut into it.