You guys with the Greg Davis Marauder mods and extension tube in 22 cal, what settings are you running? How many shots on 3000 psi fill. Any problems? Thanks, Scott

The air tube extension but still get 40 to 50 good shots at 25 yds my Mrod was really a loser when I got but after GD tuned it WOW what a good shooter.
PS I fill mine to 2750 psi at 890 fps

3100 psi. Mine is a .22, without the air tube extension, I get 37 shots at 50yds with no shift in POI....but get 40 full shots at 50 with usable hunting accuracy...Ie, under an inch....but at 25yds, I get 57 shots with no POI shift.

I must add that this is with Greg's work, and my fine tuning with Greg's assistance....his work truly balances the valve/striker/port configuration to ensure excellent performance. But I've yet to hear of someone receiving one of his tuned guns getting less than 30 full-power shots at 50yds.....

s/f

Jamie

I got a .22 cal mrod that I bought from Greg Davis, although Roald did the tune. I have the extension air tube and only get 36 useable shots. anything after that the poi changes.

and the finite adjustments required were very, very meticulous, and minute at best....well recorded, every step, over 3 separate sessions. The transfer port adjustments provided the most benefit, however, these were made in 'tweaks'....just barely moving the allen wrench, and firing a string...trial and error on the port would add, or take away up to 10 effective shots...literally 1/8th of a turn would cost several shots, even though the velocities were fairly close on paper....the shot count was very dramatic....

Again, it's about total balance of the firing system as a whole, working with all three adjustments, burning a lot of air and pellets in the process, but now, I have a rifle that will shoot 37 shots with only a 16fps ES....not bad for an unregulated gun!

s/f

Jamie

Could you tell us the caliber and settings you came up with? Thanks, Scott

work in any other gun, due to machining inconsistensies in the individual components...of the 11 I've tuned, none have even been close in settings. Between spring tensions, adjustment threads, etc....there are far too many differences in guns for settings to be close....

s/f
Jamie

Did you try making an alternate transfer port restricting screw? Don't know if you've had it out for a look see, but from the factory, it's business end is pretty neanderthal. I've got a bunch of replacements with different configurations on the end to try and give better control on the adjustments and flow efficiency but haven't had the hours to dedicate to it. (Especially after the buuku hours spent on barrel issues) Do you know if Greg reconfigures that screw with his tune? Or would you have to kill me if you told me

don't know if it's part of his recent/current tunes though. I haven't tried it, but I know Bob D. was playing with some different designs as well...if and when I get the time, I plan to try some different ones as well.....I'm assuming that I may be able to tune it even deeper...but don't expect to get many more shots per fill, but perhaps some less touchy adjustments.....time will tell....

s/f

Jamie

Grag does not reprofile the TP adjustment screw. As noted before he hasn't had time to do any engineering work. He's too busy cranking out guns he has in queue.

It didn't fit. The extension screwed in easily into the stock airtube but the fill cap was bottoming out when trying to screw it into the extension.

Looky here! You can see where it was hitting right after the threads.
[IMG][/IMG]

Being I waited 5 months to get it I didn't want to go through the ordeal of returning it and waiting again. Went out and bought a new wheel cylinder hone and went at it nice and slow. Had to bring it down a few thousands until it would screw in all of the way without scuffing. Took about a half hour but now it's all good.

Bob
I live in a State of Confusion (Jersey)