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trouble with psi affecting accuracy
Posted:
Fri Dec 24, 2010 8:12 pmby pb95
i have a .22 cal marauder that i recently purchased. I am having some issues regarding the fill pressure affecting my accuracy. I cannot get my gun to group well over about 2100 psi. It would be fine for target shooting, but i intend to hunt with my marauder. I am shooting crosman premier 14.3gr pellets. I am concerned with the knock-down power of low pressures and need to tune it to about 2800psi or so to be satisfactory for my preferences. I have no previous experience with PCP's and i am not exactly sure how to tune my rifle to group well at higher pressures. It looks like i am patterning a shotgun at 40 yards when i get up to about 2400 psi. I have lots of experience with firearms and i am confident in my shooting skills, so i am sure it is an issue with the gun. The only thing i know to do is tweak the velocity a bit, but higher velocities supposedly shoot worse groupings. I greatly appreciate any recommendations or tips on tuning my mrod to higher fill pressures.
Thanks,
Peyton
Re: trouble with psi affecting accuracy
Posted:
Sat Dec 25, 2010 5:46 amby Artilheiro
I advise you to use heavy pellets such as Beeman Kodiack (21.4gr), H & N Barracuda (21gr) or JSB Heavy (18.1gr). Try to adjust your gun so that it has a speed of at least 280m/seg (919 ft / s) with JSB Heavy. To obtain this rate you should charge at least 2600/2500psi and then to increase (clockwise) to progressively load the hammer spring. For this setting, it is essential to use a chronograph. Good luck.
Re: trouble with psi affecting accuracy
Posted:
Sat Dec 25, 2010 6:23 amby Lammy1000
What are your current settings?
I agree w/above poster...turn the spring tension to ~4 turns in and shoot it.
Re: trouble with psi affecting accuracy
Posted:
Sat Dec 25, 2010 11:22 amby Supercharged86
Unfortunately PB95, you'll need to chrony your shots to tune it properly. Fill pressures alone don't mean anything, it works in conjunction with the hammer spring, stroke and port (V) settings to obtain the overall velocity; you could be over or under clocking them. Then of course there's the possibility your Mrod doesn't like those pellets. Steve