airmax mk II pistol
This has probably been asked on YF, but will seek opinions here. Opinions on performance of the MRod Air airmax mark II pistol in .22. Accuracy, power, general comments? Thanks in advance.
Love my Airmax Mk II pistol, in 0.22.
It is more accurate that I am, power is easily adjustable up to 15 ft-lbs or so, if you chose, threaded barrel takes a LDC if you are so inclined, and easy to disassemble and work upon, though they shoot very well right out of the package. Velocity consistency can be improved with an aftermarket regulator (with works better than the one built into the gun).
I think it's a very reasonable pistol for the price, especially if you like to tinker and learn how things work and start some amateur airgunsmithing up. Most people I've heard ended up with very satisfactory out-of-the-box results, however the .22 I received did need some work on it. It's now incredibly accurate even with CPHP straight from the tin, pretty easily holding nickel to quarter sized groups at 20 yards (can pull in tighter with good ammo).
Mine out of the box I can't say shot very well and had a slow leak from the o-ring in the air intake valve (which I've ended up replacing about 4 times now, it's probably the most frequent trouble area if you encounter leaks).
The barrel was also fairly rough and had a dinged crown, I've since gone in and re-crowned and lapped it which cleaned up quite well.
My regulator also had been assembled incorrectly and had the Belleville washers incorrectly stacked (had almost zero ability to adjust) along with the regulator valve seat being both backwards and rough on the sealing face, so had machined a new one out of acetal/delrin to replace that one. Prior to this it simply never had a regulated shot string. Now it holds pretty consistently within 3-10 fps.
It needed a fairly thorough cleaning and lubing up, had a lot of some harder caked in brown grease stuff throughout. Once all that was out and everything lubed up well with silicone grease and a little moly grease for the metal-to-metal areas it made a healthy difference.
I also went through and polished up the trigger mechanisms and lubed them up with moly, made for a silky smooth pull (no "that's what she said" comments please).
Have done some other mods as well that helped tweak the performance some, but these above were the main things that presented problems when I first received mine. I've probably put somewhere around the order of 7,000 - 10,000 rounds through it since then, and should have plenty more to come now that I have a Yong Heng compressor (am not going to miss the hand pumping...).
Once I realized the reg wasn't working at 15 foot-pounds and reduced the power, my .22 AMP Mk II got these results (as excerpted from my upcoming book)-
16 grain Air Arms, 3000 PSI, 30 shots- Lo= 581, Hi= 606, ES= 26, SD= 9, Av= 596 FPS/12.6 FP
My best accuracy results at 35 yards (the maximum field target distance) so far, as also excerpted from Custom, Classic and Otherwise AWESOME AIR PISTOLS!-
"Apparently the dialed-in feeling wasn’t my imagination, as the five groups calculated to an extremely gratifying .61” c-t-c! Being that I consider 3/4” average groups at 35 yards to be pistol field-target-worthy accuracy, all questions about the AMP’s potentials had been answered in no uncertain terms. YESSS!!!"
Be aware you're not likely to get results like this straight out of the box, but the Air Max is a tinkerer's dream. Also be aware that those 5 consecutive five-shot groups at 35 yards would have gone into a 25 shot group about the size of a quarter. 😍
"No brag; just fact."- Will Sonnett