Bout time for a new post on this site. It's a long 'un!

Joined: September 7th, 2001, 3:52 am

January 14th, 2018, 8:13 pm #1


I wanted to wait until I had my .22 MRodAir Air Max Precision completely sorted out before posting about it; but got so tired of seeing nothing new here decided to post results so far.

Impressed with the design, features, execution and quality of the gun, initial velocity testing on the brand-new pistol left much to be desired. Matter of fact it was downright erratic; moreso than an unregulated gun. So much so that I jumped right into it, thinking even if I didn't find the problem I'd learn to work on it. And though I did not find the inconsistent-velocity problem, did thoroughly clean and degrease everything inside, scrub the bore, drill and tap the grip-frame, and install a set-screw to anchor the ***-end of the barrel.

Unfortunately the velocity issue persisted, so I started monkeying around with the power-adjusting features in hopes of finding consistency at high power (15+ foot-pounds). Backed the transfer-port screw out of the way of air-flow, then concentrated on the hammer-spring adjustment; that being the power adjustment I'm most familiar with anyway.
Though I was able to easily get the power-level i wanted, the pistol was still acting like an unregulated gun.

So then I also started messing with the regulator adjustment, trying to find a combination of regulator and hammer-spring adjustments that would give high power and consistent velocities. After a LOT of monkeying and testing, best I could get was an unregulated-type bell-curve power-band at good power, but disappointing number of shots per charge. These were the best results-

With 18.1 grain JSBs at 2800 PSI, a 15 shot power-band returned this- Low= 591, High= 625, ES= 34, SD= 11, Average= 607 FPS/14.8 FP. Also, five consecutive five-shot groups at 35 yards averaged 1.31” center-to-center.

Accuracy wasn't bad; but for this field-target shooter, nothing to get excited about. With a couple days worth of monkeying and testing at that point, I put the gun away for awhile. A couple subsequent accuracy-test sessions yielded the same bench-rest results, no matter how hard I tried. So "awhile" became quite awhile.

Occasionally I'd handle and admire the gun, and think how nice an air pistol it could be if performance was as impressive as the features, configuration and (subjective) 'feel'.

Finally got around to searching the forum for information yesterday, specifically looking for others' Air Max Precision testing and 'smithing results. More specifically, some very impressive, REGULATED-consistency power-bands I thought I'd seen before. Found them, and based on the information decided to try backing-off the hammer-spring tension to more sane power levels to see if I could find regulated consistency. Happy to report IT WORKED!

By that time it was 1 AM and 30 degrees, and my fingers were so numb that loading the gun was painful. However I found what I was looking for; albeit at a less-magnum power level.

16 grain Air Arms at 3000 PSI returned this 30 shot power-band- Low= 581, High= 606, ES= 26, SD= 6, Average= 596 FPS/12.6 FP.

Duly inspired and unable to resist, I managed to load five more pellets to shoot a 35 yard group. Since that group went barely over an inch, of course I had to try another in spite of increasingly painful digits. VIOLA! A penny spanned the center-to-center of the five-shot group... YESSSS!!



After fine-tuning the trigger adjustment to a cleaner break, I couldn't resist shooting a few more groups today in spite of 20 MPH+ crosswinds that were inflicting 2-3" of drift (at 35 yards). That three groups maintained a 1" average in such conditions reinforces my hopes of 3/4" averages in still conditions. And though that still wouldn't put the gun in the same accuracy league as field-target pistols, I consider 3/4 - 1" groups at 35 yards fine accuracy for most any other air-pistol purposes.

It sure is rewarding to get impressive performance out of a new gun. All the more gratifying the more fussing, testing, 'smithing, aggravation and PAIN it takes to finally get there. Especially when you've started thinking "there's no way to get there from here".

Mighty happy and RELIEVED to finally get there!
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Joined: September 7th, 2001, 3:52 am

January 15th, 2018, 12:19 am #2

With the weather wizards issuing a "winter weather warning" for my area, I hoped to get a little more shooting in before it hits. Thankfully the wind lay completely right before sunset, so thought I'd shoot as many five-shot 35 yard groups as possible before dark.

Managed to get in five groups, on a single fill BTW. To say I was happy when the average group-size calculated to just .70" would be a gross understatement. Matter of fact, though it's still not really suited to field target competition, it is approaching a field target pistol level of accuracy. WOW!
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Joined: June 4th, 2013, 4:42 am

January 18th, 2018, 6:19 pm #3

These inexpensive pistols seem to group well nearly universally. Glad to see you are having a similar experience. I got a .177 a few months ago and it grouped great...in fact the first time I squeezed the trigger on a pest, it was a chipmunk at 35 yards that went down instantly to a brain shot. After tinkering with it a bit, I settled on tuning it up from 8fpe to 12fpe because it is more consistent with a higher (than stock) regulator setpoint. Some folks gave up and ordered an aftermarket regulator. Mine is working much better after burnishing the regulator seat but still suffers from some nonlinearity if I fill to the 220bar limit. It’s great from 200 bar down to 120 bar so I just use it that way. I don’t need many shots for the way I use it for close range pesting.

It’s among the most pellet agnostic airguns I’ve seen. Seems to shoot everything to a similar POI at 25 yards and although it has some preferences for best results (JSB 10.3gr, RWS Superdomes, and Polymags), it is minute of squirrel brain at that distance with most pellets.
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Joined: September 7th, 2001, 3:52 am

January 18th, 2018, 7:16 pm #4

It seems the AMP regs are a bit temperamental, but you and I managed to find reasonable sweet-spots for them. Interesting we both found the sweet-spots around 12 FP; there may be a lesson there.

I'd like to ask one favor, if you don't mind. If you have them available, could you post details of your best shot-sring(s) including pellet, charge-pressure and shot-count specifics? Many thanks Bud.

P.S.- Great shot on the chipmunk considering that (brain) sweet-spot was probably about the size of a TACK!
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Joined: June 4th, 2013, 4:42 am

January 18th, 2018, 11:23 pm #5

I'm only getting a bit over 20 useful shots with a 12fpe tune in .177 caliber.



Efficiency isn't too bad for a short barrel at this power level. In .22 cal (or with a heavier pellet), it would be a bit better.

I haven't kept pictures of groups but someone asked me to try the Polymags for them and honestly this was the first and only group at 25 yards, and not only is it a pretty good group for me with a pistol (resting air tube on a bag) but also a good example of the POI consistency because it was sighted for Superdomes at the time.

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Joined: June 4th, 2013, 4:42 am

January 19th, 2018, 4:22 pm #6

It seems the AMP regs are a bit temperamental, but you and I managed to find reasonable sweet-spots for them. Interesting we both found the sweet-spots around 12 FP; there may be a lesson there.

I'd like to ask one favor, if you don't mind. If you have them available, could you post details of your best shot-sring(s) including pellet, charge-pressure and shot-count specifics? Many thanks Bud.

P.S.- Great shot on the chipmunk considering that (brain) sweet-spot was probably about the size of a TACK!
or is that perhaps an autocorrect of SPA?
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Joined: September 7th, 2001, 3:52 am

January 19th, 2018, 7:13 pm #7

I mean the factory regs on the Air Max Precisions (AMP). nt
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Joined: September 21st, 2009, 8:40 pm

February 5th, 2018, 6:38 am #8


I wanted to wait until I had my .22 MRodAir Air Max Precision completely sorted out before posting about it; but got so tired of seeing nothing new here decided to post results so far.

Impressed with the design, features, execution and quality of the gun, initial velocity testing on the brand-new pistol left much to be desired. Matter of fact it was downright erratic; moreso than an unregulated gun. So much so that I jumped right into it, thinking even if I didn't find the problem I'd learn to work on it. And though I did not find the inconsistent-velocity problem, did thoroughly clean and degrease everything inside, scrub the bore, drill and tap the grip-frame, and install a set-screw to anchor the ***-end of the barrel.

Unfortunately the velocity issue persisted, so I started monkeying around with the power-adjusting features in hopes of finding consistency at high power (15+ foot-pounds). Backed the transfer-port screw out of the way of air-flow, then concentrated on the hammer-spring adjustment; that being the power adjustment I'm most familiar with anyway.
Though I was able to easily get the power-level i wanted, the pistol was still acting like an unregulated gun.

So then I also started messing with the regulator adjustment, trying to find a combination of regulator and hammer-spring adjustments that would give high power and consistent velocities. After a LOT of monkeying and testing, best I could get was an unregulated-type bell-curve power-band at good power, but disappointing number of shots per charge. These were the best results-

With 18.1 grain JSBs at 2800 PSI, a 15 shot power-band returned this- Low= 591, High= 625, ES= 34, SD= 11, Average= 607 FPS/14.8 FP. Also, five consecutive five-shot groups at 35 yards averaged 1.31” center-to-center.

Accuracy wasn't bad; but for this field-target shooter, nothing to get excited about. With a couple days worth of monkeying and testing at that point, I put the gun away for awhile. A couple subsequent accuracy-test sessions yielded the same bench-rest results, no matter how hard I tried. So "awhile" became quite awhile.

Occasionally I'd handle and admire the gun, and think how nice an air pistol it could be if performance was as impressive as the features, configuration and (subjective) 'feel'.

Finally got around to searching the forum for information yesterday, specifically looking for others' Air Max Precision testing and 'smithing results. More specifically, some very impressive, REGULATED-consistency power-bands I thought I'd seen before. Found them, and based on the information decided to try backing-off the hammer-spring tension to more sane power levels to see if I could find regulated consistency. Happy to report IT WORKED!

By that time it was 1 AM and 30 degrees, and my fingers were so numb that loading the gun was painful. However I found what I was looking for; albeit at a less-magnum power level.

16 grain Air Arms at 3000 PSI returned this 30 shot power-band- Low= 581, High= 606, ES= 26, SD= 6, Average= 596 FPS/12.6 FP.

Duly inspired and unable to resist, I managed to load five more pellets to shoot a 35 yard group. Since that group went barely over an inch, of course I had to try another in spite of increasingly painful digits. VIOLA! A penny spanned the center-to-center of the five-shot group... YESSSS!!



After fine-tuning the trigger adjustment to a cleaner break, I couldn't resist shooting a few more groups today in spite of 20 MPH+ crosswinds that were inflicting 2-3" of drift (at 35 yards). That three groups maintained a 1" average in such conditions reinforces my hopes of 3/4" averages in still conditions. And though that still wouldn't put the gun in the same accuracy league as field-target pistols, I consider 3/4 - 1" groups at 35 yards fine accuracy for most any other air-pistol purposes.

It sure is rewarding to get impressive performance out of a new gun. All the more gratifying the more fussing, testing, 'smithing, aggravation and PAIN it takes to finally get there. Especially when you've started thinking "there's no way to get there from here".

Mighty happy and RELIEVED to finally get there!
I’ve been admiring the Mrodair airguns for sometime.
However, it seems that many of the persons buying the Mrod airguns are doing-so with full-expectations that these airguns are gonna need to be tinkered-with
just to get them to funtion properly.

That’s not what I’m looking-for.
As such, is there anyone who is in the business of tuning the Mrodair airguns?
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Joined: September 7th, 2001, 3:52 am

February 5th, 2018, 7:50 pm #9

My experience with MRodAir guns so far is though they may not need to be tinkered with to make them function, they have potentials way beyond what they display straight out of the box. I was about to say, "that's why God created Crosman"; but that may also be only partly true.

My experience with Crosmans has been that, though they less often need 'tinkering' per se, they most always benefit greatly from fine-tuning adjustments. Thankfully Crosman supplies excellent owners manuals that detail the many adjustments... written in English, no less, with photos too!

I'd paraphrase all this by saying the MRA Chinese guns are fantastic bargains; all the more so for those who ENJOY tinkering with their stuff to reveal the POTENTIALS. Of course the more expensive the gun(s), the less likely it requires any monkeying to perform well. That said, I've also experienced some sore disappointments from some very expensive airguns.
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