FX FX MKII to MK3

I did a conversion last summer, from .25 MK2 PP (Power Plenum), to a Power Block and larger Plenum.
I had in mind to generate higher power output for shooting heavier then 40gn slugs with higher then 1000 fps for longer distances for example 200 meters or eventually beyond.
It was a new learning curve tuning with the larger plenum.
And I can save you some money and hassle - don't buy the tungsten hammer weights unless you upgrading the caliber larger then .25.
The next thing I learned that tinkering about speeds 1000-1050 fps is wrong. Not the speed but the RPM of a slug delivers.
Next thing I learned, try and test more amo, a friend's tune advise from forums not necessary will work.
The next thing I learned, that at my club the management didn't allowed me shooting a longer then 100 meters, with an airgun. I had to do presentation to the board members in open meeting, to show them what the Impact is capable of producing numbers... BS but anyway. Finally they gave me the 200 M range access but I didn't renew the membership for '23.

So, if you stay .25 and below, 100 M and below, 40gn and below ... the MK2 PP can save you the $$$$ it is a very capable machine.
Better investment is getting a variety of liners.
I ended up with 5 so far

Now, back to OP. What the M3 can give you more then the MK2 have?
Dials and buttons, you will play with a first couple days and just forget about for a next while ... The radar/chronograph numbers are the important for precision, and not what the micro or ma ro means....;)
 
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I did a conversion last summer, from .25 MK2 PP (Power Plenum), to a Power Block and larger Plenum.
I had in mind to generate higher power output for shooting heavier then 40gn slugs with higher then 1000 fps for longer distances for example 200 meters or eventually beyond.
It was a new learning curve tuning with the larger plenum.
And I can save you some money and hassle - don't buy the tungsten hammer weights unless you upgrading the caliber larger then .25.
The next thing I learned that tinkering about speeds 1000-1050 fps is wrong. Not the speed but the RPM of a slug delivers.
Next thing I learned, try and test more amo, a friend's tune advise from forums not necessary will work.
The next thing I learned, that at my club the management didn't allowed me shooting a longer then 100 meters, with an airgun. I had to do presentation to the board members in open meeting, to show them what the Impact is capable of producing numbers... BS but anyway. Finally they gave me the 200 M range access but I didn't renew the membership for '23.

So, if you stay .25 and below, 100 M and below, 40gn and below ... the MK2 PP can save you the $$$$ it is a very capable machine.
Better investment is getting a variety of liners.
I ended up with 5 so far

Now, back to OP. What the M3 can give you more then the MK2 have?
Dials and buttons, you will play with a first couple days and just forget about for a next while ... The radar/chronograph numbers are the important for precision, and not what the micro or ma ro means....;)
Just disagree with one point. Fps vs rpm.

I understand that when we increase fps, the rpm are automatically increased
 
Yes, but in conjunction with FPS. The more FPS, the higher the RPM with the same twist rate.
Depend of a perspective.
For a fixed distance let say 20 yard , the projectile will have a calculated fixed number of turns, regardless of it will get there in 0.1 second or 2 or 10.
How many times of 18 inches in a 20 yard length (for a 1:18 twist rate) ? That is a static number... the fps is a variable ES/SD and you chasing it for accuracy on POI.
 
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To the die hard MK2 fans, if there’s one upgrade towards an M3 that you will all benefit from and thank me later on convincing you yo do this upgrade, it’s to switch to the M3 cocking system. That’s new cocking block, front and rear block, short throw linkage and a new larger cocking handle.

It’s only a matter of time when the pin that ties in the cocking block to the cocking linkage snaps, especially if yours has the years in. And when it snaps, there is no “oh just pull the sheared piece out and replace it with a new pin”.
Nope, not gonna happen, unless you just mangle your cocking block in trying to pull a stuck pin that’s sheared flush to the blocks underside. A new MK2 replacement block is like $80.
The m3 system is designed so it the pin ever breaks, it truly can be easily replaced. The other great plus to this upgrade- no more rubber balls up front!!

Utah air has this whole upgrade kit at a reasonable price
 
I replaced that kit to ST I think twice now, the ST handle was snapping into the front block edge ... forgot several times to push it back by hand and released the shot. Usually that bends the pin as well. I cured that habit about a year ago but still remember my shame :)
Would this cooking kit something new to M3? I never look back since my affairs with ST.
 
The Twist Rate drives the RPM ;)
Not only.

Here is the formula:
MV X 720/Twist Rate = RPM

 
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I agree with you.
But most of people misunderstanding the basics and posting questions "what is a best speed for my M3 for shooting xyz named slugs".
Most of them don't know what the TR does, for a given style of shooting or distances.
Just for excersise we can recalculate couple scenarios, what the "pro" is not saying why he shots that particular slug with a speed of 935 fps for example and the other one with 895 and the third guy with let say 980.
Would you agree with me that the TR of 1:16 or 1:18 or 1:24 or 1:27 needs different fps for a same quality precision?
Just for example shooting ZAN 38gn (I am improvising now these numbers for pictorial only)
1:16 - 880 fps
1:19 - 920 fps
1:24 - 950 fps
1:27 - 1020 fps
What is common in these numbers? Speculating the RPM would be pretty close or targeting a same ballpark? Not saying how wide is a ballpark but let just say +/- 25 fps.
(On my tablet right now but next time I am back to PC I will make the formula.
 
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Why I prefer ZAN's? Because back in time I asked the guy what speed he would recommend for a 41gn?
He said the best performance is @ 965 from a SH liner.
But I don't have the SH I have the S only?
Then go with zyx speed.
He trusted me with he's numbers and I am trusting him with my business.
But just to make sure I have tested all of these last summer... changing speeds and monitoring the group sizes.

20231213_151043.jpg

Every liner I measured myself the TR and engraved into liner. Just in case if I loose the sticker again :)
btw, I have 3 more liners but winterized with my guns.
 
I replaced that kit to ST I think twice now, the ST handle was snapping into the front block edge ... forgot several times to push it back by hand and released the shot. Usually that bends the pin as well. I cured that habit about a year ago but still remember my shame :)
Would this cooking kit something new to M3? I never look back since my affairs with ST.
This is the upgrade to the mk2 cocking assembly
 
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