N/A FX Crown, FPS can be adjusted with the airflow reduction wheel.

Melo,

Your power wheel has a two lobed cam on the inside. The newer Crown wheel is single lobed and is numbered sequency from 1 to 23. Both have been used on the Crown II. I have the newer one and find it easy to use after I took the adjusting mechanism apart and figured out how it worked. I suggest that you get the newer wheel. That way the steps on the wheel are linear. The steps on the transfer port may be too wide for what you want to do.

Power adjustment on the Crown is a black art.

Ron

How big of a difference are you talking between the two pellets?

Greg (@NAProf) has done extensive analysis on the Crown and reports that:

#1: Each full rotation of the Internal hammer spring (IHS) adjuster results in 0.5mm change in hammer spring compression.

#2: Each click on the 1-23 current External hammer spring (EHS) adjuster wheel results in 0.2mm of change in hammer spring compression.

So, 1st off I would suggest upgrading/replacing your ABC wheel with the current 1-23 wheel to enable finer adjustments.

Also, there is nothing wrong with using your transfer port adjuster to manage velocity. I have 3 FX Crown Mk2s and have not really explored that - I tend to always use Medium for .177 and .22 and High for .25 caliber. Now you have me wondering if 1/2 way between Medium and High will or 1/2 way between Low and Medium will give stable results...

One thing I've noticed across my 3 Crown Mk2s... I've got the regs set at 120, 130 and 140 bar (as per FX rifle gauges). Perhaps because the stock Crown has a stiffer hammer spring than the Dreamline, I've found that these higher reg pressures work extremely well (with Medium transfer port setting) - regardless of even shooting .177. On my Dreamline Classic, I'm using a reg setting of 95-100 bar with .177 and getting great results. Perhaps I'll experiment using 100 bar reg when shooting .177 with Crown, but I'm getting ES of 10fps and great accuracy with the current 120 bar.

Hope this info/experience helps you "Crown-o-holics"...

-Ed

Melo said:

JSB 0.67g – 10.34 gr Pellet Velocity by Power Setting
View attachment 595464
In this way it delivers the FPS with a regulator at 100 bar, my optimal FPS to achieve would be those 879
I understand that the new 23-position wheel would be the most suitable and the jumps would be smaller, but if by closing the airflow I get the desired fps, the rifle remains consistent and precise, then I will save those $43 for the wheel plus $20 for shipping and once it is working, it is something that will not be manipulated every moment.

Click to expand...

At what setting is the transfer port adjustment, please?
Also, without criticism, what is it about 879fps that makes it optimal for you?

just my 2 curious
Edward

Melo said:

FX Crown, can the FPS be adjusted with the airflow reduction wheel, or am I wrong?
I have a FX Crown MKI in .177, which loves almost any pellet, but I have two weights that stand out and the rifle becomes super accurate and consistent.The problem I have is when adjusting the power for those particular pellets, or at least for one, the power wheel, the one that is numbered, when going from one number to another, or letters, on the power scale, the jumps are too large and are not close to the FPS where those pellets work well.I solve this by disassembling the stock and adjusting the hammer spring with its wrench and using a crony until I get the desired FPS, the issue is that I don't want to be disassembling the stock every time.As a test, I moved the airflow adjustment wheel very slowly and I could see that the FPS was varying. I continued moving it slowly and with the help of the crony I got my desired FPS, simply by reducing the airflow.
Now I have the PCP set to the appropriate velocity using the power scale wheel for one pellet, and when I want to use the other pellet, I simply close the airflow to a predetermined point.
Is this the correct way to achieve my velocity, or is it detrimental to close the airflow?

View attachment 595132

Click to expand...

Hi Melo,
This is a 3D Model of the Crown Transfer Port Cams on a MkII.

The inner cam is fixed vertically by a screw into its end. When you turn the black wheel, you are aligning on of the three sizes of holes drilled into the outer cam. There is a ball bearing and spring in the action which drops into a detent to tell you when you have the holes lined up.

My personal opinion is that this is not a way to adjust pellet velocities, other than in a very macro sense. It is my first setting when trying a new pellet. I have had many different size and caliber barrel kits for my two Crowns, and the projectile, barrel length and caliber pretty much decide which of the three settings on the transfer port I choose. Once I tune the rest of the rifle (and it is very, very tunable) I might come back to the Transfer Port if I can't get the accuracy I think it should have. I found that no matter the weight and size of a .22 pellet they all were more accurate using the medium setting. Heavy slugs in .25 needed the high setting. My .177 pellets like the Medium setting also - but I am not shooting the at 12 FPE as you would for WFTF Field Target. I shoot them at 20 FPE.


Cheers,
Greg

Melo said:

FX Crown, can the FPS be adjusted with the airflow reduction wheel, or am I wrong?
I have a FX Crown MKI in .177, which loves almost any pellet, but I have two weights that stand out and the rifle becomes super accurate and consistent.The problem I have is when adjusting the power for those particular pellets, or at least for one, the power wheel, the one that is numbered, when going from one number to another, or letters, on the power scale, the jumps are too large and are not close to the FPS where those pellets work well.I solve this by disassembling the stock and adjusting the hammer spring with its wrench and using a crony until I get the desired FPS, the issue is that I don't want to be disassembling the stock every time.As a test, I moved the airflow adjustment wheel very slowly and I could see that the FPS was varying. I continued moving it slowly and with the help of the crony I got my desired FPS, simply by reducing the airflow.
Now I have the PCP set to the appropriate velocity using the power scale wheel for one pellet, and when I want to use the other pellet, I simply close the airflow to a predetermined point.
Is this the correct way to achieve my velocity, or is it detrimental to close the airflow?

View attachment 595132

Click to expand...

You can absolutely do this. I tested it some when I had a time that worked great for 25s and 18s. Max for 25s and min for 18s.

By switching the transfer port from high to medium it gave me a few more test settings for the 18s.