Hi guys, I have an fx crown mk2 0.25 with 600mm, the maximum I got was 836 fps with 33.95 gr with 105 bar, wheel on high and number 23 on the hammer, I can get more without having to change anything, increasing the pressure on the regulator only decreases my fps
FX Fx crown mk2 synthetic 0.25
- Thread starter Douglas campanha
- Start date
Have you tried to adjust the internal hammer spring? Need to take the stock off and use a 2?mm umbraco to tighten it up
Upvote 0
The Crown will get you more power than that, but it will take more reg pressure. I would have guessed that you would want to be up between 130-150 to get those pellets where you want them, but have never shot .25 in the Crown .25. Someone here with one will probably chime in. Do some searches until then on the Crown here in this forum, and you may find them.
Upvote 0
The one real downside to the Crown MK2 is the need to remove the stock to get to the internal/micro hammer spring adjuster. I have two of them and both have the Saber Tactical chassis. That chassis is a real pain to remove whenever you want to make micro adjustments to the hammer spring. Other than that I love the Crown MK2.
Have you watched the AEAC video on tuning the Crown MK2? It is an excellent tutorial that will really help you. It demonstrates how to get to and use that micro adjuster.
Kenny
Have you watched the AEAC video on tuning the Crown MK2? It is an excellent tutorial that will really help you. It demonstrates how to get to and use that micro adjuster.
Kenny
Upvote 0
The first pcp i bought was an crown mk2, I put a slug power kit in it and with 145bar i shot 33gr slugs around 960fps.
This is 155m
This is 155m
Upvote 0
Hi Doug,
As others have stated above, you will need to remove the stock to access the internal hammer spring adjuster. Removing stock requires that you first remove the safety and hammer spring adjuster wheel - super simple - watch a video.
I like to remove the internal adjuster from the rifle, and measure it exactly when I’m setting up my Crowns.
I have your EXACT setup: FX Crown Mk2 .25 with 600mm superlight barrel. Here is some EXACT baseline data that may help you set up your Crowns:
Reg pressure: 140 bar on gauge
Hammer Adjuster total length: 0.9395 inches
Power Wheel on 9
Transfer Port Adjuster on Medium
Gives 878fps with 43F temperature using 25.4g
I set up the rifle (internal adjuster) so that I was getting 880fps at a lower setting on the power wheel with 25.4g so that I had “headroom” on the wheel to shoot 30 and 34g pellets. (I LOVE the 25.4g .25 pellet for accuracy).
So now you have details on the hammer adjustment to 1/10,000 of an inch for your EXACT rifle… so get out your Allen keys, take the rifle apart and GET TO IT, lol.
Hope this helps and Good luck,
-Ed
Upvote 0
And just remember when you take the power wheel there is 2 small steelballs there that are easy to loose
Upvote 0
An extra bit of info applicable to both the Crown and Maverick hammer spring adjusters - courtesy of NAProf (Greg) who is our “super tech engineer” in the 30 & 40 yard shooting Challenges here on AGN.
Summary of Greg’s findings:
Each full turn of the INTERNAL adjuster results in .5mm compression of the hammer spring.
Each click of the power wheel (23 numbers power wheel) results in .2mm hammer spring compression.
So you can see that the internal adjuster needs to be set to accommodate the pellet weight/velocity you desire… and the power wheel can then be used to fine tune velocity.
Hope this helps you understanding of how hammer spring preload can be effects managed on the FX Crown Mk2.
-Ed
Summary of Greg’s findings:
Each full turn of the INTERNAL adjuster results in .5mm compression of the hammer spring.
Each click of the power wheel (23 numbers power wheel) results in .2mm hammer spring compression.
So you can see that the internal adjuster needs to be set to accommodate the pellet weight/velocity you desire… and the power wheel can then be used to fine tune velocity.
Hope this helps you understanding of how hammer spring preload can be effects managed on the FX Crown Mk2.
-Ed
Upvote 0
You need to adjust the internal hammer spring pre-load, as stated in many replies before
Then you will be able to get much more out of this rifle. Upvote 0
Yes, that is because the increase in regulator pressure makes it harder for the hammer to “open the door” to release the air.
You need to “run into the door” harder (increase hammer velocity) to release the air when the “wind” (regulator pressure) is pushing to door shut.
Simply put, your internal hammer spring adjuster is set way to low for 34g pellets.
Once you increase the hammer spring preload, you will find that higher regulator pressures will result in higher velocities.
Your Crown with a 600mm barrel will easily push 34g pellets over 900fps (if desired) once you properly set reg pressure and hammer spring preload.
Your current 105bar reg pressure is just NOT an appropriate/optimal reg pressure for .25 caliber .
-Ed
Upvote 0
Hi Doug,
IMHO Ed has it right. He understands how the Crown works and has your setup. I also think his shooting at the 40yd AGN Challenge is proof positive that the .25 Crown is a winner.
The only point that Ed makes that may need clarification is the measurement of the "Hammer Adjuster" length. Perhaps I can provide a couple of views from my Sketchup CAD model of the crown action to help you see what Ed is measuring.
Below are two images taken from my 3D model. The first shows the mechanical parts of the Crown Mk II action from the right side. The piece in blue is the Spring Carrier. Inside that is the Hammer Spring and inside that is the Additional Hammer Weight. The spring and the weight slide into the actual hammer. The image shows how the trigger sear holds the hammer when the rifle is cocked. The image is of the rifle cocked with the breech open. This image gives you an idea of the positions of all the components inside the block.
This next image has all of the components stripped away except for the Spring Carrier (blue cylinder), the Hammer Adjuster (blue piece attached to the Spring carrier), the Internal Hammer Adjuster (IHS) screw (short gray piece sticking out of the hammer adjuster), and the Power Wheel.
My interpretation of what Ed is measuring (correct me if I am mistaken Ed) is the length of the Hammer Adjuster plus the amount of the IHS that is sticking out of the Hammer Adjuster. You can change that length using a 1.5mm hex from the barrel end of the Hammer Adjuster. one turn of the IHS moves the tip of the IHS 0.5mm. That is effectively how much you are changing the length of the compressed hammer spring. Of note is that each click of the Power Wheel changes the length of the compressed spring almost exactly 0.2mm.
I hope you have found my pictures and explaination useful. I love shooting my Crowns and believe that are terrific, beautiful rifles that can also be amazingly accurate.
Cheers,
Greg
IMHO Ed has it right. He understands how the Crown works and has your setup. I also think his shooting at the 40yd AGN Challenge is proof positive that the .25 Crown is a winner.
The only point that Ed makes that may need clarification is the measurement of the "Hammer Adjuster" length. Perhaps I can provide a couple of views from my Sketchup CAD model of the crown action to help you see what Ed is measuring.
Below are two images taken from my 3D model. The first shows the mechanical parts of the Crown Mk II action from the right side. The piece in blue is the Spring Carrier. Inside that is the Hammer Spring and inside that is the Additional Hammer Weight. The spring and the weight slide into the actual hammer. The image shows how the trigger sear holds the hammer when the rifle is cocked. The image is of the rifle cocked with the breech open. This image gives you an idea of the positions of all the components inside the block.
This next image has all of the components stripped away except for the Spring Carrier (blue cylinder), the Hammer Adjuster (blue piece attached to the Spring carrier), the Internal Hammer Adjuster (IHS) screw (short gray piece sticking out of the hammer adjuster), and the Power Wheel.
My interpretation of what Ed is measuring (correct me if I am mistaken Ed) is the length of the Hammer Adjuster plus the amount of the IHS that is sticking out of the Hammer Adjuster. You can change that length using a 1.5mm hex from the barrel end of the Hammer Adjuster. one turn of the IHS moves the tip of the IHS 0.5mm. That is effectively how much you are changing the length of the compressed hammer spring. Of note is that each click of the Power Wheel changes the length of the compressed spring almost exactly 0.2mm.
I hope you have found my pictures and explaination useful. I love shooting my Crowns and believe that are terrific, beautiful rifles that can also be amazingly accurate.
Cheers,
Greg
Upvote 0
This thread is a brilliant example of thoughtful forum members pooling their knowledge to help a member in need. I love it.
Kenny
Kenny
Upvote 0
Yep, exactly Greg.
Also, I think my way of measuring the total length of the internal adjuster is more precise than trying to measure the length the screw is extended or counting threads exposed, etc.
Personally, I think having these external adjuster wheels is both a blessing and a curse for FX…
…. if the wheel didn’t exist and newbie guys had to take the stock off and screw in a single screw (like on a Dreamline Classic) to adjust the hammer spring tension, they would grasp much more quickly how to set up their rifles (I.e. balance reg pressure and hammer spring tension)..
… if the wheel runs out of preload, they get confused. We’ve seen these same questions on the FX “power wheel” rifles dozens of times on AGN.
Steve’s video on the Crown is a pretty nice tutorial, but really doesn’t address setting up your Crown for multiple pellet weights - I.e. set the internal adjuster so that your lightest pellet is at the velocity you desire with the power wheel on a low number. Then you can dial up the power wheel when you use a heavier pellet without having to remove the stock and mess with the internal adjuster again.
-Ed
Upvote 0
Some guns require a journey to get exactly what you want from them, and that is part of the fun.
The fact you can get a whole lot from the crown does indeed not make it any easier.
But, to be honest, I have cursed that hidden screw more than I'd like to admit.
Upvote 0
Make sure to read the posts from these guys telling you to increase the internal hammer spring. The outside wheel is dependent on the internal setting. These are two of the most helpful people around when it comes to the Crown.
23 on the wheel is just as high as the wheel goes, but 23 can be very different after adjusting it internally. 15 could technically be higher than your current 23, after adjusting the internal hammer spring.
Upvote 0