Hello , just a simple question : is it possible to install a bigger plenum chamber on a FX Crown 1st generation ? I didn't see any tuning part to do so . Thanks.
FX Crown MK1
- Thread starter aldea6
- Start date
No. The plenums are under the stock, and so you’d have to modify the stock for it to fit. It’s been done, but the additional plenum can’t be too big, so not sure how much worth it is in the end.
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You can replace the plug with an expanded chamber/plug which will increase the plenum size and do have affect on the power, not huge but there is a bump in power especially with MK1. BUT you will have to drill out that section of the stock as it blocks the area for the plug/plenum, if you are handy and have the right tools it's easy.
AGN member @cfs916 makes a beautiful plenum for the crown, I just don't have the gusts to drill my stock! If you are willing to drill/modify your stock then reach out to @cfs916.
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OK thanks madeintheuk
That's great ; I've a shop very well equiped and I think that , with careful measurements and patience , i'll do it.
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This should work,
europeairguns.com
Main block Crown Picatinny
<p>You can order the main block with your rifle's serial number engraved on it upon request. This personalized service costs 30€, payable via gift cards.</p>
europeairguns.com Upvote 0
There's been a number of other plenums made, but most are rather awkward.
This one is not so bad, but requires a modified (or older) barrel, and a longer valve stem/spring.
This would also require a longer valve stem, and would make the gun overall very awkward.
I'll also refer you to some info on port work. My mk1 continuum picked up 50fps on 380mm .22 barrel, and 75fps on 700mm .22 barrel without touching the factory tune. Just port work.
Well, I guess I never made a post about it, so I'll just tell/show you. On my barrels I flare the port into a bellmouth that starts at .30" and tapers down to factory bore size, but also radius the 90 degree turn inside of the port. Also cut the probe to match.
Running the transfer port wheel on "high" creates a .30" opening, and the venturi or bellmouth creates a pressure spike, and smooths airflow. Additional tip. Leaving a somewhat rough finish in the ports actually helps air velocity. Polishing it smooth creates additional turbulence.
This one is not so bad, but requires a modified (or older) barrel, and a longer valve stem/spring.
This would also require a longer valve stem, and would make the gun overall very awkward.
I'll also refer you to some info on port work. My mk1 continuum picked up 50fps on 380mm .22 barrel, and 75fps on 700mm .22 barrel without touching the factory tune. Just port work.
Well, I guess I never made a post about it, so I'll just tell/show you. On my barrels I flare the port into a bellmouth that starts at .30" and tapers down to factory bore size, but also radius the 90 degree turn inside of the port. Also cut the probe to match.
Running the transfer port wheel on "high" creates a .30" opening, and the venturi or bellmouth creates a pressure spike, and smooths airflow. Additional tip. Leaving a somewhat rough finish in the ports actually helps air velocity. Polishing it smooth creates additional turbulence.
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I disagree. When I bought my first “high end” pcp it was a wildcat mk2 with 600mm barrel in 25cal. I bought it used on recommendation from Augie (@Bigragu) here, and after chatting about wanting more power, I shipped it to him, and he gave it the works. My point is, I received a rifle back that was shooting substantially more accurate and more powerful than the one I purchased, and it gave me ZERO issues in the time I had it. I then sold it to another member here who was just as ecstatic as I was to own it.
Would I have tackled the job myself? Back then, HECK NO, maybe now I could a couple years later, and much more knowledgeable, but you don’t need to do the work yourself. There’s guys like Augie out there that can do it for you, and are much more knowledgeable than your or I will ever be about pcp’s.
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I clicked the link and saw the Crown MK2 main block, but no explanation was given as to this being a swap out for the MK1 block. I'm guessing this won't fit a MK1 rifle?This should work,
Main block Crown Picatinny
<p>You can order the main block with your rifle's serial number engraved on it upon request. This personalized service costs 30€, payable via gift cards.</p>
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I would maybe possible to put a chamber on the side of the action , kind of an hollow plug but with a larger volume . Of course , the aesthetic will suffer 
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Not sure, best to reach out to @.cfs916.
The internal plenum is quite small so this should present significant plenum increase percentage wise.
The internal plenum is quite small so this should present significant plenum increase percentage wise.
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This is my first idea : drill a hole through the stock and the plenum , make a thread in the plenum hole and screw and external volume ( black cylinder on the stock), add the necessary O-ring to avoid leaks , etc....This is only a fake assembly , just to show the idea . After all it would better better .....to get a Maverick 
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