Modify Crown mk2 stock for easy access to internal hammer spring adjustment.

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MEC17670

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Hey Guys and Gals,
For all those FX Crown lovers out there, we all know how much a pain in the rear end it is to fine tune the internal hammer preload while tuning for accuracy. In and out of the stock multiple times so each fine adjustment can be grouped.
Got an idea about resolving this inconvenience. Why not cut a small tuning slot in the stock, in my case synthetic, that allows access to the adjustment screw. I can't see any reason that it would hurt the structural integrity of the stock by doing so. The slot would not have to be to wide and it could be made long enough , depending on how you have your gun set-up, to make those super fine adjustments.
Has anyone out there done this before?
Your thoughts?
Thanks Mike
 
i don’t mind removing the stock to mess with the micro adjuster. I bought this rifle to be more simple than an impact. If I wanted to tinker that much, I’d buy another impact. I also like the gauge placement as to not interfere with the beauty of the Minnelli stock.
To each their own of course.
 
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madeintheuk said:
i don’t mind removing the stock to mess with the micro adjuster. I bought this rifle to be more simple than an impact. If I wanted to tinker that much, I’d buy another impact. I also like the gauge placement as to not interfere with the beauty of the Minnelli stock.
To each their own of course.
Click to expand...
With a Minnelli stock, I wouldn't do it either.
 
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I've thought about this, too, and wondered why FX didn't make a provision. However, I think the slot cut in the stock would not allow you enough room to rotate the hex wrench very much at all. You already can only rotate it about a quarter turn with the stock off. So, now add another 0.25" 'wall' out from the screw and it would make it a real PITA to even insert the wrench into the screw, much less be able to get any movement. Hard to explain, but think about it and maybe you will see what I mean.

The guys I've seen making that adjustment have left the stock off and laid the action on the side, then fired their string from there.
Rather than take the stock off and on multiple times and take multiple chances to loose those little balls and springs each time you remove the HS wheel.
 
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huntr said:
I've thought about this, too, and wondered why FX didn't make a provision. However, I think the slot cut in the stock would not allow you enough room to rotate the hex wrench very much at all. You already can only rotate it about a quarter turn with the stock off. So, now add another 0.25" 'wall' out from the screw and it would make it a real PITA to even insert the wrench into the screw, much less be able to get any movement. Hard to explain, but think about it and maybe you will see what I mean.

The guys I've seen making that adjustment have left the stock off and laid the action on the side, then fired their string from there.
Rather than take the stock off and on multiple times and take multiple chances to loose those little balls and springs each time you remove the HS wheel.
Click to expand...
Diffently food for thought.
My thoughts were to make the slot wide enough to allow a the long end of a ball head 1.5(I think that's correct) to be inserted into the adjustment screw, leaving the short end out. Trick would be giving the short end of the wrench ample room as it lays length wise on the stock.
I'm surprise the SaberTac didn't leave a machined slot. Maybe a t type with the t closest to the adjustment screw.
Got to check on the price of a new composite stock possibly for R&D.
Thanks for your input, you pointed out a definite obstacle. Folks like yourself is what makes this forum so good.
Mike
 
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There was a thread a few years ago that showed one guys fix. Instead of 'slotting' he simply dropped a cut opening from the top edge of the stock to the adjustment spot. This was on a wood or laminate stock. The thread hadda picture of the work and it did not look bad at all.
I tried a quick search, but it didn't come up with that thread. You might try your own search to see if it comes up though.
mike
 
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MEC17670 said:
Diffently food for thought.
My thoughts were to make the slot wide enough to allow a the long end of a ball head 1.5(I think that's correct) to be inserted into the adjustment screw, leaving the short end out. Trick would be giving the short end of the wrench ample room as it lays length wise on the stock.
I'm surprise the SaberTac didn't leave a machined slot. Maybe a t type with the t closest to the adjustment screw.
Got to check on the price of a new composite stock possibly for R&D.
Thanks for your input, you pointed out a definite obstacle. Folks like yourself is what makes this forum so good.
Mike
Click to expand...
You won't be able to get the long end in, I don't think. Didn't take the stock off to actually see. From memory, the recess in the action where the adjustment is, isn't long enough to do that. Try it with the stock off and see if you can do it.

A cut out, like Revoman referred to, might work if you beveled the bottom edge to allow more swing room for the hex. But, you're opening up that access point for dirt and debris to more easily get in. How many times are you going to make that adjustment? It's not a routine adjustment, like changing the HS wheel setting.

Personally, sometime when I get a wild hair, I'll go to the effort of making that tuning adjustment. But, I'm not bencherest shooting just plinking and hunting, and my gun is shooting good enough for me at this time. I followed AEAC Steve's method of taking the slack out of the adjuster on the low setting so that all the numbers have some effect on HS tension. Once I found the regulator pressure that that the hammer spring could handle, I can shoot 15, 18, and 21 grain pellets, in the 860-880+ fps range, by adjusting the HS wheel and the TP setting.
 
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Revoman said:
There was a thread a few years ago that showed one guys fix. Instead of 'slotting' he simply dropped a cut opening from the top edge of the stock to the adjustment spot. This was on a wood or laminate stock. The thread hadda picture of the work and it did not look bad at all.
I tried a quick search, but it didn't come up with that thread. You might try your own search to see if it comes up though.
mike
Click to expand...
That would make life easier for sure. I'll take look around, also.
Thanks for the heads up.
 
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I did this a couple of years ago. It may make your gun less valuable if planning to sell it, as some may not like it. Maybe it would look better without the lip, over the wheel? It personally does not bother me, as the gun feels the same when shooting it.
I think it makes the gun more user friendly when adjusting it. You can reach the internal hammer adujster with an allen key, with the stock on.

IMG_20220908_182634.jpg


IMG_20220908_182701.jpg
 
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MEC17670 said:
Diffently food for thought.
My thoughts were to make the slot wide enough to allow a the long end of a ball head 1.5(I think that's correct) to be inserted into the adjustment screw, leaving the short end out. Trick would be giving the short end of the wrench ample room as it lays length wise on the stock.
I'm surprise the SaberTac didn't leave a machined slot. Maybe a t type with the t closest to the adjustment screw.
Got to check on the price of a new composite stock possibly for R&D.
Thanks for your input, you pointed out a definite obstacle. Folks like yourself is what makes this forum so good.
Mike
Click to expand...
You cant get the long end of an allen wrench into the screw even with the stock off. Like huntr said the slot in the receiver isnt long enough to get the long end of the allen into the screw.
 
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tor47 said:
I did this a couple of years ago. It may make your gun less valuable if planning to sell it, as some may not like it. Maybe it would look better without the lip, over the wheel? It personally does not bother me, as the gun feels the same when shooting it.
I think it makes the gun more user friendly when adjusting it. You can reach the internal hammer adujster with an allen key, with the stock on.

View attachment 288424

View attachment 288425
Click to expand...
Those are great photos on how you modified your Crown. Great access for fine tuning.
That mod might even increase the value of you gun.
Thanks for sharing.
 
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MEC17670 said:
I came from the other end of powering up than Steve. 2 ways a achieving the same results.
I'm able to turn PW down and with the use of TFP on medium shoot the 25.39 pellets from 880 to 935. 895 seems to provide best accuracy for my barrel 600mm .
Click to expand...
That's interesting, because I can't get those velocities with the 25 gr. That may be the nudge I need to try that method of tuning it. I kinda' wondered if it would increase velocities. I'd love to shoot the 25's because they have proven accurate in other guns and a nice increase in fpe. Mine is a 500mm.
 
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huntr said:
That's interesting, because I can't get those velocities with the 25 gr. That may be the nudge I need to try that method of tuning it. I kinda' wondered if it would increase velocities. I'd love to shoot the 25's because they have proven accurate in other guns and a nice increase in fpe. Mine is a 500mm.
Click to expand...
GhostRanger suggested that
tuning method to me. You could look up my post , read it and give it a go.
The 600mm barrel really helps. I have a .22 500mm barrel kit that tried but found that I couldn't get the same results that I could with the .22 600mm barrel kit.
I have my internal pre-load pretty close to maxed out , running between 155 and 160 reg pressures, depending on ambient temperature. Slug transfer port, ome , tried the huma, but test revealed i would need a higher reg pressure due to the larger size to get the same results. Power wheel is set on 22. Once i achived close to my targeted velocity, i shot groups with bracketed power settings to see which setting gave me the best groups. 21, 22, 23, 24. Right now shooting Neilson 26.8 slugs 975 ftps and with the 29.5 slugs 945 .
As I use it for hunting , shot count at 44 is not an issue, I carry an extra gun air vessel in my day pack, so 88 shots at close to 60 ftlbs. with the 29.5 slugs. The 29.5 slugs are very accurate in the wind. With a bc of .091 , it shows.
I started this post as a way just to tweek the harmonics using micro adjustments with the pre- load.
An 1/8 of a turn might just hit a very sweet spot as I am close to it. Shooting groups with the stock off won't work.
I've tried using a heavier huma spring but found it hard to find the right dwell time. Also tried a pin probe but the alinement was constant enough allowing the slug to push the oring out of my breech. Something else to address.
Hope some of this info helps . Have fun,
Mike
 
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