Ernest Rowe FX Crown Hammer Kit

[sniperlabyo]

Other mods that will increase your speed. 

Open up the air restriction by;

1. New design Large VS bore to 6.50mm from 5.57mm and larger valve pin 7.40mm

2. Enlarge the barrel PT by oblong or double TP on barrel and probe, I seen more speed gain with DT.

with extensive testing the crown valve and pin hasn’t failed at higher reg pressure of 160-165b, I’m not telling you to use higher regulator pressure, just for me knowing the possibility.

the crown has limited plenum chamber, actually there are 2 in the action, the restrictions is a small opening from the larger chamber to the smaller chamber where the valve and seat are located, I will grind away to enlarge the opening to increase flow and maintain higher bar in the shot cycle.

the mods parts will be available soon, Will report later what speed I’m getting. Last time i check was over 900fps + with 25gn RD with 500mm barrel.

I have power tuned the impact past 100fpe, now I have more time to brain storm the crown to achieve max FPE.

 

[Bob_O]

Thank you Ernest.

If I do anything more, it would be your new VS and pin. I don't want to put a dremel or other rotary tool to my gun.

And I would prefer to stay at 150bar or lower, as shot count is already suffering at 150 compared to 130 or even 140bar. 

If I need to shoot the 21gr or 23gr slugs faster than what I can get with drop-in parts, I will just go for a 600mm barrel.

 

[BDX]

If I need to shoot the 21gr or 23gr slugs faster than what I can get with drop-in parts, I will just go for a 600mm barrel.

Bob, So just to be clear here, FX doesn't make a 600mm Crown barrel from what Mike at Utah Airguns told me so one would need to buy a 600mm Impact barrel and adapt (if necessary) to fit the Crown action? and of course keeping the Crown stock shroud you have 100mm (~4") of exposed barrel at the receiver end?

George 

 

[Bob_O]

You wouldn't have to adapt anything from what I've been told, it's a direct swap. Yes there would be 100mm of sleeve showing with the shorter Crown shroud, which wouldn't bother me one bit.

 

[BDX]

You wouldn't have to adapt anything from what I've been told, it's a direct swap. Yes there would be 100mm of sleeve showing with the shorter Crown shroud, which wouldn't bother me one bit.

Great to get a confirmation. It's been a bit rough to sort some of the barrel configurations out...and 4" of exposed sleeve wouldn't bother me a lick...might even be a bit slick looking. Just to round this out I guess I'll write FX and ask the cost of a 600mm sleeve and just for S&G's write Mike and ask if I can change my slug liner preorder to a .22 600mm. As usual when all the cool stuff is coming down I find myself away from my "laboratory" for another couple of weeks...

 

[Bob_O]

You can't get just the sleeve, I asked for that a week ago and was told those parts weren't sold individually.

 

[stoti]

I'm sure Neil Clague could make a sleeve easy enough.

Stoti

 

[Bob_O]

Did my first sub-1" 5-shot group at 100 yds today.

16*F, 5 mph wind from the right.....3" drift. JSB 18gr at 928fps avg at 60*F. One-half mil dialed in for windage.

This is the top left group of the overall target.

View attachment MTU0NzY3NTM1Ml8xMDk0OTM4ODY1YzNmYTZkOGMxMzc4MC41ODE4NTk5Ml9PUkdfRFNDMDM2MjN+Mi5KUEc=

Here's the overall target. 

Half of them the shots were strung out by the wind. 

The center group was TIGHT but for the one shot when the wind let up.

The top center group was off the reg.

 

[Tomiboy]

Nice shooting Bob! 

 

[STO]

You can't get just the sleeve, I asked for that a week ago and was told those parts weren't sold individually.

This is a question I too had, and the answer that you can not is genuinely annoying. Sure its all well and good they make oodles of barrel options, but if you can't actually fit said barrel options without buying a whole bunch of stuff you don't need....... strikes me it increases the price needlessly. 



Congratulations on the excellent shooting there by the way Bob. Looking good. Always thankful for more data to sift through as well, thanks for taking the time to post about this series of mods you're undertaking. 

 

[HD2010]

Great shooting Bob, especially at that temperature.

 

[Bob_O]

Thank you guys!!

The group officially measured in at 0.96".

Oh, this was with pellets straight from the tin and from the magazine. I didn't even check them for deformed skirts like I usually do.

Also, from a bipod with the rear on a small bag.

 

[stoti]

Nice shooting Bob! I tried to get some chrony readings after I got my kit installed but it was too dark after my son's BB game. Hopefully tomorrow it won't rain all day. I'm curious to see the results! Thanks for the imput earlier today. I appreciate it, saved me some time for sure!

Stoti

 

[Bob_O]

Yes Sir! Glad you got it done. If you've already adjusted your D5 screw for maximum hammer spring compression, make sure to start your tuning with the hammer wheel on MIN.


I hope the weather isn't too bad for you tomorrow. I'll have a video uploaded in an hour or so......how to reset the hammer wheel to MAX.

https://youtu.be/uvTZ4cmYDO4

 

[stoti]

Yeah, I'm not worried about the power wheel, I've adjusted that screw a lot. I backed it off a bit when I had it apart, so it shouldn't be anywhere near maxed out. Hopefully it's about right so the power wheel is correct... max on the wheel is actually the maximum velocity. Might need some minor adjustments when I start the chrony work but no big deal. Every time I've adjusted my reg. setting up or down, I've adjusted the hammer spring too, I've done it lots. I'll let you know tomorrow what kind of increase I got. Have a good one. Stoti

 

[heavy-impact]

Use the other end of your caliper to measure depth. That's why the bar sticks out.

Thanks for the video and congratulations on the sub 1" group at 100yds.

 

[Tomiboy]

Nice video Bob!

 

[Bob_O]

Heavy,

Those are the cheapest calipers ever, they don't measure that way. 

 

[sonny]

looking good Bob, keep them groups coming!

 

[Hepotter]

The speed of sound is roughly 1125 fps at, or slightly above, sea level. That's roughly 767 miles per hour. (@ 68 degrees F)

Our experience has been even the heavier .22 pellets/slugs begin to wobble at, or perhaps a bit above, 1000 fps. This is assuming the shape of the pellet/slug is NOT aerodynamically enhanced, such as boat-tailed, sharply tapered tip, which can greatly help stabilize the flight of the projectile at high speeds.

In my experience, regarding heavier .22/.25 slugs weighing in at 21gr to 34gr, max accuracy was achieved between 850 fps to 980 fps. Again, this was dependent on weight and shape of the projectile. (skirted domed pellet v. blunt nosed slug)

I'm curious, are you seeking max speed (fps), max power (fpe), or max accuracy? 

My unpleasant experience was those three factors didn't always mix well. I was trying to balance the three important factors of projectile shape, weight, and speed...and still maintain accuracy. Eventually I settled on using only one brand pellet, one pellet weight, and one speed to be able to continually achieve consistent results. In .22 caliber it was 850 fps, 21gr, JSB. However, in .25 caliber it was H&N 31gr Barracuda's at 900 fps. Those were my magic numbers for the pcp's I was using. Everyone's mileage will vary here...just too many variables of guns, altitude, temperature, barrel lengths/quality, and ammo. 

So I'm raving on here...no particular point to make, everyone can argue the points in mention...just curious where you are headed with this project? I don't even know what a Slug-X Liner is!