 |  | | | |  | |  |  | pics of my latest build 2550 32.5 fpe disco carbine... |  | |  |  | |
 Posted: Wed May 26, 2010 10:11 pm |
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| 80 grit |
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| Joined: 26 May 2010 |
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I started with a stock discovery valve which I modded by opening up the hole a bit and countersinking for poly tubing...but I was not able to achieve over 620 fps. I noticed that the valve spring is very stiff in the disco valve, and since I do not know how heavy the disco hammer is (I assume it should be around the same as the Crosman 22xx hammers...), I decided to use a boss valve that I had waiting in the wings with a much "lighter" valve spring. The result was 18 good shots ranging from 730fps to 769 fps with 25.4 gr JSB Exact Kings with my power adjuster on max compression. I will play with it to see what kind of shot count I can achieve on a little less fpe.
I can't say if it was the actual lighter valve spring or the valve itself, as I did not deduce as I should have by keeping the disco valve in place but using the "boss valve face" with lighter spring... Instead I just opted to put the "boss valve" in and be done with it. I am convinced, through my limited, but accelerated experience with these 22xx's...that the "Boss valve" would edge the "disco valve" by a considerable margin, and I'm sure most of you would agree with that.
Accuracy testing will commence when I find some time, but I have yet to be let down by a LW barrel.
This is what this baby has in her:
Disco tube, Crosman trigger frame, TKO trigger spring kit, Mountain air trigger shoe, .25 LW 24" barrel blued and accurized by Mountain air, Crosman steel breech, MA .25 brass bolt probe, HDD (otherwise she will degass with one or two trigger pulls :P , Muzzle mack power adjuster and Stock adapter, M4 six position stock, 60 gram polished Crosman hammer and heavier gauge hammer spring (sorry, not sure what it is from...) MA muzzle brake modified by me to clear fill cap, Scot (GTBJ) custom made condor foregrip, modified by me to fit this project (trunk liner and rustoleum olive drab paint applied by me), 3x9 nikon prostaff with digi tape treatment, Mac 1 one piece drooper, wally world flavor of the month bipod.
She is light, she shoulders well, she hits hard enough for small game, and I am confident she will be accurate to boot!
Here she is:
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| Posted: Thu May 27, 2010 12:41 am |
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| kanyon |
| Silver Status Member |
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| Joined: 09 Aug 2008 |
| Posts: 1582 |
| Location: New Zealand |
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hi....
very nice build...
looks like it will do the job...
Pete |
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| Posted: Thu May 27, 2010 3:34 am |
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| broommaster2000 |
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| Joined: 10 Mar 2007 |
| Posts: 5714 |
| Location: City of Groningen, Groningen, The Netherlands |
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Your airgun, it is epic! A very good first post!
Of course, now we expect you to keep that up! 
It looks like you painted a couple of parts, am I right? |
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| Posted: Thu May 27, 2010 6:38 am |
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| 80 grit |
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| Joined: 26 May 2010 |
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Thank you, and yes, I used truck liner (not bed liner)---it is more "textured" than the bedliner, then I painted the parts you see with krylon camo olive drab.
I am going to see if someone---perhaps Rick---can make me a decent (thicker) grip that I will trunk line and paint as well. Also, I will add a nice sling for carrying. |
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| Posted: Thu May 27, 2010 10:33 am |
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| yourdaddyjoe |
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| Joined: 26 May 2008 |
| Posts: 4027 |
| Location: Tatorville, USA |
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Sweeeeeeeeet job, Joe!....
Thanks for sharing photos... |
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| Posted: Thu May 27, 2010 10:42 am |
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| oddtodd |
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| Joined: 30 Dec 2008 |
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| Location: Richmond, IN USA |
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| Beautiful rifle. One that deserves the title of airgun porn. lol Keep on building! I made custom grips for all of my 22xx pistols. Cocobolo is a b!tch to work with. It was a factory grip, but I had to totally reshape it to fit my hand. THe dremel tool got a workout on that one! lol |
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Airguns: Two starlings talking "Larry, did you hear that? Larry?? LARRY!!!!" |
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| Posted: Thu May 27, 2010 7:36 pm |
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| 80 grit |
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| Joined: 26 May 2010 |
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Got her to put out 36.5 fpe earlier this evening...and she is a tack driver! 1/4" to 3/8" groups at 25 yards...(see my other post). I do need to sort this "problem" out with the hammer cocking. Way to hard to cock...something is not right. Will take it all apart again...but I am waiting for all the advice I can get before I do  |
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| Posted: Thu May 27, 2010 10:18 pm |
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| Mark5043 |
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| Joined: 12 Apr 2009 |
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| 80 grit wrote: |
| need to sort this "problem" out with the hammer cocking. Way to hard to cock...something is not right. Will take it all apart again...but I am waiting for all the advice I can get before I do |
Very nice build...quality AG porn to sweat over...  Sounds like you have coil bind from the hammer spring..have you tried backing off the power adjuster a tad?Just a small adjustment on my Disco made a significant difference in the force required to cock it,with no real loss in power.Bob...Joe..where ya at,this gentleman needs your expertise...  |
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Last edited by Mark5043 on Thu May 27, 2010 10:27 pm; edited 1 time in total
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| Posted: Thu May 27, 2010 10:22 pm |
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| 80 grit |
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| Mark5043 wrote: |
| 80 grit wrote: |
| need to sort this "problem" out with the hammer cocking. Way to hard to cock...something is not right. Will take it all apart again...but I am waiting for all the advice I can get before I do |
Very nice build...quality AG porn to sweat over... Sounds like you have coil bind from the hammer spring..have you tried backing off the power adjuster a tad?Just a small adjustment on my Disco made a significant difference in the force required to cock it. |
Mark, it was not coil bind as I went through a variety of springs, a variety of spring power adjustments, and a variety of different power adjusters..but alas I have good news to report.
Dave G saved the day! He replied on the yellow and told me to check the hammer pin for bends, and he told me to look for drag evidence on the inside of the tube and sure enough...he was right. The hammer I was using was certainly dragging. It made a perfectly shiny strip dead center in the tube. I opened up one of my other 22xx guns and took out the hammer to try a different one and sure enough...no drag, and she cocks like she is suppossed to. Now I can enjoy searching for the perfect bell curve. Thanks again Dave! |
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| Posted: Thu May 27, 2010 10:38 pm |
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| Mark5043 |
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Great! Glad you got it solved...I learn something new everyday here.. 
I remember I had a drag issue once coming from my 2300KT that took a minute to figure out.I had the trigger stop screw set too far out .What happened was the sear was not retracting fully,and slowing the momentum of the hammer down.  |
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| Posted: Fri May 28, 2010 7:02 am |
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| 80 grit |
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| Joined: 26 May 2010 |
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| Mark5043 wrote: |
Great! Glad you got it solved...I learn something new everyday here..
I remember I had a drag issue once coming from my 2300KT that took a minute to figure out.I had the trigger stop screw set too far out .What happened was the sear was not retracting fully,and slowing the momentum of the hammer down. |
Thanks! Yeah, without these great airgun forums I'd be a white flag flapping in the wind!  So glad to receive direction from those who have been there and done that.... |
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| Posted: Sat Jan 22, 2011 8:41 am |
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| GrizzlyMan |
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| Posted: Sat Jan 22, 2011 10:26 am |
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| 80 grit |
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| Joined: 26 May 2010 |
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| GrizzlyMan wrote: |
| Thats one sweet rifle! |
Thanks...it happens to be 4 sale. If interested, or if you know someone...
jostal31@bellsouth.net
Thanks.
Joe |
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