GTA
PCP - HPA - C02 Gate => PCP DarkSiders Forum => : daved December 20, 2007, 06:26:53 PM
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But I think I might have finally cured the leak in the B50 I got from Dano. Won't know for sure 'til morning, it's undergoing an overnight pressure test, but I'm feeling pretty good about it. If I'm right, the problem was a bushing on the firing valve. It wasn't drilled concentric with the valve body, and was binding the valve stem and cocking the valve on it's seat. I spent several hours on this thing tonight, literally going over it with a magnifying glass. Did a thorough deburr and polish, plus trigger polish and adjust. I'm really looking forward to shooting it tomorrow, and I anticipate some more tweaking in the near future. I think I'm going to end up with a real nice shooter here, despite Dan's conviction that it's cursed :-). I'll keep ya'll posted. Later.
Dave
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Yeah Dave I`ve been eyein those myself,been busy doin PCP conv.Gonna get me one of those next,kinda experimental,got alot of time on my hands,so I figure when the winds howlin and the snow swirlin,it`ll probly be spread out all over LR floor(wife loves it)!Dave have you got "the book" about the b-50-51?I downloaded it from that other forumn,I think it`s mostly notes and obser. from biged in tenn,he`s a guru when it comes to these,search on the yellow and you`ll find it,or if ya need it shoot me your address and i`ll burn it to a disk and mail if need be.
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So far I'm enjoying my B50 that I got for Christmas. I only paid $80.00 for a full, visually inspected, hydro-tested last year, used 50 CF tank at my local scuba shop. That and my saddle valve, hose, and necessary fittings to fill only cost me about $160.00 USD. I seem to have gotten off cheaply compared to what I've been seeing on the net.
That SOB sure is fun to shoot. Powerful and no recoil. I don't see where it's all that loud, though. I hear about how loud these things are but you can't prove it by me. Yes it's louder than my 2100 or QB78 but I'm not all that sure it's any louder than my HW80 or TF99.
Is there an airgun out there that DOESN'T like the CPHPs? All my .177s and .22s seem to prefer them.
My B50 is a .22 BTW.
I plan on doing a full polish, lube, and tune. Also some stock work. I need a shorter butt plate. Since I'm a southpaw, I need to plane off that cheek piece and contout the comb over to the left some.
I've just been using a cheap Daisy dot sight on mine. I have a BSA 4-16x40 with illuminated reticle, but my high rings for it and for my TF99 are on backorder.
First time I filled it, I just barely cracked the valve open, and air leaked from the tank QD. So I opened it just a little more and heard the fill valve in the gun open. Could only get 1000 PSI so I opened it just a tiny bit more and it very quickly jumped up to 3000 PSI. These things DO fill fast.
I think I'm a junkie for the precharged pneumatics now. These scuba guns are sweet.
Now, to buy a couple more QB78s and a Crosman 2250 to convert to PCP/HPA.
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You know what's going to happen now right? I am going to sell my Sumatra Carbine and buy a B51......hehe....or not:)
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I'd like to have your Sumatra carbine.
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Jaymo - 12/30/2007 8:34 PM
I'd like to have your Sumatra carbine.
She's the short brunette on the left:
(http://www.gatewaytoairguns.com/airguns/photos/get-photo.asp?photoid=849)
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Heck, I'd take either one, although I do have an affinity for carbines. I just can't afford her right yet, after buying scope, rings, scuba tank, saddle valve, hose and fittings for my B50.
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Dano,does that mean the carbines for sale?You have had it a couple o weeks now...
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But it is much better. Before, it would leak down completely in 2 or 3 days. I last filled it Christmas Day, haven't had time to shoot is since then. 2400 psi fill, just checked it, it was down to a little under 1000 psi. I think it's possible the rest of the problem is having to reuse orings, I need to order some new ones. The only other possibility, which I didn't think of until it was all back together :-(, is a crack or something in the firing valve. Next time I tear it down, I think I'm going to try and Zyglo the valve body, see if something shows up.
My headache now is valve lock and consistency. I shot a couple of 60 shot chrony strings, one filled to 2200 psi, the second filled to 2500 psi. The first one was a near linear drop in velocity from 866 to 565 fps. Deviation and spread got steadily worse as the velocity dropped. The second string was much more interesting. It started at 838, climbed to 917 by shot 15, then a linear drop again to 781 fps. The really interesting part was that shots 11-20 had a SD of only 4.01 and an ES of only 13.9 fps, 21-30 were 6.84 SD and 20.3 fps spread. All shooting was done using CPH's, apparently it wants to shoot these at over 900 fps. This is with a lighter than stock hammer spring set up for max power. If anyone's that interested, I have chrony spreadsheets and graphs that I can post.
I'm not sure what to do next. The lighter hammer spring is still giving me way more power than I really want, but it's forcing me to walk a really fine line, with valve lock if I step over it. But to get the consistency I want, I have to push that line. And even then, I'm only getting 20 really good shots. Supposedly, the stock spring will let me fill to higher pressure, but it wastes air, especially with a .177. My options at this point seem to be, go back to the stock spring, switch to a lighter pellet, and I've considered trying a lighter valve spring, the stock spring looks like it came out of my Suburban. I'm not crazy about the lighter pellet, I'm only able to shoot at 10 yards right now, but the CPH's are one holers at that range. Tried some CPL's earlier, not nearly as good.
The other thing that bugs me is the hammer. Compared to my Talon, this thing is massive, over 150 grams with the spring guide top hat. For comparison, my Talon's original hammer was only 11 grams, the custom I'm using is about 70, and I have a heavy one at 110 grams. I tried the heavy one in my Talon, but I actually get more power and better consistency from the one I'm using. I'm thinking the same might hold true for the B50, but I'm not sure just how to do it.
Despite all the above, or maybe because of it :-), I'm really enjoying this rifle. My only regret is I don't have as much time as I'd like to spend on it. And one of these days soon, I'm going to have to break down and get me a mini lathe. Just too many things I want to try that require some machining ability. I can see why they have such a loyal following, and I still think it makes a great compliment to my Talon. And I WILL get it ironed out, then it will be time to order a 51 stock for it. Will keep ya'll posted, later.
Dave
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Yes, I am back home in Texas. We are observing "California New Years" here and that will be coming in a few minutes. My plane landed about 2 hours ago and I am finally responding to a few emails and posts that I just didn't have the time, or the computer access, to answer before now. With that said...........
.......there is one thing that some of the tuners of the B50 have done to improve shot count and consistancy. The lighter valve springer (McMaster Carr) will get you 30-40 fairly consistant shots, but it does not cure all. The next thing is to tinker with the transfer port size. I know you mentioned no mini-lathe, so turning a new transfer port wont happen unless you have someone manufacture it for you...., but there is hope for the mini-lathe impaired. One idea I toyed with is to heat the brass transfer port and drop a small dollop of solder into the port hole. Redrill to the right size, and voila, new transfer port. If you don't like the results, drill back to standard size, removing the solder, and no harm done. My guess is that you could also get replacement transfer ports from John Ye at Xisico for a few bucks a piece, then have 2-3 different sizes to mess with. As with your Talon and the top-hat adjustment, your most consistant velocity adjustments are going to be made by limiting the amount of air that can pass through the port. Even if you have the stock spring installed, much like setting the Talon on 10, you can only get so much air through a restricted port. I know, I know, I gave up on the B50...., but I did get your brothers Talon to shoot pretty consistant...so I think I may be onto something here:)
The firing valve is a new valve poppet from Xisico, I only doubt it's leaking because the valve that came with the gun had a crack and it leaked down FAST! I've also done the bathtub test on that gun and only found bubbles coming from around the valve body. I always felt that there is a nick or gouge in the tube preventing the oring from sealing right. You mentioned in an email about polishing the tube, so now it could just be bad o-rings. The one you need I believe is a 1mm thickx25mm O.D. o-ring. The next time you have it apart down to the fill nipple, valve and tube try filling it to about 1k psi and dunking it in a tub of water. Be sure to dry it out FAST, those things corrode if you look at them the wrong way, and give it a good wipedown with a rag saturated with silicon oil. You'll see all of the leaks real fast, and that should put you on the right track. When you get totally frustrated, just relax and realize that there is a beautiful B26 in Texas that shoots beautifully and never leaks:)
Ok, "California New Years" is over. It's just about time to unpack and get into bed............
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tat2dman - 12/31/2007 6:36 AM
Dano,does that mean the carbines for sale?You have had it a couple o weeks now...
It might mean that. I originally posted that I wanted a .177 pcp repeater in trade for my FX Black Widow.....the fact that someone offered up a .177 Career 707 II AND a .22 Sumatra carbine in trade was a nice surprise...I never wanted the .22 Sumatra, just icing on the cake as they say:)
I haven't shot either gun except in my garage to confirm that they both functioned properly, which they do. The Sumatra has a couple deep scratches in the buttstock, but otherwise it's in tip top condition. I haven't yet decided whether or not I am going to strip and refinish the stock, or just sell/trade it as-is. If someone were to show some interest in it now I would sell it for the right price, but until I decide what I am going to do with the stock I wont list it in the classifieds. I am seriously considering buying another B51 in the hopes that I wont get another cursed one:)
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You Big Softy Dano....:) Just can't stay away from them Chinese PCP's....LOL
Welcome Back Dano, we all missed ya..:)
Gene
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Gene_SC - 1/1/2008 5:32 AM
You Big Softy Dano....:) Just can't stay away from them Chinese PCP's....LOL
Welcome Back Dano, we all missed ya..:)
Gene
Softy nuthin', I just emailed Dave and told him that the next time he thinks about buying something from me he should take that danged, cursed, leaky B50 and smack himself up side his head a couple times to cure him of those thoughts:)
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No worries, pal, all you have right now are lever actions, and I don't like lever actions :-)! Which is a relief, I'd hate to mess up that nice green and black stock on my hard head. I still don't think it's cursed, just feeling rejected by it's former owner, but I'll get it past that. It perked right up when I promised it a new scope once we got this leak fixed ;-). Later.
Dave
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Ahhhhhhh! The love for our toys just keeps growing..:)
Good Luck Dave
Gene