New Discovery numbers

[kirby999]

This time , since I found out the Disco likes Kodiaks , I thought I would run a few across the chrony and see how she does. Remember, I changed the hammer spring out for the out of my Crosman 2250 ; a lighter one. I started with about 1500 psi , just to see where the sweet spot would come in and if it was different than with the lighter JSB's . First shot 739fps. a little low , and it took it 10 shots to drop the pressure down to around 1200-1300psi ( my normal starting pressure) and the fps went up to 778.4fps on the 11th shot. 25 shots later in shot 775.0fps and in between it went up to a peak of 795.4fps; for about a 25fps extreme spread . Accuracy with Kodiaks is not as good as what my AirArms shoot , but out to 30 yards ,It has no problem keeping all the shots inside a 1" orange dot. Energy comes out to from 14.265 on the low end to 14.895 on the high side. That should be plenty to take care of Mr. Treerat . LOL. kirby

[Gene_SC]

Very nice David..:) Why do the numbers start out low and go high...? I know you probably have explained it beore but do it again for this old fart..:) I love that stock.. Does it feel comfortable to shoot. Does your trigger finger feel good?

Thanks for sharing those numbers with us.

Gene

[kirby999]

Unregulated PCP's will start low and the higher the fill pressure the lower they will shoot , to the point that they will develop valve lock if you over fill one. This is because the valve is fighting against it's spring force and the fill pressure. The hammer and hammer spring remain a fairly constant force each time it forces the valve open . More pressure , the valve close faster , reducing the amount of air released and reducing the speed of your pellet . Each PCP should have a "sweet spot " this is the ideal pressure where you will get the most shots in a particular range .(25-30fps spread is a good range IMO, 20 fps is excellent, 40fps is OK ) If I were to fill the Disco to 2000psi with the lighter hammer spring I have in it , the pellet speeds would start in the 5 or 6 hundreds with the Kodiaks and build until the enough pressure is released as to optimize the valve spring , pressure combination.  The stock feels great to me ; a lot better than the factory one, the trigger is OK . The trigger is not as bad as I expected . It's probably in the 4 pound range and feels ......... well like a plastic trigger. LOL IMHO the Discovery is NOT a beginners PCP. That might surprise some folks; I had hoped it would be. To shoot like I would like for it to, I would have to spend more on it than I could buy a nice ready to go PCP for the beginning. But I demand more out of my rifles than most do. This is a PCP for someone who wants something different that they don't mind tinkering with . This would make an excellent hunter , especially if someone is going to get the pump. At a 1300psi fill pressure, it wouldn't take long to pump it up and it delivers plenty enough accuracy and power to whack a tree rat out to 35-40 yards . I'm still debating on whether I'm going to keep this one or not. I won't be spending any more money on it . kirby

[Gene_SC]

OK then, that explains why the pressure changes. Because it is unregulated. That also explains the sweet spot of your pressure. I only have a FX Cyclone and it is regulated. I can pretty much fill it to 2800 psi and set the FPS range I want. But I do not know if the adjustment actually changes the spring pressure or changes the size of hole where air passes through. Maybe I should find this out..:)


THanks for the explanation David.
Gene

[melloroadman]

Kirby were you hoping for a Air ARM S 200 TARGET rifle or equivalent can I ask ? And what scope do you have on the rifle in the picture ? Marvin

[kirby999]

I was hoping for a little better than what I'm getting . I don't think 3/4" groups at 30 yards instead of the 1" I'm getting ,would be too much to ask for . I have a pump 1377 Crosman I built that shoots that , I really thought the Disco would be better out of the box. The scope that's on it now is a BSA 4x16x40 IR mildot . To be honest, I wanted one because it was new and I thought I could improve it without spending a lot of money on it . I've yet to find an American air rifle that can shoot with the Europeans. The closest I've owned has been the Talon SS . kirby

[melloroadman]

Kirby I understand what your saying . MY 1377  carbine with a 24 inch barrel is as accurate at 16 yards as my Discovery and RWS 46. I have not had a non windy day to try out side shooting at 25 and 50 with the discovery or the 46 but I hope to very soon. And I fill as you do that the groups at 25 or 30 should be 3/4 and I think mine will do it . Especially after I do the trigger mod that will cost under $5 . I do not even expect a American made air gun to come close to the European made any more. When I bought my Discovery I knew I would have to work on it some to be truly happy with it but it has more than met my expectations so far. It has introduced me to the PCP rifle at a price I could afford . And yes I know that as I progress I will probable be looking at a higher end model as well . Like the Air ARMS  S 200 target .Marvin

[kirby999]

You're right on Marvin , I keep hoping some American company will produce something that will compete . I could do a few more things that would most likely improve the Discovery a little more , but for now , I'm working on getting another stock made for one of my AA carbines and I'd rather throw my money toward it. I wouldn't mind having one of the S200's . have you seen this one over at Airgun Sport that belongs to Rich in PA? http://www.network54.com/Forum/543831/message/1208380571/Scoping+sweety+... It's the nicest one I've seen. kirby

[melloroadman]

Kirby that is one good looking S 200 . Thanks for wetting my appetite. Before you give up on the Discovery invest $5 in the trigger. By the way when you have the stock off your Discovery to do the trigger why don't you send me the stock to see it in person and to try its fit to my hand . Marvin