S200 velocity curve

[Jordan]

My AA/CZ S200 seems to demonstrate a velocity curve, in that the pellet velocity increases and then drops again as the cylinder pressure changes.

For instance, if I fill my cylinder to ~185 bar, the initial velocity is less than when the cylinder reaches ~150 bar. It will then remain stable to about 110 bar, and begin to drop again.

I'm guessing on the exact pressures as I don't have a gauge on the cylinder, and haven't tested it - and I'm estimating velocity by the relative POI.

Is this a known issue w/ the S200's?

Is there a fix (e.g. a regulator)?

[luftskytter-]

This is normal with an unregulated gun.
The low initial velocity is due to moderate "valve lock".
This is actually a good thing if balanced correctly because it flattens the overall curve. A stronger/tighter hammer spring will increase the optimum starting pressure. This will also increase velocity and the penalty will normally be fewer shots. You should check out how this affects your accuracy at the desired shooting distance. A regulator will cure this and also increase your number of shots.

[Jordan]

Thanks.

Does anyone sell a regulator to the S200?

Also what is the recommended cylinder pressure to avoid valve lock for this rifle?

I'm shooting to about 80yds so the change in POI from the initial velocity is significant. It's a nuisance trying to guestimate the drop before the velocity stabilizes.

[pilkguns]

This gun is a 10m gun and shoots very accurately for 80 shots at that distance. I would suggest you get a gun designed to shoot at distance you wish rather messing up a good gun r

[Jordan]

Is a regulator kind of a hack?

For the record, the accuracy has been extremely good at 80yds w/ the JSB domed pellets I've been using. And I haven't altered any of the factory settings.

I don't want to increase the pre-set velocity, just to avoid that initial change in velocity.

Also I don't think that I have their 10M model. Mine has a two piece stock and adjustable butt and cheek. But it didn't come with sights, and has a muzzle extension w/ a dovetailed muzzle weight. I haven't seen this combination in the research I've done. So it might be something that the shop put together.

[frog5215]

Jordan, a regulator sits between the reservoir and valve. I guess there's an expansion chamber so the valve sees a constant pressure over a wide range of reservoir pressure until the reservoir pressure drops to the regulated pressure, then velocity will start to drop.

If properly designed, a non-regulated gun has a metering valve where the gap between the valve head and body, combined with valve spring serve to reduce velocity spread. At higher pressure, the pressure closes the valve quickly. As pressure drops, the valve stays open a little longer, passing a larger volume of lower pressure air, keeping velocity up.

Detailed data on shot count after a fill, related to POI is just something field target shooters have to put up with if they don't have a regulator.

I have no idea whether he does one for the S-200 ( I have one of these, too), but Joe Korick has done work for the biggies.

[robf]

Is a regulator kind of a hack?

For the record, the accuracy has been extremely good at 80yds w/ the JSB domed pellets I've been using. And I haven't altered any of the factory settings.

I don't want to increase the pre-set velocity, just to avoid that initial change in velocity.

Also I don't think that I have their 10M model. Mine has a two piece stock and adjustable butt and cheek. But it didn't come with sights, and has a muzzle extension w/ a dovetailed muzzle weight. I haven't seen this combination in the research I've done. So it might be something that the shop put together.

A regulator lets a fixed volume of air through, at ideally the same pressure. For an s200 it would be a custom aftermarket fit if there was one, but I would think for the expense you might be looking at a better rifle.

To solve the curve, chrono the gun over a 100 shots and see where there is a significant curve, and then just keep where it's flat.

the s200t doesn't always come with sights, but the t version has the adjustable stock. The two piece is the old stock version. The dovetail on the muzzle is normal for the T but there is a 6 & 12 ft-lb version, as well as some that come with or without diopters.

[Jordan]

Robf do you know how to identify the 6 v 12 ft-lb - is this evident in a series number or some other marking?

[frog5215]

Shoot over a chronograph.
Likely, if it came with match sights, it's adjusted for 10M work, with lots of shots @ 550-600fps, vs no sights, with fewer shots per charge intended for silhouette/field target/hunting.

In a steel trap @ 10M if 8gr pellets completely disintegrate, its running hot. If some or many pellets pancake, it's slower; around 600fps is a break point.

It's only a difference of hammer spring and transfer port adjustment.

If you have a scope mounted a normal distance above the bore, a 600fps gun will need 8-12 minutes of correction between 20 and 45yd settings, a, 800fps gun will be MUCH less, possibly 3-4 minutes. This is with 8gr domed pellets like Premier lights or JSB Exacts, RWS Superdomes.

[robf]

Robf do you know how to identify the 6 v 12 ft-lb - is this evident in a series number or some other marking?

best way as suggested is to chrono it... which I assume you must have done to find the curve.

i'm not sure there are many/any differences... my s200t was a 12ft-lb gun and just was missing the diopters and also had a screw in cylinder with a guage on the end.

however the non T, but 12ft-lb has a quick fill over here.

at 12ft-lb the bracket for concistency is reckoned to be around 40 shots.

it's a great little rifle, and supremely accurate, but it does have it's failings, and I think if you've out grown it, the best thing is to go onto something that doesn't have them rather than trying to make it do what you want.

[dezyboy]

Tweaky sells and fits regulators for the S200. and the S200T

http://overdale.homeserver.com/bt/index.php .. this will give you every shot with only a 6 ft ps variable ;)

Hope that helps :)

[angelmr]

The regulator is good thing, but shooter will outgrow this rifle much before he will feel need of regulator.
I owned one CZ200S and by my opinion this rifle, regardless of it`s impressive performance, is verry basic rifle. It is good for children, but lack of regulator have minor influence. I think, it is more effective to by bether rifle for the cost of fitting regulator in AA200/CZ200.

[dezyboy]

The regulator is good thing, but shooter will outgrow this rifle much before he will feel need of regulator.
I owned one CZ200S and by my opinion this rifle, regardless of it`s impressive performance, is verry basic rifle. It is good for children, but lack of regulator have minor influence. I think, it is more effective to by bether rifle for the cost of fitting regulator in AA200/CZ200.

I kinda disagree with you, I have one of these and would not swap it for the world.. after I paid £90 for the regulator it seemed a different rifle, also adding £90 to the second hand cost of a S200 wouldn't even buy a new S200 let alone an upgrade so cost is an important factor. If you like the rifle but your only want is shot to shot consistency .. then the reg is for you. If money is not an issue ... well that's an entirely different issue ;)

[angelmr]

I partialy agree. I loved my CZ200. But it is too light, and the stock is too short for adults (I am 190sm in height). Also my stock was older wersion from two pieces, which has problems with moving point of impact. In adition I used my CZ for field target with scope. But rifle is quite short for 10m precision shooting. Also bolt action is weac point. Mine broke less than 5000 shots, and locking of bolt mechanism is not werry reliable. It jumps and have some air leaks.
About the price: I don`t know what is the cost in your country, but here in istern europe it is about 500 euro new one (I saw second hand for over 300£ in England). With custom made stock, and the regulator it will jump twice and more. Whic is too expensive in terms of potential to buy second hand FWB 600, 601, 602 or Anschutz 2001/2002 series from e-gun for 4-500 euro (found some under 300 euro).
Generaly speaking, all these problems are minor, and rifle is still verry acurate. But it is suitable for specific target group of shooters. It is not competitive with hi end second hand rifles at the same price.

[dezyboy]

See your point about the FWB and Arnie , was not aware you could pick them up so cheap second hand. The S200 does hold a good second hand price as it is a popular rifle, so I see your point.

I partialy agree. I loved my CZ200. But it is too light, and the stock is too short for adults (I am 190sm in height). Also my stock was older wersion from two pieces, which has problems with moving point of impact. In adition I used my CZ for field target with scope. But rifle is quite short for 10m precision shooting. Also bolt action is weac point. Mine broke less than 5000 shots, and locking of bolt mechanism is not werry reliable. It jumps and have some air leaks.
About the price: I don`t know what is the cost in your country, but here in istern europe it is about 500 euro new one (I saw second hand for over 300£ in England). With custom made stock, and the regulator it will jump twice and more. Whic is too expensive in terms of potential to buy second hand FWB 600, 601, 602 or Anschutz 2001/2002 series from e-gun for 4-500 euro (found some under 300 euro).
Generaly speaking, all these problems are minor, and rifle is still verry acurate. But it is suitable for specific target group of shooters. It is not competitive with hi end second hand rifles at the same price.

[Jordan]

So what would be a suitable rifle to upgrade to?

I don't use the S200 as a match rifle. It's currently mounted with a scope and used as a trainer for my service rifle, which is why I'm shooting to 80yds. I have a scaled XTC course set-up. The elevation adjustments work out to 1/2 of my service rifle adjustments, in clicks.