Understanding Transfer ports?

[Gecko]

Had a enjoyable shoot with my hatsan 55s 177 today which has had the piston lightened, piston has delrin bearings front and back with a 14mm ally nose exstension.
I think it has a 28mm bore and a rough measurement of the transfer port i would say is 3.2mm dia x 12mm length.
would the gun benifit from a reduction in transfer port diameter?

[TonyL]

It all depends on the balance!

Very dependant on the spring fitted - rate, preload force etc. And also the pellets!

I don't know the length of stroke on these and henceforth, the swept volume and SCR.

That TP size actually sounds very usable.

Did it feel "slammy" or "bouncy" in your view? As in a too-large TP would give the slammy sensation, and vice versa.

If it feels nice and smooth and not too lively, I'd tend to leave alone.

[Shed tuner]

As T says, not enough info..
test with light / medium / heavier pellets and report back (e.g 7.3, 7.9, 8.4 grains)

[Gecko]

It was doing 820fps(11.8ftlb) with 7.9grain crossman premiers over the skan chrono, with a 3fps spread over 3 shots.
Will try Falcons(7.33) and exacts(8.44) next time at the club.

[NickG]

It was doing 820fps(11.8ftlb) with 7.9grain crossman premiers over the skan chrono, with a 3fps spread over 3 shots.
Will try Falcons(7.33) and exacts(8.44) next time at the club.

Not absolutely sure, but seem to remember that when I did it, it was slamming slightly, there is still plenty of weight in that piston. So that may be an option, be good to see what its doing with the three weights of pellet.

[Gecko]

I wasnt that happy with accuracy of it at the airgun gathering, since then though the Hawke scope on it the internals feel apart.
Since fitting another scope on it the accuracy has come back
Its settled down nicely the chrono results of the 3 shots where 717fps, 719fps and 718fps so very consistent with pellets straight from the tin.

[Gecko]

Did some chronoing today at the club with the hatsan 55s i put the rear of the front iron sight agaisnt the chronos barrel rest so the muzzle distance was consistent this made the barrel further back then when i did my last 7.9grain results.

average of the first 3 shots on each pellets, Falcon Acc+ (7.33), Crossman Premiers (7.9), JSB exact (8.44) and JSB heavy (10.34)

7.33g = 11.97ftlb 857.3fps (857fps, 856fps, 859fps)
7.9g = 11.59ftlb 812.6fps (813fps, 811fps, 814fps)
8.44g = 12.02ftlb 800.6fps (804fps, 799fps, 799fps)
10.34g = 11.54ftlb 709.6fps (712fps, 709fps, 708fps)

So theres the first 3 shot average results, i dont no how to interpret them seems the 7.33 and 8.44 give the highest similar power but the 7.9 and 10.3 give lower but similar power.

[TonyL]

Looking at the above, I'd just be tempted and happy to drop the power via shortening the spring slightly and just shoot the thing.

[TonyL]

Amongst your "fettlings", chaps, how would you rate the gun build quality wise, in terms of component quality, expected longevity and internal finish?

I can't get this desire out of my system to get a "utility / budget" rifle and the 55/60 do seem to tick a lot of boxes, taking into account the Quattro trigger (on the later models) and the tempting prices.

From what I've seen before, they're basically a Turkish built Stingray, so some Venomac input on the Brum original?

[Shed tuner]

Looking at the above, I'd just be tempted and happy to drop the power via shortening the spring slightly and just shoot the thing.

Absolutely, looks very well balanced...
As T says, just collapse a coil to get down to 11.5 and shoot it

[vobster]

Had a enjoyable shoot with my hatsan 55s 177 today which has had the piston lightened, piston has delrin bearings front and back with a 14mm ally nose exstension.
I think it has a 28mm bore and a rough measurement of the transfer port i would say is 3.2mm dia x 12mm length.
would the gun benifit from a reduction in transfer port diameter?

Very interestng. What the accuracy like?

[NickG]

Amongst your "fettlings", chaps, how would you rate the gun build quality wise, in terms of component quality, expected longevity and internal finish?

I can't get this desire out of my system to get a "utility / budget" rifle and the 55/60 do seem to tick a lot of boxes, taking into account the Quattro trigger (on the later models) and the tempting prices.

From what I've seen before, they're basically a Turkish built Stingray, so some Venomac input on the Brum original?

I found the build quality internally to be very good, Its a lot of rifle for the Money, When Gecko bought it he gave it to me , to "see what I could do", so worked with the standard spring and trans port, the piston weighs a ton, so lightened it, added some bearings, along with an o ring nose to short stroke it a bit, and that's how it came out.
He was pleased with it until john budd got him thinking about trans ports at the springer bash ;

[Shed tuner]

He was pleased with it until john budd got him thinking about trans ports at the springer bash ;

Lol, thinking can't harm

[NickG]

Lol, thinking can't harm

I think you may have inspired him,

[TonyL]

I found the build quality internally to be very good, Its a lot of rifle for the Money, When Gecko bought it he gave it to me , to "see what I could do", so worked with the standard spring and trans port, the piston weighs a ton, so lightened it, added some bearings, along with an o ring nose to short stroke it a bit, and that's how it came out.
He was pleased with it until john budd got him thinking about trans ports at the springer bash ;

Thanks for that, Nick.

Of all the "budget priced" rifles, these are the ones that I keep coming back to, but some inside info on internal build quality is appreciated. I did own a (Turkish) Stingray II, .177, about six years ago. A bit lively, but never played with the internals. The main reason it went was that I was given a tidy Airsporter Stutzen for free. Funds were tight and I was fancying another 97. I did a straight swap for the two of them for a brand spanking new '97.

The trigger was okay-ish, but with the Quattro trigger on the newer models making it more appealing, I think things are tipped heavily on favour of the Hatsan.