Canadian Airgun Forum

I got my Orcair Chrono working without the app. I think it works decent enough. My HW30S was around 535-650 depending on pellet weight. My hatsan at44 .25 was 750 with 25gr. My TX was 650-780 depending on pellet weight.
I tried the two cadet rifles I have here. A 753 and a 953, they were both taken apart and lubed and had the hammer and sear polished. There seems to be a major difference in velocity. The 953 consistently shoots 10.3 at 440, everything else except the Finale Match LP4.50 at 460-480. The finale Match are consistently 510-517 over 20 shots. Any ideas in the major difference in power. I may have tweaked and polished a few things but from my reading these guns even rated at 520 fps in the US shoot sub 450 fps.

_________________
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7

Power output for a certain gun should be certain.

The muzzle velocity differences are based on the pellet. Not only the weight, and the size (head size, skirt size) and the design plus material (softer or harder)... But on a good quality pellet, the shot to shot difference should be in a decent range too.

I believe all the X53 in Canada are the detuned 495fps version?!

_________________
~Plinkers~
FX M3 Compact
XS28M .25 @ 26fpe
HW45 Beast
6mm AW-Custom Z-Killer DE
~Competitors~
FWB300SU
Tau-7/IZH-46M/FWB-65/CP88
~Target~
HW 30s/35e/97k
CZ200s Laminated @ 10fpe
AA ProSport 177 @ 12fpe
HW 40+Extender/Scoped P3/70/75

Thats what I thought as well. My problem is if she goes to the provincals and they have a chrono. As technically her just would be pal rated with the 7.56 grain FN pellets.

_________________
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7

It's great you got your chrongraph working. Your 953 is tuned close to 500 fps for sure, and like YepYep says depends on the actual pellet you chose whether you will get 480 fps or 510 fps. Generally, the lighter pellet will be at the high end. If they are weighing around 7 gr it's possible. Did you buy the 953 new or used, and if used has the PO tuned it? The most often thing done is to fill the pump cup with some sort of epoxy, JB weld for example, and that gets you an extra 30-40 fps with standard pellet. Out of the box with 7.3 gr pellets (standard weight) I have found my x53 rifles usually struggle to make 460 fps. With the cup filled (runeth over even) they get close to 490 fps with standard pellet. even Hobbies that are 7 gr If I recall correctly. I have yet to get one over 500 fps - which I presume is your problem, you are concerned yours is a bit too fast. In that case you can detune it a bit. First you have to determine if it's been uptuned - and i'm getting ahead of myself since it may be straight stock, un-modded.

_________________

))))----//----------==
Age quod Agis, et semper ubi sub ubi.

It's the standard piston and tube. Actually it's the one out of the 753. They are the same part number from Daisy. Only thing I did was shim the hammer spring 3/16". I had 8 of them here I was working on. All the hammer springs were different lengths, I tried shimming this one for shyt and giggles, no idea if it helped as I didn't get the chrono until yesterday.

_________________
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7

Depending on the number of shots on it after its been lubed i would put a hundred round down the barrel then check .Spring guns will shoot a little high or low after a tune did you see any smoke ...even a wisp

_________________
VE7SHM//VE7ZJ

Moderator

https://scrapc21.ca/

Its a SSP so generally it won't diesel at all.I'd take out the shim on the hammer spring and run it over the chronograph again. Probably un-shimed will bring it back to sub 500 (if that's what you're after, I have no idea what the rules are for your daughter's competitions).

_________________

))))----//----------==
Age quod Agis, et semper ubi sub ubi.

Opps no spring .......... But lubing it can and will change FPS lube will make it seal better higher pressure so a little more FPS shoot it a little more see if it settles down .And I am assuming you lube the seals ...

_________________
VE7SHM//VE7ZJ

Moderator

https://scrapc21.ca/

It's had a couple of tins through it since it was last lubed. It shoots good as is. I was just surprised it pushed a 7.56 grain pellet that fast. The 6.9 grains were 50 fps slower, maybe the heavier pellets have a softer skirt and seal better. 10.4 grain Diablo heavies were 440 ish. The two lighter pellets were 4.50 the AA Diablo heavies were 4.52

_________________
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7

Well after two tin it should be good to go ....Then i would give Dukemeister idea a try. were did the gun come from ?

_________________
VE7SHM//VE7ZJ

Moderator

https://scrapc21.ca/

I can't see a shim on the spring on a single pump pneumatic making any difference. It should only have so much air in there. The 753 I bought new about 3 years ago. The 953 was bought around the same time by a lady for her son. He shot about 1/2 a tin of pellets through it. When I got it there weren't any clips or the single shot adapter with it and the front sight/barrel weight was loose. I'd have been frustrated I couldn't hit anything if I was him too .
It didn't shoot very well. I took the tube and piston out of the 753 and put in it. It was a night and day difference. I think the tube was a hair too long, you had to hold pressure out on the cocking lever to get the tube to fill with air, you'd hear it go in. It was hard for her to get consistent shots. The piston, tube, valve body, trigger group, hammer spring, hammer, sear, and bolt are the same part # for the 753, 853C and 953.

_________________
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7

If there is shims on the hammer spring and i don't know never owned one (Daisy cadet rifle ) removing a few shim could lower FPS by not opening the valve up as much or decreasing the amount of time the valve stays open (Dwell )

_________________
VE7SHM//VE7ZJ

Moderator

https://scrapc21.ca/

There may be some benefit to digesting this 5 parter- part 5 has links to the previous 4.
https://www.pyramydair.com/blog/2016/06 ... 53-part-5/

_________________

))))----//----------==
Age quod Agis, et semper ubi sub ubi.

I've read all the parts a couple times as well as the comments. One guy claims to have rebuilt 100's for the rotc and couldn't get them much over 450-460. Maybe my chrono isn't quite accurate.

_________________
TX200 .177 10-50×60 Hawke Sidewinder
HW30S, Diana 280
2x FWB 700 Junior, FWB 700 Alum
Hatsan AT44 .25
Daisy Avanti 753S, 2x Daisy 953 cadet
2x Tau7

Well, there is that, no chronograph is absolute. Also my experience with x53 is always under 500 fps, some close with Hobbys. But yours could be hot.

_________________

))))----//----------==
Age quod Agis, et semper ubi sub ubi.