been at this one now for 5 weeks on and off, trying to not make it a chore as it truly was promised as a favour for mate at the club..the issues:
original power was just under 9FPE but with massive detonation/lots of smoke and very slammy.
Had a PTFE seal, have machined up new piston heads to take HW seal, AA seal and finally an O ring seal, i read that webley may have used an imperial size tube (25.4) so I made up a second set of piston heads slightly over size to ensure a good fit and seal, out of the 3 tried the O ring is super consistent shot to shot..BUT only 8FPE and ONLY with .22 superdomes, the standard seals gave similar power but with wider shot to shot fps variance.
Swapped springs, presently using a Titan no11 that came right out my 77k running 3mm Transfer port and 25mm piston in .22 giving 11.4fpe..these little springs are awesome so i know it is not the spring.
swapped the loading tap O ring..will do this again though, i was wondering if adding a second O ring on the opposite side of the pellet port would help so its sealed from both sides?
Is there a known problem with leaky loading taps/breeches on these rifles?
added preload...does next to nothing apart from making the gun harsh to shoot, right now at 500FPS is lovely but the mate is looking for 10FPE which i just can not push it too.
It feels like a hw35 with leaky breech except its stopping at 8fpe where most 35's stop around 9.5 or so...
I need to gain around 50fps if possible, im staring to think it will never happen
It might be lost volume in the tap, Original 50's (mine included) are prone to this. It might be the case with your Tracker. If I spread the skirt of the pellet out a bit so the pellet does not "drop" all the way to the bottom of the tap then it makes more power and isn't so "slammy".
See here for more info.
P.S the tap on my rifle seals perfectly, hence my theory towards lost volume.
Last edited by coburn; 21-08-2012 at 01:37 PM.
I will experiment more and report back, i have some milbro ultra's here than a larger in the skirt (much like old wasps) so will try these also. I know a lot of lads swear by superdomes in older airsporters now as they seal better like the old wasps did so there may be something in pellet size for this little tracker.
I spread the skirts buy rubbing the pellets in a circular motion whilst pushing down on them using the lid of a pellet tin as a smooth surface,a bit hit or missconsistancy wise. I suspect a pellet sizer that sizes the skirt up would be the best answer.
If you look at how deep a pellet tap is on a tap loader, and consider that if the pellet were at the bottom of the tap, then treat the wasted space as an extention of the transfer port you can see how losses occur.
Interested to hear how you get on.
P.S With the skirts opened is it less "slammy"?
I machined an additional 2 o ring grooves on the tap, one either side of the port..velocity went up on the slower pellets, a minimal gain on the superdomes (8 to 10FPS at best)
I spread the skirts on Falcons (which were rubish to start at around 6FPE) and they fly at 8.5FPE
Im slowly tiring of this little tracker...I will go add 3mm more preload and its is done, what ever it gives it gives..if it hits 9FPE i think he will have to live with it.
Regards it being slammy, its not at all slammy now even with unsized pellets
Is the cylinder been put out of true by diesling then, so that the seal is not capable of making proper contact all the way through
'Belled' cylinder can happen, especially from your intitial description of rifles behaviour
Fortunately it doesn't happen often ..............
I only know because of a second hand rifle I had once ...........never heard of it before, was eventually diagnosed by an expert thankfully , not that it helped as there isn't really a solution to that beyond a highly malleable seal , depending on where the 'bulge' is
I meant to add is there any signs of the tap being misaligned? I rember Jim Tyler writing on just this subject recently in the AGW.
I suspect that misalignment would effect accuracy rather than power.
Its gone back in the box for today, tomorrow it gets the added 3mm preload, if it gains it gains, if not it will be removed and he can shoot what ultimately is a sweet 500FPS .22 tracker that barely recoils. It would actually make for a great 20yard barn gun imo..i will suggest it.
Just shows different rifles have different characters, my D52 was a struggle to bring down to 11.5 even when short stroked by near 50% of the stroke length and this little Webley is completely the opposite although is sweet to shoot.
Got to love springers
Checking if the tap is aligned is a pretty good idea. As a Tracker is an Osprey with a different piston seal and a piston weight, have you got the piston weight in the piston? From memory I think I had a Viscount with a cut down barrel doing 10.5 using a meteor spring, which tend to fit better than Webley springs. I think Airgunner .177 put up a thread about tuning his Osprey and got it up to 10.5 ish. That had the Osprey piston but using an O ring instead of the 2 ptfe jobbies. Maybe the spring is too much for the gun? As Mick T20 reckons Hawks are better with a smaller transfer port, you could try sleeving the port down. (I,m sorry I diddn't read if you had done this or not)
Drastic afterthought---On the Hawks and Vulcans, air can get round the threads of the cylinder end bung--- MAYBE submerge the action in the bath and push the piston and check for any bubbles/airleaks?
Last edited by ggggr; 21-08-2012 at 05:19 PM.
I'm still thinking
Someone gave me one of these to tune the other day. --- You lot have put me right off the job now.
Mind you I chroneod it when it came in and it was doing 550fps with Superdomes.
The piston had a single PTFE seal,it was wrecked, i machined the piston back and have added a Phosphor bronze nose to the piston with O ring...polished the rear skirt, it feels like its on bearings now, really very smooth.
So the piston is heavier than it was, I will try adding a little weight in the way of a new front spring guide machined from steel or maybe brass if i have some spare, and see if that brings the power up any.
The gun had pissed me off before, i may have another go tomorrow.
Mick...you have a gun making more power already, this gun i doubt has ever made more than 8.5 to 9fpe.
I was going to ask about trackers tomorrow on the forum too. I love the look of them, but i'm some what put off. Hope you get it sorted though, good luck
I have a skanky old Tracker that I recently acquired, i'll stick the Combro on tomorrow and see what it's running at...
for my gunz guitarz and bonzai, see here
As a resident of the East End, I will let you in on a little bit of the Cockney argot
Ospreys & Trackers = a lot of old knackers
Haenal & Hammerli = come join the family
The wisdom of ages.
I dived into the pages of Chris Thrales excellent Webley rifles book last night and when it first came out Webley advertised the velocity as 560 in .22 despite it sharing the then Vulcan powerplant. Interestingly this was inceased to 600 fps once it was updated with the Vulcan MK3 internals.
Out of interest my old "knacker" Osprey in .177 makes between 8.4 to 9.5ftlbs, thats with the original PTFE rings and a new std spring from Chambers fitted last year.
You should be seeing 10.5ftlbs