Quote from: Bayman on June 17, 2022, 02:40:23 PMHector thanks for trying to get things back on track. The thread has gotten very deep into some technical topics I never understood and find quite interesting. It's also been a place where some people have come to aire their biases and ego. I'm not interested in either.To get back on topic, it was suggested earlier that spacers could be added to JM kit to pick up the power. This is true but there's only so much you can do with spacers. In this application I seriously doubt there's enough room for spacers to make up the difference in power between the two kits. The spring is simply weaker. Keeping this fair and current, the Vortek stepped tophat was pretty much a gimmick. It's not used on the Hw80 full power kit. It was used on the Weihrauch 25 & 26mm kits. I have installed a bunch of these kits and I've never seen more than 15 fps difference between the high and low tophat settings . It's usually ten fps. I've discussed this with Tom at Vortek. I haven't seen a stepped tophat from him in months. He may have abandon the concept.Thank you for adding your knowledge to the thread and being a gentleman.Be wellRonRon;I do agree that you can only do so much with spacers.But I have found that, in a properly sprung system, a LITTLE spacing can make a rather large difference.I don't have data about JM or Vortek springs, having dropped their use some time ago in search of utmost log term consistency, but using a Titan XS #1 (0.127" WD, 0.827" OD, 31 coils in 11") as an example on an LGV that is using an OEM piston and seal, a 0.160" spacer at the rear, increases ME by a bit over 1/2 ft-lb. from slightly under 12 ft-lbs to over 12 ft-lbs Do bear in mind that it is less than 1 W.D. and yet the difference in ME is a full 5%By the same token, increasing the spacing to 0.195" produced nearly no difference, and at 0.275" the rifle would not cock/latch. Which would seem to indicate that the LGV had "maxed out" its internal capacity. In yet another instance, a D54 with an ORing sealed piston and a Titan XS #4 spring (0.142" WD, 0.890" OD, 28 coils in 9.9"), originally tuned for the 8.49 grain pellets was yielding 8.7 ft-lbs with the H&N's BFT (9.57's), but a spacer of 0.320" made the energy jump to 12.11 ft-lbs, that is 3.4 ft-lbs, or 39% of energy gain from a relatively thick spacer, but perfectly doable in most large formats. Dropped down to a 0.200" spacer and the output became 11.7 ft-lbs, which is perfect for WFTF level shooting. Again, showing the higher versatility of larger compression chambers.I have found this seemingly inconsistent/irrational behaviour almost across all the calibers/energy levels, which means that some testing may be beneficial in most cases; so I have made sets of 5 calibrated spacers that allow me to go from 0.0400" to 0.430" and they are a useful tool to decide where to trim a spring or how to make a top-hat. ;-)Spacing (front and rear) and weighing of the piston/front end of the spring are just tools in the tuner's toolbox.And, as fickle and variable as airguns are, it is interesting to leave no stone unturned, sometimes you may find that the stone is a geode ;-) !Keep well and shoot straight!HM
Hector thanks for trying to get things back on track. The thread has gotten very deep into some technical topics I never understood and find quite interesting. It's also been a place where some people have come to aire their biases and ego. I'm not interested in either.To get back on topic, it was suggested earlier that spacers could be added to JM kit to pick up the power. This is true but there's only so much you can do with spacers. In this application I seriously doubt there's enough room for spacers to make up the difference in power between the two kits. The spring is simply weaker. Keeping this fair and current, the Vortek stepped tophat was pretty much a gimmick. It's not used on the Hw80 full power kit. It was used on the Weihrauch 25 & 26mm kits. I have installed a bunch of these kits and I've never seen more than 15 fps difference between the high and low tophat settings . It's usually ten fps. I've discussed this with Tom at Vortek. I haven't seen a stepped tophat from him in months. He may have abandon the concept.Thank you for adding your knowledge to the thread and being a gentleman.Be wellRon
Ron,Enjoy the weekend! Having a compression tube that widens at it base(ie. transfer Port) does not sound like a good thing!If I understand history correctly Air Arm's only break barrel model, the Pro Elite, had the inverse problem. The compression tube narrowed closer to the transfer port.This lead to piston heads breaking off and almost sent the company into Bankruptcy.Until you get the compression tube dimensionally correct, the idea of an expanding parachute seals seems like a band aid on a bigger problem. Think about honing the comp tube?-Yogi
I think my final arrangement will likely be a standard Vortek seal & PG4 kit. I'll just have to accept that 18 fpe may be this particular guns practical limit in 20 caliber.Be wellRon
Being anal pays off in the end Good work my friend.
Please see my previously posted R1 chrono results using the older .152 wire Vortek PG2 spring.Along with the Aussie Custom Air seal for comparison.
I do not think I am anything but a DIY amateur in the art of tuning an airgun.I do follow the basic 1st steps of cleaning all and de-burring the compression tube before proceeding any further.I have asked alot questions here on GTA and have been well advised by many members including Ron ( Bayman ).I have learned some basic skills - but again I do not profess to be any kind of expert.My chrono results table for my two well adjusted and mannered R1's is how my R1's have progressed.They both are accurate and well behaved in the shot cycle in my opinion. ( My R9 5mm with a ARH Hornet Spring is in my opinion a smoother shooter and equally as accurate )
My R9 started as a .22 from Flying Dragon - I moved .22 barrel to the R1 and put a .20 barrel on the R9( also added a TH and SS washer to piston end of spring )
I'm sure ED will chime in on this 1
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