new member with tx200

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sussexa
Posts: 12
Joined: Sun May 06, 2018 6:55 pm

new member with tx200

Sun May 06, 2018 7:50 pm

hi all, just to introduce myself here as may be posting on and off in the future.
just thinking of getting back into airguns having been out for too long.
decided to go spring again as the tinkering is what i enjoy the most.
just playing with a tx200 .22 (think may be a mk 2 ,as has no barrel threads for silencer but has arrestor holes on top and antibeartrap ser no 037xxx), was running a poor 8.5-9 ft lbs ,decided to order a tbt maxi pro kit with short stroke conversion (for the advantage of the more efficient seal and choice of replacements and the reduced hold sensitivity of the shorter lock time) ,stripped and polished internals today and have just finished rebuilding it in several different combinations.
first i polished the compression tube on some precision bar, was picking up some tight spots so polished , degreased , fitted with new breach seals and left at that(3.74mm transfer port as measured)
the tbt piston head and seals although good i decided to debur all the inside and outside corners with a sharp blade ,hopefully to reduce and high spots and reduce break in time.
same with the spring guide , almost forgot to check and cut to length as with the short stroke head on there it didnt cock cut about 16mm off as i didnt want to end up trimming all day.
the spring supplied in the kit is inches longer than the spring that came out of the gun, and there was the first problem.
when it came to rebuilding with the short stroke conversion on it had what must have been 3 inches of preload and i just couldnt get the pin back in.
so to plan b i removed the short stroke head and replaced the old worn air arms piston seal and reduced the preload to 2 inches maybe and just managed to get the pin in, success.
rebuilt and tested on a chrony (airsoft x3200 i think accuracy unknown, also have a combro but shot it with my last break barrel some years ago, im assuming not the only one)now the truth be told some 2 ftlbs over the legal limit at 670 fps for rws super point @14.45gn( all i had now but i have a selection pack on the way to test a few pellets and vaying head size , in some jsb diablo , air arms field and h and n in 5.51 to 5.53 , with plans to find the best liked pellets )
so well over legal and now im guessing its a much stronger spring to take into account the reduced volume with the short stroke head, i strip again and notice the preload had much reduced with only 10 shots firedspring settled a bit shorter, so refit again the short stroke head (with loctite)and relube (with the supplied bumslide)again.
better now after only a few shots it was low 561fps and high 576fps around 10.5 ft lbs.
wanting a bit more to start with i fitted the 2 supplied power washers and soon rebuilt again only to find i could now not cock the rifle , it just wouldnt latch , so settled on 1 power washer and ran across the chrono again.
now running around 562fps on the low side and 582fps on the high side at 10.8 ft lbs now this was the first 10 shots after rebuilding again.
so, what are the thoughts here , i have read about the transfer port being on the large side already so leaving as is.
as it is now i have the short stroke head a white hw seal, a tbt top hat and slip washer in the piston, the supplied spring, the tbt spring guide , and 1 power washer on the rear guide , all lightly lubed with bumslide.
what to do now?
add piston weight ? , swap the tbt top hat back to the metal std one?
or do nothing and see how it settles in over a few hundred shots?is it likely to settle and come up or settle and drop down.
thanks for any advice , and to come trigger polish another day.

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TenMetrePeter
Posts: 1043
Joined: Wed Jun 29, 2016 5:40 pm
Location: Luton Beds UK

Re: new member with tx200

Mon May 07, 2018 9:59 am

Hello and welcome sussexa.
Some interesting technical procedures there. Remarkable how bad it was originally and how dramatic the power increase. Good to see you took the legal route and got it down again!
I would let it settle now especially if you have done anything to the barrel like lapping it. There's a chance it could creep up again after a tinfull.
Yes trigger polish next!
PS contact Combro. Repairs usually quite cheap. They used to send out free casings but they are still inexpensive.

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sussexa
Posts: 12
Joined: Sun May 06, 2018 6:55 pm

Re: new member with tx200

Mon May 07, 2018 1:21 pm

thanks , no not lapped the barrel but as unknown to me and barrel and cocking arm showing fair bit of surface rust ,i gave it a good scrub with a brass brush and some jenolite i had from the past , hope not too severe , followed by a swab with the wooley , and finaly a few shoot through pads till clean followed by one or 2 with some pellet lube on them and then another couple dry.
i have a bore snake on the way as feel this will be enough to give a quick clean between testing the pellet batches to find the one i will use.also i did not realise the baffles were fully enclosed when i bought the shoot throughs, and although all shoot throughs came out i think as they were backed up by pellets i dont see the need to ask for trouble.
regarding bore lapping is this something i should consider? had youtubed it and not found much about for air rifles.
i know that fire lapping is a thing in rimfire etc , can compound be added to pellets and shot through ?
or is it simply coating swabs with compound and pulling through ?
thanks again

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TenMetrePeter
Posts: 1043
Joined: Wed Jun 29, 2016 5:40 pm
Location: Luton Beds UK

Re: new member with tx200

Mon May 07, 2018 2:42 pm

Nah. No need. :lol:
There are barrel lappers on who spend hours lapping with made to measure lead laps and compound til there's no machining marks (and bore scopes to check it with.)
I call them worn out at that stage, but that's just my opinion and they win trophies. 8-)

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Timmytree
Posts: 969
Joined: Sun Feb 15, 2015 11:50 am

Re: new member with tx200

Wed May 09, 2018 1:14 pm

I might be piddling up the wrong tree on this but I thought the Mk 2 stroke was already shorter and more efficient than the Mk 3? If so that might explain why you had fun getting the spring in with an additional short stroke head.

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sussexa
Posts: 12
Joined: Sun May 06, 2018 6:55 pm

Re: new member with tx200

Fri May 11, 2018 4:51 pm

could well be the case , i didnt measure the stroke before or after.
im really shocked how its settled , i havnt shot it all week , 500 air arms field 5.52 have turned up so tested with those to carry on the break in before testing the selection packs of only 25.
weighed at actual 15.98gn (16gn advertised) they are now being kicked out at an avg 576fps +/- 8fps which works out avg 11.8ft lbs for 40 shots straight from the tin not washed or lubed or sorted.
now thats still a bit too close for comfort i think , or is it ?
next time its out of stock for trigger or blueing i think im going to take out that 1x power washer , or shall i continue to test as is ? theory being , will the best pellet at 11.8 ft lbs be the best at 11ft lbs ?
thoughts welcome and thanks for the replies so far

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Timmytree
Posts: 969
Joined: Sun Feb 15, 2015 11:50 am

Re: new member with tx200

Sat May 12, 2018 7:36 am

11.8 is too close for me. Thats only a couple of fps from the red zone.
Try some lighter pellets such as JSB Exact Express or AA Field Express, they will almost certainly be more efficient.

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sussexa
Posts: 12
Joined: Sun May 06, 2018 6:55 pm

Re: new member with tx200

Sat May 12, 2018 9:49 am

my thoughts too but as been out of the scene for a while im supprised how many posts i see with brand new guns getting tested over 12 ft lbs and wondering what the likely hood of falling foul to being tested and also being found over ?
if i set at 11 with 5 or 6 different pellet sizes and weights and they test with some odd ball that sends it over 12ft lbs where do you stand ?
back to testing today though and i have done some more shot strings with , silicone lube and napier lube and both these added another 0.3 ft lbs with the aa fields 16gn bores snaked each swap.
so stripped again and removed that single power washer
tested again in different order as fairer test and still too high with the power washer out , infact if anything a little
higher than with it in ?

going to continue to test the selection pack as is but all dry , find the highest and use that to set power with probably a spring coil collapse or is it recommended to cut and refinish say 1/2 coil or 1 coil.
or could i skim top hat a few mm's
i will need to lose at least 0.5 to 0.75 ft/ls to be safe ,
thanks again in advance

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sussexa
Posts: 12
Joined: Sun May 06, 2018 6:55 pm

Re: new member with tx200

Sat May 12, 2018 3:18 pm

finished testing and very surprised how the power velocity and consistency varies brand and head size.
also i dont think i shot enough to settle it down again after removing the power washer, which by the way the spring has settled a bit more and plenty easy enough now to split and refit , even though it was only the trigger block and rear guide that was disturbed.so the first 2 groups tested started high and dropped through testing
the results are minus the highest and the lowest fps from each group of 10 and then avg
h+n ftt 5.54 14.78gn avg fps581 -avg 11.08 ft lbs +/-10fps
h+n ftt 5.53 14.83gn avg fps543.-avg 9.71ft lbs +/-4.9fps
aa field 5.51 15.96gn avg fps557-avg 11ft lbs +/-5.6fps
aa field 5.52 16gn avg fps564-avg 11.31ft lbs +/-2.78fps
jsb jumbo rs 5,52 sized 5.52(skirt) 13.43gn fps580.8-avg 10.10ft lbs +/-4.33fps
jsb jumbo 5.51 15.89gn fps554-avg 10.84 ft lbs +/- 2.66fps
jsb jumbo 5.52 15.97gn fps559-avg 11.09ft lbs +/-2.43fps
jsb jumbo 5.53 15.94gn fps568-avg 11.42 ft lbs +/-3.72fps
then repeated the lube test
aa field 5.52 15.98gn napier 565fps -11.33ft lbs +/-3.29fps
aa field 5.52 15.98gn silicone 564fps-11.3 ft lbs +/-4.86fps
aa field 5.52 15.98gn dry 565fps-11.3ft/lbs +/-1.6fps

now judging by the results in the order tested it was still settling as the variations were getting lower in general as i went on the h+n might not have had a fair test being first but seen as power is so low unless they are super accurate their not on my list.
the power is now where i consider safe , and consistency is very good for a springer still within its first 200 shots
tha aa field was preferred in 5.52 vs 5.51 so they make the list after ive used this tin up
the jsb rs are not on my list not sure if its the weight or the sized skirt it didnt like ?
the jsb jumbo 5.51 look to be off the list low power
the jsb jumbo 5.52 and 5.53 are both on the list. will try later lubed also
i really need a long range accuracy test now with the pellets i have left , but not for a while as i have the blue to attend to first.
im guessing the law doesnt use lubed pellets in any way so i think im safe now power wise as is.
the lube didnt add as much power this time at the lower power , barely any more , unless the barrel is now pretty lubed.
other thoughts
overall so far likes the heavier pellets better , likes the larger head sizes better (although not too large as the h+n was worst and had largest heads)
all the skirt diameters were fairly close at 5.65 to 5.68mm( apart from the sizedj sb rs, i thought it was the head that was sized not the skirt, didnt seem to help anything too much anyway so sizing skirts not on my list either)
the head sizes measured way below whats advertised with digi vernier calipers , or my calipers are out, or im squashing the head 0.04-0.05mm every measurement
aa 5.51=5.46
aa 5.52=5.46
h+n 5.53=5.49
h+n 5.54=5.50
jsb rs 5.52=5.47
jsb 5.51=5.47
jsb5.52=5.47
jsb 5.53= 5.47

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Blackbaronfish
Posts: 3690
Joined: Sun Feb 15, 2015 6:20 pm
Location: Nuneaton

Re: new member with tx200

Sat May 12, 2018 5:33 pm

Welcome to the AAOC Sussexa
It’s very difficult to measure the head sizes as you’ve found out. The sizes given are what the dies were and transportation changes things

BBF
Did I mention that I'm the only one to have attended EVERY meet since we started

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