Tx200 zero transfer port

[wonky donky]

Did a bit more today, machined the barrel with a shoulder..not enough really but I'm being cautious here for reasons I won't disclose now.

Grooved the compression plugs to take a slightly beefier "O" ring than standard.

Extended the thread on the barrel, bored & blued one compression plug & fitted it in the tube. checked I had got the barrel flush with the rear & not gone too far.

So here are a few images.

Looks perfect Tony - Dave, you finished yet ?

Funny you should ask Jon...YES JUST BEEN SHOOTING IT MATE!

[Shed tuner]

Looking good Dave
No groove to retain the barrel o-ring though ?

PS This a mk1/2 ?

[Orlando D.]

reason I say this- if you able to keep tight dimensions as wanted- its possible that the barrel may not align with the compression tubes due to manufacturing tolerances in the receiver, especially if your cylinder is buttoned or fairly tight..

Its just a thought- the cone shape should help in the final aligning the cylinder over the barrel..... its probably harder to set the head space though..

Personally- I do prefer the way you are doing it now though.. If all is good it should be a nice set up..

Keep it going!! looks great so far..
Cheers-O.

[wonky donky]

Looking good Dave
No groove to retain the barrel o-ring though ?

PS This a mk1/2 ?

Doesn't need one, the "O" ring stays in place inside the new compression tube block much like the standard TX but without the TP.

The compression tune is from a mk3, the piston was out of a tube with 10 abt indents, so mk2?. I left the standard rod in. Standard but burnt TX seal, MK2 spring with piston weight, spring binds as it's bent inside the piston.

I will do a tune when I get time, I suppose you want to know what it's shooting? AA 4.51 & JSB 4.52 exactly same fpe AAD express 4.52 0.04fpe lower guess why I've omitted the first figure!

No bangs Jon......told you! I will adjust everything as & when I get time, shot cycle is very quick & feels slammy, very little recoil, can be made much nicer.

[wonky donky]

reason I say this- if you able to keep tight dimensions as wanted- its possible that the barrel may not align with the compression tubes due to manufacturing tolerances in the receiver, especially if your cylinder is buttoned or fairly tight..

Its just a thought- the cone shape should help in the final aligning the cylinder over the barrel..... its probably harder to set the head space though..

Personally- I do prefer the way you are doing it now though.. If all is good it should be a nice set up..

Keep it going!! looks great so far..
Cheers-O.

Yes I did think about sleeving the barrel & machining a cone on the end then fitting a Feinwerbau 300s coned breech seal into the plug...

[Orlando D.]

Yes I did think about sleeving the barrel & machining a cone on the end then fitting a Feinwerbau 300s coned breech seal into the plug...

The Steyer works the same except the oring sits on the cone of the barrel, its a thin oring..

the standard FWB desing may not let you pull the barrel back as much as you want, but from what I seen, i guess you could reshape it and do it.. a plus is the FWB would allow a nice cush affect on the cyl...

I have a Steyer barrel here, but do not know how to post pics .. I can from my phone and email it to you... has a great camera.. ill try..

O..

[Shed tuner]

Doesn't need one, the "O" ring stays in place inside the new compression tube block much like the standard TX but without the TP.

The compression tune is from a mk3, the piston was out of a tube with 10 abt indents, so mk2?. I left the standard rod in. Standard but burnt TX seal, MK2 spring with piston weight, spring binds as it's bent inside the piston.

I will do a tune when I get time, I suppose you want to know what it's shooting? AA 4.51 & JSB 4.52 exactly same fpe AAD express 4.52 0.04fpe lower guess why I've omitted the first figure!

No bangs Jon......told you! I will adjust everything as & when I get time, shot cycle is very quick & feels slammy, very little recoil, can be made much nicer.

This is really cool... I'm genuinely surprised the pressure isn't causing things to burn, or the pellet to disintegrate, but happy to be proven wrong on this one ! I guess if you do need to introduce some lost volume to manage pressure, you could add some zephyr type grooves to the comp end plug inside face - so at least it would be purposeful.

Worst case you could stick a 25mm OD, washer down in the end of the comp tube with say a 4.3mm hole (to stop pellets falling back into the tube by mistake, make it 1mm thick. OK, you'd have a 1mm port, but I bet it'll still be sweet....

So this is full weight piston, 83mm stroke, stiff mk2 spring with a heavy weight - bet it's pokey I only run my 5.3mm ported guns around 77mm, I think you need a nose extension or a longer rod I'm thinking lose the piston weight (replace spring) and 65-70mm stroke

I've a spare inaccurate barrel and a ropey comp tube end plug, I feel some butchering coming along - just need to wait for that die...

[T 20]

Worst case you could stick a 25mm OD, washer down in the end of the comp tube with say a 4.3mm hole (to stop pellets falling back into the tube by mistake, make it 1mm thick. OK, you'd have a 1mm port, but I bet it'll still be sweet.....

Hi Jon

This is why I suggested (somewhere on here) the Chinese/FWB cone breech seal and 1mm long transfer port.

If you think about it it makes life a lot easier in quite a few ways.




All the best Mick

[Shed tuner]

So many great minds thinking alike one one thread - we're wasted I tell you

[Orlando D.]

This is really cool... I'm genuinely surprised the pressure isn't causing things to burn, or the pellet to disintegrate, but happy to be proven wrong on this one ! I guess if you do need to introduce some lost volume to manage pressure, you could add some zephyr type grooves to the comp end plug inside face - so at least it would be purposeful.

Worst case you could stick a 25mm OD, washer down in the end of the comp tube with say a 4.3mm hole (to stop pellets falling back into the tube by mistake, make it 1mm thick. OK, you'd have a 1mm port, but I bet it'll still be sweet....

So this is full weight piston, 83mm stroke, stiff mk2 spring with a heavy weight - bet it's pokey I only run my 5.3mm ported guns around 77mm, I think you need a nose extension or a longer rod I'm thinking lose the piston weight (replace spring) and 65-70mm stroke

I've a spare inaccurate barrel and a ropey comp tube end plug, I feel some butchering coming along - just need to wait for that die...

You could set it in the step in the Comp tube... make choose a few different port sizes.. O.

[prosport.177]

Looks good .). Been wondering over this.
Question if pellet drops out of breech does it end up in the comp tube?

[Shed tuner]

Looks good .). Been wondering over this.
Question if pellet drops out of breech does it end up in the comp tube?

Yes Hence the conv about a 4.3 mm bored washer, creating a 1mm port variant.
TBH though, in 10 years and 10s of 1000s of pellets through my TX, whilst I've dropped a few in the loading area, I've never had one fall out of the breach once loaded !

[prosport.177]

Yes Hence the conv about a 4.3 mm bored washer, creating a 1mm port variant.
TBH though, in 10 years and 10s of 1000s of pellets through my TX, whilst I've dropped a few in the loading area, I've never had one fall out of the breach once loaded !

Cheers jon, somehow i missed this reply on the thread. I see it crossed your mind to
.)

[slugger]

I love the idea of this, but I am left wondering about consistency... with no transferport are you not going to have massive variances in fps with different brands/makes of pellets ? surely some of the traditional transfer-ports job is to restrict flow/air-speed, without that effect I image it would be very pellet fussy in terms of fps to avoid slam ? or am I not thinking right ? seb

[Shed tuner]

I love the idea of this, but I am left wondering about consistency... with no transferport are you not going to have massive variances in fps with different brands/makes of pellets ? surely some of the traditional transfer-ports job is to restrict flow/air-speed, without that effect I image it would be very pellet fussy in terms of fps to avoid slam ? or am I not thinking right ? seb

I think that's a concern. I was thinking more of things like variation in pellet seating depth too... i.e. even with a pellet it likes, 0.1mm extra seating depth changes the "lost volume" by 5%...