Tm Aug High Cycle Cylinder Volume

[THE FNG]

Noob question.

I've recently acquired a tm high cycle aug in a trade and I love it to bits.

I'm considering using it on my next skirmish (some time away) and I was hoping to bump the fps a little as they shoot 260-270 stock.

I wasnt going to touch the gearbox as they have been designed specifically for low torque motors and low power springs

I was going switch the inner barrel; I bwive they come 260mm stock and I was thinking of adding a 300+ tbb. 

I've viewed the cylinder volume chart online but I'm rubbish at tech work. 

I beleive the high cycle has a 3/4 hole. If I have interpreted the chart correctly I could install up to 350mm inner barrel.

Am I right in believing this, are there any other variables I need to consider and would anyone roughly be able to guess at what length I would be in danger of shooting over 350 fps?

I appreciate this may be a "how long is a piece of string" question! 

I'm not aiming for 350, more like 300 to 320 just so the hits are felt. 

Chart for reference.

View attachment 60555

 

[Skara]

I'd just get a tighter barrel, same length but 6.03/6.01 in diametre, the stock one is 6.08. That way you'll get a nice boost in energy output without risking going over the 1.13J limit for full auto.

Just keep in mind that it'll most likely creep if you use some heavier weights like 0.28/0.30s, but I'm pretty sure it'll never get to the legal limit.

 

[Adolf Hamster]

Cant say ive ever really noticed much meaningful velocity change in aeg's just from mucking about with barrels, only thing has a big impact is the loss from the hop once its set for heavier ammo.

 

[Rogerborg]

Cant say ive ever really noticed much meaningful velocity change in aeg's just from mucking about with barrels

I have, but it's not an exact science.

Before: CYMA M4 with an 280mm sloppy-bore, an M100 spring and stock piston and nozzle and cylinder ported for that barrel = 330fps.

Aft4er: A shorter 229mm ZCI 6.02mm, ZCI rotary hop and maple leaf rubber = 374fps.  Oops, I've had to throw in an M90 spring to get it down to 340fps.

I did stretch the piston o-ring and grease inside the cylinder, but otherwise it was all outside the gearbox.  I really didn't expect that, but that's what I saw.  Could be the barrel, could be a better seal at the hop rubber, but either way, quite the jump in energy.

However, swapping the stock barrel on a JG G36 for a 6.02mm 247mm ZCI and a maple leaf rubber added only a little energy, so... not an exact science.

What I would suggest is improve the stuff outside the gearbox first, then then piston air seal, then finally change the spring to match.

 

[Adolf Hamster]

Could be the barrel, could be a better seal at the hop rubber, but either way, quite the jump in energy.

See my feeling there is a nozzle-hop airseal improvement in that example much moreso than simply the barrel diameter.

See we should be changing only one thing at a time when tinkering, but lets face it aint nobody got time for that....

 

[THE FNG]

I have, but it's not an exact science.

Before: CYMA M4 with an 280mm sloppy-bore, an M100 spring and stock piston and nozzle and cylinder ported for that barrel = 330fps.

Aft4er: A shorter 229mm ZCI 6.02mm, ZCI rotary hop and maple leaf rubber = 374fps.  Oops, I've had to throw in an M90 spring to get it down to 340fps.

I did stretch the piston o-ring and grease inside the cylinder, but otherwise it was all outside the gearbox.  I really didn't expect that, but that's what I saw.  Could be the barrel, could be a better seal at the hop rubber, but either way, quite the jump in energy.

However, swapping the stock barrel on a JG G36 for a 6.02mm 247mm ZCI and a maple leaf rubber added only a little energy, so... not an exact science.

What I would suggest is improve the stuff outside the gearbox first, then then piston air seal, then finally change the spring to match.

By chance I have a maple leaf hop rubber and nub spare. Will give that a go and check the seals etc. Then maybe view a tbb.

Thanks all for the advice.

 

[Rogerborg]

See my feeling there is a nozzle-hop airseal improvement in that example much moreso than simply the barrel diameter.

You might very well be right, I've got no hard evidence, because...

See we should be changing only one thing at a time when tinkering, but lets face it aint nobody got time for that....

That, really.  What I would suggest is that if you are going to change the barrel, do that first as it's about the easiest thing to do, then it's a fixed point and you can work backwards from there.

 

[Skara]

See we should be changing only one thing at a time when tinkering, but lets face it aint nobody got time for that....

It's more the hassle of constantly having to remove/insert the gearbox from/in the receiver (with V2s) that the time spent to experiment with parts.

 

[Adolf Hamster]

That, really.  What I would suggest is that if you are going to change the barrel, do that first as it's about the easiest thing to do, then it's a fixed point and you can work backwards from there.

i tend to think the opposite way round, on the sliding scale of cost/benefit the barrel tends to be pretty far down that list.

It's more the hassle of constantly having to remove/insert the gearbox from/in the receiver (with V2s) that the time spent to experiment with parts.

any gun with recoil says hi

 

[Rogerborg]

i tend to think the opposite way round, on the sliding scale of cost/benefit the barrel tends to be pretty far down that list.

But they're so shiny.  Bear in mind that my gnus are all poverty-spec so a £14 or £15 ZCI is a real treat for them.  Although at least they've all come with brass-ish barrels, rather than the tin foil one that Luke found in a Nuprol.

 

[Iceni]

I'm considering using it on my next skirmish (some time away) and I was hoping to bump the fps a little as they shoot 260-270 stock.

I wasnt going to touch the gearbox as they have been designed specifically for low torque motors and low power spring

Use it before you do anything to it. Make a judgement about what you want from the gun.

If you decide it needs gearbox tweaks then be warned it'll no longer be a TM high cycle. The only difference in the TM and a Snow wolf/JG/APS short AUG is the gearbox. Everything else is identical.

With that in mind If you were to want to upgrade the internals I would buy a second gearbox to play with and leave the stock TM one alone. It takes a few seconds and one screwdriver to swap the gearboxes.

It also means you have a complete spare gearbox for pissing about with, without loosing the ability to use the gun. Just be warned, it's normally cheaper to outright buy a cheap AUG variant and use it to tinker with rather than just buy a gearbox. Typically a complete JG gearbox is £50-65 if you can find them, a complete AUG from Gunfire is £100. Broken/faulty Augs are pretty common as well and you can pick them up cheap as people make several mistakes with upgrades that make them really bad, and a platform with no end of issues (this is actually false if you understand the platform).

This also means you have to be careful about upgrades, A TM HC with gearbox upgrades is no longer a TM HC and whilst you might think you have added value to it, it's probably the reverse. An upgraded JG on the other hand is still a JG and again there is no real added value in major gearbox tweaks. It's a really hard call to make upgrading an AUG you have to love it and want to use and keep it, as there are very few people that will see the value your add in upgrades. 

 
Both of my AUGs are heavily upgraded internally:

The ASG/JG A3 has:

35K motor
Solid brass spring guide
POM silent head set
AOE correction
Stainless bushings
Shimming
Flat hop w/ prommy purple
ZCI inner barrel
ZCI Air nozzle
Oversized piston O-ring
Body sound damping - internal
Gate nanohard
Silver wire


The APS A1 has:

SHS bore up kit - cylinder - head set - air nozzle
ZCI 16:1 gears
25K motor
Solid brass spring guide
ZCI inner barrel
Prommy purple (mounded)
Stainless bushings

Shimming
Oversized piston o-ring
Xcoretech xet304u
Silver wire

Both guns are very similar. The A3 is super quiet - you can't hear it outside of about 10M, And makes a fantastic mobile sniper platform for getting unseen kills.

The APS is a lot noisier but it makes up for that in it's trigger response.

If I were to do a 3rd AUG it would be to these specs:

ASG ultimate CNC 30K
13:1 gears
Short stroke 2 teeth
320mm ZCI inner barrel
Silent head set
Stainless bushings
Solid brass spring guide
Flat hop w/ prommy purple
Xcoretech xet304u
Silver wire

The hop unit doesn't need to be changed in my opinion, the stock ones are very capable, but require building correctly. Likewise you can't shim the inner barrels and there are a few tricks to making them right unlike an M4 if shimmed it'll cause all sorts of issues and it's one of the most common causes of people thinking the platform is bad.