Durability Desired, PDI 170

[ILLusion]

I'd say to go with a Systema silent head set. It makes a huge difference as far as gearbox durability goes.

What is your reasoning for going with an Infinity Torque Up gearset? That's overkill. The PDI 170% I would highly recommend a gear set that increases torque levels, but infinity torque up is excessive. If your reasoning is simply due to Guarder's price point and the fact that they don't carry any torque levels in between, then I suppose that's fine. I'd still recommend you go with a Systema torque up or Prometheus double torque up gear set and maintain use of full-tooth pistons. (Half-tooth are required for infinity gear sets)

Yes, Systema piston heads are compatible with Guarder pistons. The fit may be a bit tight, but it'll work.

Originally Posted by Drake

That statement has always baffled me.

Will an aluminum piston head increase the spring/gun's power? Haven't compared weights, but for the sake of argument we could suggest the aluminum piston head is lighter than the polycarb one thereby having less inertia and permitting the spring to uncompress more quickly. The difference would be insignificant in terms of having a real impact on the mechbox's integrity.

Some people have also suggested it's the "metal on metal" impact that's damaging. Given equal amounts of energy and the soft nature of aluminum, I think it'd have to be tested. But even if that were true, the piston head never comes in contact with the mechbox: it impacts the cylinder head. So if there really is more wear from metal-on-metal impacts vs plastic-on-metal of equal force, the real part that should be avoided would be the upgraded metal cylinder heads, since they're what's pressed up to the mechbox and transferring the force of the impact from the spring/piston to the mechbox shell.

Long live good ol' Marui plastic cylinder heads.

It's been tested and proven that aluminum piston heads will lead to catastrophic failure of the mechbox due to increased vibrational impact. Keep in mind the rigidity of aluminum. Compared to other metals (such as steel and titanium), it is VERY stiff and rigid and causes huge vibrational transfers through contacting materials. Aluminum piston heads are also heavier than synthetic (POM, silicon, polycarbonate) piston heads.
I was witness to a study that MadMax performed that proved these theories. The results of that study were never published, but the aluminum piston head was proven to be the worst piston head you could use if you were looking for durability.



Regarding the Pro-Win's enhanced air chamber seal - the increased seal won't be realized until you break the 450fps barrier.

[Taito]

I've used the following combination in my RPK with fairly good success and very little if no visable wear after 20K rounds. I was driving a 650mm tightbore, so some of the parts might be a little overkill for a 400fps setup. I'm not suggesting that you go my route as the spring/tightbore/bearing spring guide and piston head pushed the FPS up to the mid 400s, but just take a look and see what you can take for your own use.

Stock CA Ver 3 Shell
Prometheus Double Torque Gearset
Prometheus Bore-Up Cylinder Set (Bearing Piston Head)
G&P Polymidal Piston (Full Tooth)
Prometheus Bearing Spring Guide
Prometheus Anti-reverse Latch
Prometheus Tappet Plate
Systema M140 Spring

Cheers,
Vic.

[CDN_Stalker]

Originally Posted by Taito

I've used the following combination in my RPK with fairly good success and very little if no visable wear after 20K rounds. I was driving a 650mm tightbore, so some of the parts might be a little overkill for a 400fps setup. I'm not suggesting that you go my route as the spring/tightbore/bearing spring guide and piston head pushed the FPS up to the mid 400s, but just take a look and see what you can take for your own use.

Stock CA Ver 3 Shell
Prometheus Double Torque Gearset
Prometheus Bore-Up Cylinder Set (Bearing Piston Head)
G&P Polymidal Piston (Full Tooth)
Prometheus Bearing Spring Guide
Prometheus Anti-reverse Latch
Prometheus Tappet Plate
Systema M140 Spring

Cheers,
Vic.

Is a very good chance the gun he's using that spring in has a version 2 mechbox, since those are the only ones that break (yes, seen a couple V3 mechboxes break, but that is extremely rare) even with moderate upgraded springs (my PDI 150% destroyed my stock V2 mechbox within 2 months of basement shooting, not gaming since it was over winter, and the only upgrade was spring and bushings).

[Taito]

Originally Posted by CDN_Stalker

Is a very good chance the gun he's using that spring in has a version 2 mechbox, since those are the only ones that break (yes, seen a couple V3 mechboxes break, but that is extremely rare) even with moderate upgraded springs (my PDI 150% destroyed my stock V2 mechbox within 2 months of basement shooting, not gaming since it was over winter, and the only upgrade was spring and bushings).

I would definately try to increase fps via effenciency (lower air loss) than running a stiffer spring then. I've seen a couple of broken V2 gearboxes and it's normally at the front of the cutout for the cylinder. Never a stock TM gearbox, but alsways one pushing a stiffer spring.

[Greylocks]

Originally Posted by Colin_S

Why is a "better quality spring" easier on the mechbox? After all doesn't a Prometheus or Systema M120 (or whatever model fires 400 fps) have the same output energy as a PDI 170%? If it doesn't, how come these less energy springs are able to push BBs at the same level?

The quality matters because PDI has claimed that a 170 should produce 400fps, but they vary QUITE widely and are inconsistent. The other companies produce exactly what they claim.

[CDN_Stalker]

Originally Posted by Taito

I would definately try to increase fps via effenciency (lower air loss) than running a stiffer spring then. I've seen a couple of broken V2 gearboxes and it's normally at the front of the cutout for the cylinder. Never a stock TM gearbox, but alsways one pushing a stiffer spring.

I agree there. My MP5SD I got up to (I'd say unintentionally) 387fps. At first it sat at a pretty consistant 350fps, then I installed a bearing spring guide, went up to 365fps, then I installed a 330mm stock inner barrel into it (10cm above the 229mm that was in there) and that itself ended up adding another 20fps to tmy total.

I have a Prometheus 110SP spring in my other MP5, and aside from bushings is the only upgrade. Beginning of this year my SD tanked out of me withthe cracked mechbox (was shooting max 300fps), so I used my other one all year, about 15 or so games, and it shoots 365fps, still has the stock version 2 mechbox, and is running and shooting great. Case in point, Prometheus springs are very good even on stock mechboxes. And since my barrel is only 229mm in that gun, anything with a longer barrel and that spring will be sitting at a higher fps (and a lower chance of mechbox breakage).

[Colin_S]

Originally Posted by Greylocks

The quality matters because PDI has claimed that a 170 should produce 400fps, but they vary QUITE widely and are inconsistent. The other companies produce exactly what they claim.

Greylocks, that doesn't answer my question nor was it what I'm asking. pizzainthemorning stated that his PDI 170% is pushing 400+ fps in his ver 2 mechbox and was asking how to make it more durable while keeping a similar muzzle velocity. Some of the answers here were to change to a higher quality spring of the same FPS but if the spring outputs the same energy, how would that stop the mechbox from cracking?

Originally Posted by Spawn28

i just put in a guarder 120 spring in my M15A2 and im gettin 405 fps consistant and seems like there isnt as much pressure on the mechbox as the stock ca spring that was only giving me 320 fps

Agreed much better quality and less pressure = longer mechbox life

That's a rather ludicrous statement. You're saying a high tension spring like the Guarder SP120 outputs less energy into your mechbox than teh stock low tension CA spring yet you get a higher fps?

The stronger the spring, the more damage it does to the version 2 mechbox.

[TokyoSeven]

Many points have been covered already this morning and Im not sure what I have to add. I will attempt to provide some insight as best I can as many have already stated helpful tid bits.

If you want keep that over 400 mark, I would say change the spring so something like a guarder sp100 or systema m120 and just upgrade your barrel, airseal nozel, and make sure youve got a good air tight hopup. But you wish to keep your PDI 170, so those options maybe out for you. However out of my two M4s, My M4 RIS has a higher FPS than my M4 MRE,My RIS has a guarder sp100 while the MRE has an sp110, but the RIS also has an upgraded deep fire airseal nozel and tighter barrel. So even though the MRE has a stronger spring, the RIS still has a higher fps due to having more efficient parts.

Unfortunetly my RIS also has an aluminum piston head on a systema red polycarb piston and aluminum cylinder head while the MRE is just stock piston head on a red systema polycarb with a stock cylinder for now, eventually my RIS may explode, it may not. I cant really say. As preventative maintenance I should replace just because.

The thing about reenforced mechboxes is that they arnt designed to last forever, they just take longer to break than regular mechboxes. Ultimately your goal should be to find appropriate parts that would compliment the other parts in reducing the stress.

Although if its in your budget and you can get one, a pro win mechbox may suite your needs if your goal is to continue running with that PDI 170.

Unfortunetly, unless I am blind, I did not see what type of aeg you are running this pdi170 in. If its anything wit a version 2 mechbox, well to be honest, I cant confirm this but some people just say v2's are garbage regardless how they are set up, thats not my opinion, just what some people have stated. I dont know, I havent had any major issues with any of my M4s. Nothing that wasnt fixable atleast.

[pizzainthemorning]

Great guys, thanks for all the info so far.

It's a V.2 mechbox I'm running in my G3 as a sniper platform. FPS limits aren't really an issue because I likely won't be gaming on any fields with it. And in case you're wondering.... yes, cost is a factor (so no pro win for me, not now anyway).

Three things still though:

1. Spring Quality: Go with prometheus, or should systema or guarder be fine?

2. Piston: Aluminum or polycarbonate? I've read that aluminum ones can get chewed up leaving little bits of metal in your mechbox which isn't good.... but I've also read that they're more durable so I don't know what's going on.

3. About how much fps will a "silent" piston headset eat up?

Thanks,

Alex

[bean]

if you are worried about the mech box exploding look for a mthaynes gear box. they are hard to come by but far superior.

[CDN_Stalker]

I've had experience with Promtheus, they are damn good and pretty close to what the rating states (dependant on the barrel length of course.)

See about getting a King Arms Reinforced Mechbox from Jugglez (airsoftparts.com), they are about $40. I haven't tried them yet but I have four on order (two for a client, one for my MP5SD and one for stock)

Piston, stick with a polycarb one, it'll be nicer on your mechbox.

Piston head............. I've seen everything form 10fps to 30fps droppage in velocity.

If range is important to you (looks like it considering G3 as sniper rifle) you should go with what was mentioned above, get a 120 spring that is trustworthy, then focus on getting parts that'll make the airflow more efficient, such as piston head, cylinder head, nozzle, good hop up rubber (KN RH75 would be good for you, it's rated for guns 400+fps), and a tightbore (adds about 10fps). And use heavy BBs, no lighter than 0.28g.

[ILLusion]

Originally Posted by pizzainthemorning

3. About how much fps will a "silent" piston headset eat up?

If installed properly, none.

[mateba]

if you already have a bearing spring guide get rid of the bearing piston head. Its pointless and it will reduce the weight slamming into to your MB. Swiss cheese your piston to further reduce weight or start modding your piston head or/and cylinder head. Understand, these mods will reduce MB ware but there will be a FPS drop. You could use a SystemA silent head or bore up kit to pad your cylinder/piston head or an Angle head which use a form of an air brake if you don't want to do the mods. Air brakes are the most effective and they tend to quite your gun done too.

You can make an air brake
http://64.233.179.104/translate_c?hl...3DgJ0%26sa%3DG

or a padded cylinder head
http://64.233.179.104/translate_c?hl...3DgJ0%26sa%3DG
http://64.233.179.104/translate_c?hl...3DgJ0%26sa%3DG

you could also stretch for a CNCed MB.

[pizzainthemorning]

Thanks guys, I really appreciate it. I think that's all the info I need.

Thanks,

Alex

[TokyoSeven]

For springs, I always either rock a systema m120, or a guarder sp100 or sp110. With either of those you will always be in good hands.