[Faitfull]

Would a dmr build around a gearbox with the longer cylender in a cyma t3 gearbox give me longer effective range than a v3 gearbox with full cylender giving than barrel lenght is proberly volumed?

Aiming to get prober long range game outdoor around 2.4 to 2.8joule

 

[Plazmaburn]

Doubt it, as that really doesn't do anything for range. That is all from your hopup, bb weight, and power applied to the bb.

 

[Whamhammer]

Doubt it, as that really doesn't do anything for range. That is all from your hopup, bb weight, and power applied to the bb.

I partially disagree, having a longer cylinder increases volume, which improves the cylinder to inner barrel volume ratio, making the system more able to support shooting a heavier BB, which heavier BB’s matched to a solid cylinder to barrel volume , helps to increase range, consistency, and accuracy.

 

[Whamhammer]

I partially disagree, having a longer cylinder increases volume, which improves the cylinder to inner barrel volume ratio, making the system more able to support shooting a heavier BB, which heavier BB’s matched to a solid cylinder to barrel volume , helps to increase range, consistency, and accuracy.

Greater air volume also puts less strain on a DMR gearbox as well.

 

[Doctor Jest]

Plazmaburn runs a couple of SVDs with T3s in, I guess he realises that ;-)

Strictly speaking, he's correct, and equally so are you -but I would add a nuance to:

heavier BBs matched to a solid cylinder-to-barrel volume, help to increase range, consistency, and accuracy.

Using heavier BBs alone only increases range, as my experiences with Digicon BBs in the past taught me. Heavier, higher quality and heavier BBs are the "Holy Grail" as they increase consistency and accuracy through minimal deviations of weight, surface finish, diameter, hygoscopy, and fewer internal flaws. The number of times I prayed for heavier ammo finished to the same standards as the Maruzens of choice (tm)....

Would a dmr build around a gearbox with the longer cylender in a cyma t3 gearbox give me longer effective range than a v3 gearbox with full cylender giving than barrel lenght is proberly volumed?

Aiming to get prober long range game outdoor around 2.4 to 2.8joule

The real advantage of a T3 is that you'll reach 2.4 to 2.8j more easily and the replicas with that gearbox also have the rather splendid CYMA copy of the Real Sword SVD hop - which is excellent.

 

[Leo Greer]

You can very easily adjust your barrel length to perfectly match your BB and cylinder. Cylinder size is irrelevant in achieving perfect voluming, as barrel length can also be adjusted. Shorter cylinder, shorter perfect barrel.

I agree with the good Doctor Jest—long cylinders increase J-creep potential immensely in the same way that HPA does, which takes strain down, and, I believe, actually increases accuracy.

Shorter barrels are by nature more perfectly straight, so I would use the shortest barrel possible above 330mm that provides you with perfect volume on a full cylinder.

 

[Plazmaburn]

I partially disagree, having a longer cylinder increases volume, which improves the cylinder to inner barrel volume ratio, making the system more able to support shooting a heavier BB, which heavier BB’s matched to a solid cylinder to barrel volume , helps to increase range, consistency, and accuracy.

Greater air volume also puts less strain on a DMR gearbox as well.

While you are not wrong, you just walked down a rabbit hole that was already implied.

Would a dmr build around a gearbox with the longer cylender in a cyma t3 gearbox give me longer effective range than a v3 gearbox with full cylender giving than barrel lenght is proberly volumed?

Aiming to get prober long range game outdoor around 2.4 to 2.8joule

Just using a longer cylinder does not mean you get more range. You could have the best built gearbox ever, but if your hopup is crap, say this one, Hop-Up Chamber for Marui / CYMA / Echo1 / JG M14 Series Airsoft AEG Rifles, Accessories & Parts, AEG Internal Parts, Hop-Up, M14 Series Hop-Up - Evike.com Airsoft Superstore, there is very little you can do to increase your range.

Plazmaburn runs a couple of SVDs with T3s in, I guess he realises that ;-)

Strictly speaking, he's correct, and equally so are you -but I would add a nuance to:

Using heavier BBs alone only increases range, as my experiences with Digicon BBs in the past taught me. Heavier, higher quality and heavier BBs are the "Holy Grail" as they increase consistency and accuracy through minimal deviations of weight, surface finish, diameter, hygoscopy, and fewer internal flaws. The number of times I prayed for heavier ammo finished to the same standards as the Maruzens of choice (tm)....

The real advantage of a T3 is that you'll reach 2.4 to 2.8j more easily and the replicas with that gearbox also have the rather splendid CYMA copy of the Real Sword SVD hop - which is excellent.

Docter Jest said it best. While I most certainly do have 3 t3 guns, 1 of which is highly illegal to use basically everywhere, 4.4j with .48g, full auto. (I built it to see what it would suffer.)

Ultimately looking at the question, using an extended cylinder or a standard full cylinder at a given power will not auto-magically give you more range. What it will do is let you achieve that power easier with the longer cylinder, to better use heavier bbs. Which was not the question. (Matter of fact a stock Echo1 CSR already has that power level out of the box, just FYI. It also has the better clone of the Real Sword Hop up, IMO anyway.)

 

[SiliconeSword]

That thing needs ceramics

 

[Leo Greer]

While I most certainly do have 3 t3 guns, 1 of which is highly illegal to use basically everywhere, 4.4j with .48g, full auto. (I built it to see what it would suffer.)

I’d be interested to hear how you built that and how it performs…

 

[Whamhammer]

You can very easily adjust your barrel length to perfectly match your BB and cylinder. Cylinder size is irrelevant in achieving perfect voluming, as barrel length can also be adjusted. Shorter cylinder, shorter perfect barrel.

I agree with the good Doctor Jest—long cylinders increase J-creep potential immensely in the same way that HPA does, which takes strain down, and, I believe, actually increases accuracy.

Shorter barrels are by nature more perfectly straight, so I would use the shortest barrel possible above 330mm that provides you with perfect volume on a full cylinder.

But cylinder volume is only LITERALLY one of the two factors contributing to the cylinder to barrel volume ratio, its even in the name. Saying cylinder size is irrelevant is like saying the amount of air in an engines air-fuel ratio is irrelevant because someone can just adjust the amount of fuel to add to the engine, to achieve the ratio. 🤷‍♂️

The principle is to do the most amount work, with the least amount of strain on the system; if one is building their setup with towards the amount of joules to the weight of BB that is used, and then dropping the amount of spring tension needed to get that work done, for that BB, at that power level, then the system is optimal. The biggest problem that I have with the idea of Joule Creep, is that the assumption is that the proper point of metric is against a lighter (usually much lighter) weight BB, than what the person is using, which goes against the whole point of building an effective
DMR/Sniper rifle. The better fields/events have rifleman/smg’s chrono at a weight closer to the more realistic weight BB that those classes would use, and DMR/Snipers chrono with a weight closer to what they use; otherwise either end up having themselves chronoing closer to what their actual performance will be at, and the most efficient DMR/Snipers end up chronoing at power level that is actually lower than their actual performance, and less than honest players tuning to chrono with the lower weight BB’s at the field limits but really are performing at higher energy levels with the heavier BB’s that they actually use.

DMR and Bolt Action Sniper Rifles are like high torque engines, that pull the most weight, at a lower engine speed, efficiently, versus a high horsepower , high speed (high RPM) engine that is used to just get lighter load capacities to a speed, quicker, efficiently. The longer cylinder length is akin to having a “stroker” engine, which is very popular for people that want high torque engines, that aren’t looking to have a high top end (equivalent to our rate of fire). Even if one uses the principle of shortening barrel length to get to the cylinder/barrel volume, a shorter barrel tends to cost less than a longer one, with the added benefit of not having as much of a chance to being the most straight during production.

All things considered equals, unless scarcity/cost is a major consideration or the longer cylinder gearbox product has quality issues, why wouldn’t a DMR/Sniper owner want the longer cylinder?

 

[Whamhammer]

And yes, I agree that a good hopup assembly, bucking & nub, and heavy, high quality BB’s are critical; that is entirely implied. Having the a longer cylinder only serves to better support those aspects.

 

[nearsighted_ash]

And yes, I agree that a good hopup assembly, bucking & nub, and heavy, high quality BB’s are critical; that is entirely implied. Having the a longer cylinder only serves to better support those aspects.

Completely agree. If everything else stays exactly the same. Longer cylinder = More air volume + More piston inertia due to longer acceleration = More output energy, more flat trajectory range before the Magnus effect kicks in, and more range in general.

 

[Leo Greer]

I never stated that longer cylinders were worse. I simply stated that cylinder length is irrelevant for perfect voluming. Which, it is. Perfect voluming is getting the highest air efficiency out of either your cylinder size or your barrel length, whichever you choose to make the standard, with the BB weight you’re hoping to use.

Ideally, people would all chrono with their game ammo, in joules, with their hops set to what they typically play with. Joule creep is simply a method by which one might use a weaker spring to do the work of a stronger spring through increased efficiency, increasing silence, durability, and I believe accuracy (I can’t quantify this claim. It’s a hunch and a shakily substantiated observation of mine. I have no science to reference here)

A longer cylinder allows a longer theoretical time for the piston to accelerate. However, depending on piston weight, cylinder friction, spring strength, BB weight, BB size, hop rubber, etc… the piston may not actually ever accelerate faster than an ordinary AEG piston. I believe 1tonne talks about this in a stickied post about cylinder weight.

I will also point out that ported cylinders actually allow for a higher pressure spike at the hop rubber over full cylinders. This is because the piston experiences no pushback for the first part of it’s travel, and is able to gain momentum freely, before “striking” the air and gaining compression, and abruptly transferring that gained energy to the air in the cylinder before beginning to travel again.

This may not be possible to hear on video, but I have a build with an 18g piston assembly and 60% ported cylinder where you can hear the piston slap as a separate noise over the barrel pop. I.e. the piston is slowed and creates enough space to separate the sounds. Interesting this rifle is also very consistent, despite possessing a light piston.

trying to post video here…

Conversely, longer full cylinders create a
constant gradual pushback against the piston, which may not be the best for optimum speed,

I suspect top piston speed while retaining okay volume is:

50% cylinder.

35g piston assembly.

M135 equivalent or higher.

The pressure spike at the hop rubber would be crazy compared to what folks normally build.
Not that this idea is useful at all, just a though experiment.

 

[Faitfull]

Thank you for taking this discussion. I find it very interesting and learn alot.

It sounds to me like a ordinary gearbox lenght like v3 and v6 can reach the desired joule, however a longer cylender gearbox can do it with less strain to the gearbox, and therefore last longer and perhaps be a little less noisy?

Hopup unit was mentioned. What makes a hopup unit good or bad?
The finish? The way hopup is aplied? Or?
I see some people prefer a m14 to dmr, and the mentioned bad hopup unit comes in these guns. So just wondering .

Also what backing would you recommend to use. Rhop? Flathop? Maple leaf or begadi?

When I was newer to airsoft I got horrible result on range and accurate shooting. My jg 1601t performed badly. However after I learned some teching. It showed up, that it had a 480mm inner bras barrel combined with a 3/4 ported cylender. Big oufff. No wonder about the poor performance, it was terrible under volumed.

Regarding joule test. Where I live, the rule is that you most always chrono with the ammo and hopup you use in your gun. If you dont, it is considering cheating and you get a warning.

A little side note. I like to design and build stuff. I have a 3d printer that often ends up in my attempts to do things. I was thinking that a optimal design proberly have the weight balance point in the trigger hand and the scope so close to the barrel as possible. Would this be your choise as well and other ideas?
Still tempted to go for a svd However

 

[Leo Greer]

Thank you for taking this discussion. I find it very interesting and learn alot.

It sounds to me like a ordinary gearbox lenght like v3 and v6 can reach the desired joule, however a longer cylender gearbox can do it with less strain to the gearbox, and therefore last longer and perhaps be a little less noisy?

Hopup unit was mentioned. What makes a hopup unit good or bad?
The finish? The way hopup is aplied? Or?
I see some people prefer a m14 to dmr, and the mentioned bad hopup unit comes in these guns. So just wondering .

Also what backing would you recommend to use. Rhop? Flathop? Maple leaf or begadi?

When I was newer to airsoft I got horrible result on range and accurate shooting. My jg 1601t performed badly. However after I learned some teching. It showed up, that it had a 480mm inner bras barrel combined with a 3/4 ported cylender. Big oufff. No wonder about the poor performance, it was terrible under volumed.

Regarding joule test. Where I live, the rule is that you most always chrono with the ammo and hopup you use in your gun. If you dont, it is considering cheating and you get a warning.

A little side note. I like to design and build stuff. I have a 3d printer that often ends up in my attempts to do things. I was thinking that a optimal design proberly have the weight balance point in the trigger hand and the scope so close to the barrel as possible. Would this be your choise as well and other ideas?
Still tempted to go for a svd However

You are correct about longer cylinders potentially allowing for less gearbox strain. In practice this isn’t always true, but if you build it well a longer cylinder should help reduce wear and tear.

Hop units are good or bad based on how well they do their very simple job: provide firm consistent pressure on the hop rubber, and do it while remaining stabile against the receiver set and gearbox.

Though I do have an M14, I’ve been content to leave it alone so far. I will say that out of the box the hop unit was very stable to compared to similar V2 units (V2 tend to be pretty shaky). I’ll let someone else comment on the ins and outs here…

I recommend Begadi, Maple Leaf, or flathop for a beginner, as they can all be easily done. Maple Leaf may have compatibility issues, though, depending on where your rifle was made. Taiwanese hop units usually fit them without mods (G&G) whereas Chinese made units do not (Prowin, Arcturus). For an extremely in depth discussion of how to accurize your replica, check the link in my signature.

I could be wrong here, but I believe most competitive shooters like to have the weight balanced behind the grip, so they can manipulate the weight easier. I could be wrong though, and this is airsoft: do whatever makes you happy!

 

[Whamhammer]

I never stated that longer cylinders were worse. I simply stated that cylinder length is irrelevant for perfect voluming. Which, it is. Perfect voluming is getting the highest air efficiency out of either your cylinder size or your barrel length, whichever you choose to make the standard, with the BB weight you’re hoping to use.

Ideally, people would all chrono with their game ammo, in joules, with their hops set to what they typically play with. Joule creep is simply a method by which one might use a weaker spring to do the work of a stronger spring through increased efficiency, increasing silence, durability, and I believe accuracy (I can’t quantify this claim. It’s a hunch and a shakily substantiated observation of mine. I have no science to reference here)

A longer cylinder allows a longer theoretical time for the piston to accelerate. However, depending on piston weight, cylinder friction, spring strength, BB weight, BB size, hop rubber, etc… the piston may not actually ever accelerate faster than an ordinary AEG piston. I believe 1tonne talks about this in a stickied post about cylinder weight.

I will also point out that ported cylinders actually allow for a higher pressure spike at the hop rubber over full cylinders. This is because the piston experiences no pushback for the first part of it’s travel, and is able to gain momentum freely, before “striking” the air and gaining compression, and abruptly transferring that gained energy to the air in the cylinder before beginning to travel again.

This may not be possible to hear on video, but I have a build with an 18g piston assembly and 60% ported cylinder where you can hear the piston slap as a separate noise over the barrel pop. I.e. the piston is slowed and creates enough space to separate the sounds. Interesting this rifle is also very consistent, despite possessing a light piston.

trying to post video here…

Conversely, longer full cylinders create a
constant gradual pushback against the piston, which may not be the best for optimum speed,

I suspect top piston speed while retaining okay volume is:

50% cylinder.

35g piston assembly.

M135 equivalent or higher.

The pressure spike at the hop rubber would be crazy compared to what folks normally build.
Not that this idea is useful at all, just a though experiment.

There is certainly additional friction that adds to a slight disadvantage of longer cylinders for piston travel/speed but heavier piston and the extra travel distance more than makes up for the friction/drag.

Either way, its better to have the extra volume, otherwise, we would all be using AEP cylinders.

The whole think with Joule Creep is
1) its 90% described as a negative aspect
2) is viewed not in the eye of the BB that’s actually used but some consensus standard weight
3) Joule creep is actually just the observation of the efficiency curve of the set system to move different weights of BB’s.
4)Many fields have adopted chrono testing with a specified weight of BB, that they provide, not the weight of the user; I understand this as there are people who try to cheat the system, but if a field is testing with a .20/.25 or so BB, and I am using .43’s, there is going to be (in many cases) where the data is skewed incorrectly. When testing apples to apples, joule creep isnt a consideration.

 

[Leo Greer]

There is certainly additional friction that adds to a slight disadvantage of longer cylinders for piston travel/speed but heavier piston and the extra travel distance more than makes up for the friction/drag.

Either way, its better to have the extra volume, otherwise, we would all be using AEP cylinders.

The whole think with Joule Creep is
1) its 90% described as a negative aspect
2) is viewed not in the eye of the BB that’s actually used but some consensus standard weight
3) Joule creep is actually just the observation of the efficiency curve of the set system to move different weights of BB’s.
4)Many fields have adopted chrono testing with a specified weight of BB, that they provide, not the weight of the user; I understand this as there are people who try to cheat the system, but if a field is testing with a .20/.25 or so BB, and I am using .43’s, there is going to be (in many cases) where the data is skewed incorrectly. When testing apples to apples, joule creep isnt a consideration.

Absolutely. There are certainly better cylinder volumes and worse cylinder volumes for the general weight class of ammunition we are attempting to fire.

I imagine to counteract the heavy piston you have to have a heavier spring as well, or you’ll lose pressure at the hop rubber, since the heavier piston is slower to accelerate. (I may be crazy, but in my mind higher pressure at the hop rubber is better)

When playing at my field, I find the question is mostly irrelevant, since I’m the only one who could knowingly build a JC optimized rifle. However, we’ve started having players show up with HPA rifles… chrono under 400 with .20g… switch to .32 to play… 450mm inner barrel… loud pop that can be heard across the field… sound familiar to anyone? Chances are that it’s not intentional, but I’m speaking to the field owner this Saturday.

 

[Whamhammer]

Absolutely. There are certainly better cylinder volumes and worse cylinder volumes for the general weight class of ammunition we are attempting to fire.

I imagine to counteract the heavy piston you have to have a heavier spring as well, or you’ll lose pressure at the hop rubber, since the heavier piston is slower to accelerate. (I may be crazy, but in my mind higher pressure at the hop rubber is better)

When playing at my field, I find the question is mostly irrelevant, since I’m the only one who could knowingly build a JC optimized rifle. However, we’ve started having players show up with HPA rifles… chrono under 400 with .20g… switch to .32 to play… 450mm inner barrel… loud pop that can be heard across the field… sound familiar to anyone? Chances are that it’s not intentional, but I’m speaking to the field owner this Saturday.

To answer your question about the additional spring rate needed, depends on how the piston and spring guide is set up, if they are set up to have the same length of gap, from the front of the piston, to the front of the mounting area of the spring guide, there shouldn’t really need to be an increase in spring rate at all, only if the gap is extended, would there need to be compensation.

As far as losing velocity towards the end portion of travel, that shouldn't happen at all, as the piston velocity is parabolic, the end of the travel is still going to be the greatest velocity, and because the piston is longer, heavier, and had more time to travel, the velocity and air volume coming out at once should be higher than a 15 tooth piston. The same laws of physics that apply to the BB, also apply to piston, mass is still squared.

 

[Whamhammer]

Absolutely. There are certainly better cylinder volumes and worse cylinder volumes for the general weight class of ammunition we are attempting to fire.

I imagine to counteract the heavy piston you have to have a heavier spring as well, or you’ll lose pressure at the hop rubber, since the heavier piston is slower to accelerate. (I may be crazy, but in my mind higher pressure at the hop rubber is better)

When playing at my field, I find the question is mostly irrelevant, since I’m the only one who could knowingly build a JC optimized rifle. However, we’ve started having players show up with HPA rifles… chrono under 400 with .20g… switch to .32 to play… 450mm inner barrel… loud pop that can be heard across the field… sound familiar to anyone? Chances are that it’s not intentional, but I’m speaking to the field owner this Saturday.

Weeeeeell, some of the popping isn’t intentional 😁 I have put a full cylinder and a metal piston head in my Thompson, even though I don’t run heavy BB’s in it, partially to just get the popping sound, as the rate of fire (13 RPS) and the pop sound give it a experience for the user, and everyone around it. Its between a 1J-1.49J setup, so I am willing to give a bit of efficiency up for fun with lighter BB’s. Also covers up some of the famous “loud Thompson gearbox” that they are known for. Now I always make sure that I am in compliance with both the BB weight that I am using, and the bb weight that the fields test at.

Most of my other rifleman class only stuff gets full cylinders and whatnot because I do run between .32g-.36g.

 

[Leo Greer]

To answer your question about the additional spring rate needed, depends on how the piston and spring guide is set up, if they are set up to have the same length of gap, from the front of the piston, to the front of the mounting area of the spring guide, there shouldn’t really need to be an increase in spring rate at all, only if the gap is extended, would there need to be compensation.

As far as losing velocity towards the end portion of travel, that shouldn't happen at all, as the piston velocity is parabolic, the end of the travel is still going to be the greatest velocity, and because the piston is longer, heavier, and had more time to travel, the velocity and air volume coming out at once should be higher than a 15 tooth piston. The same laws of physics that apply to the BB, also apply to piston, mass is still squared.

Piston travel is parabolic, but the pressure spike at the hop rubber occurs almost immediately after the piston achieves compression, wherever that happens to be. Heavier pistons accelerate more slowly,

Heavier piston = slower piston acceleration = less pressure behind the air at the hop rubber spike.