Hey yall, I am so very sorry to post yet another DMR build thread, but after hours of scouring forums, reading related links, and going so far into airsoft tech work that I got lost, I am now, yet another, DMR noob. I have some questions based off a build I am wanting to do so let's get strait into the build. I will have links attached to the parts I am looking at using for this build and will cover all the information that I know/will calculate when time comes and ask my questions at the end.
Field Rules
The local field for where I live seems to have a very unique rule set compared to the ones I have been seeing throughout the threads. But the only ones that matter for this thread is the DMR rule set. They allow DMRs as long as they have a 20 inch outer barrel assembly. This can include any mock suppressors or just a whole barrel that is 20 inches long. However, the total gun length has to be 35 inches when the stock is in the shortest position if it is collapsible. The field joule limit for DMRs is 2.8 joules which appears to be higher than most field regulations. The minimum ingagement distance for DMRs is 100 ft. The gun must have a fire rate of one bb/sec and locked into semi or safe.
Goal
The goal is to build a DMR that will be right at field limits for FPS with the lowest possible spring rating to reduce stress on the gearbox and noise, have a slow fire rate, and be very accurate(this is a given in any DMR build).
The Gearbox
This section will cover the whole entirety of the gearbox build. I am most familiar with V2 gearboxes having done some tech work on previous rifleman builds. Because of this, I am trying to stick with the v2 gearbox which is very hard to achieve the power output result I am wanting without putting extra stress on the shell.
Shell:
From reading through the forums, it seemed almost as if the shell of the gearbox was one of the more overlooked items in the build. However, to me, a strong build is going to start from the gearbox shell itself. For this, I was originally planning to use the Krytac Nautilus V2 gearbox due to its outstanding strength, however, after doing my research, I found that this gearbox is very proprietary and thus does not accept a wide range of components. Since then, I have planned to go to the Retro Arms CZ Billet 8mm V2 gearbox. The construction is made of 7075 t6 structural grade aluminum, and after building aluminum boats for 4 years I have faith that with the right bearing and shimming of the gears it will hold up to what I want to do. However, I can change just a few of the following components if need be to use the krytac gear box.
www.evike.com
Bearings:
The next part I will include will be 8mm ball bearing by prometheus. I believe that these will help reduce the friction of the gears and increase the longevity of an aluminum gearbox.
www.evike.com
Gears:
Following the prometheus train, I am going to use prometheus tripple torque gears for a v2 gearbox. I want to use these due to the higher spring rating that I will be using within the gun to ease the amount of stress the motor will see.
www.evike.com
Mosfet:
This is probably one of the more confusing parts for me. From reading forums it seems as if everyone is including a mosfet, but the types and styles get scrambled in my head, due to this, i am going with the only mosfet I know of that is reliable based on research. I will be going with a Gate titan v2 advanced mosfet. This is how I will obtain the slow fire rate within the gun, and hopefully if possible the semi or safe only opperations. I will also have the precocking option enabled because why not! However, this brings the topic of anti reversal latches.
Anti-reversal Latch:
After reading countless of threads, the question of the ARL still lingers within my mind. The Gate titan mosfet does have the electric braking feature which is theory would eliminate the use of the anti reversal latch. However, for gearbox safety, many users are recommending to keep it installed. The one worry that I have with that, is being locked into semi only, I would hate to get 10 shots through and have the gear box go into the dreadful semi lock. This problem is easily solved with aegs that can fire full auto, but when your gun is permanently locked into semi, you would have to remove the spring to relieve tension on the gears. Without the ARL, you would not have the semi seizing problem. If an ARL is needed, I will go with a prometheus hard anti reversal latch.
www.evike.com
Trigger:
Once again another underlooked component of the gun. Due to using the Gate titan mosfel, I will be using an adjustable MAXX trigger due to the precise adjustment to ensure positive contact and prevent damage to the mosfet.
www.evike.com
Piston:
This is yet another Grey area for me. Based on the reading, you would want a heavier based piston due to forces with the lighter BB due to basic physics. If you are trying to push a heavier BB down a barrel, you have negative forces upon the bb traveling through the inner barrel compressing the air infron of it, in which will cause a need for more energy from the piston. The larger the mass of the piston, the less affect the negative forces will have. Within this, in my mind a metal piston would be ideal due to its high strength from impact, and the weight compared to a plastic. The number of teeth the piston should have is also confusing and if they should be full teeth or if the last two should be incremental to the rest. From reading, it seems as if a v2 piston should have 16 teeth, however some are made with more and some are made with less. Because of this, my piston is still unselected.
Cylinder:
For this, I am going to use a full MAXX cylinder to allow the most volume possible out of the gearbox. This will also allow for my to make adjustments and decrease the volume by finite amounts as needed to perfectly match the barrel length and volume while only trying to adjust one variable being the cylinder.
www.evike.com
Air Nozzle:
For this, i plan to match the cylinder and go with a MAXX double o-ring 21.25mm metal air nozzle. This length should seat very well within the hopup and the double o-ring will help prevent leakage of air.
www.evike.com
Cylinder Head
I plan to go with a double o-ring MAXX cylinder head as it should be compatable with the cylinder and air nozzle.
www.evike.com
Piston Head:
For this, I thought it be best to continue with, you guessed it, MAXX. I will be using a MAXX double o-ring piston head. This piston head is my choice do to the other components used as well as the ball bearing allowing spring life and performance longevity so it is reliable and the same every shot. I will also utilize a sorbothane pad if needed to adjust the AoE and reduce noise from the piston head
www.evike.com
Cut off lever:
Once again, another component i have no idea about. If someone would like to send me to a forum to read about the use of this, or explain, I would be so greatful for that!
Selector Plate:
For this, I will just be going with a regular run of the mill selector plate due to modifications that will need to be made to lock into semi only.
Tappet Plate:
The tappet plate from my understanding is what holds the air nozzle. Due to the fully upgraded parts and potentially high shock from a m160 spring (could be higher or lower depending on seals to get to 2.8 joules) I will be going with a prometheus reinforced tappet plate.
www.evike.com
Hopup
The hopup that I will be going with will be a MAXX CNC rotary hopup due to the components used and the high precision and adaptability by MAXX on the hopup unit itself.
www.evike.com
Barrel
The inner barrel is yet another area of conflict. However, I do know that I need to match cylinder and barrel volumes to help reduce noise and reduce the needed spring size in the gun for maximum output of the BB. For this, I am mostly confused as to if I should use a precision TBB (6.01) or a precision WBB (6.04+) after reading multiple forums, there is a mix of both answers. Some saying 6.01 is better for accuracy, while 6.04+ is better due to an air cushion around the bb, preventing it from hitting the sides of the barrel where on a 6.01 it could bounce back and forth between the tight tolerances. When reading about the barrel length, are you wanting to match your barrel your your cylinder volume size. Or your cylinder volume to your barrel? Also, it is a cardinal size to slap in extra long inner barrels, however, when you are at a required barrel length of 20 inches, it is best to have an inner barrel that is near 20 inches, say 500mm due to a loss of 9mm in the hopup, to allow guidance of the bb up till it leaves the barrel. With this, would the cylinder being a V2 gearbox and not an elongated V2.5 have enough air volume to support a 500mm inner barrel?
Motor
For the motor I will be using a Prometheus high torque motor. This will increase the motors time to full speed and help longevity with heavier springs.
Springs
When it comes to springs, i will be trying a vatiety of sizes starting at a m150 to see where my FPS will be at. My goal is to achieve a energy near my field limits without ever going over it.
Building
When building this gun, I know it will take time to precisely tune and shim every component to eliminate wiggle, movement, noise and prevent any air leakage. But would this build achieve me goals in the gun or what would yall suggest. My biggest questions are the blank spots within the build such as the piston and cut off lever. As well as the questions mentioned is the barrel section. I'm very sorry for the long post as to being a DMR noob, I hope I laid out enough information though for my questions to be answered. I have tried to do my dudiligence and research, but there is only so much you can answer on your own without asking questions. Happy shooting!
Field Rules
The local field for where I live seems to have a very unique rule set compared to the ones I have been seeing throughout the threads. But the only ones that matter for this thread is the DMR rule set. They allow DMRs as long as they have a 20 inch outer barrel assembly. This can include any mock suppressors or just a whole barrel that is 20 inches long. However, the total gun length has to be 35 inches when the stock is in the shortest position if it is collapsible. The field joule limit for DMRs is 2.8 joules which appears to be higher than most field regulations. The minimum ingagement distance for DMRs is 100 ft. The gun must have a fire rate of one bb/sec and locked into semi or safe.
Goal
The goal is to build a DMR that will be right at field limits for FPS with the lowest possible spring rating to reduce stress on the gearbox and noise, have a slow fire rate, and be very accurate(this is a given in any DMR build).
The Gearbox
This section will cover the whole entirety of the gearbox build. I am most familiar with V2 gearboxes having done some tech work on previous rifleman builds. Because of this, I am trying to stick with the v2 gearbox which is very hard to achieve the power output result I am wanting without putting extra stress on the shell.
Shell:
From reading through the forums, it seemed almost as if the shell of the gearbox was one of the more overlooked items in the build. However, to me, a strong build is going to start from the gearbox shell itself. For this, I was originally planning to use the Krytac Nautilus V2 gearbox due to its outstanding strength, however, after doing my research, I found that this gearbox is very proprietary and thus does not accept a wide range of components. Since then, I have planned to go to the Retro Arms CZ Billet 8mm V2 gearbox. The construction is made of 7075 t6 structural grade aluminum, and after building aluminum boats for 4 years I have faith that with the right bearing and shimming of the gears it will hold up to what I want to do. However, I can change just a few of the following components if need be to use the krytac gear box.
Retro Arms CZ Billet CNC 8mm Ver.2 Gearbox Shell for M4 / M16 Series Airsoft AEG Rifles (Color: Black)
Shop Unlike most other gearbox shells on the market, the Retro Arms CZ gearbox shells are precision CNC machined out of a solid block of billet EN AW 7075 T651 aluminum giving them unmatched durability and resilience. Combined with reinforcement of key stress points and stainless steel...
Bearings:
The next part I will include will be 8mm ball bearing by prometheus. I believe that these will help reduce the friction of the gears and increase the longevity of an aluminum gearbox.
Prometheus Stainless Steel Bearings - Set of Six (Size: 8mm / Krytac Compatible)
Shop Compatibility: All 8mm gearbox including Krytac Material: Stainless Steel Manufacturer: Prometheus ... , Accessories & Parts, AEG Internal Parts, Bushings & Bearings
Gears:
Following the prometheus train, I am going to use prometheus tripple torque gears for a v2 gearbox. I want to use these due to the higher spring rating that I will be using within the gun to ease the amount of stress the motor will see.
Prometheus EG Hard Gear Reinforced Triple Torque Gear Set for Airsoft AEGs
Shop ... , Accessories & Parts, AEG Internal Parts, Gears
Mosfet:
This is probably one of the more confusing parts for me. From reading forums it seems as if everyone is including a mosfet, but the types and styles get scrambled in my head, due to this, i am going with the only mosfet I know of that is reliable based on research. I will be going with a Gate titan v2 advanced mosfet. This is how I will obtain the slow fire rate within the gun, and hopefully if possible the semi or safe only opperations. I will also have the precocking option enabled because why not! However, this brings the topic of anti reversal latches.
Anti-reversal Latch:
After reading countless of threads, the question of the ARL still lingers within my mind. The Gate titan mosfet does have the electric braking feature which is theory would eliminate the use of the anti reversal latch. However, for gearbox safety, many users are recommending to keep it installed. The one worry that I have with that, is being locked into semi only, I would hate to get 10 shots through and have the gear box go into the dreadful semi lock. This problem is easily solved with aegs that can fire full auto, but when your gun is permanently locked into semi, you would have to remove the spring to relieve tension on the gears. Without the ARL, you would not have the semi seizing problem. If an ARL is needed, I will go with a prometheus hard anti reversal latch.
Prometheus Hard Anti-Reversal Latch for Version 6 AEG Gearboxes
Shop Compatibility: Version 6 AEG gearboxes Material: Chromium Molybdenum steel... , Accessories & Parts, AEG Internal Parts, Anti-Reversal Latches
Trigger:
Once again another underlooked component of the gun. Due to using the Gate titan mosfel, I will be using an adjustable MAXX trigger due to the precise adjustment to ensure positive contact and prevent damage to the mosfet.
Maxx Model CNC Aluminum Tunable Advanced Trigger for M4 / M16 Series Airsoft AEG (Style: E / Blue)
Shop Compatibility: Tokyo Marui, G&P, Marui, ICS, Classic Army, G&G, Krytac and other compatible M4/M16 series AEGs Material: Aluminum, Titanium Manufacturer: Maxx Model... , Accessories & Parts, External Parts, M4 / M16 External Parts, M4/M16 AEG Triggers
Piston:
This is yet another Grey area for me. Based on the reading, you would want a heavier based piston due to forces with the lighter BB due to basic physics. If you are trying to push a heavier BB down a barrel, you have negative forces upon the bb traveling through the inner barrel compressing the air infron of it, in which will cause a need for more energy from the piston. The larger the mass of the piston, the less affect the negative forces will have. Within this, in my mind a metal piston would be ideal due to its high strength from impact, and the weight compared to a plastic. The number of teeth the piston should have is also confusing and if they should be full teeth or if the last two should be incremental to the rest. From reading, it seems as if a v2 piston should have 16 teeth, however some are made with more and some are made with less. Because of this, my piston is still unselected.
Cylinder:
For this, I am going to use a full MAXX cylinder to allow the most volume possible out of the gearbox. This will also allow for my to make adjustments and decrease the volume by finite amounts as needed to perfectly match the barrel length and volume while only trying to adjust one variable being the cylinder.
Maxx Model CNC Hardened Stainless Steel Airsoft AEG Cylinder (Model: Type A / 450-550mm)
Shop CNC Hardened Stainless Steel Cylinder - TYPE A (for 450mm - 550mm barrel length) is precisely machined to ensure consistent air compression and improve durability for most standard airsoft AEG gearboxes. The Cylinder is made of high strength stainless steel with high polished internal...
Air Nozzle:
For this, i plan to match the cylinder and go with a MAXX double o-ring 21.25mm metal air nozzle. This length should seat very well within the hopup and the double o-ring will help prevent leakage of air.
Maxx Model CNC Aluminum Double O-Ring Air Seal Nozzle for Airsoft AEG Series (Length: 21.25mm)
Shop Standard label for nozzles are by gun and version, MaxxModel measures by millimeter so technicians can tune the depth the nozzle travels, essential for BB groupings, rate of fire, and speed; depth of the nozzle travel is between .1mm to .5mm or more depending on the brand. General Nozzle...
Cylinder Head
I plan to go with a double o-ring MAXX cylinder head as it should be compatable with the cylinder and air nozzle.
Maxx Model CNC Aluminum Double O-Ring AEG Cylinder Head
Shop Compatibility: Most AEG Gearboxes Material: Aluminum, Rubber Manufacturer: Maxx Model... , Accessories & Parts, AEG Internal Parts, Cylinder Heads
Piston Head:
For this, I thought it be best to continue with, you guessed it, MAXX. I will be using a MAXX double o-ring piston head. This piston head is my choice do to the other components used as well as the ball bearing allowing spring life and performance longevity so it is reliable and the same every shot. I will also utilize a sorbothane pad if needed to adjust the AoE and reduce noise from the piston head
Maxx Model CNC Aluminum Double O-Ring High Performance Ball Bearing AEG Piston Head
Shop Compatibility: Most popular AEG pistons Material: Aluminum Manufacturer: MaxxModel... , Accessories & Parts, AEG Internal Parts, Piston Heads
Cut off lever:
Once again, another component i have no idea about. If someone would like to send me to a forum to read about the use of this, or explain, I would be so greatful for that!
Selector Plate:
For this, I will just be going with a regular run of the mill selector plate due to modifications that will need to be made to lock into semi only.
Tappet Plate:
The tappet plate from my understanding is what holds the air nozzle. Due to the fully upgraded parts and potentially high shock from a m160 spring (could be higher or lower depending on seals to get to 2.8 joules) I will be going with a prometheus reinforced tappet plate.
Prometheus PERFECT Tappet Plate For Tokyo Marui AEGs (Version: Standard V2)
Shop Compatibility: Tokyo Marui V2 gearboxes Material: Reinforced injection molded polymer Manufacturer: Prometheus ... , Accessories & Parts, AEG Internal Parts, Tappet Plates
Hopup
The hopup that I will be going with will be a MAXX CNC rotary hopup due to the components used and the high precision and adaptability by MAXX on the hopup unit itself.
EMG / Maxx Model CNC Aluminum Hopup Chamber for M4 / M16 Series Airsoft AEG Rifles (Model: M4A / EMG Blue)
Shop CNC Aluminum Hopup Chamber M4A Pro (with BB Latching System) unit is precisely machined to perform accurately and consistently on Tokyo Marui (include G&G, KRYTAC, except KWA) Standard M4/M16 AEG series rifles. The Hopup Chamber M4A unit is built with an aluminum rotary dial knob for fine...
Barrel
The inner barrel is yet another area of conflict. However, I do know that I need to match cylinder and barrel volumes to help reduce noise and reduce the needed spring size in the gun for maximum output of the BB. For this, I am mostly confused as to if I should use a precision TBB (6.01) or a precision WBB (6.04+) after reading multiple forums, there is a mix of both answers. Some saying 6.01 is better for accuracy, while 6.04+ is better due to an air cushion around the bb, preventing it from hitting the sides of the barrel where on a 6.01 it could bounce back and forth between the tight tolerances. When reading about the barrel length, are you wanting to match your barrel your your cylinder volume size. Or your cylinder volume to your barrel? Also, it is a cardinal size to slap in extra long inner barrels, however, when you are at a required barrel length of 20 inches, it is best to have an inner barrel that is near 20 inches, say 500mm due to a loss of 9mm in the hopup, to allow guidance of the bb up till it leaves the barrel. With this, would the cylinder being a V2 gearbox and not an elongated V2.5 have enough air volume to support a 500mm inner barrel?
Motor
For the motor I will be using a Prometheus high torque motor. This will increase the motors time to full speed and help longevity with heavier springs.
Springs
When it comes to springs, i will be trying a vatiety of sizes starting at a m150 to see where my FPS will be at. My goal is to achieve a energy near my field limits without ever going over it.
Building
When building this gun, I know it will take time to precisely tune and shim every component to eliminate wiggle, movement, noise and prevent any air leakage. But would this build achieve me goals in the gun or what would yall suggest. My biggest questions are the blank spots within the build such as the piston and cut off lever. As well as the questions mentioned is the barrel section. I'm very sorry for the long post as to being a DMR noob, I hope I laid out enough information though for my questions to be answered. I have tried to do my dudiligence and research, but there is only so much you can answer on your own without asking questions. Happy shooting!
