SR25 from scratch.

[B.O.P. Hawk]

In my Airsoft endeavor, I am always trying to be unique. The SR25 is not a rifle I see much on the field, nor is a perfectly upgraded designated marksman's rifle. I have undergone a project that would give me those two things. My objective is to make a semi-automatic, 450 fps AEG that has an effective range which rivals my bolt action: 300 feet or more.

I have budgeted this project at $600.

A friend of mine is providing me with a few parts to create this weapon. Below is a list of the parts that i need to complete the gun, but I am unsure of what parts will be compatible with the JG SR25 receivers I am being given.

The Parts:
CA reinforced piston (FMT)
G&G Aluminum Piston Head with bearings
Systema A1000 type 0 Cylinder
Bravo heat treated Gears, standard ratio
AMP high torque motor
E1 metal hop unit. Will shim.
E1 h-nub
G&G hop rubber
Madbull 6.01 Ultimate, 509mm TBB
King Arms g27 grip
modify sp110 spring
G&G v2 spring guide

the rest of the parts are provided or optional, and are guaranteed to be compatible, but will all of these parts be?

Do you have any suggestions? I'm not looking for "don't buy this!" unless you have experience to back it up.

There is also a classified ad if you have any of the parts I need for cheaper than listed on ASGI or AONW.

[Minerva]

The Parts:
CA reinforced piston (FMT)
No. SHS 15 tooth.
G&G Aluminum Piston Head with bearings
Sure why not
Systema A1000 type 0 Cylinder
Yup
Bravo heat treated Gears, standard ratio
Bravo = Lonex and Lonex is nice
AMP high torque motor
For a DMR get the JG M42
E1 metal hop unit. Will shim.
No. The hop is no place to skimp in a DMR
E1 h-nub
Sure but an R-Hop would do WONDERS
G&G hop rubber
If it's the green one then yes. Also like Systema's though..
Madbull 6.01 Ultimate, 509mm TBB
No. 6.03.
King Arms g27 grip
modify sp110 spring
Lulwut? It's a DMR. Put an M120-130 in her
G&G v2 spring guide
Sure if it has bearings. Why not get an aftermarket one though?

Oh and AoE correct, Sorbo the CH, shim by the bevel and O-Ring mod the hop up

[league 4]

Well... The upgrade list won't work. JG SR25's use a custom cylinder, but the way you word it makes me think that you aren't getting the gearbox since you say JG SR25 receiver, so you'd need to buy an elongated gearbox shell and then you'd need a longer piston, different set of gears, different spring, etc.

[B.O.P. Hawk]

CA reinforced piston (FMT)
No. SHS 15 tooth.
Why the different piston? what will that do?
AMP high torque motor
For a DMR get the JG M42
Ok, but according to reviews, the AGM preforms better and is cheaper...
E1 metal hop unit. Will shim.
No. The hop is no place to skimp in a DMR
What unit would you suggest?
E1 h-nub
Sure but an R-Hop would do WONDERS
Never heard of an R-Hop...
Madbull 6.01 Ultimate, 509mm TBB
No. 6.03.
In my experience, there is about three inches more of variation for every 50 feet with a 6.03, as opposed to a 6.01. That extra foot of variation at 300 feet can be costly if I am trying to remain undetected.
modify sp110 spring
Lulwut? It's a DMR. Put an M120-130 in her
With all of the other compression parts, I was thinking an sp110 would be enough. I own a 130 if it is not, but that may put me over 450 fps.

Oh and AoE correct, Sorbo the CH, shim by the... O-Ring mod the hop up

English please... It would be nice to know what those mean.

[B.O.P. Hawk]

...the way you word it makes me think that you aren't getting the gearbox since you say JG SR25 receiver, so you'd need to buy an elongated gearbox shell...

I am getting the shell from Falcon. We think it fits normal parts, and the nozzle and piston head are both elongated.

[league 4]

The gearbox shell or just the externals? The piston head is not elongated, and the only JG SR25 I've seen had a standard length nozzle. This is the only cylinder head that will work:

http://www.airsoftpost.com/product_info ... s_id=36138

[Falcon7]

...the way you word it makes me think that you aren't getting the gearbox since you say JG SR25 receiver, so you'd need to buy an elongated gearbox shell...

I am getting the shell from Falcon. We think it fits normal parts, and the nozzle and piston head are both elongated.

It's a CA reinforced sr25 shell.

[Minerva]

CA reinforced piston (FMT)
No. SHS 15 tooth.
Why the different piston? what will that do?
It's a stronger piston. IMO the prommy hard is the only one stronger, but sooo much more expensive.
AMP high torque motor
For a DMR get the JG M42
Ok, but according to reviews, the AGM preforms better and is cheaper...
AGM=/=AMP. Reviews mean little to nothing if they come from people who don't know much. Trust me. JG blue.
E1 metal hop unit. Will shim.
No. The hop is no place to skimp in a DMR
What unit would you suggest?
Prommy chamber?
E1 h-nub
Sure but an R-Hop would do WONDERS
Never heard of an R-Hop...
It's a small piece of concave tubing that fits over your hop window to sort of "cradle" the BB. Look it up or PM me for info.
Madbull 6.01 Ultimate, 509mm TBB
No. 6.03.
In my experience, there is about three inches more of variation for every 50 feet with a 6.03, as opposed to a 6.01. That extra foot of variation at 300 feet can be costly if I am trying to remain undetected.
It is a wide misconception imho that the tighter the bore the better. This was all based off of the theory that the BB bounces aroudn the barrel and flies out at a straighter vector, however, recent tests have shown that it actually rides the top of the barrel so the 6.01 madness may very well be way off and barrel quality has oh so much more to do with range then tightness of bore.
modify sp110 spring
Lulwut? It's a DMR. Put an M120-130 in her
With all of the other compression parts, I was thinking an sp110 would be enough. I own a 130 if it is not, but that may put me over 450 fps.
It could but the spring you had is rated at 350-380fps..

Oh and AoE correct, Sorbo the CH, shim by the... O-Ring mod the hop up

English please... It would be nice to know what those mean.

AoE (angle of engagement) correct is making sure the sector gear engages the pickup tooth of the piston at a 90 degree angle.

Sorbothane, is a rubber compound that is very helpful in reducing the strain from the piston slamming up against the front of the gearbox at higher velocities. It's also imperative in spacing the piston so your AoE is correct.

CH is your cylinder head.

Shimming is spacing your gears so they rotate smoothly without contacting each other or any other parts in the gearbox with just a LITTLE bit of play. I say by the bevel, because you have to think, the Pinion gear is the only stationary gear in the gearbox. If you make sure it meshes with the bevel, you will have a cooler, quieter gun.

O-Ring modding the hop up is taking the spring spacer that pushed the hop up against the gearbox and spacing it with stationary spacers instead of the variably ranged spring.

Ah, here I was thinking you were going to custom fit a gearbox to a receiver..

piston head elongated

Not possible.

If you are getting a EV2 then that's a tad different..


I know what I said is a lot to take in so feel free to ask questions.


EDIT: If you are using a CA25 shell your parts list is WAY off.. If you didn't know that I honestly and strongly suggest seeking professional help. Not being rude, just that you may be getting in way over your head.

[league 4]

EDIT: If you are using a CA25 shell your parts list is WAY off.. If you didn't know that I honestly and strongly suggest seeking professional help. Not being rude, just that you may be getting in way over your head.

This, kinda. You need an elongated cylinder, brand doesn't matter for it, and elongated piston, and a different gearset. You also need a PSG-1 spring.

[B.O.P. Hawk]

piston head elongated

What I meant was cylinder head.


The fact that I need help is the exact reason I posted this topic. There is nobody local to where I live, at least for an extremely busy high school student like myself.

So far, I have learned that I need to change a few parts on my list, which was exactly my objective.

Edits to my list of needs/wants for this Project:
SR25 gear set
PSG-1 Spring
Long Cylinder (unported)
Long Piston



Pending more information... This information may not be applicable

[league 4]

Oh, and I just remembered, I think you need a longer tappet plate too.

[Minerva]

Oh, and I just remembered, I think you need a longer tappet plate too.

Yup. Also, all of those mods I stated still NEED to be applied

[B.O.P. Hawk]

So, I have all of the parts that I was going to get from falcon, and it turns out that the compression is elongated, but the cylinder head is also. A normal sized cylinder fits to the back of the cylinder spot if the head is in, but it does not go all the way to the front. The piston fits as normal because of how much farther back the head fits, including the sector gear's AoE.
The only concern I have is that I will not get full compression, or enough to get the BB out. Is this a Legit concern?

Also, I plan on keeping the cylinder head I have and just getting the long Cylinder and a normal Piston. Since I got the stuff from Falcon for free, I'm probably gonna buy a JG SR25, put all of these reinforced parts in, then buy the parts that still need to be upgraded and install them.

[Minerva]

So, I have all of the parts that I was going to get from falcon, and it turns out that the compression is elongated, but the cylinder head is also. A normal sized cylinder fits to the back of the cylinder spot if the head is in, but it does not go all the way to the front. The piston fits as normal because of how much farther back the head fits, including the sector gear's AoE.

Please for the love of god, do not shove non elongated parts into an EV2. This is a pretty bad lego build as it is, you don't need to start throwing incompatible parts into it too..

[Nec]

I think this is every kids dream, to make a "DMR" gun from scratch... What I wanto know is where do they get the money? Mommy or Daddy?