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ASG M40A3 Sportline Upgrade/Mod Guide

22K views 37 replies 9 participants last post by  B.i.G 
#1 · (Edited)
Remove all stock screws and pull stock apart
18540

Fill with foam to reduce sound and make feel less cheap.
(I used Calmflex F2 and various scrubber pads)
18541

Put back together without losing a screw like I did
18542

Fill with more foam
18543

Remove trigger and barrel/hop chamber
18544

Disassemble trigger
There's a hidden screw behind the safety, so pull the safety back
18545
18546

Polish here and here on the trigger and main sear.
This will reduce trigger pull weight and improve longevity
18547

Polish on the front and back of the piston sear too.
This also helps with trigger pull weight and longevity.
18548

Add better grease and re assemble.
Grease reduces friction, improving trigger pull, bolt pull, and longevity.
18549


Wrap a layer of Scotch tape and a layer of aluminum tape on this part of your barrel.
This will center it in your receiver better.
You also need to poke out that hole.
This improves accuracy/range, sound, and stability
18562

Cut a piece of aluminum can and put it in the receiver to make an ejection port cover like so.
This improves sound and keeps out sand, dust, dirt, and everything bad
18565

18561

Make a cylinder guide sleeve like so.
You want it to be a sliding fit on your cylinder, and a tight fit in your outer barrel.
I used a notebook cover and some tape, but a soda bottle or Delrin tube would be ideal.
This improves bolt pull, sound, and longevity
18564

Make a barrel spacer out of painters tape and install the hop chamber, barrel, and cylinder guide sleeve.
This improves sound, accuracy/effective range, and rigidity
18566

18567

Wrap electrical tape on both ends of your spring.
This improves sound
 

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#2 · (Edited)
Put trigger back on receiver
18550

Polish the inner barrel with metal polish and clean until clean.
This improves accuracy/range as well as possible FPS.
18551

Crown the end of the barrel
(I used a knife and sandpaper)
Improves accuracy/range
18552
18553

Sand hop chamber face flat.
Improves nozzle seal
18554

18555

File and sand where you see this brass residue.
Improves bolt pull and push as well as not making metal dust
18556
18557

Apply a band of super glue around the bucking and let dry completely.
Improves air seal/FPS a lot
18558

Shim hop arm with aluminum tape or similar and glue a piece of rubber between the two prongs
(I used 4 layers to get the right thickness)
This will prevent you from having the weaker half of your hop adjustment, but that doesn't really matter unless you like firing .20g BBs.
This improves accuracy/range a ton.
18559
 
#5 · (Edited)
Black Dog's Notes on this:

I would like to make a couple of additions to it, in this post, I will be talking about parts compatibility from the VSR10 and the modifications needed for them to fit, as well as what one can do with the stock parts to improve performance.
Most of this info is sourced from various youtubers who I will link at the bottom of this post as well as @T4nkcommander on this forum.

The Trigger:
One can't do much to this. The one upgrade part that does fit is the 2nd 45 degree sear from the VSR10.
Other than that, you will either have to manufacture your own components or just do what @SiliconeSword sword did and polish up your stock sears and buy a new gun when they break.

Cylinder:
Not a lot that one can do about the actual cylinder. Any cylinders that one might find for an 'asg m40a3' are for the proline version.

Cylinder Internals:
APS2 internals fit.
Hopup Rubber:
VSR10 hopup rubbers do fit, however, as @T4nkcommander informed me, the the bucking slot is on the opposite side of the chamber. You will have to cut off the ridge on the side of VSR10 buckings for them to work.
The stock barrel is bridged so ML buckings don't work. Either remove the bridge or use a different bucking like a Madbull, 9ball or Unicorn.
Rhop and Flathop also work.

Barrels:
VSR10 barrels fit.
Lambda, Maple Leaf and Lonex recommended (by me).
Add barrel spacers made of masking tape or something else (hockey pucks like @Zero Roaster maybe?)

Hopup Unit:
Action Army hopup unit (the only one that you should bother changing the stock one to) works, however, mag mod is required.

Mag mod:
13:43 in this video:
(1) M40A3 Sportline Full Upgrade How To | SaltyOldGamer Airsoft Guide - YouTube

Video Links:

Also, if mods could please move this post to below the last post @SiliconeSword made in his upgrade guide, that would be brilliant. Thank you in advance.
 
#36 ·
Guys I need help with my ASG M40A3 Sportline... I installed the Action Army VSR10 Hopchamber, maple leaf bucking, and precision inner barrel.
The gun is shooting way low and very unconsistent... I checked and noticed that the nozzle barely reaches the chamber. If I keep the bolt pressing foward while I shoot I get better results. Anyway to fix this or any cylinder head with longer nozzle I could use?

PD: I also want to upgrade the power group... So it uses APS2 part but a VSR10 sear? WTF?
 
#6 ·
Alright, I've reached my 20mb limit, so just text from now on

Wrap solder and electrical tape on your piston

Wrap electrical tape on both ends of your spring

Put lots of teflon tape on your cylinder head

Put teflon tape on the bolt handle shaft until your bolt handle is snug

Put everything back together and use it


After all of this, I gained .09J, ability to hop heavier BBs, much better accuracy/effective range, much better sound, and a dope paint job, so I'd definitely recommend do this if you own one of these.
 
#7 ·
Alright, I've reached my 20mb limit, so just text from now on

After all of this, I gained .09J, ability to hop heavier BBs, much better accuracy/effective range, much better sound, and a dope paint job, so I'd definitely recommend do this if you own one of these.
What range you getting now (and what bbs?) Stock, my rifle would shoot both .36g and .40g bbs quite accurately out to 240ft, whereupon they'd drop like a rock - both full hop.

I put the upgrade spring into it which seemed to give me an extra 40ft, but then also put a Mr. Hop bucking into it. I ended up cutting up too much of the barrel, and thus left a big hole in front of the bucking, which I patched with teflon tape. This, coupled with the horrible hackjob on the bucking left me surprised it worked at all - that said, I'm now launching .46g bbs to about 250ft, whereupon they drop like a rock. I'm convinced a barrel and new (unmolested) bucking will have the gun shooting like a laser out to 300ft. Gonna take the gun apart in the meantime and see if I can fix the airseal, as that seems to be my problem.

Regarding sears - this sear will fit, but the sear housing unfortunately will not. My youtube playlist for helpful videos regarding the gun: https://www.youtube.com/playlist?list=PLbBcQaDdqeQX4dqnZ4hkxbJQasePuNzB-

I plan to do a proper review on the gun, but overall for $80 it is a great buy. Most of the cost goes to performance, but for an entry level sniper that's exactly what you want.
 
#12 ·
Get yourself a more powerful spring and put it in, then see how you like it. That'll get you some familiarity with the takedown and make a major upgrade to the guns performance with minimal effort. I've seen several people argue that a good spring is all this gun needs performance wise. I think the stock hop up is pretty weak, but a more powerful spring really will make the gun sing.
 
#13 ·
I put in some BLS .36g and got a max range of maybe 65m, at 1.10J.
Here's a VIDEO of me recording through the scope using the before mentioned power and BBs.
The range is 60m exactly, with a decline of 6m, and the target is a 320mm steel plate.

I will be doing more air seal mods and putting in an R-hop to hopefully gain better accuracy, power, and range, but even then I would still not get this rifle as it sort of sucks.
 
#17 ·
So I tried to remove the trigger box and met some resistance. I unscrewed the four small screws, two at each end, and something else was holding it in place. I wanted to check before just giving it a good tug that there wasn't something else holding it in place.

Second, you mentioned electrical tape on the spring ends, is that flat over the 'opening' as it were, like an end cap, or around the ends to make them a bit thicker?
 
#38 ·
So I tried to remove the trigger box and met some resistance. I unscrewed the four small screws, two at each end, and something else was holding it in place. I wanted to check before just giving it a good tug that there wasn't something else holding it in place. Second, you mentioned electrical tape on the spring ends, is that flat over the 'opening' as it were, like an end cap, or around the ends to make them a bit thicker?
Unscrew the cylinder head and the trigger unit will come out easily.
 
#18 ·
I bought the black version.

It definitely lost power over time, but I just finished putting in an R-hop and doing lots of air seal stuff to the bucking and I'm up to 1.69J, way better than 1.10J.
The cylinder air seal is good, but the hop chamber and bucking need even more super glue that I thought, and I had to use RTV glue to glue the bucking to the barrel for a somewhat decent seal.
 
#20 · (Edited)
#23 ·
ok ignore me. you're going to want to sit down before you read the stupid mistake I made because you'll be laughing too much...

I took the old spring out yesterday, set it down on the work mat in front of me beside the upgrade spring. Then when I went to put it back together, I picked up the old stock spring again...

So, on the plus side I got an extra 15fps with the mods I did. Now with the actual proper spring it's hitting 400fps with .4s.
 
#26 ·
Well I don't have the space here to properly test it. I went to an indoor range nearby and shot about 28m down a hall. That was laser straight with .4s

I won't be able to test it properly until next Saturday when we have my first game.

Bolt pull is good though, fired about a hundred shots in an hour and it hasn't killed my shoulder. I work a physical job which helps. Handles nicely, weight is good. I got 15 hits on 15 targets in 29 seconds on their shooting game.
 
#25 · (Edited)
Well, I sorted out my gun. Ended up ditching my botched barrel, and cannibalized my old M324 to replace it. A quick unbridging using my dikes and the Mr. Hop fit well on the barrel. Interestingly, the old barrel had the same grooves to match the hop up chamber, so it was an easy fit (tho I had already removed the groves in the hop up unit).

My gun now has the following modifications:
  • ASG specific spring (supposedly 510FPS, longer than stock spring)
  • VSR upgrade sear (sear only)
  • Mr. Hop bucking (and teflon tape)
  • Teflon tape on cylinder head
  • Can mod (reduce noise)
  • Old stock UTG M324 barrel
I just confirmed today I could reach 310ft with .45g bbs with about 1/3rd hop, shooting into the wind (on and off, sometimes quite strong). The trajectory with .45s is a little more arced than I'd prefer, dropping approximately 10ft at 310ft. .40g bbs seemed to have the best flight pattern flying more straight to about 270ft with about the same level of hop. I did record a few shots and may upload later if I feel so inclined; if I do, I'll update this thread with links.
 
#28 ·
Back when I got mine it WAS at 1.9J or so, but power just went bad.
After everything I did plus R-hop, I have got to 1.59J with a .36g BB, so it's certainly better than 1.10J, but definitely not 1.9J sadly.

Anyways, I'm giving the gun back to my friend as I borrowed it for this tutorial, so he'll have an improved rifle.
 
#32 ·
Remove all stock screws and pull stock apart
View attachment 18540
Fill with foam to reduce sound and make feel less cheap.
(I used Calmflex F2 and various scrubber pads)
View attachment 18541
Put back together without losing a screw like I did
View attachment 18542
Fill with more foam
View attachment 18543
Remove trigger and barrel/hop chamber View attachment 18544
Disassemble trigger
There's a hidden screw behind the safety, so pull the safety back
View attachment 18545 View attachment 18546
Polish here and here on the trigger and main sear.
This will reduce trigger pull weight and improve longevity
View attachment 18547
Polish on the front and back of the piston sear too.
This also helps with trigger pull weight and longevity.
View attachment 18548
Add better grease and re assemble.
Grease reduces friction, improving trigger pull, bolt pull, and longevity.
View attachment 18549

Wrap a layer of Scotch tape and a layer of aluminum tape on this part of your barrel.
This will center it in your receiver better.
You also need to poke out that hole.
This improves accuracy/range, sound, and stability
View attachment 18562
Cut a piece of aluminum can and put it in the receiver to make an ejection port cover like so.
This improves sound and keeps out sand, dust, dirt, and everything bad
View attachment 18565
View attachment 18561
Make a cylinder guide sleeve like so.
You want it to be a sliding fit on your cylinder, and a tight fit in your outer barrel.
I used a notebook cover and some tape, but a soda bottle or Delrin tube would be ideal.
This improves bolt pull, sound, and longevity
View attachment 18564
Make a barrel spacer out of painters tape and install the hop chamber, barrel, and cylinder guide sleeve.
This improves sound, accuracy/effective range, and rigidity
View attachment 18566
View attachment 18567
Wrap electrical tape on both ends of your spring.
This improves sound
Remove all stock screws and pull stock apart

Fill with foam to reduce sound and make feel less cheap.
(I used Calmflex F2 and various scrubber pads)
View attachment 18541
Put back together without losing a screw like I did
Fill with more foam
View attachment 18543
I have to say that your method of using bits and pieces of foam to fill and deaden a hollow rifle stock is the most ridiculous thing I've ever seen. ALL the left over air-spaces IN the foam and around the foam undo ever attempt to absorb rattle or harmonic echo from a shot. Also, it adds nothing to giving the stock any more "heft" (weight) to better steady aiming capabilities. In precision (target quality) rifles, balance is top priority, but the area forward of the receiver (the barrel area) should be heavier than the rear of the rifle. You obviously don't shoot REAL guns or rifles.
 
#35 ·
You obviously don't shoot REAL guns or rifles.
Point 1 see quote above

Point 2 it's a game not an in depth war simulation (casual skirmishes make up the major of game played) people work all week than on a day off go shoot some plastic balls at other consenting players have a laugh and go home. (I understand milsim events but they make up a very small % if games so can't be taken as the majority of why people play if anything most people treat it more like a real life video game.

Point 3 I thought you were plinking rather than playing based on another post, it's a common occurrence for people to assume Airsoft snipers are equivalent to airguns, if I misunderstood that part I apologize.

Also point 4 & 5 surely you can't be that dense with that response? You can't say I never said anything about real guns and than instantly respond shouting look what I shoot and have done for a job. It completely undermines your own argument.

We are a forum for Airsoft players who snipe, we go out at the weekend with our toys hope the wind isn't bad/erratic enough to ruin all the tinkering we do with our replica's.
 
#33 ·
Shooting real guns is irrelevant, the principles of how Airsoft guns works is 100% different to real steel.

An Airsoft gun us designed for ranges up to 100 metres and to be safe against human targets. (This means they have a limit to range and accuracy due to being a safer designed projectile). In Airsoft ranges of engagement mobility and stealth are more of an advantage than anything else.

The difference in an AEG Vs sniper range advantage in Airsoft can be anywhere 0 to 50 metre's depending on field energy limits.

I gather you are using these for plinking, don't mistake them for a replacement airgun (most common comparison) they are designed for a different purpose.
 
#34 ·
1) I made zero reference to any comparison between real guns and airsoft guns in use. Cite where I did.
2) Tactics are tactics, airsoft "pretenders" that have no real Mil experience are the ones "playing" and essentially "plinking".
3) I've been involved in "Team Airsoft" for about 9 year, mostly Mil Vets. I'm only New to trying a sniper roll.
4) If I "plink" (target shooting, 600 to 1000 yards) its with an FN FNC Match Grade in 5.56 NATO, and competition "Mil Run n Gun" (Rifle / Shotgun / Handgun.)
5) 20 years (ret) in the USAF 20th Spl Ops Sqn (Green Hornets), 27th Spl Ops Wing. Pilot and Spl Ops.
 
#37 ·
Yeah, so this is one of the issues with the Sportline: it has a very short nozzle. I'm not actually sure how to fix this, other than soldering something on/adding on jb weld in a circle around the nozzle. This seems in and of itself to be a bad idea.

Yes it uses a melange of parts. Gun is weird.
 
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