REVIEW // ASG M40A3 McMillan Spring Sniper Rifle

The Remington M40 is a bolt action sniper rifle which was co-developed and adopted by the USMC. A rifle that chambers the 7.62 NATO caliber round, the M40A3 variant was developed to be used by Marine snipers with a match grade barrel. Unfortunately this rifle was succeeded by the M40A5 in 2009, but with the McMillan stock, the M40A3 has little difference to that of the M40A5. The ASG licensed VFC M40A3 is very much a cool representation of that rifle.


The M40A3 is such a beautiful sniper rifle (in my opinion), with the McMillan stock in olve drab. There is no reason why a player who is fond of sniper rifles wouldn’t love this rifle, unless it was too big for them. Now I’m an averaged sized build for a European, but this rifle with all the stock links attached, is way too long. I had to take all the links off the stock to be able to comfortably shoulder the rifle.

ASG M40A3 (10 of 23)

The M40A3 is not only long but also quite heavy. However this is not the kind of heavy that would put one off purchasing the rifle as it means that it is very sturdy and can take quite a bit of a beating. The weight doesn’t cause considerable discomfort as it is mainly balanced behind the pistol grip. This means that a lot of the weight helps with shooting the rifle whilst standing… yes. Standing!

My experience with bolt action rifles are limited at this moment in time, however having played with many variants of the TM VSR, I can say that the pull action of the bolt is very smooth compared to other counterparts, albeit still heavy due to the fact it is cocking a heavy spring. Nothing can compare with the pull of a gas bolt action rifle, however for a spring action rifle, the bolt action of the M40A3 is very satisfying.

ASG M40A3 (22 of 23)

There are a few interesting differences in this rifle which make the ergonomics stand out. For one, the pistol grip is not angled as much as would be expected for a normal rifle. In fact, the grip is almost ninety degrees to the angle of the barrel. This can be a bit weird for the average sniper, but can be adopted quite easily due to the fact the grip is quite large. I personally end up slanting my grip of the rifle just before shooting as it feels more natural.

I’m happy to see that there is quite a bit of texture on the rifle which includes the pistol grip and the front of the rifle frame. This has proven useful in keeping grips of the rifle in more exciting weather conditions. Even the bolt handle has some texture on it, just to give that added grip if you use your fingers instead of you hand, to pull the bolt back.

ASG M40A3 (11 of 23)

NOTE: The M40A3 does not come included with an optical device of any sort and hence will require one for aiming. Might be worth getting a larger optic than what I have pictured.

Sniper rifles are designed to be fitted with optical devices of different types, at different angles and hence require adjustment for the user to be able to aim down the optical sight with their cheek gently resting on the rifle. The McMillan stock caters for this, using an anodized cheek riser which surprisingly does not feel cold to the touch whenever touching it. Although the bolt is not particularly ambidextrous, the user can move the adjustment screws for the cheek riser to either side of the stock.

ASG M40A3 (18 of 23)

The butt pad is finely textured and has been capable of keeping the rifle shouldered whilst firing pretty effectively. Just take note that the stock is adjusted via two long allen screws hidden in the butt pad. Remember that the links simply slide out of position and do not require the screws to be removed entirely.

The bolt housing has a very nice finish which of course is complimented by the rest of the rifle. VFC is known for great externals on their RiFs and this is no exception. Everything from the handling of the bolt to the safety switch, feels solid and unlikely to fall apart after many hard felt battles. As said before, the bolt travel feels smooth for a spring sniper rifle and after much stress testing, has not caused misfeeds unless done so via human error.

ASG M40A3 (Internals) (22 of 55)

One of the most interesting features of the ASG M40A3 has got to be the hop up adjustment dial. I’ve been quite critical of the placement of this dial due to the fact it rests on the underside of the rifle stock handle and in my opinion was likely to get caught or snagged on different items whilst playing. I was so happy to be proven wrong. I even purposefully attempted to get the hop up dial snagged on a branch and it just wouldn’t budge.

The dial adjusts in clicks which can only be adjusted when given enough force, this is no flimsy dialing device. I have to say that this hop unit will be very difficult to adjust without actually trying. No branch or rock is going to be able to change your hop adjustment… Unless you willfully smash the rifle against a rock or a hard place (ASG does not recommend this, nobody does).

ASG M40A3 (Internals) (11 of 55)

The top rail of the bolt housing presents the top picatinny rail system which is the only way to mount an optical device to the sniper rifle. Please take note of the size and length of the optic before mounting as the rail is 12 cm in length. It is also nice to see the ASG logo and the caliber, although some users may have preferred more realistic trades considering the rifle is licensed by McMillan.

ASG M40A3 (Internals) (13 of 55)

The amount of quick detach points on this rifle amazes me. I’m not sure how many are on the real stock, or if there are any actually on it. The back of the stock consisted of three QD points and the other three QD points are found at different points near the front of the stock. Alongside those QD points, there is a bipod mount on the front which allows for the associated bipods to be fitted (I unfortunately did not have one for the purpose of this review).

ASG M40A3 (Internals) (12 of 55)

The stock has an interesting feature which may be a hint to future accessories and/or releases of which have not been advertised yet. As you can see in the picture below, their are a number of grooves which could potentially be taken out and swapped with other accessories. Please be aware that at this moment in time, it is only speculation and may not lead to any accessories actually being made for this part of the rifle.

ASG M40A3 (Internals) (15 of 55)

Another feature to the rifle which seems to be hidden is what looks to be a replaceable thread head. I wasn’t for the life of me, able to remove this thread without damaging the head so I unfortunately have no pictures. All I can say is that there is a thread the barrel allowing for a thread adapter to be applied to the barrel (will update this review when further information is gathered).

ASG M40A3 (Internals) (18 of 55)

Now the real rifle uses an internal magazine. This means that the rifle does not have a magazine that merely comes out of the bottom. The airsoft version however will need to cheat a little with a magazine of which is hidden in the bottom of the so called “mag well” of the sniper rifle. This internal magazine contains 20 bbs which in my opinion is more than enough before reloading. It is not known if ASG will release a modification for an external magazine to be used instead.

ASG M40A3 (Internals) (21 of 55)


The ASG M40A3 contains some features which are found commonly in all airsoft spring sniper rifles, and more. The following are the features and specifications of the ASG M40A3:

  • Package Includes ASG M40A3 (size varied length links for the butt pad), Magazine, Manual, BBs and an adjustable allen key
  • 1:1 Scale Spring VFC licensed M40A3 Sniper Rifle
  • Six QD Mount Attachments
  • Replica Workiing Safety Lever
  • Length: 1130 mm (Rifle) ~60mm (Barrel)
  • External Adjustable Hop Up Dial System
  • Color: Olive Drab (McMillan Stock) Black (Barrel)
  • Magazine Capacity: 20 + 1
  • FPS Variance of 410 – 430 FPS (0.2 g)


The rifle has been built to perform out of the box and hence the internals are supposed to match that statement. From examining the internals of this rifle, it is apparent that this rifle is mostly TM VSR parts compatible. Only certain external parts of the bolt are not compatible with VSR parts of course.

ASG M40A3 (Internals) (33 of 55)

The entire internal assembly of the rifle can be taken apart from the McMillan stock with just a few screws. From here, the user has the ability to adjust the stroke and the trigger pull of the rifle’s response. This is quite a cool feature which I am happy to see in a sniper rifle as I’m sure, every user would like to make their rifle’s trigger pull made to match just for them.

ASG M40A3 (Internals) (36 of 55)

With the barrel disassembled from the bolt housing and the barrel screws taken out. The hop up housing can slowly be taken out with the inner barrel in tow. Be careful when you get to this part as there are two springs on either side of the housing which are exposed. Do not lose these as they are there to keep the loaded bb in place before shooting.

The hop unit is adjusted from the bottom which much like the ASG CZ75 pushes a bar to adjust the hop from above. This has shown to be very effective and secure as long as the screw that pushes the hop adjustment stays in place. I would like to see ASG keep to this method of hop for any of their proprietary systems as it’s proving to be very sturdy.

ASG M40A3 (Internals) (52 of 55)

The internals overall within the ASG M40A3 are very durable with a very low tolerance in measurements. There is a lot of room for upgrades, however this rifle does not look like it will be needing any upgrades to perform well in a skirmish.

More pictures can be found of the rifle and its disassembly in the gallery. ASG have also been able to provide an exploded diagram of the rifle.

ASG M40A3 Exploded Diagram


The M40A3 is a spring operated sniper rifle of which after many shots, settled at 420 fps using 0.20 bbs. The bolt action of the sniper rifle is smooth but does have a certain level of resistance. This resistance is however not too strong as to make you feel like you have to break your arm to pull it. The rifle is fairly accurate as long as their is little wind to cause disturbance in the bb’s flight. The following target was shot at under mostly minimal wind force coming from the right of the target.


The M40A3 is one formidable sniper rifle. As seen from the performance and internals. There seems to be little need for upgrades outside of the box, however it does not mean that it cannot be made a better rifle with more upgrades. This is definitely a good platform to start with. It is quite a heavy rifle which may deter some users who aren’t as capable to heft the weight, but it does make it feel like a more solid airsoft replica due to it.

I have thoroughly enjoyed playing with the M40A3 as it has had little need for me to upgrade or tweak from the moment it was taken out of its box. I personally did not enjoy having to reload the internal magazine every 20 rounds. Not only did this remove the realism for me, but was also quite finicky for me to perform at first. Overall this is a great platform for anyone who wants to take a sniping role.