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M40A3 McMillan – BREAKDOWN

The new must-have sniper rifle?...

We have truly taken this rifle down to its very last screw and bolt to find out exactly how this rifle holds up against many of the other available "budget" introductory Airsoft spring powered sniper rifles out there. In short, we are incredibly impressed! Continue reading below to find out everything we now know about it. For production information on the ASG - M40A3 McMillan Sniper "Click Here".

What do you get for your money?

First of all, you are getting a very sought after M40A3 stock that just feels amazing to hold. Very comfortable and visually striking compared to alternative slimline stocks you are normally used to seeing. On Tokyo Marui and other branded rifles, the M40A3 stocks are rare to find and highly desirable due to popular use in films and real steel shooting.

With this being a "budget rifle" you are getting a hollowed out stock with metal weights, but the hold and comfort are still absolutely fantastic. Now let's start breaking it down...

Breaking it in two:

As already mentioned, this is a hollowed out stock that features alloy weights but you could quite easily split it and pack it out with plasticine or expandable foam to make it feel a bit more robust.

First of all simply remove the under rail by removing the 2x screws.

You can then start to take each screw out of one side of the body and split by hand or a very thin blade.

The sling mounts do not need to be removed, but you can do so very easily should you want a flusher finish. Just be sure to chop off the mounting studs after.

Once split you can see there are three weights to balance out the rifle when being held up in the air.

The front inside also features the magazine release catch mechanism. This is a closed unit and unlike many other rifles out there, you do not need to fear of this part flying out and getting lost when disassembling your sniper!

Additional features:

As you may have already seen, the rifle features an adjustable cheek rest that requires you to simply undo the four screws. The cheek rest then has 4x positions that the rest will lock into once the screws are tightened back up.

The stock is also adjustable with 4x plates that can be added and removed until you have a desirable length once shouldered.

The cylinder and outer barrel are also stabilised with a very thick polymer locking unit as pictured below.

This unit keeps everything rock solid and provides one of the most satisfying bolt pulls we have ever experienced. Even when you fit a bigger spring inside the cylinder, everything still functions very smoothly and straight.

The inner barrel also features a polymer 2 part stabiliser, you can add more home-made ones by simply wrapping the inner barrel in insulation tape should you desire.

Hop-up chamber:

The hop-up chamber is very similar to the ones found in the SSG69 spring rifles, however, the M40A3 is far better quality with a better finish and just feels more pleasant to physically slide the hop pressure adjuster too.

Straight out of the box this hop-up unit will life a 0.40g BB very happily once you upgrade the cylinder with an ASG - High Power Spring - SSG69.

Do not let the polymer construction put you off. This is a hard ABS material that delivers excellent and precise pressure upon your hop-up rubber/bucking.

The cylinder:

The cylinder only requires a spring upgrade for this to become a very competitive rifle on the field. Yes, you can replace the piston and spring guide with alloy alternatives, but we would honestly find this a waste of money. Just like the SSG69, this rifle can be upgraded to 500fps with just a high powered spring purchase.

The nozzle is tight straight from the factory, but with some long needle nose pliers it comes off very easily revealing the heavy greased insides. We would recommend a quick clean and Abbey Silicone Oil is used before your first skirmish to improve your range upon your first few shots. You may also see an additional FPS increase.

Overall verdict:

Do not upgrade anything over than the spring! This rifle performs very well and with the spring upgrade and right BBs, plus a good setup scope you can achieve some seriously impressive range on the skirmish field competing very nicely against well tuned Tokyo Marui platforms.

The rifle is lightweight, easy to pull the bolt, cheap magazines to buy as spares and can be heavily customised. A few customisations we recommend are to fill the stock with either plasticine or expandable foam, a one-piece homemade barrel spacer (paper wrapped tight around the inner barrel) and a camo paint job.

Want one?

Keep it clean, use quality ammo and set up your scope properly and you will not be disappointed. For your own ASG - M40A3 McMillan Sniper "Click Here".


Written by Karl, who has written a total of 202 posts.

Posted in Patrol Base News | 4 Comments

4 thoughts on “M40A3 McMillan – BREAKDOWN”

  1. Ant

    Going to get one of these as the weekend from Patrolbase. If i get the upgraded spring will it still be within the limits of outdoor UK sites using say .32 or .4 BB’s ? Cheers Ant


    1. PatrolBase Milky

      Hi there,

      My first thought would be to review what weight of BBs you’re using. Whilst a Rifle may be over the limit using 0.2g BBs, the use of heavier BBs might bring the total energy under the limit for that new weight of BB. It might also make matters worse. Another choice would be to try another spring, trim coils off what you have or to reduce velocity by another means (maybe a widebore barrel?). For the best advice, you would be best off speaking to our workshop team, who have far more experience than myself.

      01484 644 709

      Many thanks!


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