6mmProShop PDI Custom Upgraded USMC M40A5 Bolt Action Airsoft Sniper Rifle (Model: OD Green / Gun Only)

"I bought this gun in 2019, but hadn't been able to do much with it till now.

Initial impressions
Externals are good quality. No wobble, scope rail works great, solid construction all over. The gun is heavy. Since I work out, no big deal. Can be a pro or con, so keep that in mind.

Internals
The trigger group is pre upgraded, which is awesome, and also the reason I bought the gun. It makes further upgrading a breeze.

Barrel has been fairly accurate for me so far. The gun uses a 370mm AEG barrel. YES, you read that right. If you buy anything longer, you WILL have to do some substantial modification. The front end is pinned and the inner barrel will not fit through the pinned adapter unless you drill it out. Again, it uses an AEG barrel and AEG buckings.

Stock hopup packing and nub are crap - replace these first. They will hop up to .32 comfortably and are barely adequate for .36, but anything heavier will need better bucking and spacer.

Piston and spring guide are plastic. Replaced with AA VSR-10 parts. Cylinder is steel and shouldn't need replacing. Air seal is perfect with Teflon tape around cylinder head. Upgraded spring to S&T 500 fps spring, but the setup will take VSR springs if you so desire.

Hopup unit is a copy of a PDI. It uses 2 arms and is adjusted from the bottom via 2 grub screws after pulling the bolt back. It needed some modification to work the way I wanted it to. It uses an O-ring for tension, but the o-ring wouldn't give enough tension to hop anything over a .32 very well. I used a cut pen spring taped over the arms as a booster spring mod and now it will comfortably hop .36 on less than half adjustment. Adjusting and tuning can be a pain, but it is not a bad unit overall.

To center the double hopup arms, I used a strip cut from a coke can as a shim. The strip measures 3mm by 12mm and is bent into a U shape. I put the strip into the channel behind the hopup arms so it keeps them centered over the ML Omega nub.
The hopup window in the unit is wide, so I used two tiny pieces of eraser to keep the ML nub centered in the window.

Upgrades
ML MR Hop AEG bucking
ML Omega nub
Teflon tape wrap around bucking inside the hopup unit
Two tiny pieces of eraser to center the ML spacer in the window
A 3mm x 12mm coke can arm shim
Booster spring mod

Action Army VSR-10 90 Degree piston
Action Army VSR-10 Spring Guide
S&T 500 FPS Upgrade Spring or VSR-10 springs

370mm AEG barrel of your choice
Cheap 3-9x40 scope. Evike sells one by Matrix for under $40.

Performance
The following info is using Matrix .36 BBs.
I have not been able to chronograph, but I can eyeball things pretty well and I can measure.
This setup has no problem hitting a man sized target out to 230 feet. A little height adjustment using the scope's mil-dots and I can still hit a torso reliably at 250 feet. At 270 feet I end up lobbing a little bit to hit a human size target, but it is pretty reliable with the hopup adjusted right.
My guess is with this setup the rifle is somewhere between 2.4j and 2.6j.

A note - this is the same rifle as the CYMA M40A3. I got this on an epic deal back in 2019 for cheaper than the CYMA.
This S&T one has a different muzzle device and a fixed magazine attachment that does nothing but get in the way. Those are the only extra things you get for $35 more than the CYMA one. Keep that in mind when you are ordering, as you can get the CYMA version and an AA piston for the same amount as this rifle now.

All in all, this rifle is worth it and has been a joy to play with for me, and I do recommend it.

"I bought this rifle in 2019 on a sale on Evoke but only recently got around to playing around with it/modding. I feel confident enough to review about it now.

This is the same rifle as the Cyma CM700 M40.
The primary reason I picked it up was the pre-upgraded steel sears/trigger parts. This allowed me to do some decent upgrades without much added cost.

Out of the box It will hop BBs up to .32 very well, and .36 to a fairly reasonable distance, but any higher than that will need some modding.

Externals. The rifle is well put together and solid. It's fairly simple to work on and I did it without even referencing videos.
It is heavy so be in shape if you're planning on doing useful airsoft sniping.

Internals. VSR compatible piston and spring guide. I installed the 500 FPS spring sold here for this gun, as the one in the gun was the 430 fps spring. Springs are 7mm inner diameter, but I haven't tested larger springs.
Bought Action Army 90 degree piston and Action Army spring guide.

Barrel is 370mm. Since I plan to stick with heavier BBs I don't feel the need to get a longer one. Accuracy with stock barrel has been fantastic so far, I just keep it clean.

PDI type hopup. For me, it was underwhelming initially, and the most difficult part of the rifle to deal with. The o-ring didn't have enough strength to pull down the double arms to hop anything over .36. the stock bucking is underwhelming as well, because even on max hop, sticking into the chamber, it lacked the oomph to lift .40s.
I fixed this by doing a few things.

Added:
60 degree Maple Leaf MR HOP
Eraser nub that fits the hopup window better
Will put Omega nub in soon
Small v shaped spacer between the hopup arms to keep them apart
Boost spring mod

Now the rifle is capable of hitting shots on a slightly larger than man sized target at 270 feet about 5/10 times. I have only tested this with Matrix .36 so far, and testing has been brief/not super extensive.

I might install Action Army L96 hopup in the future. Refer to Wawan's guide on airsoft sniper forum. Post #56.

Double arm spacer - made of aluminum from a coke can. I cut a strip long enough to fold in half with some tiny wings on the back to keep it from slipping between the arms. Measured roughly 3mm by 18mm. It sits in the space at the rear of the unit perfectly.

Boost spring mod - pulled a cheapo clicky pen apart and cut the spring to a little less than 1cm. Taped on top of the arms with electrical tape and simply pressed between the hopup and outer barrel.

Eraser nub - T-shaped to add more pressure to the bucking.
I did not have to shave the hopup arm.

I added teflon tape to the cylinder head and to the outer barrel where it screws on to the receiver.

Paired with an inexpensive 3-9x40 for looks as I usually keep It on 3-5 power.

For me, this has been a great project gun that didn't break the bank and had a lot of what I needed in it already.
The fiddliest part of the project was the hopup, but If you are creative and feel like putting a few hours of work and creativity in, you won't be disappointed. Alternatively buy the AA L96 chamber and do a little modding to the gun.

I'm extremely pleased with the performance and have never owned a gun that shot this far or this straight.

"Great out of the box starter sniper.
Hopup adjustment is a little tricky at first, it's 2 allen keys that adjustment two separate bars. It works well as you can adjust them separately to curve bbs left/right slightly. (Get them straight)
Barrel is 363mm, not 455mm, and is a AEG window. Piston and guide are plastic, but 90deg metal sear. I upgraded mine with 170M spring. Shooting right at 3j now. Shoots fairly quite otb, but it's not completely silent. Probably slightly over volumed.
Chassis feels very sold. Bolts and barrel rail clamp everything very securely. No wobble or rattles.
Barrel extension is pinned, glued on. Once that's removed, the adapter for it has a allen grub screw. Once removed the adapter is screwed on, 14ccw. So adding a suppressor is possible but the outer barrel threaded adapter ID is not big enough for a extended Barrel to pass through with out machining it larger.
Scope rail is very solid and my scope was easy to line up true to the barrel.
Overall I'm very happy with it