Lonex Compression Upgrade Set w/ POM Type Piston Head for Airsoft AEG Rifles (Model: MP5-K)

"The head is very tight to fit, seemed to help by leaving it in the freezer for 20 minutes.

I haven’t got to the chrono yet

The build is a cm68d
All stock except the following

R nub
Prommy bucking
Zci 6.02 barrel
Lonex cylinder kit
M110 spring

I used white lithium grease in the cylinder cylinder, as well as for assembling.

Gun shoots great with .25 or .28 but I haven’t gotten to the chrono with .20 see what my “official” fps is

It shot 380/ .20 for the first skirmish before upgrading. then by the end of the day I was loosing velocity and getting terrible action. Which is what led me to do these upgrades.

It’s a great kit and I also dig the rest of the set up too. And depending on chrono I may choose a m113 or m115

"in 1 year I have purchased 2 of these kits, one for my Krytac P90 and one for my Umarex Mp5A5 with Avalon gearbox, these are my experiences:

For the Krytac P90, the corresponding kit fits and works like a charm, despite the P90 being a really solid replica from Krytac, the only issue is the air sealing that came with my replica, so tried this kit in it and it fixed it without any missfit issue and really helped out to get the best this amazig replica can offer!

And for the Umarex Mp5A5, don't use the corresponding kit in that particular replica, the tolerances are really different, only the cylinder was ussable. Is not the kit's fault since I just purchaed it thinking that the replica probably came with air sealing issues like most of the replicas, but shame on me, the air sealing in the Avalon gearbox is top noch, no leaking of any kind, the air nozzle came with a O-ring and the cylinder head is all metal with a excellent O-ring, so no need for this kit, aside that the messurements are totally different, so when I chage the stock pieces to this kit the air nozzle simply didn't feed since is more larger than the stock one as well as the cylinder head, so I went back to the stock one and all fixed.

Thanks for reading and I hope this helps!

"I used this kit (G3 SAS) with my ICS CXP15 with a 208mm barrel. Wormed fantastic, let me drop the spring down to an M90 while maintaining the same fps and range and my box will last 3x as long now. Great combo.

"Picked up the 'M16A2' version of this compression set for an SPR build. Very well made as one would expect from Lonex, and best compression I've EVER had from cylinder/piston combo. The cylinder head is indeed very hard to install; I used lithium grease and a bench vise to very carefully press it into the cylinder. POM piston head is well made with a threaded metal center pin/nut for the fastening screw that holds it to the piston, instead of threading into the soft POM of the piston head. The included nozzle with mine is red aluminum with a double o-ring, and is 21.5mm long, may actually be too long for some hopup chambers; I'll know when I try it in the Maxx Hopup that I'm waiting for. Compression is absolutely perfect, even with nozzle pulled out into firing position. Due to the amazing compression and crazy tight fit of the cylinder head, I think these cylinders actually have a slightly smaller inner diameter. Happy with it, would buy again.

"This is a great set. All the parts are made incredibly well and work perfectly with one another. The price isn’t too bad either, considering the quality that you’re getting. One thing to note, the fit between the cylinder and cylinder head is TIGHT. Like, so tight to the point I had to remove an o-ring from the cylinder head to get it to fit in the cylinder properly. Even then I was still getting perfect compression! Lonex compression parts are some of the best on the market, and this kit is no exception.

"Two Thumbs Up. You get more than you pay for.

"This cylinder set is great. I honestly use it in all my build. I have been hearing about people complaining about the tight fit with the cylinder and the cylinder head. I'm not saying people aren't the smartest but its a double o-ring cylinder head. It is meant to be tight so you can get the best air compression.

"Great set for lct ak’s. The cylinder head holes were a tight fit into the gearbox halves but they do fit. Everything else fit perfectly.

"BEST COMPRESSION KIT ON THE MARKET. I have purchased several of these kits before for customer builds and every single time they have allowed for flawless compression and show no signs of failing. First off, the cylinder head. This piece has 2 O-rings and is finely CNC'd, fits perfectly with the o-ring nozzle. Getting the cylinder head into the cylinder is rather hard, but i would rather deal with a much tighter fit to maximize air pressure. The piston head is my go-to, and when paired with an SHS piston gives the most bulletproof compression setup.

PROS:
Great machining
super tight air seal
o-ring nozzle
kit comes in all manner of different gearbox versions

CONS:
honestly no complaints

Get this kit, you wont regret it.

"Pros: Perfect Airseal with all these parts in use, solid construction, bearing on the Piston head. Make sure to add grease on all o rings and inside the cylinder.

Cons: my cylinder came sticky......Evike?

"I have sets of their AK style and M4. The head is a freaking pain to get into the cylinder but it means that it’s a perfect air seal there.
The POM (and the o-ring that comes with it) also create a perfect air seal.
I know the other reviewer mentioned not having an aluminum nozzle, but I’d say it’s better to have plastic. However, I’m also not running high-stress DMR builds. The plastic has been great for my high ROF 350fps setups and my 400fps setups.

"Only working on a few guns and upgrading them this is by far the best cylinder set that I have used. I used this set in a krytac spr mk2 with the lonex red m179 piston and achieved an impeccable air seal. Using an m120 I get around 470fps. This set is quit compared to others I’ve used and shows minimal ware after a few months of playing. All in all I strongly recommend this.

"Works great in my classic army p90

"To start, the cylinder head does not fit, at least for the one I received. Just as the review above says, no matter what you try and/or do to make the cylinder head fit into the cylinder, it won't go. Not a deal-breaker tho. I still get a great air seal using my stock G&G ARP9 cylinder head with the rest of the set. Not as much seal as I'd like, but still very manageable and a noticeable increase in air seal and performance. Overall has great construction/build to the whole set...of course besides the fitment of the cylinder head. Other than that, no complaints. Happy with my purchase regardless. If you do happen to get a properly fitted cylinder head, man are you in for a good time and a great air seal for your airsoft gun.

(This is my honest opinion and review considering I have bought many items from a reputable brand such as Lonex. In this case, I more than likely just received a faulty one: Therefore, 4/5 rating)

"While this product seems like good quality, there's a huge issues. The cylinder head is to large in diameter to fit in the cylinder without a lot of force. I'm sure once you get it on there it seals really well, but it's a bit ridiculous. I would heavily recommend buying each part separately.