TNT Airsoft APS-X Hop-Up System KWA LM4 Gas Blowback Rifle Retrofit Kit (Length: 370mm)

"I bought this a while back and i just have to say..... WOW!!! Just wow!!! Performance is out of this world !! I had to trim the nub (that adjust the hop up) so that i could shoot .28 and after trimming, it shoots perfect. I was also able to chrono with .40 bbs and it was shooting at 335 fps so... I think it also upgraded the fps on my gun as well!! So... overall id say, get this upgrade sooner then later because its just that good!!!

"Best upgrade for the lm4 hands down. Just get it.

"I got one of these for my LM4-C after the stock hop failed after several years. The new unit is relatively easy to install and works very well. I thought that the stock gun shot very well and was accurate, but this upgraded unit leaves the stock hop very far behind. Accuracy and consistency are excellent, beyond what I expected. I would recommend anyone who has an LM4 based system to make this upgrade sooner rather than later as the performance is unreal.

"Bought the 370mm kit for my PTS MASADA GBB. Easy install, practically replaces the original as if it was OEM. Green Gas range averaged over 450fps, and using co2 450fps mags it averaged closer to 500fps. I use the Masada for target practice at ranges varying from 25 - 35 yards with 6mm steel ball bearings, the tight bore helps prevent even these heavy rounds from just sliding out of the barrel. Would totally recommend it for small game hunting and target practice, for PVP, you might be fps restricted in some places.

"This is a good upgrade to a limited system. I would like to say though this is not without some minor flaws one being the nub. I noticed this really only likes to hop bbs .32 and higher so I had to make a nub to remedy the issue. It’s a file on cultz that can be printed for free. After this I realized I didn’t account for joule creep so I got a barrel to match the length of the outer barrel instead of buying a shorter one. If you only play indoors with a .25 bb weight limit then matching your outer barrel is feasible. If you are planning on using it outside then plan on buying a restrictive rocket valve or buy a shorter barrel to alleviate joule creep. I’d shoot 390fps with .25s but around 470fps with .32s making this a problem. All in all this is a good solution if you are willing to pay for it but by no means is it exactly a drop in solution if you plan to use it in a multitude of game arenas.

"On the PTS Masada it gave me the double feeding issue commonly seen on the LM4 line of gas blowbacks. Before the upgrade the replica ran without any issue. After reinstalling the older Hop Up it worked perfectly.