VFC Airsoft GBB M733 & Mk18 Mod 1 Review: Infinite Possibilities

[@ExplosiveEnterprises]

As usual, we have a few notes that came up after filming: -After editing, we removed the forward assist to swap it out, only to discover it’s entirely fake. It has no hook to interact with the bolt carrier, and the design is different enough that it cannot be made to work. A real forward assist is drop-in and does function as it should, turning minor malfunctions into major ones at the press of a button. -We forgot to mention that VFC HK416 magazines are known to have issues with sealing. Stick to Gary or the new T91 magazines. -The new Unicorn GBB bucking, 60D, has comparable accuracy to the W-Hold but better consistency in amount of hop applied, and is easier to fit in the VFC hop unit. -A few of the ARs, like the HK416, have a separate pin to secure the hop arm which can wobble and degrade accuracy. Replacing the pin with a 8mm x 2mm roll pin (it will take some force to install it into the hop arm) fixes this. We’ll update this comment with any further developments or clarifications.

[@Pick4Green]

Nice video. I don't think I've seen it, but "One piece outer barrel" don't work with the specific VFC guide hop, you should buy GHK 2022 hop unit to adapt with it if I remember correctly

[@oranda2000]

@@Pick4Green Indeed

[@macgriggs9350]

I would bet money that the reason the forward assist isn't funtional is bc they know people are going to break their nozzles by pushing it during a malfunction. So they disconnected it. VFC knows us gorillas all too well 😂

[@jasonli3638]

Question re: Unicorn bucking - is this their competition-grade or precision-grade bucking?

[@AntonChou]

@@jasonli3638 Both will work and it's probably the only bucking I'll use on VFC.

[@regimes]

I cannot stress enough how pleased I am to have found a channel as autistically inclined towards details regarding real steel vs airsoft. Thank you for everything

[@AleksWorkshop]

Heart sunk when you tested the surface finish

[@calvino5381]

Yooo it’s him

[@simplyheck]

I'm already getting attacked 30 seconds into a 52 minute video

[@kamonbrown_]

😂😂

[@Brickface999]

gotta appreciate XE's dedicartion to the minute details that, like, 5 people care about.

[@TheLuftwaffe1940]

And I’m one of them.

[@yosyp5905]

@@TheLuftwaffe1940 I'm the second!

[@sappygoober]

third

[@aguy5225]

fourth

[@ErickBee]

Shiet, I think the 5th dude is late. Anyone seen him?

[@ccreamy7321]

babe wake up, new XE long review just dropped

[@BadaBingPictures]

Amazing work, gents! Came for the GBBR’s and left with interesting AR history that rivals Small Arm Solutions.

[@Auloss]

1:46 BRAZIL MENTIONED

[@pyroromancer]

The TM M733 AEG that debuted just after the G36C so many years ago was my 2nd airsoft replica. it's got a special place in my heart.

[@AnvilAirsoftTV]

Thanks for this comprehensive review. I’ve got an M16 on the way for review (reference books at the ready). I’ll send people your way for the internal parts review.

[@Geoffvader]

Great video - My M733 had some funky issues out of the box which I'll post here for anyone interested: 1) the nozzle would push loaded bb's beyond the hop contact patch while firing, resulting in inconsistent hop and bb's rolling out of the barrel. This was rectified by concaving the nozzle outlet significantly using a deburring tool and sandpaper. 2) As shown in the video, my bolt carrier cracked too. Although it was after two games which was disappointing... 3) It only likes to use 70D hop buckings, any softer and bb's will get jammed below the bucking upon loading, followed by the bucking lips folding and subsequently tearing.

[@its_my_purpose_gaming8928]

mine has crushed bbs into the lower and disabled the trigger twice now when I tried to fire auto... and yes if I don't have a ton of hop on bbs roll out or shoot at like 150fps

[@Jrob992]

VFC won my heart with the GBB saw. Most fun airsoft gun I’ve fielded so far.

[@LordJameh]

This video was very informative, and useful in a way to me that it probably won't be for anyone else I was having issues with my VFC Scar H magazine leaking, and I've been waiting for a proper valve key to arrive. Seeing your takedown of the magazine for this gun, it looked very similar, so I went to take apart my mag to see how similar it is. In doing so, I discovered that the internal o-ring on the knocker valve had moved, and that's what was causing the leak. So I adjusted it from the bottom of the magazine, as it doesn't quite come apart in the same way, and bang, problem fixed. Thank you for giving me the courage to understand the gun I have, and thank you for the amazing very in-depth content 👍

[@8od493]

I got a mk18 recently and have had trouble finding any good video information on it. So glad you posted this. Love your videos man, such great stuff

[@jorritb02]

Is it worth the money?

[@8od493]

@jorritb02 yeah I'd say so. You will definitely want to invest in a new barrel/bucking pair though. + a custom hop arm for regular nubs is a good idea. Other than that it's good to go

[@thisisbadstuff]

The offset nozzle has been that way since WA and carried over to basically every WA derived platform, be it VFC, GHK, or Vipertech. It's mainly there to account for the dust cover latch clearance indention on the right side of the carrier.

[@maximilianglaus9811]

I was laughing so hard about the removing of the hand-guards. It's fun seeing my own experiences reflected in your review. Reminder I still want to tip you guys directly. Please open a tip jar or what ever. :)

[@kanewilson3591]

This is the big fat juicy long form XE review I've been waiting for, especially since I'm considering options for a new GBBR and I was already heavily leaning towards a VFC V3 AR platform I will never stop watching and reccomending the videos on this channel, whether they're 2 minutes long or 2 hours long Would be nice to see a video introducing us to the rest of the XE crew, and maybe a short list of the best / worst GBB guns they've all owned / used As always thanks for filling the void in the GBB youtube content, you provide something that nobody else does, and that the whole community craves Keep up the good work, and godspeed 🤙🏼

[@mppewpew]

I want to thank EE as I dropped my phone in water a few days ago and i have been using this video as a way of measuring how my speaker sounds. Good video too

[@tastyfish1032]

Awesome! Possibly the best in depth VFC GBBR review I’ve seen. Thank you!

[@clannkymcgigers5275]

Now i am not looking to buy ethier of these replicas but I love learnng about different replicas. And this is by far the best review on some airsoft products I have ever seen. Was long but was need for the info but did not feel like 52 minutes. Loved your knowledge of the real rifles. The detail you went into with the externals as well as the internals with cheap fixes as well as other parts you could buy to improve performace was amazing. With the whole price match up at the end was amazing and shows that you have done an extensive ammount of research for this video. Just an outstanding video well done keep up this amazing content and you have got a sub and a like from me sir 👍👍

[@johannesbjerkejannesson428]

again with absolute bangers of videos. Really great man!

[@macgriggs9350]

I have the XM177e2 (which barring some minor external differences like no brass deflector and a teardrop forward assist is identical to the 733) and i can say my experience with it is consistent with your review. I keep it well maintained as per your GBB mainenance video. It is my most consistant rifle especially compared to my previous experience with KWA and GBB pistols. The thing just works. I will have to try that buffer swap as that seems like a game changer as well as your advice on the hop up and barrel. I you didnt mention it but locktite on the carry handle rail screw is also a must as the thing will come loose under recoil or gameplay. The ones on amazon can be hit or miss and I've been through a few but the best one has the name of "Toopmount". Just remember to get it very tight and use some locktite too and your good to go. The electrical tape idea isn't bad either. Another great review from XE

[@foxgamer1793]

It would be really funny if the redacted sponsor is GHK after your review on the GHK ak lol.

[@sogerc1]

Explosive Enterprises and other nerds: the dust cover spring has a weird inward bend Me: Oh look it has a fixed carry handle, close enough

[@joejoeseesingtons]

Good Stuff boys keep em coming

[@azzamat001]

Just picked up my lastest boomer musket (the 733)

[@mareklesniak8768]

VFC V3 URGI 10.3" version also has steel barrel (same design, with aluminium add-on and that new hop-up adjustment). Although those steel components are not that bad, they are noticeably worse compared even to cheap real steel mil-spec components so I suggest to swap them out. Trigger especially, because it doesn't have polished sear surface, so its operation is far from being smooth. The hammer has to remain from VFC because the real one differs in some key areas and it won't work correctly. Also, keep the original auto-sear as real steel mil-spec, although it fits, it's upper tab is a tad too long and will break after several shots, probably from hitting the BCG where it shouldn't (yeah, guess how I know that...). Auto-sear pin also has to remain original from VFC as the hole is on the smaller side of mil-spec so real steel won't fit. Real steel mil-spec mag catch spring won't fit, because the V3 valve knocker assembly has smaller hole for that spring, which is a bummer as the original from VFC is softer compared to real mil-spec and I think V2 valve knocker design can take real steel mil-spec mag catch spring with no issues. Mag catch tab and button both fit and work fine, though the button sticks out a bit more (VFC's is thinner). Real steel mil-spec bolt catch won't work at all due to ASG's fundamental design differences vs real rifle, but the spring also won't work (too long compared to VFC's). Overall, VFC might be done relatively well compared to other ASG but in absolute terms, their steel parts are made of low-ish quality (not bad but not decent either). EDIT: I suggest steel bolt carrier from Z-Parts. Based on some other reviews on YT, it appears to be of a better quality than the one from Crusaider.

[@DragonNectar]

when is dad coming back then? My gun is all set up

[@PatrickBergensen-kali-yuga2005]

Love VFC

[@yukiiwao5967]

I always look forward to you uploads and have been a massive help for gas replicas. The thorough videos are extremely helpful.

[@eratno111]

I hope you get to do a video when the WE V3 comes out.

[@peter11256]

So, VFC's ARs are light, pretty, really close to the real thing in terms of compatibility, have good recoil and operation feeling, and are priced very competitive. At what cost ? They shoot like crap and some parts break prematurely sometimes. Tbh, that was exactly my sentiment as an owner. Awesome in-depth review as always, very entertaining as well. Congrats, pops!

[@opairsoft8100]

Lmao at the shot like crap and some parts break.

[@DragonNectar]

My BCM with a unicorn barrel is a laser

[@TehPh1L]

Really appreciate the lengthy in-depth video!

[@stewbacca117]

The M733 was one of the most fun guns I've run and I kind of want one of my own, although my teammate's has also been chewing through BCGs. The guide hop is a great idea - I just wish they'd made the gas adjuster on the FAL drive a similar system... because that would be swish. No need for the faux piston, just more utility.

[@Gallacherboy]

The M733 is a retro beast, always wanted one. Surprised at how it kicks and rattles during full auto - this would be a cool platform for a Blood Diamond build, I am South African myself 😅

[@merlinhopkins1089]

I did not know about that hammer screw thing. Will keep that in mind when it gets cold again.

[@jackt9937]

New vid dropped lets gooooo

[@Zejected]

Good video. Can't wait to try the 416 in the winter with the adjustment screw

[@WolfMan-nf4lv]

Thanks as always for the in depth video! The information brought forward is much appreciated, including the info on the real thing 🙏 After watching this, I worry about some of the quirks of this system (mostly the hopup), but overall, I still think I’m gonna end up getting a V3 AR cause of the all around decent performance/realism/design. I might think on it a little longer though

[@icolater27]

Great review as usual. Looking forward to the ghk v3 review to compare.

[@Lt.Chris909]

amazing work as always bud, love these videos

[@msgtvarela]

Hk53 review next….

[@ABSTRACT278]

LETS GOOOO, HE IS BACK

[@PDyl-an]

NO WAY 😭😭 thats my watermark on the spongebob meme, i posted that pic on tt like 6 months ago too lol

[@kriegsmarinekonigstiger4038]

Babe wake up new explosive enterprise video dropped

[@johannesbjerkejannesson428]

keep em coming, we addore these! How did u guys get so good? How long in the gbbr game?

[@kotwikotwi]

35:50 I've tried the real carbine buffer on both 733 and flat top sr16. It works perfectly on 733 or any carry handle models but remains about 5mm bolt bounce on flat top models. I highly recommend you try the metal camber if you can find them. It significantly reduce bolt bounce.

[@AntonChou]

On current V3 version ARs there are a few things people complain about: 1. 2-piece alloy barrel, even the steel version VFC makes has a alloy base. Breaks if the muzzle slams on something hard. Aftermarket one piece steel ones like Z-part is the usually go-to for upgrade. But it's not compatible with guide hop. 2. Horrible buffer design. Not only it does not look authentic, causing unnecessary stress on buffer tube, does not do what it's supposed to do(eliminate bolt bounce), it also tends to unscrew itself after some use. PITA if it disassemble itself inside the buffer tube. 3. Guide hop design, good in theory but often disappointing in execution. On most ARs it tends to walk itself loose resulting poor hop performance. On HK416s it's even worse due to the long flimsy plastic connector arm design. Only on MCX and MPX it's tight enough to stay in place under recoil, but poor hop arm design so the overall hop performance is still bad. Common practice is to replace the outer barrel and hop chamber altogether to fix both issue at once. In my experience GHK mod is not optimal due to the plastic construction and flimsy plastic hop arm, not ideal to lift BBa heavier than 0.36g. And it's not easy to center contact patch nor it's a drop in fit. Aplus ones and TNT ones both use proprietary bucking design so if you can't get replacement bucking it's a no-go. Also TNT's chamber is dimensionally incorrect, so the whole inner barrel assembly can slide forward and backward. Maple Leaf 's new chamber and unicorn bucking is the one I recommend if you want to go this way. Or buy ESD's ER-15 and use whatever bucking and barrel you like to unlock VFC platform's full potential.

[@AntonChou]

Two minor things I forget to mention: 1. Strange for you to call VFC's buffer spring weak. Maybe it's not as strong as VT but definitely stronger than something like WE , AMG or RA, not to mention GHK's puny ones. 2. Alloy trigger tends to bind up after some use, causing failure to reset similar to MWS one's. A quick filing or upgrading to steel ones should fix the issue.

[@fjjwfp7819]

Newer guns now come with steel chamber pieces like the 733 in this video, can be seen by the parkerized finish. The mk18 on the other hand is evidently a older sample with the powder coated alloy chamber still.

[@AntonChou]

@@fjjwfp7819 Good thing it will not shear off like the older alloyed ones, bad thing it's still a friction fit held together by two screws that needs to be checked periodically.

[@opairsoft8100]

416a5’s guide hop doesn’t undo itself from recoil Heck even the 417 doesn’t undo itself under recoil and that has close to twice the recoil of their m4’s

[@fjjwfp7819]

​@AntonChou people with steel barrel bases have reported no barrel wobble, likely due to better tolerances, and since it's now steel, the screws are usually torqued much tighter now and threadlocked so it's basically never going to loosen. In fact people have reported it to be the same difficulty to remove like the gas key screws even with heat.

[@aaron4820]

Turns out my dNa M16A1 carbine also has the adjustable hammer thing! Did not know this!

[@jackanderson3940]

I really like the 3 VFC gbbrs I own, it’s annoying how you have to play the customs game in the US, and even that that doesn’t 100% ensure it’ll go through, but it’s well worth it. They are like Honda civics. Affordable, decent build, okay stock, but the the ability to easily personalize is the best part.

[@rfirtfan2809]

I see that video that shows up in the google images :)

[@TehSnake586]

Exellent review

[@cmdrlt.evildead5328]

Dam I’m just getting into GBBR’s and bought a TM CQBR Bkock1 would love to see a breakdown video like this on that and other TM’s

[@Cloudy42787]

Where can I buy the MK18?

[@Holanduzo]

39:42 what inner barrel you installed? thanks in advance.

[@62341]

ackualy if you have nods red dots on the carryhandle is perfect cowitness.

[@IM2BASED4THISPLACE]

I was impressed with how fast you talk but then I realized I have it set on 1.5x play speed

[@ArmandD]

I would love to see a video all about the M14, as it's a platform full of potential

[@cillblinton8181]

Would be interesting for sure. We m14 is riddled with design flaws so i wonder how XE would fix them

[@hfa762g]

hell yeah!

[@Jerv165]

Interesting how you added golden eagle as an "option". If you modify a GE to run VFC mags, wouldn't eliminate the magazine issue? Wanna know more about your thoughts on how GE and other WA clones as well. Very interesting

[@VIIStardust]

I'm definitely in the father less group... love a modern look :3

[@jaylink7865]

Dude I just bought a 416a5, is the bolt lock reliable this time around? Or is it still bullshit… I know it’s not a model you covered here, but I get ALL my gbb info from you. So if you happen to read this and know, I’d appreciate any feedback. Thanks man. Oh, great video as usual.

[@ExplosiveEnterprises]

Hey there- we don't have any direct experience with the 416, but coincidentally Bada Bing just released a video on it that you might want to check out.

[@oranda2000]

Bolt lock works fine with STANAG type mags. VMAG and HK mags suck though. You might need to put a bit of heatshrink on the bolt catch lever or bend it a bit if it still doesn't work but most of the time, that's a mag issue, not a gun one.

[@milantrenovszki2628]

@@oranda2000 Works with V3 VMAGs out of the box. After a while, the ambidextrous bolt catch might get sticky, and wouldn't go all the way up, disassemble, clean, lube (and file if necessary, check lower for wear where it might rub against it).

[@mandrakevermilyea7488]

Be me. Real AR15. Built as a duty rifle. Anderson lower, bushmaster flat top upper. Retro car 15 stock, 6 Pos buffer tube. Retro skinny handguard with cut A2 grip as a fore grip. Aimpoint pro and holosun magnifier. Long fin 3 prong flashhider and 16in barrel. Blooddiamomd/BHD paint job.

[@boostav]

I see the DnA review is coming ;)

[@NeoMartel]

What about bolt catch pins and spring?

[@Nick-hm9rh]

I know this is an annoying question but where would you say does the VFC mk18 stand in terms of quality in comparison to other brands? I just want a good, realistic and durable base to build an ar15 with for playing every now and then. Unsure if i should grab this or a TM MWS.

[@devonadair1852]

jokes on you i gave up on dad coming back years ago

[@EthanL2023]

Thanks for the review! Based on your conclusions towards the end of the video it seemed like you were saying the VFC GBB system is the best all around GBB AR option as long as you are willing to trouble shoot + tinker. Is that right? Would you say people who prioritize out of the box performance (but are willing to lightly tinker) should go for an MWS clone or would you say VFC is the best mid-tier option?

[@opairsoft8100]

They are about the same, just comes down to what you want more, realism or a little less realism

[@jcreati0ns]

Finally some confirmation that the hop unit has issues. Was struggling alot with consistency in my BCM. Did you try to mod the hop arm by grinding it a little and glue a piece of rubber as nub on the contact point?

[@christophergoking]

My bcm mcmr shoots like a confetti gun.

[@jcreati0ns]

@@christophergoking I had the same issues. Tried the T&T unit and some other ML buckings. Nothing helped. I now have a new inner, stock hop unit with modded arm and a pdi w hold. So far this has been the best combination for me. But compared to my buddy with Mws, it's still awful.

[@christophergoking]

Well honestly youtube warned us about the VFC BCM MCMR vs the TM equivalent. Sadly vfc seems to be out performed by WE and other less heard of brands. My vfc g19x shoots better than ny vfc bcm mcmr but my clubmates WE pitviper shoots I would say 60-80% better than my vfc Im keeping my g19x but idk what to do with my bcm cuz its no good at games

[@christophergoking]

@@jcreati0ns found out I was given a V2 not the V3 of the bcm mcmr 11.5 But eventually I fixed the accuracy issue with a 300mm 6.01 inner barrel and a 70D silicone hop up rubber. I added an NPAS to shoot .40g and is ended up doing very well. Unfortunately I traded it in for a 14.5 v3 Negative note: The mag parts like the rubber orings and everything rubber makes me second thought owning a gbbr because its too much of a headache to have to maintain all these magazines and always have to deal with bloated and shrunken rubber parts without any supply of spares in the country. If I had an option to have it shopped every so often, Id like the platform, its very fun.

[@jimmybutler5683]

What is the difference between VFC V2 and V3 system

[@baconbrain]

I was going to buy the vfc sr16 but the double eagle emg mws clone was so much cheaper. The realism of vfc is great but my wallet comes first ;_;

[@christophergoking]

Can you review the vfc bcm mcmr 11.5 gbbr v3

[@opairsoft8100]

It’s literally the same as the mk18 just with different externals…

[@desertstriker8]

Sucks seems no shops i trust overseas have them in stock :( Would kill for a VFC M733

[@josephxiong6476]

How do the receiver materials compare to a 7075-T6 receiver? Do you think the VFC receivers are able to take a beating? I somewhat have a concern about receivers cracking or bending buffer tubes if I accidentally drop my gun or bang it a little too hard.

[@Jakkudama]

Great vid. Would you consider doing one on the UMP gbb in the future?

[@ittipatp1653]

I dont think the matte black on every vfc receiver is anodized since I can wipe it with thinner.

[@callsignvalkyrie]

Where my shade as an AK runner?

[@jakovmx1856]

Hi, does your MK18 holds hop consistent? I have a problem with mine, after certain number of shots it seem to loosen up and start to over or underhop.

[@MK384]

any recommendations for retailers that sell VFC GBBR's?>

[@ArenBerberian]

Thanks for this. Will you be reviewing their new XM16E1 and M16A1s as well? Just bought the XM as my first propper GBBR.

[@ExplosiveEnterprises]

We actually just got our hands on an M16A1, and may do a shorter review to cover some of the ways it differs from these examples and show how it compares to an original Colt rifle. No promises on when that will be, though- we've already got a lot in store for you guys.

[@ArenBerberian]

@@ExplosiveEnterprises Great! Watching your vids is what convinced me to try a GBBR, so look forward to seeing how I get on with it.

[@baytisoy8888]

Need tips on how to fix the rear reciever pin coming loose after a some firing

[@maclainherbers6373]

What are the differences between DNA and Vipertech’s guns? Which one is better?

[@carlsonvicta699]

The new vfc m16a1 next pls

[@RazorNLD]

I have a question about the hopup and innerbarrel. For my sites .30, are the max for outside play and .25 for inside. I've heard that T.N.T. systems are good, but from .36 and higher. Is this true or can I still use a T.N.T. retro kitt for my M733? + can I use a crazy jet 6.04 with the T.N.T. retro kit or isn't this recommended?

[@CptnKnuckles492]

The best platform is the one you actually train and become proficient with

[@opairsoft8100]

Lmao at the training part

[@depressedtuna7455]

What inner barrel did you use to increase the performance for the m733 Also nice video man.

[@maclainherbers6373]

I have a Marushin M1 Garand 8mm that I am willing to lend for content (like for an M1 video :D)

[@Nishye501]

I’m probably the first one I’ve spent 1000+ dollars on nerf in the past year (on four blasters)

[@hayman1222]

Will you guys ever do a review of the modify pp2k?

[@user-bg8dr6by6m]

nice

[@mountainadventures7346]

I just found DNA GBBRs. They are expensive like a Vipertech but I understand they use VFC mags? What do you guys know about them? Awesome video! Thank you!

[@opairsoft8100]

Watch the video

[@mountainadventures7346]

@@opairsoft8100 I did watch the video.

[@jonasstribrny1263]

hi I just want to ask a qestion. I want ti run an gbbr and i want to go for the propane but I live in czech rbublic and here are sold only propane/butane tanks can i use it in an gbbr? oh and also great video!

[@MK384]

where do you buy your VFC GBBR's?

[@opairsoft8100]

Overseas retailers

[@Gallacherboy]

If you wear those Aviators with a collared shirt and AR in hand - my first question is - Are you LaCIA?

[@Syvern.]

Will you be making a video on the E&L QBZ-191 that just came out?

[@larshenrik8900]

Can you do a review of the VFC hk416D?

[@Zynophage]

You gotta check out the gasblowback P90. I heard it gets abit too hot and i want to know how to reduce the fps and joules in it

[@opairsoft8100]

Same as any other gas gun, npas/shim rocket valve and or shorter barrel

[@Fede_uyz]

What do yall think of the EMG gbbr guns? Im looking into the EMG mk18

[@jokeygjhin9431]

22p19s , my bolt carrrier crack too :V

[@Fernando-ry5qt]

How the heck does that system ensures the gas output is consistently pushing the bolt back? I am just too used to see valve locks that this is melting my brain.... Do you have a technical explaination?

[@opairsoft8100]

There is enough gas throughput that allows the bolt to fully cycle even after the hammer and thus valve knocker to reset

[@Fernando-ry5qt]

@@opairsoft8100 that sounds troublesome if the gas pressure falls due to climate.... wonder how the heck that system is more efficient than a WE or Magna if they have no way to control the gas output..... damn engineers are brilliant...

[@peter11256]

@@Fernando-ry5qt how do you control the gas output on the WE ? Genuinely asking.

[@Fernando-ry5qt]

​@@peter11256 When you pull the trigger, the valve knocker opens the mag reservoir and the "valve lock" which is a small piece in the trigger box, locks the valve knocker in place, forcing the mag to stay open until the Bolt gets to a particular position, at that moment the lock sets the knocker free and the valve finally shuts close. the idea behind it is that if it takes more pressure to move the bolt, more gas is liberated, if the gas evaporates fast enough to move the bolt fast, then it closes faster.

[@Fernando-ry5qt]

The trigger box has a small piece called valve lock, which locks the magazine reservoir open until the bolt reaches a particular position, this helps the bolt move even at low pressure in theory@@peter11256