MBAR Update #2

[@Mike-B-Jackson]

16:02 - Not really sure I agree that the ACR failed because of "barrel assembly kits." The ACR took standard AR15 barrels, the only difference was a relief cut for the piston support. You would need to transfer over the piston, gas block, and nut assembly of course. I think the real reason it failed was mainly the cost, and to some degree the lack of aftermarket support. Replacement hand guards etc didn't really pick up speed until it was on its death bed. Anyway, I like the design here. It reminds me of what DesertTech was trying to do, hopefully successfully (THEY failed because they were just horribly unreliable. lol). I really like the witness hole for checking/clearing the chamber - something a lot of bullpups seem to overlook.

[@who-isjohngalt]

Never knew the ACR used AR barrels, I always heard people complaining about not being able to get a specific barrel or something, and when I watched the barrel change videos I figured it was proprietary. Anyways I won't be charging a royalty for anyone who wants to make accessories, to help the aftermarket to grow. I will be releasing the specs for all of those to encourage those who are interested. Should avoid the problems the ACR had there. I think the desert tech bullpup has a lot more problems than just QC, I think the design was flawed to begin with. I really like their bolt actions, so I had high hopes for the semi auto, which didn't materialize.

[@diet_dr.demoncore]

this is BASED

[@DrWolfensteinz]

The more you show about the MBAR, the more and more excited I get for the design. The chamber checking capability is fantastic and surprisingly simple. Are there any design considerations for OOBs and other catastrophic incidences with the gun? It's a common complaint from people that don't like bullpups that they are worried about the gun detonating right under their face. I know the Kel-tecs all have a steel cheekpiece to help redirect everything, just in case.

[@who-isjohngalt]

The MBAR magazine/chamber is much further forward than a traditional bullpup due the downward ejection, as a result, a steel cheek piece wouldn't really do much because the detonation would not occur under there. The steel charging handle is what would block it. Like most other modern firearms there are a lot of safety features that I've added to prevent the rifle from accidentally firing. I'm not sure if Kel-tecs have polymer upper receivers, but the MBAR is made out of aluminum. I think a catastrophic malfunction would be dangerous on any rifle if the user isn't wearing proper PPE. I can't say for sure if my design can completely eliminate the risk, but I can say it won't be any worse than any existing design. The next video will go in depth on the fire control and safety system, if you've been impressed so far I have much more to show.

[@DrWolfensteinz]

@@who-isjohngalt I appreciate the response, and I personally had no real concern, just something that I recalled from prior discussions with others and wanted to see what you had to say about it. I'll certainly be waiting to see more of the project, been stumbling around trying to find a .308 bullpup that hits the right parts of my brain, and the MBAR certainly appears to be just that.

[@Goldberglimited3377]

Instead of the smaller screws for the handguard, maybe consider adding a channel in/ under the barrel nut/block for one long screw like the HK or geissles do. Another idea would be to add the appropriate hex key or allen tool and stow in in the grip or stock.

[@Goldberglimited3377]

Another idea would be to add small designs, indexes that line up when the upper and lower are snapped and pulled back into the correct position.

[@joshmckinney3254]

Really impressed with what the work you have done so far, particularly the attention to detail with the the malfunction view port. I would however be concerned about the edge case of an over-pressure event. It's incredibly rare but it does happen, and if it were to happen with this platform, I suspect it would be fatal. It's just VERY close to the users face and that little plate on the charging handle likely wouldn't provide near enough protection, and that's ignoring all the various gaps around it required to let it slide open and closed properly. I don't want to imply that you shouldn't design it with the functionality you've shown (I really do think it is a great solution to the problem of jams), but I would urge you to do a lot of over-pressure testing if you intend for this to ever be a publicly available product. If I'm not mistaken, DT put blow-out panels on their MDR/WLVRN line for that very reason, and theirs lacks the same kind of view port. Might be worth looking in to.

[@who-isjohngalt]

I will bring this up with some other engineers and see what they think. I don't have access to finite element software, but they do, so they can do a simulation of this situation. I'm not going to destroy the only rifle I have to test this lol.

[@mig1nc]

I'm only fourteen minutes in and need to run to a meeting, but for a military application, you really want all those screws and pins to be captured. Soldiers lose screws and pins all the time if they aren't captured. Also, if possible, you seem to have enough room to give the magazine well some more flare to speed up and simplify loading. Other than that, this is amazing work. I especially love the chamber check feature.

[@who-isjohngalt]

For the takedown pin it should be captive for sure, I just made it simple for the prototype, as this is needed for field stripping. For the screws that is hard make captive and I don't forsee anyone doing a handguard/barrel change out in the field, that's more of something you do in the armory.

[@mig1nc]

@@who-isjohngalt I would definitely buy one. I hope you find a good manufacturer to license the design.

[@who-isjohngalt]

@@mig1nc I'm already working with several manufacturers.

[@mig1nc]

@@who-isjohngalt That's excellent news. Regarding the screws, what I was envisioning was how the SCAR does the captured screws used in it's barrrel attachment method.

[@or6060]

why not make the bottom plate part of the handguard? additionally, there needs to be a way to remove the gas piston for cleaning that doesn't require you to pull the barrel. the tavor 7 allows you to take the gas piston and oprod out through the front of the gas block, you should probably copy that. a monolithic top rail like the MCX would also be good. that way you could remove the handguard without worrying about your laser zero.

[@who-isjohngalt]

Yes you can remove the piston for cleaning, just like any other piston, I just didn't bother showing it in the video since I figured it was obvious. You just keep twisting it counter clockwise until it comes out through the front. Also I just made a piston myself for the prototype, it's a pretty generic design, I fully expect a company like superlative or adams arms to make a version of their pistons for my design once it becomes popular. The handguard has 4 alignment knobs, the two screws are countersunk heads, so they should hold zero well if you remove it.

[@mig1nc]

Can you put your X handle and other referenced links in the show notes?

[@who-isjohngalt]

john_galt_42069 Can't put the full link here, KZbin seemed to hide my last comment when I tried last time.

[@mig1nc]

@@who-isjohngalt I mean in the description field, not the comments. Sorry I appear to have used the wrong term.

[@hasanmousa4235]

Estimated weight?

[@who-isjohngalt]

6lbs

[@DrWolfensteinz]

​@@who-isjohngalt Is that the weight of the system without a barrel or with? A 6lb .308 rifle with a match oriented barrel in it would be extremely handy and afford a lot of mounting capability without becoming a boat anchor.

[@who-isjohngalt]

@@DrWolfensteinz It's around 6 lbs with a normal 16" barrel, the rifle pictured is about 6.5 lbs with the 18" match barrel I got on there. My scale wasn't super accurate though, I just stood on the scale with the rifle and then without to calculate the difference. It feels much lighter than my ARs.

[@hasanmousa4235]

@@who-isjohngalt Holy cow! Doesn't that make it the lightest bullpup?!

[@who-isjohngalt]

@@hasanmousa4235 possibly but the weight is not a huge concern, because after optics lights and lasers are added the rifle is much heavier

[@ZachBlack-e8i]

Always excited to see updates on this project and can't wait to see a test firing. Some questions did come to mind in the video: 1. With the observation port on top, is this a possible leak point for gas to the face like the x95 top rail? 2. On the barrel block, would beveling around where the feed ramps are cut eliminate a potential hang up point in feeding or could the tips of the round even feed that low? 3. The barrel block/trunnion being secured to the receiver with screws. I just ran into an issue with my MDR where, of the 8 loctited screws securing the trunnion, 6 had become loose. This seems to be a somewhat common occurrence with the design, and those screws weren't meant to be undone when changing calibers. Is there a method to ensure the screws on the MBAR would remain fastened? I really hope to see this project become successful and look forward to future updates.

[@who-isjohngalt]

1. I think it is unlikely, since the NCRH will redirect gas around it. 2. The magazine is placed much higher than you are thinking, the bevel on the barrel block would be below the magazine. 3. I have a radius'd pocket to prevent this from happening. This is also what the B&T APC uses for their barrel mount, which I took inspiration from. Although I haven't test fired this yet, I trust the Swiss.