It could use a little aesthetic help, but if it worked I'd buy it if it looked like that. I am sure the grip area is raised as high to the bore axis as possible, but if he could do anything else to push it higher it would help. I'd prefer keeping the handguard higher to the bore axis vs lowering it to the trigger guard. My RDB handguard does that and I think it's dumb. A smaller melded transition might looks nice though

Any word on if it's going to be an all polymer shell with some steel receiver inserts or something?

I think the barrel QD latch should be replaced with a fat torx bolt.
I would love to see an even longer handguard with a 1.6" ID
Make the fore end mlok and and flush QD cups to each side of the stock and muzzle end of handguard and I think it would rock

Removable handguard means Manticore Arms will have a better handguard for it.

I love the look, honestly.

I do think the handguard ID needs to be able to accommodate Sig, CGS, and Q cans. And Dead Air. So that means the ID needs to be over 1.75. 1.8 will let you have some air between the can and handguard.

I like fat cans, even though I don't think they add a whole lot on mini action calibers (especially 223) I hate fat handguards though. I think I would rather have SD handguards that fit standard ~1.5" 5.56 cans, and run a shorter handguard if I wanted to run a fat can. The modular handguard concept would let people agree to disagree though, which would be super cool

Gosh, it is ugly.  It looks like one of the bullpup kit from Hightower Armory.  Hopefully, the finished product will be more refined.  But I do like its features.  And a DI bullpup is really something.  Not sure if it is well thought out or not.  How does one clean that thing?  Can't wait for a full review once it makes to the market.

Yes, modularity will solve this problem, for sure.

Maybe we could get a carbon fiber company like Lancer or Smoke Composites to make one. Probably not enough to make a profit for Lancer though...

Tagged.

Having owned thembefore, I'm generally not a bull pup fan

That said, I like the AR parts commonality and really like that AR FCG can be used.  A nice trigger on a bull pup would mitigate my chief issue with the design.

figured i'd give my 2 cents on improvement. i always liked how the barret m82a2 was over the shoulder like a rocket launcher. it lets you get the heads up position without ridiculous risers and a chin weld. it also makes the gun shorter. brass won't hit your face because you don't have to lean your head forwards at all. similar to that cheek pistol idea that demonstrated concepts came up with.

Kind of similar to what was just posted on TFB https://www.thefirearmblog.com/blog/2022/04/29/idahoan-show-br-15/

I think with the AR platform though, by going over the shoulder you lose the advantage of inline recoil with the shoulder.

I actually think it would be cool if somebody designed a generic AR-15 bullpup lower that worked with any bufferless upper, like the FM-15, BRN-180, PSA Jackal maybe, etc...

That said, I think Senex Arms is really on the right track.

I'll definitely be a customer.

i think part of the issue is handguards. you'd have to either make a weird looking lower that works with any handguard, or make a handguard + lower combo, with a handguard for every bufferless upper.
i don't really care about inline recoil myself. rather make the gun shorter and more comfortable

Over the shoulder would have the advantage of allowing you to bear more of the weight on your torso. So it does have specific advantages, I grant you that.

If you look at the frame at about 2:59, you can see all the way through it, like there is an ejection port on both sides. Do you think that means it can be changed to a left-side ejection with just a left-side AR bolt?

Hello everyone,

Brandon Makowski, owner of Senex Arms, here. To address a few of the comments here:

1. Yes, this will make it to market. There is no doubt. I've partnered up with some great minds in the industry to help facilitate that. I've given up a lot to make it this far and there is no reason to quit now. We've been making some solid progress and are looking to send our first live rounds down range this Fall.

2. I started this in 2015. In short, I thought the x95 in 6.5 Grendel would be cool. After I learned it wasnt a feasbile task, I decided to design the MBLR-15. The design obstacles were substantial and many features took several years to develop to this point. There is a reason others haven't done it, and it's not a lack of market.

3. I'm a prior Recon Marine with 2 deployments. Function over form, every time. I can't tell you how many times we'd get a shiny new piece of equipment that was trash (Colt M45 ??). When live fire testing is proving successful, we'll reevaluate some aesthetics but bear in mind, I won't add weight, cost, or complexity to accomplish a "pretty" gun.

4. The base concept is to provide a modern bullpup firearm that gives the end user the maximum number of options. Ejection/charging side, trigger, grip, barrel, gas system, etc. The intention is to provide a baseline for aftermarket companies to expand on. I remember several companies slow to develop x95 handguards so I spent a lot of time and consideration ensuring each part is easy for the aftermarket pick up.

5. I'm truly grateful for all the feedback received, positive or negative. Whether I'm able to respond or not to each piece, I do see it and it is considered.

Thank you for your time and have a Happy Independence Day!

Hell yeah.

Awesome, thanks for stopping in.

Good luck on the project and please keep us posted - we're all rooting for you to succeed with this one.

Well, I know what will probably be my first bullpup. Hell, might even throw the 6.5 Grendel barrel in it.

I personally like the way it look on the white sheet, but I do agree, extended down the buttstock a bit and it would be perfect.

Welcome fellow firearms enthusiast!  

Got any Legos?

Make it light weight,
make it in 6.5 Grendel,
make it 1 MOA(ish),
make in <$1500,

and I'll make it mine.

I'm perfectly happy with DI. I like DI, and don't own a supressor.

Perhaps the only thing I'd like is for them to be sold as builder's kits.

Thanks for the info, I’ll be watching for updates

This is awesome. We get to hear first hand from the person who is going to be bringing this to market. Please keep us updated. Maybe start your own thread. I really want this to come to market. It’s just plane and simple awesomeness.

@BrandonMski   Oh - I missed this at first!  Excellent!  And Welcome.  

I am excited by your project and motivation, and it looks like we have both come to the same conclusion:
-Highest performance round that fits into small framed rifle (e.g. AR-15) in terms of distance and terminal performance at distance, is the 6.5 Grendel.
-The most efficient rifle form factor is the Bullpup.

Combination of a 6.5 Grendel into a Bullpup formfactor, is the ultimate optimization of weight, size, performance, and span of mission capabilities.  Everything from high round-count CQB, to vehicle gun, to precision engagement at distance with effective rounds, to gong-banging target shooting at even further distance, is what that product will deliver.  Depending on BBL length, this could be a 1000 yard rifle, sized smaller than an M4; and delivering 800 ft-lb of energy on target as far as 500 yards.  (compared to just 250 yards distance with .223 77 gr out of a 20" BBL; yet same frame rifle)

As noted, I am a big fan of the 6.5 class rounds, as to me they are the optimal of performance (both flight and terminal), to recoil and size, for what I want to do.  I own an MDRx in 6.5 Creedmoor.  Why?  Because nobody makes a 6.5 Grendel bullpup.  The 6.5CM MDRx it is the single closest thing I can get to a one-gun-to-do-it-all gun; in that it's CQB, 1000 yard target, 1200 yard gong, 500 yard hunting rifle; in a bullpup sized package as short as an M4, yet with 20" of 6.5CM power and distance.  I like 6.5 Creedmoor - a lot.  I took a >12lb 20" AR10 in 6.5 Creedmoor deer hunting for 3 days of field hiking stalk hunting; to drop a deer at 15 yards.   It was absurd.   I bought a 6.5 Grendel that week.  As noted, I like 6.5 Creedmoor a lot.  I like 6.5 Grendel even better - by a lot.  6.5 Grendel is a remarkable round.

Two problems with the MDRx bullpup (and of course all of this post is IMO):

1) It's heavy.  It's really heavy (but then, it's a .308 class rifle w/ a 20" BBL and glass that will work out to 1000 yards).
2) It's inaccurate.  The barrel mount system and frame flex in recoil.  You can literally move the barrel with your hand.  The gas system is too close to the chamber, tapping at too high of pressure with too much residual dwell time.  This gives excessive forces and movement and even though a short-stroke piston, all fired MDRx 6.5CM brass comes out dirty and sooty.   The tap needs to be about 2" further out.   But that's what I've got.  Fortunately the gas system has a good adjustment design, which helps.   To address this, I have had to carefully tune 6.5 CM loads with light bullets, and mild charges of fast burning powders.  I've gotten it down to 2-2.5 MOA, but only with considerable development effort, and even then, not necessarily every day.  There is no factory ammo that will do this or is appropriate for the 6.5CM MDRx; but that's OK, I like to reload.  And I like to tinker.

Some folks have noted a desire to make a 6.5Grendel version of the MDRx.  But that would be pointless, as it's a heavy .308 class frame gun, and downgrading it to 6.5 Grendel gives no weight advantage, and likely only a little accuracy improvement.  


As to accuracy, my general purpose target spec for a rifle is to deliver 1.5 MOA with very good ammo.  I'm satisfied with that.  Better, is better, but 1.5 MOA repeatable 5 shot groups (or at least, on average), is plenty serviceable for even bullseye match shooting in a pinch.  (and yes, I own M1 Garand's too - so, hey, not everything runs to spec )

As I'm sure you know, KelTek explored doing a 6.5Grendel of their RDB.  This actually would be fantastic, and KelTek understood the need for a decent trigger, LIGHT (or at least reasonable) weight bullpup (most are just too heavy for whatever reason), good price-point, and ambidextrous service.  It's a good design.  Except that it's also KelTek: accuracy reputation is poor, as is long-term durability reputation - unfortunately.  


Your project looks like the best one yet, and if you like, I'd be willing to work with you and beta test the unit.  Here are a few of my posts:  

https://www.ar15.com/forums/Armory/MDRx-6-5-Creedmoor-barrel-erosion-measurements-and-photos/43-536695/

https://www.ar15.com/forums/armory/So_I_got_an_AUG__A3_M1_/43-435616/?

https://www.ar15.com/forums/armory/Lazy_s_Steyr_AUG_log/43-467671/

delete

it's a receiver set. caliber, accuracy, etc. is up to whatever parts you choose to put in it. not sure why you're coming to him about the performance of someone else's product.

Note, 6.8 SPC II is actually a potentially better round for what it does over 6.5 Grendel.  Intermediate cartridges are not really designed for long range due to the lack of energy transfer over 400 yards.  The 6.8 SPC II is designed for and has better energy transfer under 400 yards than the Grendel does.  On top of that 6.5 Grendel is known to have reliability problems with magazines, while the 6.8 SPC does not.  In addition, 6.8 SPC II performs particularly well out of a SBR.

I disagree.  I think it looks fantastic.

@Marquar

Yep.  Simply install a LH AR bolt and away you go...

Please put AR dust covers on both ejection ports.

Gotcha.  Like many people, I didn't have opprtunity to watch an embedded linked video here in a text based forum, so missed that he's developing a chassy system with user supplied BBL/bol/etc.  To that end however the issue with the MDRx accuracy isn't the barrel, it's the inconsistent reciever flex between the barrel and the sight.  Since this system is a 5.56 et. al. based system, the forces will be milder and so less at risk than a 6.5 Creedmoor (where that shows up in the MDRx), but still a potential weakpoint.  The reciiever demonstrated in teh video is 3D printed plastic.  so the risk remains that it will flex and throw shots.  That said, what was demonstrated was alsojust  a concept prototype.
I look forward to seeing the full-production unit.   And as you say, apparently it's designed that the user with an AR15 compatible bolt, barrel and magazine, can run whatever they want - so long as it fits on an AR15 platform.  It looks like there's an extra mounting ring on the barrel a few inches down from  the breach, and that's the actually attachment point.  How that's secure to the barrel and how reliable that is, will be important, so I look forward to learning more on that too.  Probably can't cal it so free-floated anymore either?  Not that this is damning - people shot rifles long before free-floating was a thing, and 0.5MOA isn't the goal here.

Neat project, defeintally hope it's a home run.

Cool, thanks for the update.

Any idea if this will be a 2023 release? I'm holding off on a Springfield Hellion to see what becomes of this.

Sounds like for you, 6.8 is the way to go.  And based on the fact this is a chassy system to which you can drop your BBL and Bolt - there you go!  It's a solid round and a great hunting round.  I like its smaller diameter casing and higher pressure rating.

It also lost the VHS / BetaMaX wars and I'd rarely advise anyone today to start down the Remington 6.8SPC path, since 6.5 Grendel does everything it does, and is reliable with good mags today.   But if you are already invested - no reason not to transfer that over to this chassy.

"It also lost the VHS / BetaMaX wars and I'd rarely advise anyone today to start down the Remington 6.8SPC path"

They both lost.  I think there is more 6.8 SPC II ammo in the wild though.

There is also the 6mm arc that looks interesting.  Higher velocity projectiles that drop less at long range with higher BC.

Why do you think they both lost?   As a reloader who would pause after shooting at the distance gong range, so as to pick up area brass when done;  I'd see more steel Grendel cases on the ground last year than you can shake a stick at. It's everywhere.  And I have collected several hundred brass cases that I reload and run.  I see some 6.8 SPC, but very little; maybe a third as much as Grendel brass.  I see more .224 Valk, than 6.8 (but then, it's a gong range).  I saw maybe five 6mm ARC cases.  I just run those through the press and they become 6.5 Grendel cases.

6mm ARC is interesting as a longer range gong-banger that fits inside an AR platform.  But to me, less appealing as a general purpose round.  And too exotia for my tests - I don't run exotic rounds, and didn't commit to Grendel even until Wolf Steel became commonplace.

"Why do you think they both lost? "

Basically few to no military contracts and more availability of ammo at LGS and factory rifles in the cartridges.

But ya, as a reloader it is solves a lot of logistics problems.

@Marquar

Oh that I don’t know, I was just relaying the information the designer put out in one of his SHOT Show videos. I hope it comes out next year. It has huge potential especially with the caliber change aspect and reliability of the DI system.

Anyone know of any progress updates on this?

Nothing new on the website https://www.senexarms.com

This is the latest post on Facebook from July https://www.facebook.com/SenexArms

Couple thousand rounds through elander mags without a single malfunction.  Grendel has mags that function really well.  It is also a beast out of a 12.5" barrel.

Can't speak to your comments on 6.8 but you totally missed the mark with 6.5.

Product Development.  Where 95% done, actually equals 50% done - if you're lucky.  and you will spend the total budget spent to date, plus more, and double the time to date, to get that "almost done", last 5%

Yep, pretty much none of that original statement is true.

Well that was rude, you could have just asked for sources.

Claim 1: "Intermediate cartridges are not really designed for long range due to the lack of energy transfer over 400 yards"

Evidence 1
Evidence 2

Maximum Effective Range of AR15 and M4 from the manual is 547 Yards.

Evidence 3

As you see here, the Military clearly indicates that effective range listed is ability to hit a target, not if it has acceptable wounding potential.

For example m855 can penetrate only out to 160 meters, and the fancy unobtainable EPR is out to 400.

Evidence 4

And as you see here, the Military study affirms the lethal effective range is maximum 250 yards.

Thus, 400 yards is a reasonable claim.

Claim 2: "The 6.8 SPC II is designed for and has better energy transfer under 400 yards than the Grendel does."

Evidence 5

As you see from the chart under 200 yards 6.8 SPC retains more energy.  At 300 yards it is close and 400 yards the Grendel is better (Use the 16" barrel number instead of 24" for equal comparison).  Note this is SPC I not SPC II that allows higher energy cartridges safely.

This is particularly important when we start shortening the barrel as performance is not linearly reduced when the barrel is shortened.  See Claim 4.

Claim 3: "On top of that 6.5 Grendel is known to have reliability problems with magazines"

Evidence 6

Evidence 7

As you can see this is a known issue.

Claim 4: "6.8 SPC II performs particularly well out of a SBR"

Evidence 8

As you see here 6.8 SPC appears to be better than 6.5 in SBR land, especially as it appears to outperform 6.5 under 200 yards.

---

So as you can see Lazy, I think it is safe to say that at least one claim above is correct/reasonable.


The reason I am saying this is that it might be better to consider use case, If under 400 yards vs over 400 yards determines the more optimal design.  Especially if you are looking for long range performance (but not prioritize lethality at those ranges), something like 6mm arc may be a better choice.  Trying to do both, like the 6.5 does, is a compromise of different solutions.

However, one thing that might be worth considering is 6mm arc and 6.5 Grendel do share the same bolt head.

An Aside:  And from a logical perspective, if you look at the above data, it shows why NGSW was a thing.  They found that most of the contenders didn't really push the envelope that much over 400 yards, especially with that wind drift.  The Military wanted lethal accuracy at 500 yards as a requirement (due to engagement distances in Iraq during convoy protection where the M16/M4 guys couldn't engage targets on a canyon wall) and as such it drove a different full power cartridge design.

OP, can you change the title to 6.5/6.8 cat fight?

I am starting to agree, considering how my original statement was months ago...

I think I am liking 6mm arc more for my needs, and I am glad to hear that the Senex Rifle sounds like it will be able to support it!

I appreciate the well thought reply, and will try to respectfully address as time allows.  To summarize without current ability to post the supporting data right now - I have run the ballstics, and will post as able.  

This post is about Bullpup, the point of which is rifle ballistics in SBR sized package.  Grendel is a 6.5 mm dia bullet with a larger case capacity, allowing for greater power and flight characteristics.  Out to 400 yards the ballistics difference between 6.8 and 6.5 is quite slight.  Past that, the 6.5 starts to dominate more.  A 123 gr out of a 20" BBL has over 1000 ft-lb impact energy at 300 yards.  I'll have to look up it's 800 ft-lb distance.  It remains supersonic out past 800 yard.  Actually, close to 1000 yards, but transinic destabilization begines a little past 800.  Meaning it has longer precision range with a better BC bullet, yet one with enough mass and profile diameter to do stuff, on impact still.  It has longer legs than 6.8, and that's not a controversial new claim.  If all you ever want is 400 yards, then 6.8 will run nearly the same.  

As to reliability, there were early teething problems, not a new thing.  They got better.  I've run thousands of rounds of 6.5 Grendel at high rate of fire warm/cold with multiple magazines, and don't jam - nor do I see many posts in Grendel forums anymore of people complaining about magazines, jams, or bolt failures.  

6.8 is a good round, but for better or worse, it basically lost the VHS/BetaMAX wars, and is now a much more rare round.  No military ever adopted it, and it's relegated to speciality round that could have been.

6.5 Grendel won for the same reasons 6.5 Creedmoor won over 260.   Because the developers understood product development and product placement.  In 6.5 CM, they partnered with Ruger for the RPR to only be in 6.5 CM, and it made the difference, when the era of alternative to.308 was becoming a commerical and retail level topic.  And 6.5 CM is the long winning king of that arena, and will remain so for a long time.

With 6.5 Grendel, Alexander went to Russia, and made a pretty decent spec design 6.5 Grendel Wolf Steel round available for 25 cents a shot.   In a world where brass ammo is exotic speciality premium, that's a big deal.  For a time, all other AR's were unnecessary, as a 6.5 Grendel could be your do-all AR for all functions from hunting to cheap 3-gun blaster, with that ammo.  Sadly, that door is now closed, but the die was cast, and 6.5 Grendel won, and 6.8 went to That's a good round too - status.  

Don't get me wrong, I like 6.8.  I like it's higher pressure rating and smaller diameter (means you can stack more rounds).  But I don't like running two rounds that overlap, and between the two, 6.5 Grendel is more available with the longer legs that will do everything 6.8 can do - and more.  PSA has already announced they will be making 6.5 Grendel in steel casings, to pick up the slack.   I don't recall them saying anythign about 6.8.

The great news is you can setup a Senex with either 6.5 or 6.8 thanks to AR compatibility and the vast assortment of available barrels.

i.e. "Stop the 6.5/6.8 catfight and take it outside... or GD"

Since this design uses mostly AR-15 gas system components (bolt carrier aside), would it be reasonable to expect external piston versions of some variety?

This is exciting!
Could make for some neat bullpups and a new home for my 18" Grendel barrel with high pressure bolt...