My guess is the guys who thought it up were thinking of 40mm grenade rounds. Personally I would’ve ignored the “75 calibre” description and gone for something based around 25mm grenade rounds like the XM25, seems to be the closest thing to the spirit of a real boltgun.

This is some prime tech-heresy! What we learned is that stripped down bolter is basically a tec-9. Nice vid!

As an engineer who always wanted to be a gunsmith, I loved this Macca, thanks!

Even your Canon bolter on the bottom looks better than most- the ejection port lines up with the goddamn barrel!

one of the things you should note: yes muskets were roughly 50cal and up but their pressure curve was much lower because of the combustion rate of black powder. that lower pressure curve reduced the felt recoil by spreading the total force imparted over a greater duration. This isn't a gotcha since you could just use a cleaner and slower burning powder than modern cordite but it is something to keep in mind.

I like the idea of the giant heat sink of a Lewisgun for a space gun.

If you were inclined, come up with your own little pocket off the heresy, your own forgeworld and lore, and macca-pattern gear, were you fix some off the design issues, add your own spin but is still 30k adjacent, would make foe a very cool unique force

I enjoy any thought exercise meant to discover just how the imperiums equipment would look irl. On the point you made about the boltgun not needing to be bulky I think it would make more sense to apply a bit of our own modern logic to it. As an example a floating barrel is much smaller than the weapon appears to be, as far as i know the real reason bolters and other ballistic imperial weapons appear so big is because there are machines surrounding the actual weapons mechanisms which are meant to unjam them.

Interesting that in the Astartes video they have a much smaller (calibre accurate) barrel as well.

Always appreciate these kinds of videos, especially as someone building his own Sci-Fi universe. Always fascinating seeing how physics translates over to weapon design, especially with modern tech and seeing what can be done.

I actually really like your boltgun. I think for a more tactical legion like the XX these would look fantastic for recon marines.

Really enjoyed the Video! As some one who works with CAD a lot I all ways like seeing other peoples work with it. I just wanted to point out the reason I suspect a lot of GW's stuff is out of scale is because of manufacturing limitations in the early days meant things had to be over scaled so that they would come out of the mould constantly. Artists then made art works based on these modals leading to the current strangeness of the Russ having officially a 120mm diameter barrel despite being shown on art work and on the table top having a barrel many times that size.

Great video, Macca! I always thought GW just went with a random number for the bolter's caliber, something that sounded cool without much consideration. Perhaps, people in the 41st millennium have different classifications of calibers haha. Also it kinda feels like if one was to combine your design with the GW's original boltgun, you would get something very close to how the weapon is portrayed in the Astartes fan animation, even though its design has some minor issues as well, like ejection port being kinda too high in relation to the barrel. And regarding bolter being a caseless weapon -- I believe it's a statement that was born during the 2nd Edition (maybe even RT-era, but early boltgun design actually had something like an ejection port), when boltguns were just bricks with a mag, a handle and a barrel attached to it, no ejection ports or anything. And later the cases were introduced in some of the artwork due to them flying was a cooler look, so the weapon was re-defined as a hybrid action thing we know it today.

This is the kind of video that me and few others have been asking Ian over at Forgotten Weapons to do for ages. Instead we got Chinese Type 93 Assault Rifle from Fallout series. And when I had lost all hope Macca comes and delivers. Don't get me wrong, I'm not complaining about either. I'm just saying that machine spirits work in mysterious ways.

They probably designed the boltgun how they did because it was easy to sculpt and its bulk made a good mold for the pewter smelting they did at the time.

You should do more of these type of videos, man. Really cool and interesting.

Shortly after Magos Macca of Forgeworld Salt made this message he was executed by the high lords of Gamesworkshop for making practical sense.

I'm pretty sure that cleaning and maintenance on a boltgun would be a massive bitch. I think aesthetically the boltgun is based on the FN FAL style rifle given how it is looked and used by description in the lore. (Especially the Primaris version) A Bolt Pistol is on the other hand is probably veiwed in-universe as most gun nuts see the M1911 as given how every Guardman Officer/Commissar,Space Marine Officer/Specialist, SOB Sister Superior/Specialist and Inquisitors (and a few more that i don't remember) usually seen wielding one or some type of Bolt Pistol.

The muzzle brake has always been funny to me because like... i _get_ that it helps convey the idea that Bolters shoot really, really, _really_ big "bullets," but it leaves people with the idea that bolters fire a round the size of a soda can. Also, personally, if I absolutely, positively had to give a "realistic" bolter with that big, chunky M41A1 (oh goddammit lol) silhouette, I'd just put a grenade launcher on the underside, or one of the various combi-weapons additions. I'd also give it a sabot cup, partly for laughs and partly cause it was the only idea I had for engaging with the rifling of one of the Primaris bolt rifles.

I love this style of videos. 👌 Thanks for explaining your design process.

You call it ugly but I like the way it looks a bit I really like how much thought you put into it.

The gun you've designed Macca looks very similar to a carbine from Angels Fall First game. I like your video by the way, real interesting. I've never really thought about the Boltgun's designs from a practical point of view. Wonder what a Heavy Bolter is going to look like or an Autocannon. Or the humble Lasgun.

I think part of the functionality you didn't include in the design is that the boltgun itself is a weapon and meant to be one. I don't mean the boltgun itself and the rounds it fires, but it is also used as a club and that is it's intent in close combat, there are a few examples of space marine using polt pistols to swat away humans or smaller xenos, full length bolters as well used for clubbing smaller fighters as well as just the fact that the weapon is intended to receive damage and keep on functioning. I don't know what else the frame could have been made of, but I think maybe a little more stronger materials, maybe a little more blocky, but I am no firearms expert so I leave that to you to think of

Ive always imagined bolters being similar to 20mm autocannons. Space marines sre basically running around with handheld anti aircraft guns.

Even with a delayed blowback system I’d be worried about an out of battery. I haven’t done the math, but with a .70 round plus the gyro jet there is going to be a tremendous amount of pressure pushing back on the bolt for system to deal with. In order to compensate the weight of the bolt is probably gonna have to be significant which might put it out of the range of feasibly for unaugmented humans

I'm honestly impressed how much detail you went into and how much you know about firearms (being youre in Australia). I build ar15s and reload so I am well versed

I agree with the people defending the blocky aesthetic. The main reason light weight is valued in real life is that people are desperately weak. Space Marines are very strong and can carry much more weight for much longer. It makes sense that rugged strength would be valued over light weight. The Space Marines primary tactic is supposed to be shock assault. They don’t carry enormous patrol packs of equipment and ammunition. They want a gun that can withstand being deployed in a drop pod, used as a club and be able to operate in all atmospheres and gravities. Another thing is that the design philosophy in 40K is fundamentally different. Current design is reductionist, its sole consideration is efficiency. Space Marine equipment is artisan made and constructionist, the artist doesn’t ask, does my gun need elaborate golden scroll work? He puts the scroll work there because he wants to. That said props to you for making your own pattern of bolter good work.

Mate this is off its chops. The level of detail you put into this thing is amazing. Great video and keep up the great work.

Perhaps the extra mass comes from armor plates installed on the gun and perhaps its shooting a rimmed cartridge so the magazines are curved.

Something to note. If you go to make primaris the bolt rifle the barrel/round will lean more on the rifling rather than the gyro jets

I've only recently subbed to your channel, but going into the lore and mechanical workings with the physics of a bolt gun. The closest IRL ammunition is the 40mm grenade and the various different grenade launchers. Here in America, the Mark 19 Fully Automatic Grenade Launcher would either be a pintle mounted and a Heavy Boltgun for a Space Marine. I served 27 years in the US Army, having disassembled/stripped various types of weapons in that time. The way the 40mm round works is almost exactly how the Bolt round works, minus the penetrator tip for going through cerimite armor.

Been digging your stuff lately man!

IIRC one of the reasons for describing the boltgun as a smooth bore caseless weapon was to do with vacuum contact welding. Non lubricated metals have a nasty habit of bonding when there is no air present, so the logic was that rifled barrels and cased ammo would weld as they entered the barrel. This doesn't explain how the bolt itself avoids fusing open, but an attempt was made before rule of cool defeated it. As far as I can see; designing a fire control to be properly void proofed would require making it either a magnetic mass driver or using electro-thermal ignition instead of a physical hammer.

Hey Macca, as you stated and as is quite apparent the lore doesn't always conflate with reality nor depiction. Both relevant examples are seen with the ammunition being called 'caseless' despite certainly having cases, while a realistic Bolter at .70 cal wouldn't actually be unmanageable. Given this, I'd propose an idea to make a realistic Boltgun in keeping with the common 40mm analog, perhaps by scaling it with the muzzle break or something slightly smaller. How realistic would it be to make a 'small' arm at that caliber and how different would the resultant weapon be from what is already depicted.

for the size of the projectile and the damage being done by explosives the bolt round wouldnt need to be very high velocity so the bolt you modeled would probably be half the size. look at the inkunzi PAW and strike rounds, they have projectiles 3x the size of yours with the rest of the cartridge adding on a third of that. also combined with the gyrojet feature the barrel of the boltgun wouldn't have to be near as heavy. with rounds that size and half the propulsion of the bullet being from a rocket motor you're right the recoil would be quite manageable. i headcanon that this version of the bolt round is what sisters and commissars use and the astartes version is the proper 1500+ grain light armor busting grenade. which as evidence by the PAW is still manageable by a normal person if the recoil system is good but its still too much to get any reasonable rate of fire.

Fantastic video Macca. It's not just me that noticed when it's all stripped back it reminds me of the American Grease Gun from WW2.

I'm actually really really liking this new kind of content

Safty mechanism, the emperor protects from misfires.

My Group's headcanon on the Recoil of Bolters is that it was a rumor started by Astartes to keep the Mortals from jacking their shit.

Yes magos this guy right here, he is committing tech heresy 😂.

The internal frame you had mounted the foregrip and sight block to looked similar to a keymod foregrip, just missing the oversized holes to one end for the cap bolts to slide into.

Forgotten Weapons of the Far Future. Gun Jesus approves!

Now you should make a weapon that is truly worthy of being used by a space marine

I actually quite like you’re version of the bolter however a few changes would be to make the upper front receiver and foregrip as one solid piece connected to the weapon itself as well as to remove the red dot sight due to space marines utilizing a heads up display

Just curious you gonna make this available as an STL to print and replace GWs bolter?

I did enjoy that and appreciate your effort. Now I don't think a Blowback design is stupid, there is just more you can do. Look at post WW2 designs like Walther MPL, H&K MP5, UZI/MAC 10 and others and you will find a plethora of options how to deal with bolt travel and delay.

More than ten minutes in, and the only on-point issue you've brought up with the existing boltgun is the Heroic Scale TM issue with the muzzle device being bigger than it really should be. The rundown on early 21st century firearms design is fairly accurate, but it doesn't really seem much like the contents address the title in a particularly dedicated way.

Typically bolters are .75 cal not .70

Highest listed calibre is .998 Godwyn Ultima. Standard is a .75. Heresy is a .71 and I've never heard/seen a .60 Bolter described. Right out the gate I'm a little confused, but still intrigued.

The issue with the boltgun is that noone treats it like what it is: a grenade launcher made portable enough to be used anywhere a space marine can get to

I would like to see a gunsmith take the Beowulf round and build a bolt gun around it.

I'd like to see the 30 to 40mm boltgun

dude! i love your Bolter redesign! Could you commision someone to make drawings/concept art of it and such? this looks freaking amazing. I want to see how'd it look in color variations like the classic red, green black and gray (among others). Also, would it be possible to add a picatinny rail for the bottom, maybe for a front grip? Could it also house a buttstock? What you done, to me, looks beautiful. Doesn't seem weak or ugly.

Great breakdown mate!

That was fun.

You beat me to a lot of nitpicking. A purely powder based firing solution erases the rocket propulsion component and would require a much longer barrel, but enough propellent to escape the barrel and then allow the rocket to activate works better for me. I expect the versions used by unaugmented humans would be closer to .50 caliber, I know they are smaller in the lore to avoid obliterating the user. Thank you for this video :)

It reminds of the stemple take down gun.

I remember reading somewhere that the Boltgun uses magnetic coil relays inside the weapon to increase accuracy without needing a longer barrel, due to the close quarters that Space Marines typically fight in where every inch they can shave of the barrel counts. Not sure how "cannon" that is because of how long ago I read that, but it does make sense.

will watch this I like videos like this ❤

Nice exercise. I do suppose that when you share these guns among the guard, you adapt it more. A rifle butt (hope that is the proper translation), perhaps a different sight, grip, and fair point you made about the mag. So the human version should hold the magazines. The marines could easily hold a drum mag with more ammo, due to their strength. As to the bolt round itself. (Now the small size chemistry, hand gun rounds are not my thing), but it would be cool to expand a little on the types of rounds and give real life interpretations. Like, a shaped charge head for extra penetration, AP sabot for even more, but less range (again have no idea how the small size relates to Kinetic impact and penetration, i.e. how scalable these effects are) a hesh version, the regular slug version, a sniper version with bigger round for more range (and so a different bolt gun). There are different type of bolt gun rounds to explore. If you wish of course. But I’ll leave the thought here. As an example, there is an old artwork/picture on the AP shot from a vanquisher leman russ. And guess what… after all those years: APCR. 😝

Again, what software are you using Macca? Also props on making what is basically a closed bolt gyrojet luty! And yeah, 20mm grenades would be a more "accurate" size for how much damage they're supposed to do.

I’d love a 3D printed model of this so I can put it on my models

Boltguns never supposed to be caseless, though (at least to my knowledge). In the lore they supposed to use a small kick charge to eject it from the barrel and operate action, with bolt being then propelled with rocket engine.

Sorry mate but you’re going to have to look at this by a case by case scenario 😂😂😂

I think boltgun round should be more like 20mm x 42mm grenade it's cross section looks actually remarkably like a bolt supposed to, front is solid, then explosive, except at the back you have fuse(?) instead of rocket engine, but reduceing fuse in size seems to me like something you could actually overcome with sci-fi bullshitery, also I have an idea for that over sized muzzle break, because the rounds supposed to be explosive and Astartes don't have to concern them selves with shrapnel the bolt might be always armed if that would be the case, then problem rise when the boltgun is shot at point-blank as it could potentially explode while still in the barrel, so this "muzzle break" could potentially serve as solution giveing round space to explode into

Oh, fella, don't check out older bolter designs, you'll lose your mind. Also, nice video! My main criticism - boltguns probably have lockup, which is a whole another can of worms to build for space.

Yeah yeah you are very cool for knowing how a gun works. But if you look on page 60 of the 3rd edition rulebook, there's a cutaway drawing of a storm bolter and ammo which shows you everything you need to know. Would it work irl? Of course not but it's a ridiculous _science fiction_ setting, bolters are hardly the only break with reality OR the worst offender for that matter.

Hey macca what modeling program do you use?

I feel like the aesthetic design definitely invokes the G11 for the boltguns looks as in a wierd space age weapon that doesn't fire conventional rounds. My headcannon was that boltguns be a GMG like weapon considering the size and strength of an astartes and also the numerical inferiority they would have so a weapon that could kill or injure several people would be better than hitting one person.

This is my safety sir *hooks finger in the air*

Artwork takes precedence over written lore. With that in mind I just assume the ammo an Astartes bolter takes is MUCH larger than .7 cal Or some administratum member fudged the measurement or something. It's a millenia old gun anyways.

If I'd go for full redesign/retcon in 40K I'd replace the Bolters with Volkite wepaons. They make much more logistics sense (no ammo, perhaps recharge their power packs through the power supply of the Power Armor), they are completely fictional so they work as they are described and they avoid comparisons with real weapons and they have a similar (if not more extreme) effect to Bolters against targets. Bolt weapons can become more unique, firing larger "smart" rounds of verious types so we could give them to specific specialists, vehicles etc.

Personally, I've always thought the biggest challenge when trying to make a realistic version of a bolter is figuring out exactly how tf bolts work. They are supposed to be caseless, yet brass gets ejected after every shot; they are officially 0.50, 0.60, 0.75, 0.998 and 1 inches in diameter, depending on who you ask; they are solid enough to pierce concrete walls, yet hollow enough that they can rip a man in half with all the explosives within; the barrels are rifled, yet the rockets stabilize the bolts by themselves; pistols have less range than full bolters, even though they (supposedly) fire the same cartridges, which are (supposedly) rocket propelled, meaning the lesser barrel length of pistols should be completely inconsequential. Also, what's the official autoloading operation, of bolters? Would a gas-operated system even work on a bolter? I've always imagined they are simply blowbacks, because of all the recoil.

I'd like to see a Nemesis pattern based on your platform 👀

.. um.. without the magazine 'lips' to hold the rounds in the magazine, as soon as the bolt-carrier group is brought out of battery, the rounds are just going to leap out of the magazine and spill out of the ejection port, with the "BCG" slamming down on a round in a stove-pipe failure. Just thought you should know.

Ah, many thanks for this video. I came across an interesting artwork showing a few boltgun bits like this (the artwork itself depicts a suit of mechanical marine power armor (for tau, off all factions) with what gundam universe would call "sub-arms" which assist in firing and reloading suit-used weapons and additional upper for the boltgun with far longer barrel and so). I've been also trying to redo most of the space marine equipment (weapons armor and so on) as a side hobby for myself, this video aids in that bit. Will you cover the heavy bolter? From most descriptions (1d4chan, for all their "quirks", agrees on this as well), it incorporates coilgun tech. Edit to add: what be that 3d software used? Seems like perfect for realizing my drawings (on paper), into full 3d glory.

Those who don’t know their is a real life Boltgun it’s called the gyrojet pistol and rifle it was a canceled weapon do to not being accurate.

While this is a much more function accurate representation of the bolt gun than the space magic wrath of the emperor, there are a few key problems: -lenght of the barrel compared to the amount of propellant that needs to get burned -no rifling so you just made the ammo the gun is shooting already more inaccurate so the gyrojets need to work more -with this design it's an open bolt direct blowback system, but it's very much non-functional as the bolt is way to small to have enough mass for the weapon to not immediately explode with the force the propellant will produce -the fire mechanism is way to high for a direct blowback system from the trigger, this will increase vertical recoil -charging handle let's dust and debris get into the mechanisms of the weapon -there are too meny not made from one piece parts on the weapon -there are too meny open spaces in the weapon that don't serve any function -to compensate for the recoil I would most likely make the muzzlebrake have ports more angled on the upper side of the device as to better counteract vertical recoil

*cough* missing a stock *cough*

Honestly the design looks pretty good - i mean beautiful to look at. I've always found 40k firearms too chunky and unrealistic

i think i will headcannon the astartes as using 40mm bolter weapons, while the non astartes have the .75 bolters

I'm curious about dimensions, like what length of the cartridge in this version, what length of the entire weapon, barrel and that's probably it

Warhammer has this same problem with tanks guns vs turret sizes there is no way the gun fits inside the turret of any warhammer tank.

Now do an Ork Shoota. Waaagh

Bullets explode! Who needs accuracy?

would it be possible to get STL files for this I would love to 3d print it since I have already printed a to scale bolter with magazine and bolt rounds in 75 cal.

I bet someone might look at this and try making it irl as we speak....

Tech priests head pops up Did someone say oil?

How are some bolters belt fed Macca? Are we doing the open bolt bolter next?

What program are you using and how could I watch you model? You made out you were streaming in the previous video.

Your bolter design looks like the guns used by the slig poppers in odd world. A challenge for humans would be operating the cocking handle because blow back uses weight and spring to stop gun becoming a bomb. Better operatons could be short recoil, long recoil or roller delayed as they allowe for lighter bolt and recoil spring, yes i know these would be a pain to model.

tbf, idk if comparing a 70 caliber musket to a 70 caliber more modern gun is fair. between the 12 + pounds of most muskets, their relatively low velocity and pressure, and the fact that they are single shot weapons.

3d print when?

Can you do the lasgun

The funny thing is barring the ammunition a bolt gun is just well a gun.

what about bolt pistols they have almost no barrel.

I'm sorry if I missed it, what is the program being used here?

How many rounds in each magazine. Would

What a blast from the past. What next angry video game nerd video? :-P

Why did you decide make the weapon repetition only?