OpenBolt Designs - This is for you Clammy & Nadesh

OpenBolt Designs - This is for you Clammy & Nadesh (TheGunClub)

submitted 5 years ago by middle-path

In relation to Clammy's recent post - https://voat.co/v/TheGunClub/3149176

I wondered if one could make an open bolt RIFLE instead of a sub gun. In theory, all one would need was a heavier bolt. The weight should be proportional to chamber pressure, right? If not exactly proportional, at least in relation to it somehow.

So I did a little research and I found, of course, someone else already had the idea. I mean guns have been around a long time and I'm not even 25.

Here's a page that describes open bolt weight in relation to different cartridges of diff speed and weight.

http://orions-hammer.com/blowback/

But it occurred to me, .300blk subsonic is basically a .45acp by weight and speed. It has double feed mags and is easily suppressed. So wouldn't bolt weight be about the same as a .45acp? That's 2.3 lbs of steel.

One CUP of steel is ~4.1lbs. So with a bolt that weight one could made a blowback .300blk if only subsonic was used. 10mm would need 2.8 lbs.

But can you do 5.56? Yes of course you can. You can do anything. But what's the weight? About 7 lbs for a .223 remington.

There's more.

What about 'advance ignition'? That's pretty complicated and can't really be done by most peons in their garage, myself included. But if done, it would allow one to use the forward momentum of the bolt as a surrogate for bolt weight.

That means a lower weight for more powerful cartridges. I think if you wanted to do this, you would need to use some integral calculus. Any ideas about this? I guess we would need to start from bullet velocity and back pressure. From there we can add backward velocity. However, I'm not great at calc and don't care to do it.

@Clamhurt_legbeard @Nadeshda

21 comments

ExpertShitposter 5 years ago

I was looking at that particular orion's hammer page last year when i made a little something something in my garage. I calculated bolt dimensions for 9mm and instantly it was clear that making anything bigger than 9mm in straight blowback was pointless.

You have to consider the reason why would you even make you own gun, since its almost always be shitter than anything you can buy. The only reason is an untraceable firearm, to be used by drawing from concealment, in a time when all firearms are banned. Or if you wanted someone removed, and the gun melted down with no remorse for the cost, because it was free for you. In both cases, the gun would have to be light, no heaver than say....6lbs. If your bolt alone for .223 weighs close to that......yeah......

Luckily, recent studies have shown, that caliber wars are a meme, as there is no noticeable difference in killing power between different handgun calibers after you get into 9mm, and almost everyone dies from 3 shots of 9mm, vs 2 shots of .223. And if you make an accurate weapon, a head shot with a 9mm is guaranteed death. Considering the people who you would be fighting in such a scenario would be wearing body armor anyway....you would need to go for those head shots anyway. So killing power becomes not so critical.

One advantage you would still get from .223 is a flat shooting trajectory. If you wanted to keep within the pressure of 9mm to maintain a bolt weight of 1.7 - 1.5lbs, but flatten out the trajectory, you could make a custom Tokarev style cartage. A case turned on a lathe from a single peace of 8mm brass rod, elongated to maintain the same volume as a 9mm case, fitted with the same primer, and crimped to a 5.56mm bullet turned from a 6mm solid copper rod. Not sure what kind of velocity would you get, but it would certainly be flatter than a standard 9mm.

That's my theory at least. Its something i will test in the future when i get the time.

As for advanced ignition, i wouldn't bother with it. Even if you could make it, design should be made super simple, so that most people can do it. Otherwise you didn't make anything revolutionary, just....cool toy for your self. I would rather make a bolt action .223 at that point.

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clamhurt_legbeard 5 years ago

bolt actions and break actions are much easier to make for rifles than semi auto

best designs are probably blowback pistols

revolvers

blowback open bolt smg

bolt action rifles

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ExpertShitposter 5 years ago

Easiest design is "thread action single shot pistol". Don't ask me how i know ;D

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middle-path 5 years ago

Just like the RN-50 but I think they're fucking retarded.

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ExpertShitposter 5 years ago

I think they are brilliant. It depend's on what your goal is. If it is to make an untraceable gun for your self...yeah, its retarded, because you can do better than that. My goal is different tho.

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middle-path 5 years ago

Hmm, yeah I can agree with that.

A gun to remove a single threat in a self-defense scenario, in minecraft. Or to get to another gun? Seems pretty good.

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ExpertShitposter 5 years ago

Yeah. Imagine say, you were playing minecraft, and most characters are wearing say.....yellow vests. But the zombies and skeletons are wearing blue vests! In all the commotion, there would be plenty of time to reload say...a break action single shot. Now imagine if every tenth allied player with the yellow vest had such a pistol....

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middle-path 5 years ago

Yes, or better yet, I'm playing minecraft(yay! :3) on the 'City Name Here' server and I come in contact with a Netherman who has been terrorizing the server for years. He's levied unfair taxes and taken goods/children from the players on the server. He's essentially the equivalent of a king or senator on the server.

I'm cornered in an alleyway and the Netherman puts me in a self-defense scenario. What if, as a last resort, I am forced to defend myself with an improvised weapon with a homebuilt silencer.

I wouldn't be happy about taking the Netherman's life, but I would be happy that I had defended my own.

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ExpertShitposter 5 years ago

Netherman's have a tendency to force our hand. Nobody is ever happy about the devastation. I also hear night sights are very clear against "dark" background tones.

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clamhurt_legbeard 5 years ago

lately im looking at zombies and how they always have exposed necks and joints

lately im looking at squirrels and how small they are

lately im looking at how effective at 200 m a 22 can be

22 is very simple

very very simple

that receiver is cast zinc magnesium

so tiny and quiet

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ExpertShitposter 5 years ago

I've learned, than even aluminum is enough for a 9mm barrel. Not kidding.

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clamhurt_legbeard 5 years ago

rifling

did you rifle stuff too

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ExpertShitposter 5 years ago

No, i saw the results from a video. I'm gonna order a rifling kit, its pretty cheap actually.

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clamhurt_legbeard 5 years ago

can you order 22 barrel liners

those are nice too

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ExpertShitposter 5 years ago

If they sell em on ebay, they would probably go through, but legally no. In EU, gunparts aren't just a lower receiver. Its anything that "bears pressure".