How hard would it be to make an open-bolt machine gun firing 5.56 NATO in terms of required tools...

This question speaks volumes as to how little you know about this subject.

This is the opposite, using an 80% lower as a 100% lower.
No, I mean the whole bolt assembly and everything. How hard would it be to make a Luty SMG if you already have all the auxillary parts?

Do you have a hammer, a vice, a drill and a file?
Easymode if you have a welder and an angle grinder.

idk how well 5.56 works with open bolt straight blowback
it's a pretty high pressure cartridge

Why illegally modify a firearm when you can get what you're looking for at the armory, officer?

I've never tried this, but I feel like turning a closed bolt system into an open bolt one is a bad Idea.

Then make it use the gas system, silly billy.

It'll lock when going into battery.

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nigga u ain't making a locked breech gas operated gun in your garage

But I am using an 80% lower?
If I can get one of those, I can get the other parts to make an AR15.

>if you can use all AR-15 parts except for the upper assembly but including the barrel?
i believe there is a misconception about the limitations placed by OP between the two of us

Open bolt? Pretty difficult.

Closed bolt? Anybody could make one with a drill press and a completely legal full-auto FCG. The feds actually have no way of knowing if you made an SBR/MG/DD unless you're stupid with it.

>open bolt
>difficult
pic one

He's talking about just converting a standard AR and was too retarded to read the OP's question.

Converting an AR15 to full auto would be much easier than also converting it to open bolt.

In terms of what's available on the market, I don't see it being done without a bit of know-how or having rare info like posted.

Depends on whether or not you want a good open bolt gun. Get an oversized firing pin and you're done. Just lock the bolt back and release the bolt catch. Press bolt catch to stop firing.

Well, it will be a whole new gun only you won't have to make barrel, stock, lower, grip, magazine, etc.
I don't see why it matters that it was originally made for closed-bolt, you'll throw it all away.

you just need a heavy enough bolt, there are some brazilian homebuilt .50bmg blowbacks

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What about fluting the chamber like in the MP5?

only thing that would be difficult is engineering an auto seer that keeps the bolt open

yeah but the aluminium receiver isn't a great candidate for that kinda force, you don't want a massive weight slamming around, it would limit the blowback aspect to pistol calibers

You could try a gun like this,
en.m.wikipedia.org/wiki/Volkssturmgewehr
Pressure leaves the barrel to fill the tube around the barrel which prevents the bolt from moving back too quickly

Couldn't you just have a bolt with large holes for the gas to vent through?

if you ground off the handle on a bolt action rifle and put a big spring behind it, would it make it semi automatic or would it turn into a bomb big enough to blow your hand off?

I would never do such a thing, just curious about how the mechanics of it all works

maybe deep grooves to let gas blow by, but you need a good seal to protect the integrity of the casing, it would rupture if there's an easy path for the gasses

straight pull with enough weight to make it a blowback might work

>enough weight
when you say enough weight do you mean from the force of the cartridge?

bolt weight
orions-hammer.com/blowback/

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Aren't you fags forgetting that Stoner already designed a rifle that is convertable between open bolt MG and closed bolt rifle.
>en.wikipedia.org/wiki/Stoner_63

Forgotten Weapons even did a big walkthrough on the mechanics.
>youtu.be/vCNw9Z2Q3T0