multi-cal takedown PDW

[yeehall]

I started this project a while back, trying to make a gun that would work in multiple configurations with just a barrel and bcg swap so I could play with different calibers without buying whole other guns. Along the way I have come to realize that in order to do another caliber I would need to replace the barrel and handguard assembly, the bolt carrier, and probably the buffer assembly (usually but not always). But by the time I'm done buying the barrel breakdown parts, it'd be cheaper just to replace uppers instead. So somewhere along the line the focus shifted to portability esp for road-trips to our property in MS, so now it's a truck gun / bug-out gun / hotel-room gun, with the potential to switch calibers. I will probably make a 9mm and 22LR kit for it at some point, maybe some others, at which point I would have come full-circle to where I started with it.

 

[Qbeam]

Wow, nice set-up.

Q

 

[erwos]

This is pretty much the whole argument for .300 BLK, which functions better with a short barrel than a 5.56 anyways.

Want a PCC? Slap in a mag of subs.
Want a real rifle? Slap in a mag of supers.

Mind you, the break-down aspect of what you built is pretty cool. I assume that's the Cry Havoc QRB you're using?

 

[yeehall]

This is pretty much the whole argument for .300 BLK, which functions better with a short barrel than a 5.56 anyways.

Want a PCC? Slap in a mag of subs.
Want a real rifle? Slap in a mag of supers.

That's the plan eventually but right now its subs only--the Rosco barrel hasn't liked the supers I've run through it so far (groups opened up a lot), and its a 9mm suppressor that isn't rated for 300 supers.

Mind you, the break-down aspect of what you built is pretty cool. I assume that's the Cry Havoc QRB you're using?

Yes sir it's the 3rd gen two-pin system https://cryhavoctac.com/223qrbgen2.html

 

[erwos]

That's the plan eventually but right now its subs only--the Rosco barrel hasn't liked the supers I've run through it so far (groups opened up a lot), and its a 9mm suppressor that isn't rated for 300 supers.

That's pretty weird, maybe try different ammo for the supers.

Some pistol caliber K-cans can handle supersonic .300 BLK, the Omega 9K coming to mind here. Consult the manufacturer for information.

 

[rouchna]

I really despise this forum. Now I need to build something similar.

Having said that, I really like what you’ve done there. Awesome little setup.

 

[P-12 Norm]

I really despise this forum. Now I need to build something similar.

Having said that, I really like what you’ve done there. Awesome little setup.

Yeah, since I came back here, I have started looking longingly at various firearms I "need" (you know what that means...).
Currently looking to put together an AR in .45 ACP. Either pistol length, or SBR.

 

[John from MD]

I wouldn't worry about firing supers in a can like an Obsidian 9 if my life depended on it. My conversations with them revealed that shooting supers was not dangerous but would wear out the blast baffle faster.

 

[calicojack]

Hey OP what's the length of the barrel on that pistol? Looks like 8"? Maybe 7"? I've got a 300 Black upper and a the same brace. Thinking about the same build but using this -> https://getstern.com/rab-ad-rapid-attach-buttstock-adapter/

 

[yeehall]

Hey OP what's the length of the barrel on that pistol? Looks like 8"? Maybe 7"? I've got a 300 Black upper and a the same brace. Thinking about the same build but using this -> https://getstern.com/rab-ad-rapid-attach-buttstock-adapter/

Rosco 8.2 Bloodline

The gas port is specifically sized for use with a suppressor and it won't cycle subs without one. I drilled the gas port all the way out and put a Riflespeed adj gas block on it for maximum flexibility.

It shoots okay with some stuff, not so great with other stuff. AAC 220gr subs with the suppressor group around 1.5 MOA, American Eagle 150gr supers without the suppressor spread out to around 3.5 MOA. I haven't tried much else except some Hornady, it shot alright but left a mess, didn't buy anymore.

 

[calicojack]

Rosco 8.2 Bloodline

The gas port is specifically sized for use with a suppressor and it won't cycle subs without one. I drilled the gas port all the way out and put a Riflespeed adj gas block on it for maximum flexibility.

It shoots okay with some stuff, not so great with other stuff. AAC 220gr subs with the suppressor group around 1.5 MOA, American Eagle 150gr supers without the suppressor spread out to around 3.5 MOA. I haven't tried much else except some Hornady, it shot alright but left a mess, didn't buy anymore.

I have an exiting 10.5" barrel that is a second for an existing SBR; but I am thinking of using it in it's own pistol build using the CryHavoc.

 

[yeehall]

I was trying to stay in the 8-inch range for portability, and it also helps to keep the OAL below SBR minimums (this is a pistol). I don't remember all the OAL intricacies right now but it was kinda close when I was looking at it.

edit--I think this was back in the pistol brace weirdness, and the ATF Form 4999 (which was then replaced before it was nullified entirely) specifically said "The weapon must have an overall length between 12 and 26 inches."

 

[calicojack]

I was trying to stay in the 8-inch range for portability, and it also helps to keep the OAL below SBR minimums (this is a pistol). I don't remember all the OAL intricacies right now but it was kinda close when I was looking at it.

edit--I think this was back in the pistol brace weirdness, and the ATF Form 4999 (which was then replaced before it was nullified entirely) specifically said "The weapon must have an overall length between 12 and 26 inches."

Hmm - ok. Will have to check on that.

 

[calicojack]

I was trying to stay in the 8-inch range for portability, and it also helps to keep the OAL below SBR minimums (this is a pistol). I don't remember all the OAL intricacies right now but it was kinda close when I was looking at it.

edit--I think this was back in the pistol brace weirdness, and the ATF Form 4999 (which was then replaced before it was nullified entirely) specifically said "The weapon must have an overall length between 12 and 26 inches."

While current court rulings have put a halt to the ATF pistol brace ruling, it could be overturned and it might be wise to either go with a shorter barrel or make it an SBR.

 

[yeehall]

Keeping it as a pistol is just easier all around (less work now and less hassle to own), and it can always be converted later if someone really wanted an actual stock. One nice thing about that removable stock is it avoids the folder penalty for copycats, which applies to SBRs.

 

[calicojack]

CryHavic ordered. Big chunk taken out of my ass money-wise, but worth it.

 

[calicojack]

And I have another 22 LR upper to add to this.

 

[calicojack]

Hey @yeehall what case is that? I want one (if the 10.5" barrel will fit).

 

[yeehall]

CryHavic ordered. Big chunk taken out of my ass money-wise, but worth it.

Hey @yeehall what case is that? I want one (if the 10.5" barrel will fit).

Condor Elite Utility Shoulder Bag 7L

 

[El_flasko]

That setup is slick