Wednesday, June 26, 2013

An update to the puzzle piece AR lower

I've been on light duty around the house while my hand is healing, so I haven't accomplished much.
However, I have worked on my puzzle piece AR lower, courtesy of Jack Squat's Flat Spot.

I've knocked quite a bit of weight off this already just by milling the slots in it. It's still approximately twice the weight of a standard milspec lower, but that's far from a problem.
Hopefully this weekend I will weld the buffer tube on.

This has been fun to tinker with since my dominant hand is mostly out of service, but welding has been a real challenge. Thankfully, most of the welds were easy to grind, file, and sand out.

More projects and work soon to come, I hope.

Sunday, June 9, 2013

Making a .300 Blackout AR.........from a shovel?

Just kidding. No shovels needed.*

This post is one of a series I will be writing about the AR pattern rifle I am building in .300BLK

For starters, some background.....

The .300 Blackout, also referred to as the .300 blk, or just blk, is the brainchild of the Advanced Armament Corporation, or AAC. It is a .30 caliber cartridge that uses the 5.56x45mm parent case, and is trimmed down then necked out for a mid-weight .30 cal bullet. It allows anyone who has a AR15 to shoot an effective, accurate, powerful round using all the same equipment as the standard 5.56x45, except for the barrel. It can be loaded to subsonic levels, for very effective use with a suppressor, or to hypersonic levels as with any  normal rifle cartridge. It has taken the AR world by storm, and for very good reason.

(I know I'm not giving all of the little details on the round, but that's what the wiki link is there for.)

So, since I have mentioned on this blog before, I have machined several AR lower forgings (I've even welcomed fellow gunbloggers into my garage to machine their own and now need to build them into functional rifles. I've got plans for each of them, from different pistol calibers to standard 5.56, all the way up to a belt fed. One of them, however, will be in .300 blk, because I don't already have an AR in .300blk and everyone needs at least one AR in every caliber, right?

Since the everything about the .300 blk interchanges with the standard 5.56 AR, I've got a pile of parts here including bolt carrier groups, magazines, upper receivers, and furniture. The one thing I don't have is an overpriced .300blk barrel, and no matter where I looked, I couldn't find a barrel for less than a couple hundred bucks. My solution was simple; make my own.

I went over to the good folks at Green Mountain Barrel** and saw that, at the time, they had some 17" long .30 cal 1:10 twist barrel blanks for about 30 bucks apiece. I called some of my buddies up and got a group order going, then we all went in on a .300blk finish reamer and headspace gauges. That way, we all got a .300 blk barrel out of it for about 75 bucks each.

A barrel blank is just that, a rifled piece of alloy steel that has no chamber cut, nor a profile. Here is a pic of the barrel blank, sitting atop my table saw.

There is no chamber cut, it is just a rifled tube.

Since we are going to put this on an AR, the barrel must be turned for a barrel extension, which is what the locking lugs on the bolt engage with when the rifle is fired.
First, the barrel was turned between centers such that the entire outside diameter was parallel to the bore of the barrel, the ends were cut square and adjacent to the bore, and a .630" long section was machined down to .825" OD

Next, that same area is threaded 16tpi to match the barrel extension.

Next, we begin the task of chambering and headspacing the barrel. The barrel extension will be screwed on and off several times so we can check headspace using a GO gauge and the AR bolt.
Not shown in these pics is the floating reamer holder.

I got done chambering and headspacing, and was turning the rest of the barrel down to profile it when a very thick and razor sharp metal shaving caught me on my thumb, and cut my thumb from base to tip, all the way to the bone. Several stitches later, I've finally stopped spreading my DNA around, but this project is on hold until I can finish healing.

There's more yet to come on this installment. More as I get to it.

*No shovels were harmed in the making of this rifle.

**I've had very, very good results from GMB barrel blanks, I chambered and profiled a 20" .30 cal blank I purchased from them, for a Remington 700 in .300 WinMag.
The barrel worked out nicely, with several < 1" groups right off the bat. More than accurate enough to start with, and the groups get better as the barrel is broken in.

The "puzzle piece" AR15 lower is now available

If you had any interest in the weld-together "puzzle piece" AR15 receiver I posted about previously, the manufacturer is now releasing them for sale.

They are not listed as of 1330 central time 06092013, but the manufacturer says they will be up sometime today. If you are just too darn impatient to wait, email the owner and tell him TheRedneckEngineer sent  you.
I have no information about pricing just yet, as I've said before I have no connection to the manufacturer aside from being a overzealous customer.

Anyways, go bug Rick at and feed your habit buy some very well made gun parts.

Monday, June 3, 2013

The puzzle piece AR15 receiver, (or my personal contribution to the gun control movement.)

I have heard a number of calls for gun bans for quite some time, especially for anything that looks or functions like the AR15. Over and over again, we are told that if we just get rid of the AR15, peace and prosperity will once again touch our nation. Criminals will realize the futility of their actions since they are no longer permitted access to the most dangerous and most powerful firearm ever known to man, and will voluntarily disarm and change professions. School buses full of children will no longer be at risk of being blown off the road by some madman, spray firing from the hip a black rifle with one of those never-ending 30 round clips magazines. Aircraft can safely transverse the skies once more, with no worries of one random skilled shot from the overwhelmingly powerful 5.56x45 cartridge.

Given that our benevolent government has worked so hard to protect us from.........uh, us, through their decision to ignore all the somewhat important issues and instead concentrate on the arbitrary non-issues really important issues, I thought it was time to show my appreciation for their efforts.

This is a AR15 lower receiver. Or rather, several of them.

So is this.

What is this, exactly?

It is what I like to refer to as a puzzle-piece AR15 lower. It is yet another way for someone to build a gun with little to no special tooling. While it was originally intended to be welded together, it could be soldered, brazed, epoxied, or even drilled and bolted together.

That's correct, you can make an evil black rifle death machine high capacity ammunitions GUN that momma .gov has no control over, nor proof it exists. No paperwork, no background check, no problem.

Here is how they ship.

And here it is, mocked up for assembly.

(No, I don't make them. Don't email me and try to order one. If you want one, I'll ask the manufacturer when he plans to offer them to the public, and I'll put up a post about it.)

So, to all the gun control proponents out there who wish to deprive me of life, liberty, and pursuit of owning one of every firearm made (at least one, maybe more)........go ahead, buy one. You know you want to.