Built an AR70!

[barnbwt]

Baby's first build (not saying much; 8 welds and some grinding )

Test fire will happen this weekend most likely, provided I make up my mind on whether to go with a rail or the original sight base up top. I may or may not attach the dust cover. If things go as planned (I have no reason to doubt) I'll buy some more GI mags to convert and probably make a folding stock (you foolish 922r, you're only making my rifle more evil ). Oh, and looking into paint/parking .

Although, there is a walnut stocked version out there that is very handsome

This rifle is basically an AK upper atop and AR-style lower (trigger group is totally different and totally complex, but whatever). Long stroke gas piston with a two-lug rotating bolt. The carrier and bolt head look almost identical to an AK, the upper receiver shell/tube has a welded-in barrel trunnion which contains the locking surfaces (like the AK) and the return spring is around the piston. The upper receiver is attached by two push-pins to the lower, and is closed out by the front of the butt stock.

Semi mods were very easy, accomplished with a Dremel prior to putting together the receiver and very well documented in Arizona Response System's tutorial. Honestly, I can't imagine an AK build being much easier than this, and with these kits being ~400$ plus another ~100$ for the receiver (mine was not an 80%), the money is comparable to what nice AK parts kits are going for. Except this gun, while functioning like an AK, is far nicer and far more ergonomic. Even has a bolt hold open, winter trigger, gas cutoff switch (the grenade sight), and decent bipod. Caliber 223, takes modified GI mags (rock-in). Pretty much a SIG 550 series (SIG supposedly helped Beretta with this design )

Anyone have experience messing around with these rifles?

TCB

 

[SilverCat]

Very vey nice!! I've taken a look at those, where on earth do you don the parts?? I think that that may be an awesome rifle to use. Heck, it would also be cool to so a little modernizing on a second one and use it at competitions. You'd get alot of mods like that, I'm sure. Very well done!!

 

[barnbwt]

My kit came from Numrich (use Google to find their AR70 kits, not their crummy website search), my receiver from a private vendor who is now doing incomplete recievers, (PM me for details, I don't want to overwhelm a one-man operation should this go "viral" for some goofy reason ), and trigger modifications according to the Arizona Response Systems tutorial.

Not counting the eventual need to assemble the rifle 922r compliant at the end of the day, it's two Dremel cuts and about 10 plug welds to get things running

Major points of modification;
-drill/grind spot welds to remove scrap receiver pieces from kit parts
-cut off arm of autosear (the body remains as a spacer in the trigger pack)
-flip automatic feed tooth around and weld in place (this is the FCG denial feature to prevent restoring full auto)
-cut off trip arm of disconnector (makes it semi-auto at all selector positions)
-grind autosear trip off of bolt carrier (so it will fit into your semi-auto receiver)
-align trunnion and receiver using the lower pins and gas system, weld in place
-align, then rivet or weld ejector in place
-attach rear sight or rail (here's where my indecisive butt is stuck )
-replace select components w/ 'murican made stuff for 922r

TCB

 

[Jeremy2171]

Talk to me about modding GI mags.....

 

[barnbwt]

Someone on weaponsguild did a great tutorial (sorry, I can't link it directly due to login). Basically it was welding two .063 mag catches to the front and rear, and grinding them to the proper elevation to sit in the magwell properly. You're basically replicating the sheet-metal wrap-around at the top of the USGI mags, but only on the ends. Not bad since the mags go for like 60$ these days.

TCB

 

[stressed]

Nice weapon!

 

[barnbwt]

Thanks for the compliments, guys. Any recommendations on DIY finishes? (I'd rather not ship this one off to a painter if I can help it) I'm thinking winter camo would look pretty cool on it. I've also decided to slap the original sight on the rear, and attach a segment of rail ahead of that

Darn shame the rib on top isn't a bit narrower; you could just about add some weldment to the sides and machine it into a rail itself

TCB

 

[Shear_stress]

Awesome project!

Are complete US-made receivers still available?

 

[barnbwt]

There are a couple people making receivers (I'd avoid Cold Steel Solution's specifically considering some of the things I've heard/seen online and in person regarding everything from their designs and production quality, to their quality control and general business practices. Their AK shells are supposed to be good most of the time, though )

Believe it or not, simple rectangular tubing (in a common size, no less) works for this, but it'll have squared off corners at the top. The build I saw with this looked identical from the side, though, and properly painted, looks pretty nice (he milled the bead grooves into the exterior to beautify it as well)

I just returned from a successful range trip (the AR70, the new VZ61 Skorpion, and the repairs to my VZ58 drum conversion were all working well) in which the AR70 did just fine. This is the first time I've shot 223, so I was expecting 7.62x39 recoil, and the AR70 is just about the same on the shoulder as my VZ (which means a bit less than an AK). Groups were about 2" off the bull at 10yds, totally un-sighted in --not bad for aligning the barrel and rear sight base by eyeball . I hadn't appreciated before how similar the manipulation is to my VZ; reciprocating handle on the right, selector lever above the grip (opposite side, but safety in the same place), and bolt release (also flipped). Very familiar compared to the much more diverse stuff I usually shoot (FNAR, K31, SKS, FN49)

The next step is getting a removable rail placed up top, since the little peep sights are kinda useless in low light (test fire was about 5:30pm) and force you to lean down on the stock. I'll also see about getting a folding FAL-style stock modded to fit somehow, since I think a folder would suit the gun nicely.

No video, though I did take one; the combination of my camera/editing software makes it a royal pain to upload movies. Here's a post-trip picture of the gun, though (note the now-present sight base and more prettier welds that have been ground flush)

TCB

 

[CornCod]

Wow! What a tribute to ingenuity! On behalf of all the serious shooters all over the US who have low visio-spatial intelligence (the fancy term for poor mechanical ability) we salute you! I can't even fix the hinge on my screen door.

 

[Jeremy2171]

Look what just showed up....snagged these for a steal and the four on the left are almost brand new!



Got a receiver on order..should have it next week. I'm thinking I should order a parts kit now!

 

[barnbwt]

Nice score! Hopefully from a guy who wasn't asking the 60$ going rate. I got the dust cover riveted on the other day and took it for another spin. Everything is flawless, so far. I am told recoil is "different" than that felt from other 5.56 guns like the AR, I presume due to the higher reciprocating bolt mass. Very well-designed gun. On to the next grand adventure...

TCB

...It's a STGW57 in 7.5 Swiss running on a converted 63rnd DTM pan/drum; Der Übermensch (that pistol grip is a good 5" long, the rifle really is that enormous)

 

[Jeremy2171]

Got them for $27ea...couldn't pass that up.

Hmmm..never did get in the Swiss semi game..perhaps I should have.

I like the drum mag....looks "noice!"

 

[rklessdriver]

WOW. That is a very nice build.

I hope the dude in Oregon gets more of these recievers out. I assume that's where yours came from.

As for the finish have you considered RUST BLUING it? Would look great.
Will

 

[Jeremy2171]

Got mine done...still need to do a few little things..but it works great right now

 

[barnbwt]

Nice

BTW, Mossberg 500 pistol grips (found discarded by the thousands ) can be easily modified into a 922r compliance part.

TCB