The TRUTH About AK-47 Receiver Thickness!

[ROGER4314]

I decided to cut through the crap on the stamped AKM receiver thickness story and started carrying a 1" micrometer around with me. Whenever I got a chance to measure an AK receiver thickness then, that's what I did. I was fortunate that my Gun Shop friends let me examine rifles that they had in stock either belonging to them or items what were being worked on.

ONE Millimeter is .0393" and is roughly 20 gauge steel.
All rifles were measured at the top of the receiver just forward of the stock. There's a nice place where the micrometer will fit perfectly. Remember, the receiver is stamped as a "Flat" then bent, so it's the same thickness all over except where letters are stamped. I avoided those places.

Remember, the smaller the "Gauge" NUMBER, the thicker, the metal is. 18 gauge is thicker than 20 gauge.

I measured each one personally. Here are the results:

N-PAP folding Stock Zastava recent build = .0370"
This is .95 millimeter. 20 gauge steel.

N-PAP wood stock Zastava recent build = .0365"
This is .93 millimeter. 20 gauge steel.

Older AK from parts kit using a EwBanks receiver = .0435"
This is 1.12 millimeter. 19 gauge steel.

Romanian Wasr recent build with wood stock & side mount rail = .040"
This is 1.02 Millimeter. 19 gauge steel.

Chinese AK Older build = .0585"
This is 1.49 millimeter. 17 gauge steel

Saiga new build = .0726"
This was a surprise so I checked the trigger guard metal as well = .0615"
Receiver is 1.85 millimeter. It is 15 gauge steel.
Trigger guard is 1.56 millimeter. It is 16 gauge steel.

Conclusion:
Bashing Saiga and Romanian Wasr rifles is pretty foolish! Chinese AKM's are pretty impressive, too! These rifles have receivers that are thicker and, as a result, stronger!

Special thanks to Trinity Bay Tactical!

Flash

 

[Anger]

thanks for this ~

 

[WarBaby]

This is good information, thanks for posting this.

 

[Orbie]

Pretty cool. Excuse my ignorance but would this comparison be viable with AR lowers also?

 

[texas skeeter]

Chinese AK Older build = .0585"
This is 1.49 millimeter. 17 gauge steel


Flash

So does that mean my 1994 Norinco is 17 ga.? or does it have to be older than 94? And THANX for the info Flash. Yer alright and I don't care what they say about you ya OLD Buzzard!

 

[WarBaby]

Pretty cool. Excuse my ignorance but would this comparison be viable with AR lowers also?

 

[Younggun]

 

[CrazedJava]

Argh! I keep talking myself out of a WASR. This isn't helping!

 

[Orbie]

LOL I'm serious. Common sense says yes but...

 

[ROGER4314]

Hey Skeeter.....Glad you're back! I'm just getting older but it beats the alternatives!

Re AR-receivers. Most of them are precision castings or forgings so thickness variation is probably not of any consequence. CNC machining is so precise that variation is slight.

The exception to AR receivers is the "Billet" which is machined out of a solid block of aluminum. They are very thick in several places like the base of the mag well. The "Sun Devil" website has a great flick showing a billet receiver being machined.....Check it out!

Chinese AK receivers. I always heard that they were thicker/heavier but I only got my hands on ONE of them. I hate to form a conclusion based upon only one sample. It is probably a heavier gauge receiver but I couldn't swear to it.

I measured a bunch of AK receivers and feel pretty confident that the information posted is accurate.

RE Wasrs: I've heard people cuss the wasrs and yet the receiver material is really heavy! I had a pair of them and liked them a lot! Buy one...Buy two! One never has enough AK's.

So.....why is this receiver thickness important? I went to the Arsenal guys and wrote them a blank check to build me an AK that was competitive at 200 yards for NRA HP Rifle matches. It was a point that I was trying to make and I was willing to spend a couple of grand on the project. (Note: I was working then. Had a real job!) They turned down the job! They said it could NOT be done with a stamped receiver....only a milled one. HMMMM.

Then I wondered about the hype about some receivers being 1 1/2 MM thick. In fact, some are that thick. The next experiment is to snag a Centurion milled receiver based rifle. The checkbook says "No way!" right now. More later!

Flash

 

[breakingcontact]

Are we comparing apples to apples here? Same type and quality of metal?

 

[ROGER4314]

If I could grind a bit off of the receiver, the sparks would tell us a lot about carbon content but I'm not sure folks would let me do that.

A Rockwell hardness test would help but even though I've used the Rockwell testers, it would be plenty tough to find a place on the receiver to test. In some products, if they heat treat the complex part, they attach a test coupon of the same material onto the part with wire, put it through heat treat then test the coupon. But ..for now....we really can't say what the materials are.

Flash

 

[TXSlade]

I'll throw in a couple points, receiver thickness is of some importance, but it is a small piece of a large pie. Those of us who like to build our own AK's have learned that there are so many variations in manufacturing it's staggering. Rivet quality. Does the builder harden the whole receiver or just the key stress points. The front trunion rivets, does the builder use the barrel as a bucking bar? Or does he rivet the trunion in then press the barrel in to insure a tighter fit? Are they using swell neck rivets in the proper places and diveting the receiver before putting said swell neck rivet in that position.

Having demilled Ak's you would be amazed how a well built ak and their rivets will bond together. The rivet will actually swell within the trunion and hold the steel together as if welded. I've seen American made version I could take apart with a table knife. Although I use the "underfolder reinforcement plate" support piece for the grip, a build which uses a 1 mm receiver, I have yet to find anyone that had any trouble with a build that opted to not use it.

Lol, and I'm an M-4 guy, I just like building stuff.

 

[ROGER4314]

Talk about AK's often include claims about receiver thickness. This project was designed to prove or disprove the hype used in sales of these rifles. Most of the rifles were borrowed, new or awaiting service so we had limited opportunity to check them out in depth. Some of the hype was true. Some was ....well,...... not accurate.

Incidentally, you taught me something new, too. I saw your reference to "swell neck" rivets so I checked into them. Sure enough....new information for me! They are designed to swell when set and they make very tight junctions! Thanks for that.

In heavy manufacturing, rivets are installed red hot, set while hot and when they cool & shrink, form an extremely tight bond. It's a different process but for the same purpose.

Good posts!

Flash

 

[Acera]

If you want some good information on AKs, do a youtube search for 'Rifle Dynamics AK Builder Class'. Those guys know their stuff and explain not only how, but why certain things are done.