Jump to content

5.56 AK from a 74 kit?


Recommended Posts

Who's done this? I've been reading up this for the past few hours and I'm convinced I'd like to do this but I don't know whether to get a 5.45 or 5.56 receiver. I'm leaning toward the 5.45 receiver.

 

Anyway, here's the parts list I believe I'll need:

 

74 Kit

5.56 barrel

And of course a NoDak receiver and some 5.56 mags.

 

I hear the 5.45 bolt will work on the 5.56 cartridge with some work on the extractor so that's all right. What am I missing?

 

ETA: I figured I would mention I'm invested in the 5.56 caliber so I don't get any "why not 5.45" replies.

Link to post
Share on other sites

I have all of the parts, including the APEX 5.56 barrel. I just haven't started yet. I will be using a NDS-2EZ receiver with side rail mount.

 

The 5.45 bolt will work with 5.56. Just needs to be headspaced properly. Not everyone has to tune the extractor. Mine cycles fine in a Saiga .223 (it headspaces OK).

 

I also decided to skip over 5.45 and go straight for AKs in 5.56. I have no intention of getting into 5.45 - just 7.62x39 and 5.56.

 

Since the trunnion still has the original chamber stub intact, I've done hand feed testing using 5.56 mags and the 5.45 bullet guide. The 5.45 bolt strips 5.56 snap caps from the 5.56 mag just fine, and the 5.45 guide properly guides them to the chamber. Of course they don't go all the way in, but it was just proof testing to see if I needed to pull the bullet guide. Others have left the 5.45 guide and had zero trouble, so I hope I get lucky there. I may just decide after all to install a Bulgarian 5.56 guide when I have the trunnion fully stripped - dunno. They are extremely similar.

 

If you search around the web you'll find others that have done similar projects in the past. Usually the problems are in matching the available 5.56 barrels to AK-74 or AKM parts. The nice thing about the barrel from APEX is that it's profiled to work with a normal AK-74 kit, so you're good to go. The APEX barrel is very well made, with all the proper cuts and prep work done. My handguard retainer even slid right on and locked down without any fitting required - wasn't expecting that. I suspect this will be an easy barrel to populate and headspace.

 

FWIW I called APEX and asked about these barrels. They claim that they were sourced as a custom order from AK-Builder. Follow the paper trail some more, and AK-Builder sources from Arms of America. Who is Arms of America's barrel manufacturer? Montana Rifleman.

 

It would be nice to be able to easily use the Bulgarian 5.56 barrels, but they have several odd dimensions and fitment issues that negate using with an AK-74 kit. At the point that you're using Bulgarian barrels, you might as well just buy a complete bulgarian 5.56 rifle.

 

The trunnion doesn't seem to be picky about mags so far. The trunnion fits Polish Beryl, Promag AK-223, and Circle-10 5.56 magazines. Tapco Galils are very close but will not fit without some minor modification to the mag. If using a Galil mag is important to you, I can show you where a step down in the trunnion needs to be machined to use the mags unmodified.

 

I will probably just use Beryl, C10, or Promags with the two rifles (its companion is a Saiga .223 /w full AK-74 conversion) for a standard set of "good" and "beater" mags.

Edited by mancat
Link to post
Share on other sites

I'm glad I'm not the only one who has been looking into this. How far are you on this build? Do you have it documented anywhere?

 

Are you having any trouble with the 5.45 receiver and the 5.56 cartridge/magazines?

Edited by Jon_L
Link to post
Share on other sites

The C10 5.56 mags I have wont fit in my SGL reciever without modding it. Too wide. But your quest can be done with a little effort. Mancat, it sounds like your getting a bit closer to getting this started. Id like both of you to keep us posted on the progress. Im curious to see how much is actually involved and what you have to mod to make it run properly and what kind of issues you may run into.(if any).

Link to post
Share on other sites

I've only read into it today, so I have nothing but links for what to buy. And due to my lack of time/tools/know-how I may just get a local gunsmith to put it all together. Thanks for the support, and that avatar couldn't be better.

Link to post
Share on other sites

Actually I'm sort of curious if Bulgaria is using the same bullet guide design for 5.45 and 5.56 now. Does anyone here have an SLR-105 that they could snap a shot of? I already know what the SLR-106 5.56 guide should look like, just need to see if the SLR-105 has the old "twin cut" style guide.

 

This is the current SLR-106 5.56 guide

 

iFGUS.jpg

Edited by mancat
Link to post
Share on other sites

Yeah I have seen the SGL-31 guide. Reason I ask is because Bulgaria has deviated quite a bit from standard stamped design in the last couple decades. Their stamped SLR series are really more of a mish-mash of AKM and AK-74 designs, versus their older military AK-74s that were near blueprint identical to Russians.

Link to post
Share on other sites

Because neither steel nor Tapco Galil magazines will fit into the recess of the AK-74 front trunnion. Galil magazines are designed to fit into an AKM trunnion. One of the reasons they work with the Saiga .223 is that the Saiga uses an AKM trunnion. The AKM trunnion used in the Saiga .223 can accept either AKM or AK-74 spec magazines.

 

Now if you're just talking about using that style of bullet guide, but not the mags, there is still a problem...

 

1) The AK-74 trunnion is also already set up to use a riveted guide. Technically you could just slap in a CSS/Dinzag bullet guide, drill out the threaded hole, and rivet it in, but you're missing another function that the rifle needs; next...

 

2) The bullet guide used in most AKM and AK-74 style trunnions has a short ear on the left hand side that acts as a final ramping surface to assist the bolt in entering lockup. The Saiga (and AK-100 series) instead use a small protruding rivet (this is the "third rivet" on the upper left side of the Saiga receiver) in this location to the same effect. This rivet acts as a small static bearing. This rivet allows the Saiga bullet guides to be just a simple tab of steel.

 

You really want to have the correct bullet guide with this ramping surface in a standard build, because without it, the bolt lockup is only assisted by the camming surfaces in the carrier.

Edited by mancat
Link to post
Share on other sites

Mancat, My Izhmash plum 5.45 mags wouldnt fit into my Saiga .223. They appeared to hit in the same spots that the 5.56 C10's hit prior to modding them. Dont know what the deal was with it. I wasnt able to get mine to seat just for the hell of it. Never really thought much about it though.

 

What kind of GB did your kit come with? Did the Bulgarians ever have issues with the bullets sheering with 45 degree blocks?

Link to post
Share on other sites

There are two spots where the mag can hit in the Saiga. The mag will either hit the bottom of the locking lugs, or will hit the sidewalls of the trunnion below the locking lugs. AK-74 mags will not hit the sidewalls because all of them are narrower than the wide Saiga trunnion.

 

Most AK-74 mags will fit into the Saiga .223 but they will hit the bottom of the locking lugs. Either you mod the mag by removing a bit of the forward feed lip area, or mod the trunnion by milling a small portion of the bottom of the locking lugs until they match the AK-74 trunnion lug dimensions.

 

If you were to ask me why this was done, either Izhmash thought they needed the larger AKM locking lugs to withstand 5.56 pressures, or this was done to prevent insertion of 5.45 magazines into the 5.56 rifle. No idea to know which.

 

Another indicator that the Saiga trunnion is otherwise the same as what is used in the AK-103 or Saiga 7.62x39. My Saiga .223 will take every 7.62x39 magazine I have.

 

All Bulgarian AK-74 gas blocks are 90-degree blocks. They are identical to early-mid 80s Russian.

Edited by mancat
Link to post
Share on other sites

Cool. I figured thats what the deal was. lol. If I had to guess though, Id say they did that to keep people from inserting the wrong mags, as they do share a similar angle. Same reason they slightly changed the design of the front spine of 5.45 vs. the 7.62 mags. Not sure on the pressures though, but I always thought the pressure of the 5.45 is higher than the 7.62x39. Hard to say, but still interesting none the less.

 

Wasnt too sure on the Bulgies. Not sure on what all they copied and what they didnt. All the blocks Ive seen recently have been 90's, but I have seen a few parts kits a while back on gunbroker that had the older 45 degree blocks. Had to be old as hell though as they went to the 90 degree blocks back in '77 IIRC. I should have bought it for the hell of it .lol

Link to post
Share on other sites

Well when they made their own Type-3 milled AK-47 it was definitely a 45-degree block. But they have actually retained the 90-degree block on their current milled production rifles, which is why a newer Bulgarian milled rifle sort of has that odd appearance mix of old and new design.

Link to post
Share on other sites

I know Im late on this but....

 

I bought one like this a few years back. It was a 5.56 Norinco converted to a 5.45 with a Bugy kit. From my understanding is its cheaper to buy something like this than it is to build it. even though the 5.45 and the 5.56 are very close the 5.56 AK parts ar not standardized and stuff has to be milled out. The stuff will depand on what parts you are trying to match. From what I was told about my rifle is that the Norinco trunion would not accept the Bulgy 5.45 barrel without milliing. There were other things too but I forget.

 

What I have is....

- Norinco receiver with front trunion and trigger guard

-Bulgarian front end and bolt/carrier (from the same kit)

-Russian 100 series folding stock, FCG and break

- Unknown furniture. Either Russian or Bulgarian

 

This rifle was built prior to 922r

Link to post
Share on other sites
  • 3 weeks later...

Update: Picked up a kit off ARFCOM for $200, and am now seeing that NDS has a notice on their site about all the receivers being out of stock. I'm faxing them an order on Jan 1st to see what the wait time is and will see, I guess. Until then, if anyone has a line on a 5.56 receiver please let me know.

Link to post
Share on other sites
  • 2 weeks later...

Got the parts kit in today. Looks as though all the parts are present. I ordered a receiver the 28th, but most orders take over 2 weeks to ship so it's coming up. This guy sold me a barrel for $100 when I panicked about K-Var shutting down.

Link to post
Share on other sites

Nobody makes a 5.56-marked receiver any more FYI. The 5.45x39 receiver is going to be identical. The ejector will work with 5.56. I contacted NDS a couple of months ago and asked if they would be producing any more receivers marked with "Cal 5.56x45" and the answer was no, so if you plan to use their receiver you may also want to keep in mind that the caliber marking will be wrong.

 

Also I hope your barrel is not a Bulgarian barrel. Many of them have the wrong barrel lug collar size and length to work with an AK-74 bolt and trunnion. They are intended for use in a milled receiver or with the SLR series trunnion and bolt, which use a mix of AKM and AK-74 dimensions. Not only will the barrel chamber lug need to have its diameter reduced from 23mm to 22mm to press into the AK-74 trunnion, but this also means that once its headspaced, the barrel may not properly line up to use any factory-drilled pin channels, and the gas port may be in the wrong position. This is the reason why I skipped out on the Bulgarian barrels from K-VAR and bought one of the AK-74 profiled 5.56 barrels from APEX instead.

Edited by mancat
Link to post
Share on other sites

That's odd. When I spoke with Harlan late Dec he said he had a few leftover from the last batch that were marked "5.56," so I ordered one. It was a side-folder.

 

And now you have me worried! Haha. Is there anyway to tell if the barrel is the wrong one?

Link to post
Share on other sites

I actually think the side-folders are the only ones they made a recent batch marked 5.56. I never meant that they never made them, but only that they stopped doing custom markings or 5.56 markings. I specifically asked about the NDS-2EZ with a 5.56 marking since mine will be a solid stock. I'll just pay someone to etch it later on or do it myself somehow. I don't sell any of my AKs so I don't really care if the marking is wrong TBH.

 

The easiest way to ID the barrel when you get it is to just check the chamber lug OD with a caliper. If it's 23mm then your project just got interesting. In that case, the "easiest" solution becomes buying a matching 5.56 trunnion, bolt, and carrier from K-VAR - these parts are all incompatible with the AK-74 kit so they need to be paired up together.

 

The barrel can be made to fit into an AK-74 trunnion and work, but it involves a bit of machining work, and as I mentioned earlier the component locations on the barrel will likely change once the barrel is headspaced. If the barrel is just a blank with no gas port, HG retainer latch, or pin channels drilled, then it's really not a big deal.

 

The Bulgarians chose to abandon the AK-74 blueprints when they adopted 5.56 caliber, and instead they mixed features and dimensions of the AK-74 with the earlier AKM and milled receiver designs, so this is why things are different and frustrating. But they did the right thing for their logistics - the same parts will work in both milled and stamped SLR series rifles.

Edited by mancat
Link to post
Share on other sites

Incorrect markings aren't really a big concern to me, either, but the guy I have building it really stressed the "5.56" marking on the receiver. I have a few calipers around at work so I'll measure it when it comes in.

Link to post
Share on other sites

NDS is required to mark them by law. It means nothing to you as a owner of the receiver or any firearm that it's built with, UNLESS you want to use it to build an NFA firearm, In that case you need to have the correct caliber marked. That's my understanding of it.

Link to post
Share on other sites

No way that's true. It makes too much sense to be a law. rolleyes.gif

 

Thanks for the info, though. Also just remembered the barrel doesn't even have a gas port--its threaded and rifled, is all. Going to need machining, anyway.

 

Kind of feel like a wuss compared to you guys that build your rifles hah. I put together an AR once... ONCE.

Link to post
Share on other sites

Hmm.. The only threaded 5.56 barrels I can think of that are available on the market recently are the surplus E. German Weiger barrels. Those are going to be a decent amount of work to adapt to an AK-74 kit. You'll have to get a pic up when it comes in so we can ID it.

Edited by mancat
Link to post
Share on other sites

Sounds good. I just sent off the payment Monday so I won't get it until the end of next week. Will do.

 

Also, anyone have any luck putting a fixed stock in a Side-folding receiver? If it won't work I'll need to put an order in to Bonesteel.

 

ETA: So as not to sound like an idiot, I'm going to go further into that question: As a temporary fix, has anyone had any luck getting a fixed stock to work in a SF receiver, so this project isn't held back further so I can order the SF stock?

Edited by Jon_L
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Chatbox

    Load More
    You don't have permission to chat.
×
×
  • Create New...