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Here are the details of my .45ACP AK conversion. I was inspired by pictures of the Bizon SMG to build something similar, but

I'm not a fan of 9mm. So, I decided to make one in .45ACP. I came up with the .45 idea after reading posts on Roderus forums about pistol caliber conversions back in 2004.

I had no idea that Mike from ORF had already built one in 9mm or that someone else had built one in .45ACP using a Camp Carbine barrel. Had I known this, I could have saved myself a bunch of design work and maybe avoided a few problems. In any case, I know more about the AK design and function than I ever cared to. I had no contact with Mike during my construction, and mine came out similar to his. Mine works and I'm happy with it (sort of). I will be tearing the rifle apart and rebuilding it to eliminate a couple of minor issues that I had.

These posts are copied from my Gunco threads detailing the construction of my .45ACP AK conversion. I eliminated some of the extraneous text, but didn't proofread all of the editing. Some of the text may be disjointed, but I think you can live with it and muddle through...





Dremel bits used to modify the extractor groove.





Correct bolt on the left. SERIOUSLY screwed up bolt on the right. I should have read the markings on the cutter and not what was on the storage tube...





Correct cup depth on the left. SERIOUSLY screwed up bolt on the right. The bolt slipped in the vise and I lost my zero. I cut it too deep...





.45ACP in correct bolt on left. .45ACP in SERIOUSLY screwed up bolt on right. Notice the big gap around the incorrectly milled bolt.





This is the basic machining done to the bolt carrier. The cuts were made before any welding because I wanted to make sure all the interferences were accounted for. The cocking handle has been removed, the clearance slot for the bolt lug is cut, the ejection clearance cut is made, and the firing pin access hole is drilled. Portions of the cuts will be filled with weld once the primary machine work is completed. The rotation channel will be welded up and a notch for the cocking handle will be cut.





This shows the position of the bolt in the carrier. The bolt has been cut to the proper length. The triangular tab on the back of the carrier has been cut flush with the back surface. The bolt will eventually be welded into place.





This is a close up of the cut bolt and carrier. I considered filling the 2 upper bolt grooves with weld and reshaping the bolt, but I think I'll just silver-solder the back end and leave all the welding at the front...





This pic shows the clearance channel for the bolt lug. This is what allows the bolt to slide straight in before final welding. There are several large gaps that will be filled with weld and ground to shape before final assembly. This will allow for a more solid attachment, and prevent the possibility of cracking.

The angled cut for ejection clearance can be clearly seen in this pic. It's tough to see in this picture, but this is the bolt that I opened up to fit the .45ACP cartridge. The extractor only required minor grinding with a dremel stone to get the groove to match the cup diameter.

With the bolt in this position, the ejector lines up correctly with the slot in the bolt. The 7.62 ejector rail will work perfectly with the conversion.





This pic shows the hammer engagement with the modified bolt and carrier. The striking face of the hammer is perfectly flat against the back of the carrier. Because I designed this for blowback operation, the bolt cannot be positioned in the forward position. For proper operation, the bolt must be shortened, moved closer to the back of the carrier, and rotated.

The bolt is shortened 0.800". Because of the bolt being shortened, the hammer will not make contact. My design calls for moving the trunnion back the same distance that the bolt was shortened. This will position the back of the carrier in line with the hammer face in the same place that the original bolt stem was positioned. Hammer function is smooth and the carrier easily pushes it back down to engage the trigger and disconnector.





I performed the alignment checks using a standard OOW receiver. This pic shows the carrier moved back exactly 0.800" from the postive stop of the trunnion. This lines the carrier up perfectly with the hammer. I will be using an IBE battle blank for the .45 receiver. The dimples in a standard receiver prevent the magazine from fitting into the receiver far enough.

The thicker blank is a little easier to weld on, as well. By only shortening the receiver by 0.800", standard handguards can be used without modification.





This pic shows the carrier seated against the positive stop of the trunnion. When the barrel is installed, the breech face will be right up against the face of the bolt. This gap between the carrier and trunnion is unavoidable, because of the position of the bolt. The barrel will take up most of the gap, but I will add a small piece of sheet steel to the top cover to keep debris out of the receiver. It will also look a little cleaner. This gap is present on the Bizon, too. The Bizon top cover is stamped to cover the gap.





This is one modification that early on I realized was necessary after deciding to weld the bolt in the carrier. The firing pin retaining pin cannot be removed once installed, unless a clearance hole is drilled. Once the bolt location is determined, the clearance hole was marked and then milled. I used 1/8" carbide end mills for this step. I started with a ball end mill to make the hole in the underside of the carrier. Then I switched to a standard end mill to punch through the top of the carrier. The rounded surface inside the recoil spring tube prevents drilling through the material. The sharp corners of the mill bit easily cut into the curved surface and allowed the holes to line up without breaking a drill or screwing up the hole.

(04/26/2008 EDITED TO FIX PHOTOHOST LINKS)
 

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Acme threads being turned off so I can rethread to 3/4-16. After I got it rethreaded, I silver-soldered the sleeve on. Then I did some rough work on the lathe to check out the joint between the barrel and sleeve. I need to clean up the groove on the breech face. The groove is left over from the threads that I cut. It won't interfere with function, but it's ugly.





I still need to turn the barrel to the correct diameters for the RPK blocks.





In this pic I'm turning the finish diameter (0.908") for the breech end. Once I had the breech diameter turned, I flipped the barrel end for end and took care of the other diameters.





This pic shows the majority of the work completed. I made REALLY small cuts since I wasn't using a shaft support. I was only taking 0.005" radius cuts (0.010" off of the diameter) to avoid flexing the barrel. That takes a LOT more time, but it works well. I had the carriage feed set pretty slow and used a really narrow pointed cutter (as seen in the first pic).

That gave a nice finish that polished up easily with some emery cloth.





This is the semi-finished barrel. The big step in the middle cannot be avoided. The M1A1 barrel has a taper at this point, and changes diameter rather abruptly. Unfortunately, this is right where my handguard retainer needs to be. I'm going to install a sleeve about 3/4" long to add the necessary length for the retainer. After that, the only thing needed will be to cut the grooves for the retainer lugs and the notch for the lock, then the barrel will be finished.





It's not easy to see in the resized pics, but there is a radius at each of the diameter transitions. I used a rounded cutter to leave a small radius in the corner. A sharp 90 degree corner is a perfect place for a crack to start.

I turned the barrel to fit a Polytech gas block. The Polytech block is still too small to fit the barrel, but I will ream it out. The RPK gas block has a HUGE diameter sleeve for the barrel and it will look a little odd. Another option would be a Yugo gas block, as it's the same diameter as the Chinese piece. I would prefer to keep it as traditional looking as possible, so I think the Chinese will be the better choice.







The unmodified 16.5" M1A1 barrel has the taper right where the handguard retainer needs to be. Because of this "inconvenience", I had to turn the taper off and then fabricate a sleeve to extend the portion of the barrel where the retainer goes.

After I soldered the sleeve on, I turned the diameter to fit the retainer. I won't cut the notch for the lock lever until the barrel is actually pinned in the trunnion. Then I can use the lower handguard to set the spacing for a perfect fit.





The receiver blank is a Robert Ibe 0.050" battle blank. In this pic, I have the rails roughed and the length cut as for a normal AK receiver. The line on the top of the template is my cut line for shortening the receiver. I removed 0.800" from the bolt/carrier, so that amount must come off the receiver to get the parts to line up with the hammer. I touched off the front of the blank and then cranked the table 0.800" to check my mark. Everything lined up correctly, so I made the cut. I have the stock tang slipped inside the receiver to act as a spacer to keep the sides from flexing in the vise.


(04/26/2008 EDITED TO FIX PHOTOHOST LINKS)
 

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This pic shows the shortened .45 receiver compared to a standard 7.62 OOW receiver. The notches for the top cover are just visible at the back.





Just drilling a few holes in this pic. All holes were center drilled before following up with the bit. There's a block of aluminum in the receiver preventing the sides from crushing in the vise. The square cut out of the magwell and pistol grip nut locations are just to help line the template up with the centerline of the receiver.





After all the holes were drilled and the trigger hole was cut, I flipped the receiver over and trimmed the rails to fit the carrier. The aluminum block is just too short to be visible in this pic. I made my initial cuts and checked the fit. I purposely left the rails a little wide so I could sneak up on a perfect fit. After a couple trial fittings, I got the carrier to fit quite nicely.





Here's the fit of the hammer against the carrier. The Trunnion is in the correct location, and the carrier is where it will be on the finished rifle. The fit is damn near perfect. I guess all that planning paid off...





Just a pic of the carrier in the forward position.





This is the gap that will be filled by the breech end of the barrel. The carrier is in it's most forward position.





Another shot of the interior. I still need to deburr the holes.





Here's a mock up of the receiver with the magwell and triggerguard. I'm going to make a cover out of sheet steel to cover the gap. The screw lug from the original grip will make for easy attachment. The cover will extend down over the mag catch tabs to secure the pivot pin. I will need to trim the top of the magwell to make it perpendicular to the top rails.


(04/26/2008 EDITED TO FIX PHOTOHOST LINKS)
 

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The bolt was positioned and TIGged in place, and then the valley was filled with the MIG welder. This is the side view showing the alignment of the pieces. I milled the bottom surface flat after it was built up with weld. It won't hang up on the hammer now.





Here's a little better view of the underside. You can see the hole for the firing pin retainer. The retaining pin can be driven out thanks to an access hole that is drilled all the way through the carrier.





Here's a shot of the rails installed. The rails were shortened 0.800" just as with the receiver and bolt.





Here's the trunnion in place showing the shortened distance between the trunnion and ejector. The ejector tab will wind up just at the back of the magazine when everything is assembled.





Here's the blowthrough from the last spotweld. This will have to be TIGged up when I have the magwell welded on. Everything went fine with all the other welds, so I don't know what I did wrong. I didn't hold it any longer than any of the other welds





This is how I modified the trunnion before installation. Once installed, the trunnion was milled to clear the magazine. I needed to be sure that the trunnion still had a heavy web that crossed under the barrel. If not, the trunnion could crack.

It still might, but I won't know until I fire it. The groove is for the cleaning rod.





Once I had the trunnion installed, it was time to press the barrel. I was really sweating this one, but I borrowed a really slick jig that made the installation a breeze. I must have done something right because the barrel pressed in fairly easily.

I had already cut the grooves for the handguard retainer, so I had to make sure the barrel was lined up correctly. When I do another conversion, I'll mill the grooves after the barrel is installed.

I pressed the barrel in until it was almost in place. Then I had to check the position using the carrier and several different brands of ammo. I placed a piece of shim stock on the case head and measured the gap between the carrier and trunnion stop. I adjusted the barrel until I got the headspace I was looking for. Right now there is about 0.008 to 0.010 gap between the round and the carrier. This should be just about right for blowback.


(04/26/2008 EDITED TO FIX PHOTOHOST LINKS)
 

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After the barrel was in place, I needed to mill out the receiver and trunnion for magazine clearance. I just kept plowing through the trunnion with a carbide endmill until I had whittled away both locking lugs and the ledge where the bullet guide goes.

There is no room for the lower rivets to be installed. I had my welder TIG the back of the trunnion to the receiver to secure it in place.

The orange stuff is the preservative grease spray that I soaked everything in. I will sandblast the whole thing again to get rid of the excess solder on the barrel blocks and to even out the finish for painting.





Here's another shot showing the clearance cuts that were done on the trunnion.





And here's the barreled receiver with the barrel blocks installed. I soldered the blocks because the barrel is too thin to risk pinning. It looks bent, but that's just my stupid camera doing the fisheye trick... It's a little discolored from the welding and soldering, but will clean up really well in the blast cabinet.





I got the handguards fitted and the retainer notch cut, and I threw some cheapo Krylon satin black on it to keep it from rusting while I was at the WV shoot.

It looks bent, but my camera likes to do a fisheye thing if you're not directly over the subject.

While fitting the carrier to clear the mag lips, I managed to mill through the weld that was securing the bolt in the carrier! I soldered it back in place and it is solid now. The bolt was only welded at the stipper lug on the bottom. When I tapped the carrier with anything metal, I swear I could feel the stem of the bolt moving in the carrier. Now it's soldered solid through the whole surface inside the carrier.

I had to slightly modify the feed lips of the magazine to get the damn thing to feed properly. I squeeked 0.050" off the top of the lips in the mill, and that was all it needed. I placed the magwell too close to the barrel, and the round had to make it in at a very steep angle. This caused the bolt to jam against the round before it was chambered. By trimming the feed lips down, the round exits the magazine a little sooner and doesn't jam. By moving the magwell back about 3/16", unmodified M3 greasegun mags will work.





After some test firing, the AK.45 still will not eject properly. I examined some of the spent casings and noticed that there was virtually no mark from the ejector on the head of the case. There is a small triangular mark, but it is nowhere near as prominent as it should be.

I removed the carrier and inserted a spent case into the cup. I rotated the case until the mark lined up with the ejector slot. The ejector needs to be making much more contact with the case. The impact mark is circled in red.

When my welder attached the bolt to the carrier, he had the bolt turned slightly. It wasn't exactly square, but was easily cleaned up in the mill. This resulted in the ejector slot being turned down at an angle. To get the carrier to clear the ejector, I had to bend it (the ejector) down a little. The ejector is bent down too far to make proper contact with the case during ejection. The case just barely makes contact with the ejector, so it just sort of bounces around in the receiver instead of being thrown clear. With the ejector tip so far down, the case also flips up into the gas piston extension.

To fix this, I recut the ejector slot with a 1/8" carbide endmill. I bent the ejector back up to get a good contact. This pretty much fixed the ejection problem.





Here is my .45 conversion with the plum and laminate furniture sets...

The plum looks more black in the pic, but it is actually plum. It's K-Var U.S. made copies, except for the lower handguard. The lower is Russian plum polymer for the RPK.

I usually prefer wood stock sets on AKs, but I think I like the plastic on the .45 a little more than the laminate.



Here are the links to the threads on Gunco.net. These show a little more discussion and some of the thought process behind my conversion.

http://www.gunco.net/forums/showthread.php?t=23434

http://www.gunco.net/forums/showthread.php?t=14157

http://www.gunco.net/forums/showthread.php?t=13867

http://www.gunco.net/forums/showthread.php?t=13639

http://www.gunco.net/forums/showthread.php?t=13360

http://www.gunco.net/forums/showthread.php?t=13091

http://www.gunco.net/forums/showthread.php?t=12837

http://www.gunco.net/forums/showthread.php?t=12556

http://www.gunco.net/forums/showthread.php?t=11448

http://www.gunco.net/forums/showthread.php?t=11170

http://www.gunco.net/forums/showthread.php?t=10878

http://www.gunco.net/forums/showthread.php?t=8781

http://www.gunco.net/forums/showthread.php?t=4153

http://www.gunco.net/forums/showthread.php?t=2966










04/26/2008 EDITED TO FIX PHOTOHOST LINKS)
 

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Man that's great! A .45 AK would be awesome, I'm thinking tons of cheap available handloaded ammo.
 

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damn...dude's got skills!!! :shock:
 

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That is super-cool. It is amazing what a guy with some skills can turn out. Thanks for sharing the process, really gets one thinking what they can do with the tools they have...or should have...
 

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That is most impressive sir. I would love to see some video to get a better feel for that rifle. I much prefer the laminate furniture set.

:razz: :razz: :razz: :razz: :beer: :beer: :beer: :beer:
 

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That's totally badass. :hail:

Didn't you show some pics of the build on MIGETA a while back?
 
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