Type 81 build/conversion in 223/5.56 NATO

Thank you fellow CGN'ers for your kind words of support!

Preparing for the trunnion mods, trying to think twice before cutting off anything that I later can regret of ��
So far plan is like this:
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Orange - material to dremel off
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Plan of action so far
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In the process
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Mag now fits in, highlighting more challenges:
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Bullet tips sit too low and won't go up, unless feed ramp or magazine angle is modified. Magazine angle appears correct, judging by the top lips of it, so ramp it is.
Bolt hold-open catch no longer works, given construction of the 5.56 mags.
Mag catch internal needs to be trimmed off a bit - it does not latch, but is the easiest of all items
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If anyone knows of any AK's in 5.56 that have bolt hold open feature, I will notch mags for the catch to sit idly. If not, i fill remove the bolt catch and will leave mags intact
 
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Awesome job! And I’m glad that progress is resuming :)

Before grinding and feed ramps, I’d double check that the bolt can actually pick up rounds from the mag if it’s sitting that low.

Keep going! Thanks for posting progress pics and I’m excited to see the final result!
 
b-wingpilot said:
Awesome job! And I’m glad that progress is resuming :)

Before grinding and feed ramps, I’d double check that the bolt can actually pick up rounds from the mag if it’s sitting that low.

Keep going! Thanks for posting progress pics and I’m excited to see the final result!
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True dat! Right now back of the mag can go higher - only the bolt catch is stopping it. I will remove the catch for now. Front of the mag is at its max - the mag walls are touching the trunnion. It is possible to remove a bit of metal, but I will experiment with the elevation of the rear first, to make sure bolt can strip the round. Will need to proceed with caution :)
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Bolt hold-open catch is doing nothing, forced to its on position by the mag
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Had to remove metal from the rear of the well, 5.56 mag needs that. I don't have a mill so used dremel for now.
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Bolt catch is removed, magazine now sits great - bolt reliably picks up a round. It became obvious that the front of the magazine also needs to go up by 2-2.5mm
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To elevate the front of the mag, these symmetrical areas need some shaving. Alternatively, magazine walls could take dremelling, but I see it as a sinful way. Starting to think now that the AR mag adaptor may be the way to go for the next conversion.
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P.S. Wingpilot, saw your custom-built semi rifles on the chopping list too, sorry about that. Murray Smith is a weakling...
 
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Went to Princess Auto and picked up the most amazing 1/8" carbide burr. Not cheap - 15 bucks, but goes through metal like if it was butter. Must have for every bubba
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Removal of material in hard-to-reach places was peace of cake
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Mag sits great now. Time to shape the feed ramp
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Bolt now picks up rounds from both sides of the mag and strips them well, but the bullet tips butt into the breech, 2-3 mm below the bore.
Solution should be welding some metal onto the feed ramp, to elevate the rounds' tips. Will need to test out with epoxy putty or soft solder, to make sure it does not interfere with the bolt
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Looking good so far! I was hoping you’d bed able to get the front of the mag up high enough to not have the bullet tips hit the face of the breech. I took some pics of 2 other rifles I converted to use AK-74 mags with 556 ammo. Hopefully those will help as some reference:
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56-B81119-6-E28-4171-95-A0-3-EE0472-A81-E9.jpg


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15-F9-E13-B-1954-427-A-9062-E40-CEE664-BC1.jpg
 
Curtton said:
what drill did you used?
Click to expand...
Just a rotary tool by Dremel, with flex shaft

Wingpilot, thanks! I think I have no choice but do what you did - to elevate front of the mag even more. I also checked clearance of the bolt and feed ramp - it will not tolerate extra metal there.
I also see on your pics that chambers have own bevelled "ramps". It would help me doing that too, I just would like to preserve chrome lining, as much as I can (maybe a moot point?)
Are those your "Krink" and Valmet on the photo?
 
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romayama said:
Just a rotary tool by Dremel, with flex shaft

Wingpilot, thanks! I think I have no choice but do what you did - to elevate front of the mag even more. I also checked clearance of the bolt and feed ramp - it will not tolerate extra metal there.
Are those your "Krink" and Valmet on the photo?
Click to expand...

If it's not pointing into the hole with a ramp, it won't go in. Excellent pics, adding material won't help anyways.
 
romayama said:
Just a rotary tool by Dremel, with flex shaft

Wingpilot, thanks! I think I have no choice but do what you did - to elevate front of the mag even more. I also checked clearance of the bolt and feed ramp - it will not tolerate extra metal there.
I also see on your pics that chambers have own bevelled "ramps". It would help me doing that too, I just would like to preserve chrome lining, as much as I can (maybe a moot point?)
Are those your "Krink" and Valmet on the photo?
Click to expand...

Yup! First the Valmet M78 then the vz58 krink. And you’re right, both barrels have a bit of a leading feed ramp on the breach end of the barrel.
 
So, I removed as much metal as I could from underneath, to tip the mag up. It started feeding well, except for the last round, on all mags of the same brand. Appears that I still have to resort to grinding the leading edge, as more milling won't help
 
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Hi All,
While I am waiting for some TIG welding equipment from Amazon, I have been thinking about future conversions in 5.56. What I have discovered through measurements:
-The WK180 heavy barrel makes a great candidate for this type of conversion. It has practically the same
diameters at the gas block and handguard retainer. No lengthening of gas system is required.
- Whether you use AK 5.56 mags or NATO Stanags/Pmags, T81 trunnion constructed differently from AK's, so trimming the mags is inevitable in both cases. Trimming is very easy and non-damaging structurally.
-AK 5.56 mags are path of least resistance but are very hard to find in Canada
-Stanags/Pmags are common but require quite complex adaptor (which I am planning to weld for a next conversion)
So far I started working on lengthening of the gas system components (which is not needed if AR barrel is used). T97 barrel only has one advantage: chrome lining
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Good job on the progress so far :)

Any chance you could use a spot welder instead of TIG? I’ve found using a spot welder for thin steel wayyyy easier/better than using a TIG welder, especially if it’s going to be one of your first projects.
 
b-wingpilot said:
Good job on the progress so far :)

Any chance you could use a spot welder instead of TIG? I’ve found using a spot welder for thin steel wayyyy easier/better than using a TIG welder, especially if it’s going to be one of your first projects.
Click to expand...
Thank but unfortunately I don't have access to. Alternatively I can use solder/silver solder? There is enough contact surface there
 
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Wth, while waiting for the TIG, launched a parallel conversion, based on LMG and WK180 bbl from TNA... So much easier compared to the T97 barrel start! If anyone is going to do the same - just leave the extension on the breech and turn the whole assembly, till it fits the receiver.
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Merry Christmas folks!

Gas system lengthening. Again, not required if AR-15 barrel is used.

Making shoulder square, for better setting of an extension
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Rod is split
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Extension itself is an old shot out 22 barrel chunk, drilled for the rod at the ends. Ends of rod extend into a bushing by 20mm on each side. Test fitment
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Soldered, using high-temp fluxed silver solder
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After final turning, in comparison to the original length. Extension added some heft but hopefully still going to function
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