Fixing Mk43 Barrel Alignment

[Asomodai]

Hey gents. 

Last year I purchased a new A&K MK43 because it was damn cheap. I noticed immediately that the Outer Barrel sleeve was not drilled correctly and would not align with the front iron sight. With the stock hop rubber it meant it wasnt a problem so much, it was always going to fire to the right of the iron sight though. I wanted to use the Maple Leaf Macaron bucking, which means that if there is an alignment issue, it is likely to be more pronounced using a bucking of that sort of shape. So I wanted to straighten it out. 

It also meant the detent that the sleeve would lock the barrel to the receiver was cut to align with this misaligned screw hole. 

The offending screw hole. This was a problem as this outer barrel sleeve houses the Hop unit, which itself is bolted into. 

 So I dremelled out an oval into the screw hole and hoped beyond hope that I can apply enough torque on the screw for the outer sleeve not to slip back into its old position.

First attempt photos, forgot to take another photo of the last (better!) Alignment position. (Ignore the handle, it will always be in the wrong position)

However, when I reassembled, the Iron Sight was now wonky with the rear. 

To solve this, I needed to dremel out the detent to be wider to accommodate the new outer barrel sleeve position. However, this means the outer barrel now wobbles because there is too much play in the detent side to side. So what do I do? Stuff the detent with paper.to straighten it out. 

And the result?

Dead straight and no wobble at all.

Obviously I need to test it on a range, but I have hopes that what I have done has sorted out the not straight firing issue. What do you think? In theory this looks like a fix...

I have contacted A&K to see if they can provide me with a new Outer barrel sleeve if possible. 

 

[Zarrin]

Nice - instead of using paper to tighten that up, could you drill two holes on opposite sides of each other, thread them with a tap and die set, and introduce two grub screws that you could use not only to tighten it up but calibrate the straightness ever so slightly too ? Kind of like how a scope prism is aligned inside an optic but from both sides instead. Could be a tall order unless you have access to a pillar drill though ?

 

[Asomodai]

Nice - instead of using paper to tighten that up, could you drill two holes on opposite sides of each other, thread them with a tap and die set, and introduce two grub screws that you could use not only to tighten it up but calibrate the straightness ever so slightly too ? Kind of like how a scope prism is aligned inside an optic but from both sides instead. Could be a tall order unless you have access to a pillar drill though ?

Click to shrink...

It's a reasonable idea! However I have an aversion to tapping anything. You only get one shot at it and guaranteed to screw it up! 

I took the paper out and instead wrapped the area with the electrical tape which will probably last longer. I can always replace the tape if need be. 

We will see what happens when/if I skirmish it again!

I really hope A&K can come through with another sleeve though, I don't trust my bodge job! 

Edit: I also do not have a vice which would be pretty essential when tapping!

 

[Zarrin]

It's a reasonable idea! However I have an aversion to tapping anything. You only get one shot at it and guaranteed to screw it up! 

Edit: I also do not have a vice which would be pretty essential when tapping!

Click to shrink...

Yeah, you'd definitely need some sort of vice and a substantial setup to head into such a venture with any hope of coming out the other side with some form of success.

Perhaps some form of silicone sealant could do a decent job in place of the paper or electrical tape.

 

[Yuukan]

Hey did you find that the gas regulator where the mosfet sits was also wobbling ?