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Drill bit for rails...

700 Views 7 Replies 6 Participants Last post by  iansstud
Ive build my 1st AK pistol and have a few more on the way... (Thanks to everyone that got me addicted!!!)

Anyways I just lined the rails up the best I could with the holes on the receiver matching the holes in the rails on a tapco flat... This did not work very well and I would get bolt tilt causing a jam every 1in20.
After looking closer to what was going on. I noticed that when I would get the holes to match, the rails would be WAY to low! by ~.125" or more! If I tilted the rails up, the bolt would hit the trunnion, if too low, the bolt would tilt, and hit the magazine!
I fixed this by bending the rails a little and everything works great. but I bought an extra Flat, and will replace the flat with a new correct one!

I want to do it the correct way on the next build. I was reading Soup to nuts. "They said the trunnions will very" Is this from MFG to MFG? or each trunnion will be differ from the next?

Anyone know what size bit to use for an Egyptian kit?

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I've always used a short piece of 1/4" key stock. I assume a 1/4" drill bit would work.
You can measure the front trounnion on the left side where the red arrow is in the picture. Then find the closest drill size to that.

I also put a chamfer on the front of the rail just in case it is a little off.

You will find that the holes in the rails are a little off most of the time.
You will most likely need to egg them out just a little.
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I used 1/4" on my Egyptian Build and 15/64 on the Rommy G.
The Tapco rails are always low just using the holes. I think I measured them at 19/64" which is too low. I think AGI recommended 17/64" but I don't own their instructions so maybe somebody else can make sure what they say. They might say 15/64" which would be pretty close. The Saiga lower rail front ends are turned down slightly right before the front trunnion so a chamfer of the front edges of the rails would be similar to this. The whole rail isn't tilted down, just the front end has a slightly curve bent into it. They don't butt against the trunnion but have a slight gap. Maybe 0.030" or so. AGI instructions aren't perfect. It's always best to measure the trunnion.
Thanks to everyone!!!
and Thanks for the pics!!! I now have a better understanding of where to mesure!!!

Thanks!!! Ill be sure to post pics of the finished product!
i never use the holes to index the rails. 1/4" keystock has worked fine. some builders preffer to measure each build to establish the optimal attachment point.
I just mesured its 1/4" from the bottom of the bend in the flat to the top of the rail...

Thanks for the Info!!!!!!!!!!!!!!!!!
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