instaling lower rails

[shovelhead108]

do the rails need to be cut or filed down when building a 7.62?i read a post that said they do then read another that said they dont.i read they should measure .560 when installed and measuring from the outside of the reciever to the longest point of the rail.is this correct?

[dalegribble]

It seams that many vendors are selling the AK74 rails with the longer ejector tab. On these the ejector will need to be filed down to clear the 7.62 bolt. I filed mine down after I installed the rails. Use a hand file and go slow, checking often by sliding the bolt/carrier through. It doesnt take long to get the ejector down to size even doing it by hand. I don't think a dremel or grinder wheel should be used for this as the heat generated may alter the heat treatment of the tab. The lower part of the rails that butt up against the sides of the magazine may need to be reduced a bit as well to allow the mag to clear them. A dremel may be ok here as that part of the rail isn't hardened like the ejector. Once again, go slow and test fit a magazine until it fully enters the well. Hope this helps.

[shovelhead108]

every bit helps and is apreciated.thank you

[hcpookie]

Try it and see... the 7.62 caliber ejector is smaller, because the diameter of the bolt is (obviously) larger. The measurements are located in the Ace Arms tutorial, by SD aka 7.62x39 (on gunco):

http://www.acearms.com/tutorials/blank_build4.shtml

I would be cautious that this is an "exact" measurement, and I would hand-fit the bolt/bolt carrier to be sure you get a good fit for your carrier.

What to do if too much metal is removed?

The good thing is that this can be "fixed" if you mess up & take off too much - you would TIG weld a bead onto the end & dremel the bead down to the right size. Those that have done this have reported that the TIG heating anneals (right term?) the ejector hard enough that ejector wear is no longer a problem.

If you are worried about ejector hardness, use it some and then check the wear... you'll observe very quickly if the ejector is too soft because it will wear pretty quick. If so, then heat it with a MAPP (or Propane) torch, then quench in oil (used motor oil can work) or water. If you use oil, be careful of the fire hazard that this creates. Oil fires = bad ;)

hth,
- Jerry