*range report with 5 shot group* ak lower rail placement problem

[SKSer]

when installing the lower rails on an AK build I seem to always run into problems, this is my third reciever build of the same rifle so im trying to get it right this time. When you install the lower rails are they supposed to be paralell with the upper rail from the front by the trunion all the way back to the rear? If I make them parallel from front to back using the 1/4" drill bit method, then the holes at the bottom of the rails dont line up with the reciever. If I line the rail holes up with the reciever then the lower rails will not be paralell with the upper rails, and as you see in the example below the distance between C and D will be about 1/4" and will line up with the front trunion, but the distance between A and B will be a bit more then 1/4". So should I make them parallel with the upper rails and modify the holes in the reciever/rails or just mount them un-paralleled, thanks, Gary

[uxo2]

Your doing it wrong.

The rails are the last thing to be installed after all riveting is done.

Stop worrying about where to measure.

Bend that flat...and go to a Build party.

Besides...I have yet to see a flat bending jig that accommodates
rails already installed.

EDIT:

What is your location ?

[Noobert]

yeah, rails are only installed after bending

[SKSer]

im using this method: http://www.newsbleed.com/documents/g..._jig_gunco.pdf

the first two times I did it I didnt use this method,i cut grooves in the reciever with a dremel to help with bending, sandwhiched it between to pieces of flat steel similar to this method, but then used a sheet metal hammer to bend down the sides. The second build actually worked fine, but I just wanted to rebuild it this time due to finish issues with the outer reciever of the old one(messed up on stamping serial number, deep scratces in reciever from messed up rivets that had to be removed) , I just welded up a jig like this, and it will allow for the rails to be intalled first then bent because it just has the piece of steel in the bottom of the inside the reciever and it does not protrude into the inner reciever during the bending process, after bending is complete you just unbolt the "sandwhich" and the flat pieces just slide out.
While the reciever is still flat I clamp the front trunion in place where it will be riveted and then line up the rails and weld them on, it makes the welds really clean this way and it is easy to line them up right. My biggest problem is what is stated above though, if i make them an even paralell with the upper rails then the holes will not line up with the reciever, if i line the holes up, then It will be a space of about .280 inches where it lines up with the front trunion perfectly, then a space of about .310 inches in the middle, and a space of about .350 inches at the end of the rail pointing toward the rear of the reciever.

[uxo2]

http://www.youtube.com/watch?v=sDppu3Mcj6E

[jamesob]

you could have some bad flats or try this.

http://www.surplusrifle.com/shooting2005/souptonuts3/index.asp

[SKSer]

http://www.youtube.com/watch?v=sDppu3Mcj6E

This still doesnt show where rails are located. I understand how a flat is bent, but you have to understand as well you dont need a full blown jig to bend it either. I just need to know if the rails need to be paralell with the upper rail or if it matters, if they need to be paralell then I will modify the lower rail holes to line up with the reciever. I will post pictures of my build to show that you dont need a $200.00, 2000% marked up welded pieces of steel to bend a flat. The cutting grooves and bending method I used the first two times, is deffinately not that great, it is very hard to cut the lines straight with a dremel, but it still functioned and looked OK. With this new jig, you can put it together for like $20-25, and im highly confident it will bend the reciever just as good as a overpriced jig.

[SKSer]

you could have some bad flats or try this.

http://www.surplusrifle.com/shooting...uts3/index.asp

Thanks for trying to address the rail issue, ive seen this site plus several others and they all pretty much say the same thing, "use the drill bit to space it with the top rails" and it seems the main concern is to line it up properly with the trunion, but I cant figure out if they are paralell or not. My last build i made them paralell and just modified the reciever holes on the rails, but if it didnt matter if they were paralell or not then i wasnt going to modify the rails. the picture looking down into the reciever from the end makes it hard to determine if it is tapered or paralell as well. As far as bad flats, I did wonder this, I have the flat from akparts.com

[SKSer]

here is a picture of my actual reciever, see the slight taper, and how they are not exactly parallel. The front of the rails line perfectly with the front trunion. If they need to be paralell i will remove them and re mount them and just drill the holes straight.

[JAGGUY]

The holes never line up for me. The lower rails are parallel to the top rail and egg the holes to fit. Been that way for 3 flats so far.
-greg

[SKSer]

thank you, thank you, thank you.

[uxo2]

here is a picture of my actual reciever, see the slight taper, and how they are not exactly parallel. The front of the rails line perfectly with the front trunion. If they need to be paralell i will remove them and re mount them and just drill the holes straight.

Good luck with your build..

You really should try to get into a Build Party

[hawk81]

Yeah, the holes never lined up for me either. I just redrill them after I install the rails. The rails should be installed after the reciever is bent, so you can line the rails up with the front trunnions. Good luck.

[DB2]

Why are you welding your rails in first? I'm sorry, but that is so wrong. The rails are the last part to install on the receiver. After everything. The rails must be placed in after the front trunnion is set. The front trunnion has to be placed correctly for mag fit.

Your trusting pre-drilled holes in a flat? The rails must be paralell with the top rails. They must fit up with the trunnion correctly.

Bend your flat. Assemble the receiver. Weld rails. If you don't have a spot welder, drill and weld.

[SKSer]

I pre fit everything with the reciever still flat, its alot easier, the upper rails are all trimmed and the trunion is pre fitted, clamped in place and then the rails are installed, as you see it here, the front of the rails are aligned perfectly with the front trunion (which is not in the picture. Ive never had a problem fitting the mag with these flats, they always fit. I got this idea from another calgunner, about doing all the work while it is still flat. it really does work out good. Ill start a thread showing this method.