I have been collecting measurements from EVERYWHERE, including a local original MG42 as I have two projects being assembly of the front and rear sections of two guns back togeather.
Now, I have, what I feel are correct dimensions from the rear of the cam box window to the verticle part of the 'D' cut for the rails as per the picture below, this is very close to the 2.215" that roadrunner posted recently from his MG53 and within about 0.010" of the local MG42 that I measured.
Problem is the bolt rails I have are 2.295" as per the photo attached, what are the issues if I trim the length of the front of the rails?
in order to get an accurate measurement, you'll need to put a piece of steel the same thickness of the sidewall of the receiver behind the little tab of the rail, and measure from the front edge of the piece of steel to the front of the rail.
The tapered edge of your caliper is sitting deeper under the tab than the receiver will sit, so your measurement isn't accurate for your purpose.
I think that will eliminate most of the discrepancy.
Thanks JB
If im not mistaken, the flat edge of the tab on the rail should rest up against the flat edge of the 'D' cut out in the side wall of the rec (unless i'm not understanding you sorry), if this is in fact correct the front of the rail will pass into the cam box window.
The photo is not alowing you to see the caliper correctly sorry, it is against the flat edge of the tab. in any case we are talking about an 0.080" difference, quite significant.
crash, heres some more numbers for you. My two new rails measure 2.307" and 2.305". My two old yugo rails measure 2.219" and 2.250". Furthermore, I dont think they match my gun due to them both being right side items.
It appears to me as these are individually fitted items. Love to here more cause I'm in the same boat.
Oh yeah, Jbaum has a good point. I used a toolsteel bit and my depth mic. Even so .080" is a buttload to overlook.
Any angle off parallel will result in cosine error, so try to minimize it.
Don't worry about the rails! Rails are trimmed to fit in each receiver. EVERY RECEIVER IS DIFFERENT ESPECIALLY IF A REWELD. You should mount the rails then file flush with the cam piece opening, or use some proper sized bolts to mount the rails, mark the correct length, unbolt, trim to size then rivet. I would suggest temporarily installing your recouperator to obtain the proper rail height also before you drill rivet hole location. There is a LOT OF SLOP in the MG42 rail/feed sysetm. DO NOT GET TO ANAL MEASURING! The critical fitment is between the CAM PIECE/BARREL EXTENSION/BOLT...and you have little to NO control over that! Getting those parts TOGETHER is very forgiving with an extremely wide allowence for variations in tolerances. (Think AK Sloppy which is GOOD....vs. M16)
Use your measurements to get the receiver sections as close as possible. But it will NEVER come out exact! welds SHRINK and warp no matter how accurate you try to make it, they WILL BE OFF! Don't sweat to dimension too much...these guns are very forgiving. especially if you actually TRY to get them rewelded close to factory dimensions...
appreciate your imput and will take it on board, im just trying to get it perfect, if you ask my friends, family and girlfiend, i drive them mad! everything has to be perfect!
