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Tom Preston
October 18, 2017, 08:12
The terrible, horrible, no good, very bad receiver build went together as easily as could be! After the ejector block installation, the locking shoulder needed just a drill pass through the hole to clean it up. Barrel went on easily and seems straight. Bolt and carrier glide fine, holdopen and magazine release work smoothly.

And it won't close! It tries to, actually gets almost there- the latch snaps back a little of the way- but that's it. It closes fine with the hinge pin removed, and works easily with the hinge pin installed. It seems like the receiver is just the slightest bit too long.

This is a brand new receiver. Just remove a bit from the end? Top or bottom, or equally?

Thank you all!

stoicrabbit
October 18, 2017, 08:47
Who is the manufacturer of the receiver?
I remember there is a thread that addresses this exact issue.
What makes the thread memorable is Mark tearing into the OP for being a dumbass with the dremel.
Modify the least expensive part, usually not the receiver.
If it is a defective and out a specification receiver or one of those cheap new production "L1A1" that is another thing; hence the question on the manufacturer.

4markk
October 18, 2017, 08:57
Need a picture of the receiver.

There are a couple with known issues.

Tom Preston
October 18, 2017, 11:13
I failed to make myself clear, I took the latch out entirely and it still won't close. Just off by a couple of degrees, the receiver is just barely too long.

Looks like the contact point is at the bottom edge of the receiever, where the upper meets the lower. I'd file there, but I wondered if I were missing something.

So I looked and looked, cleaned the ends of the upper to bright, and got out the sharpie.

Sure enough, just a little long. I swiped at the contact points, re marked, repeated until full closure. Put in the latch, and it snaps together perfectly.

Now just headspace checking and test fire.

the gman
October 18, 2017, 16:46
I failed to make myself clear, I took the latch out entirely and it still won't close. Just off by a couple of degrees, the receiver is just barely too long.

Looks like the contact point is at the bottom edge of the receiever, where the upper meets the lower. I'd file there, but I wondered if I were missing something.

So I looked and looked, cleaned the ends of the upper to bright, and got out the sharpie.

Sure enough, just a little long. I swiped at the contact points, re marked, repeated until full closure. Put in the latch, and it snaps together perfectly.

Now just headspace checking and test fire.

:worthless:

meltblown
October 18, 2017, 16:54
So far so good. You get it running and you receive your WECSOG certificate of completion :biggrin:

Sort of refreshing to see someone working through the issues and not whining about it

michael_g927
October 18, 2017, 17:45
Agreed. These rifles are out dated designs made up from pieces not even made in the same millennium much less anywhere near the same continent. All the guys that make these hodgepodge conglomeration of parts into not only working, but excellent rifles, are testimate to the design and history of quality!
Sounds like the OP did a fine job. Many here would have just demonized the reciever mfg (without whoom there would be no rifle at all) rather than put the effort into fitting it up. Some would have you think that they work magic when in reality, these things are accomplished at the kitchen table on the daily!
Good job man. Pics would be cool.

gunplumber
October 18, 2017, 19:04
Who is the manufacture of the receiver? And why are you so hesitant to reveal it?

If it's a Coonan, than yes, it's probably out of spec (too long). A long-time problem. Also, Coonans have been out of spec from the beginning, inasmuch as they lack the relief cuts on the bottom corners that clear the tiny web of metal on the lower where the sides meet the recoil plate. Dan has known this since the beginning, but has told me it wasn't worth his time to do it correctly - not cost effective.

Does it happen with the receiver cover removed? If not, the recess for the nose is probably out of spec.

Or if it's a DSA, the receiver is probably out of spec (warped left) preventing proper dustcover fit, requiring a different work-around. DSAs usually do not have a too-long issue, but do have out of spec lugs requiring an oversize receiver lock - opposite of your problem.

If it's a POS CAI, then all bets are off.

It is rare for factory parts to be defective - obvious physical damage not included. These parts came off functioning rifles. There is no "fitting" except for specific parts in specific areas, which is why they are numbered to the original receiver. The parts do not magically grow larger than they were before. Wear doesn't make a part bigger! Apologists for out of spec crap should crawl back under their rocks and leave this shit to people who actually know what they are talking about. "Too small" is a wear issue. Not "too big!" (Duh!)

Both DSA and Coonan have defects in the hinge area that can give false readings on lockup.

Do not adjust the lock lug on the receiver unless you know absolutely that it is the culprit. The receiver lock is the part that is to be fitted. Maintaining the 10 degree angle, reduce the receiver lock until you obtain .060" engagement. But this is of no value until you have correct lockup without the receiver lug engaging. And I assume you know the lever is not supposed to contact the recoil plate (vertical) or the grip (horizontal) - they need a little standoff because the designer built in a mechanism for accounting for wear.

Advise to "just file on it" is retarded, because the rear sight will not be at the correct orientation relative to the receiver. It will be too low by the amount the lockup is off.

Shortening a receiver when the receiver length isn't the problem, is a work-around, not a fix. Not terrible, as an air gap is permitted (UK standard) but sub-optimal.

Tom Preston
October 18, 2017, 20:23
Thank you Mark!

I'm not hesitant to reveal it now- in fact it is a POS CAI. A local to me shop is selling poorly stored but unused ones for $200, so I thought what the hey. It came to me with no finish- I'd say in the white, but it's more like in the grey. Clearly a cast upper, milled to spec. It has the ugliest maker name and serial number markings on the trapezoid panel I've ever seen. But aside from lacking the right side ejector block pin holes, it was ready to go.

So I bought a nice G1 kit and had at it.

I thought I'd have to fight this thing every hundredth of an inch of the way, but not so. Your help has gotten me through the worst part, which was the ejector block. Truth to tell, I didn't think to check to see if it even had one! The locking shoulder hole was a bit rough, easily fixed. And the too long problem was 15 minutes of careful cut and try. Without the latch in it, so I knew that wasn't the problem.

It closes fully now, but if I put a piece of tissue paper between the recoil plate and the receiver it cuts it, and it won't close with a dollar bill there.

Unfortunately the lever does hit the recoil plate, and there is the tiniest bit of movement between the upper and lower. That probably means I need an oversize lug...

4markk
October 18, 2017, 20:38
I would test the hardness on it before you go shoot it. You don't know at what point they finished the manufacturing.

chrsdwns
October 18, 2017, 21:00
Very uncommon to have a receiver that will not close by as much as you describe.

Makes me wonder if you are working with an Argentine cast lower receiver.

The Argy upper and lower receivers were made with a modified geometry to prevent interchange with full auto FAL components.

The Argentine commercial semi auto receivers have an elevated locking lug surface on the lower and a correspondingly shortened lug foot on the receiver

if you have one of these cast lowers you will have to mill the locking surface down to standard FAL mil specs.

Tom Preston
October 18, 2017, 21:25
Those are good thoughts, and I'm considering them.

This is a Belgian made lower for a German G1, in really nice shape to my eye.

The upper doesn't say made in USA, but it doesn't say Imbel or Brazil either.

G1 SA SPORTER
CENTURY ARMS, INC.
GEORGIA, VT
CAL 308
SERIAL NO G1SA#####

The G1 original lug went in just fine. All I have to check headspace right now are some LC85s. They go in fine and lock up easily, three layers of masking tape on the case head barely closes and four won't.

How to go about testing hardness, I have no idea. Wouldn't they mill it after heat treating, in case of warping in the oven? I can't imagine they would have numbered it before it passed final hardening and inspection, but of course I know nothing of the manufacturing process. Might be they have to number the rough castings even, for legal reasons. I certainly would not think they would release it soft.