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9/22/2017 12:11:25 AM
Posted: 9/9/2005 4:52:51 PM EDT
I just purchased a set of these and installed on my rock river arms lower. the hammer pin fits flush but the trigger pin look slightly to long I can wiggle it side to side in the gun. What would cause this or did I get an out of spec set? Thanks in advance.
-sigadvantage-
Link Posted: 9/9/2005 8:45:33 PM EDT
I'm using two sets of KNS anti-rotation pins in my carbines.

A large dia. pin set for my Colt 6721 Tactical Carbine and a small pin set for my LMT M4gery carbine.

Both of them are solid, no movement at all.

Maybe you could measure both of your pins with a mic or calipers and see if there are a difference in length.

I also have a spare small dia. set and I could measure them for comparison if you wish. Let me know.
Link Posted: 9/9/2005 8:48:22 PM EDT
i have noticed that there is slight variation in the length of the pins.


but it could possibly be out of spec lowers as well.



Link Posted: 9/10/2005 6:02:56 AM EDT
I have the same pb on a Colt - no idea why or what to do about it.
Link Posted: 9/10/2005 6:04:17 AM EDT
i dont see it as a problem since its actually "anit-rotational" pins
Link Posted: 9/10/2005 6:19:33 AM EDT
That's what I thought as well, though I am surprized by the tolerances on the receivers.
Link Posted: 9/10/2005 7:16:51 AM EDT
Yeah, receiver forging tolerances are not exactly high precision.

I have not measured a large number of raw forgings, but I would suspect any given 10 to vary by +-.003 at least in thickness in a given spot around the midsection. I have +100 in a box in the garage. I'll try to measure some of them in this area and post results when I get home in a couple weeks.

When I put one of those forgings on the mill and run a dial indicator around it, the needle bobs and dips like an Arizona oiled road.

Pardon the blasphemy, but these come from a company that supplies Colt.
Link Posted: 9/10/2005 7:26:13 AM EDT
Which company supplies Colt?
Link Posted: 9/10/2005 8:02:54 AM EDT

Originally Posted By WSAR15:
Which company supplies Colt?



www.cerrofabricated.com/products_firearm.htm , l think. The logo is that little triangle
over a blue A, in any case.

They had some cool stuff on their website before, and you can see a 1911 forging now.

I asked about buying a substantial batch of 1911 recievers, but they said the dies were property of colt and they could not sell forgings made by Colt dies. I imagine Colt buys forgings from anyone who can supply a given quality and quantity at a given price - I am not into all that collector nonsense like subcontractor markings, but that is the way the real world works.

I bought a case of M16 lower forgings for an EDM venture, and got a good price break since my non-military requirements did not need that intensive QA paper trail.
Link Posted: 9/10/2005 8:35:47 AM EDT
Cerro's logo looks like a key hole. The triangle over an A is Anchor Harvey Aluminum.

Forgings outer mold line surfaces doesn't have to be too precise if it does not have to mate with anything.

As long as the measured dimensions are per engineering drawing it's acceptable to quality inspection and good enough to sell.

The manufacturer with good quality will hold a tighter tolerance and less variation. Ref. ANSI Y 14.5 and ISO 9000.


Receiver Logos and Markings Thread link
Link Posted: 9/10/2005 8:39:45 AM EDT
Duh, yah, I bought those from Anchor Harvey. I could not find their website in my favorites.

The whole EDM adventure turned out to be a bad dream so far.
Link Posted: 9/10/2005 9:19:01 AM EDT

Originally Posted By pogo:
The whole EDM adventure turned out to be a bad dream so far.


That's cool, at least you could mark them anyway you want after the machining is completed.

Why not just machine the areas with loose tolerances and just EDM the final stage of the critical areas.

EDM equipment must be expensive. I know I can't afford it.

EDM technology was great for the 1911 combat shooters like the Nowlin barrels/ other parts and there should be a some good use for it in the AR fabrication.
Link Posted: 9/10/2005 11:57:04 AM EDT
I found Anchor Harvey: http://www.forgings.com/
Link Posted: 9/10/2005 12:17:42 PM EDT
i have seen broken A's and keyholes on just about everything i own

bushmaster (both)
rra(A)
cmt(A)
Link Posted: 9/10/2005 8:18:26 PM EDT
I installed a set of pins in a RRA receiver , and found them to be to long as well. I just filled down the pins , to fit flush .
Link Posted: 9/10/2005 8:58:03 PM EDT
it didn't mess up the threads at all to file them?
-sigadvantage-
Link Posted: 9/11/2005 7:22:14 AM EDT
i would just leave it as is.

there are some lowers i have that fit perfectly
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