What does this part do on a 4586?

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I have a friendly wager ( cold beer) on the purpose of this notch on one side of the feed ramp on a 4586. Anyone know?
 

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You should see the looks I"m getting as I sit at my desk field stripping my pistol! The question was really buggin' me as I had never noticed that notch before.

Turns out it's not present on the 4566 (my carry gun), I had just assumed all 3rd Gen .45's would have similar barrel/slide structure.

Guess not!
 
Yeah, and on my 4586 it's there, but much less of a cut and on his 4586 it's much more cut in.
 
I have 20+ S&W 3rd generation pistols including the following 45s: 4506, 4566, 4576, 4516-1 and 4516-2. I've disassembled each more than once. I've never seen a cut like that. :confused:
 
that "notch" definitely looks purposeful though. Doesn't look like wear to me.
 
Mine is about the same but I have no idea what it is for. My 4566 does not have it. Maybe someone else will know.
 
Mine is about the same but I have no idea what it is for. My 4566 does not have it. Maybe someone else will know.

Mine is barely visible, and the serial number starts with TDP. My buddy's 4586, with the more visible notch, has a serial number that starts with TDU. My neighbor's 4586 serial starts with BDJ, and has no visible notch. Looks like things changed during the production run.

Deanodog, what does your serial number start with?
 
THE NOTCH IS FOR GAS PRESSURE RELEASE:rolleyes:

ONE MOLSON CANADIAN PLEASE.

If that's true, I'm out a beer since that's kinda what he said too. Odd how some 4586 have it, and some 4586 don't.

Sorry, Light beer only in our advancing age:(
 
To me that looks like it could possibly be either the result of some bad machining or some abnormal wear.

That is part of the area that rides along the lug (for a lack of better words) surface on the inside side of the frame that causes the barrel to cam (move) upwards as a round is chambered and the rear of the barrel is being pushed forward as the slide closes into battery. It also may provide some clearance for the slide rail, hard to tell by watching the slide close through the ejection port.

From the roughness, there looks to be some metal galling taking place.

All of my 3rd gens have that clearance slot, but it is not milled that deeply where it leaves a notch in the feed ramp.
 
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My 4586, serial # TDU41XX, has the same notch. Hopefully FastBolt will see this thread and fill us all in on the history and purpose of this feature and why some pistols have it while others don't.
 
I got a 4553 in today from this bunch of trade ins and it has that notch also. The notch is not square as some others and I am wondering if it is blown out from pressure at the end of the groove.
 
I want to guess.....

that cut is on the ejection side....likely more firing residue builds up on this side and the cut provide somewhat clearance for shooting poo poo!

final answer!
 
Curiosity got the better of me and I checked mine. SN TDU45XX and the slot is about half as wide and half as deep as the one shown in the first post. I can see no reason to have a slot like that as it does not match up to anything on the slide or frame. Perhaps it is for the optional chrome reverse muffler bearing!
 
I recently acquired a CS45 and noticed a similar notch.I assumed that it served as a sight opening to detect a round in the chamber.
 
my 4586 has a slight groove and my gunsmith said it looks like wear to him.. my ser# starts w/TDP.


just my 2 cents worth
 
notch

I have a 4516-2 Sn.VKP 40xx with that notch,also a light mark on each side of the lower portion of the lug . From experience i would say it's from the CNC machining
It's not in a place to have worn. It is probably caused by wear in the machine tooling prior to tool change on the CNC.
 
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