A1 upper question

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Posted: 5/9/2012 7:58:09 AM EDT

This is probably an irrelevant question, but I have never been able to figure out what
the slot in the back of a carry handle A1 style upper is for?

Posted: 5/9/2012 8:14:25 AM EDT

[#1]

I'm not positive about this, but I always assumed that it was just unnecessary for there to be material there, so they profiled the forgings like that to reduce weight.

Posted: 5/9/2012 8:42:59 PM EDT

[#2]

This ^^^ sounds reasonable, & w/o it there it would be a weak point, so to ad structural integrity would be my guess.

Posted: 5/10/2012 5:25:07 AM EDT

[#3]

Quoted:
This ^^^ sounds reasonable, & w/o it there it would be a weak point, so to ad structural integrity would be my guess.

Seems to me like you are thinking ass backward. The REMOVAL of the material would make it weaker, not leaving it.

Posted: 5/10/2012 6:09:45 AM EDT

[#4]

I'd assume that it's that way to protect the rear sight and to be able to attach accessories such as night sight/scope.

Sarge

Posted: 5/10/2012 6:10:38 AM EDT

[#5]

Quoted:

Quoted:
This ^^^ sounds reasonable, & w/o it there it would be a weak point, so to ad structural integrity would be my guess.

Seems to me like you are thinking ass backward. The REMOVAL of the material would make it weaker, not leaving it.

Additional complex contours can actually strengthen a casting sometimes, even if it reduces overall outer dimensions. Not sure that is the case here. My guess is the original designers investigated before they produced it like that. It probably is a little weaker than having solid aluminum there, but still as strong or stronger than the front of the carry handle.

Mike_NDS could probably tell us more.

Posted: 5/10/2012 6:33:39 AM EDT

[#6]

Quoted:

Quoted:
This ^^^ sounds reasonable, & w/o it there it would be a weak point, so to ad structural integrity would be my guess.

Seems to me like you are thinking ass backward. The REMOVAL of the material would make it weaker, not leaving it.

Is that not what I just said?

Just in case you are confused, the OP was referring to the thin piece of metal left in the carry handle. Now read again what I said.

Visualize the receiver without the area in question, how strong does that look. With it it is stronger.

Posted: 5/10/2012 7:36:32 AM EDT

[#7]

I think the OP is referring to the "slots" on either side of the "rib". I don't think he is asking why the rib is there, as it clearly needs to be there for structural purposes. I think he means why are the "slots" there instead of the area being solid and flush with the sides of the carry handle, basically the lack of material, not the presence of the rib.

Posted: 5/10/2012 8:14:43 AM EDT

[#8]

Yes, that is what I mean. I understand it is there to maintain structure integrity, but it almost looks as if it were
meant to serve as a rail to slide some type of attachment on or something. Not really sure why it is there, wish I
could just ask Eugene Stoner to find out lol. Too bad I didn't have this question like 15 years ago I might could have
asked him!

Posted: 5/10/2012 8:16:01 AM EDT

[#9]

Meh, It's there because it looks freakin' uglay without it.

Look at one of those Olympic A1 uppers that are basically A2 forgings with A1 rear sights...

Posted: 5/10/2012 9:31:53 AM EDT

[#10]

OK, I guess I do not know what slots the OP is referring to.

The web is the thing circled, so that is what I was thinking of.

Posted: 5/10/2012 10:13:59 AM EDT

[#11]

I think he was asking why is the material thinner in the 'slots', rather than why is there material there at all. The back of the carry handle is about 5/8" thick, except in the scooped out area. Probably just to save on aluminum.

Dead horse properly beaten.

Posted: 5/10/2012 10:24:09 AM EDT

[#12]

Quoted:

Quoted:
This ^^^ sounds reasonable, & w/o it there it would be a weak point, so to ad structural integrity would be my guess.

Seems to me like you are thinking ass backward. The REMOVAL of the material would make it weaker, not leaving it.

Is that not what I just said?

Just in case you are confused, the OP was referring to the thin piece of metal left in the carry handle. Now read again what I said.

Visualize the receiver without the area in question, how strong does that look. With it it is stronger.

Works for me!

Posted: 5/10/2012 10:24:54 AM EDT

[#13]

Quoted:
I think the OP is referring to the "slots" on either side of the "rib". I don't think he is asking why the rib is there, as it clearly needs to be there for structural purposes. I think he means why are the "slots" there instead of the area being solid and flush with the sides of the carry handle, basically the lack of material, not the presence of the rib.

How I read it too BUT he was a bit vague.

Posted: 5/10/2012 1:34:39 PM EDT

[#14]

Quoted:
I'm not positive about this, but I always assumed that it was just unnecessary for there to be material there, so they profiled the forgings like that to reduce weight.

Correct. The A1 upper [really the whole of Stoner's original design] was a marvel of weight vs stiffness optimization, especially considering that it was done without CAD. The American Mechanical Engineers of the Greatest Generation were, well... the greatest - and I put Stoner in with the top tier. This generation's greatest achievement will be figuring out how to keep their pants riding at their butt crack without them falling down to their ankles

.

Posted: 5/10/2012 6:04:16 PM EDT

[#15]

This reminds me of my friend, an engineer. On his retirement day as he is packing his desk. The bossman walks in and says "Bill, I hate to see you leaving us. Its going to be hard to find a replacement for what weve been paying you all these years."

Posted: 5/11/2012 1:03:12 PM EDT

[#16]

Quoted:
...This generation's greatest achievement will be figuring out how to keep their pants riding at their butt crack without them falling down to their ankles...

Posted: 5/11/2012 1:36:59 PM EDT

[#17]

So they'd have someplace to put forge codes.

Posted: 5/11/2012 3:49:01 PM EDT

[#18]

Quoted:
So they'd have someplace to put forge codes.

Beat me to it Morg!

Posted: 5/11/2012 4:49:12 PM EDT

[#19]

Quoted:
This reminds me of my friend, an engineer. On his retirement day as he is packing his desk. The bossman walks in and says "Bill, I hate to see you leaving us. Its going to be hard to find a replacement for what weve been paying you all these years."

OOF !!!

Posted: 5/11/2012 4:49:36 PM EDT

[#20]

Quoted:
So they'd have someplace to put forge codes.

Makes sense.

Posted: 5/11/2012 5:46:01 PM EDT

[#21]

Quoted:

Quoted:
This ^^^ sounds reasonable, & w/o it there it would be a weak point, so to ad structural integrity would be my guess.

Seems to me like you are thinking ass backward. The REMOVAL of the material would make it weaker, not leaving it.

Additional complex contours can actually strengthen a casting sometimes, even if it reduces overall outer dimensions. Not sure that is the case here. My guess is the original designers investigated before they produced it like that. It probably is a little weaker than having solid aluminum there, but still as strong or stronger than the front of the carry handle.

Mike_NDS could probably tell us more.

That's a complex subject. I have heard that you cannot accomplish increased rigidity by removal alone. If I recall rightly, you're referring to how stress is lessened by not having angles and corners. (See below: Notice the curve of the non-thread portion of the shaft. It is to prevent stress points that can lead to breaking.) From my amateur thought rigidity and durability are two separate concepts. Can you elaborate? And if I said anything wrong please let me know. Materials fascinates the hell out of me.