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As far as screws go, like others have mentioned, there are grades. Having said that, I’ve seen far more hex heads stripped than torx.

For Phillips, I’ve never seen one stripped when used in a low torque application. The problem is most folks use the wrong size Philips head bit and a drill, so when combined they strip a screw very easily.

I think the grip screw is a perfect example of where a Philips would excel.

But back on point, RA said on a Facebook post their site crashed due to the extra traffic.


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I've seen socket head cap screws in stainless, which are not as strong as the black steel screws.
I meant to specify black oxide finish socket head cap screws, which seem to follow a uniform class/rating/grade.

From the MSC Direct website:
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Socket head cap screws are not grade designated as are hex head cap screws. A standard inch series socket head cap screw is 20% stronger than a Grade 8 hex head cap screw and 50% stronger than a Grade 5 hex cap screw. The tensile strength is a minimum 180,000 psi for sizes 1/2′′ diameter and smaller and 170,000 psi for 5/8′′ diameter and above (Tensile strength may vary according to heat treatment and manufacturer.) Low head, flat head and button head cap screws are rated 10,000 psi lower due to the head configuration and are seen more in lighter duty applications.


As an alternative drive, Torx Plus (Star Head) screws offer more contact points allowing for a higher level of torque transfer and extended tool life. Additional benefits include faster tool engagement and reduced camout and end load.

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I seem to remember grades for metric and sae being different scales. I am not sure if those were merged. 12.9 seems to be applied to both metric and sae.

Phillips are great, as long as they don't rust in place.
 

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I've seen socket head cap screws in stainless, which are not as strong as the black steel screws.
I meant to specify black oxide finish socket head cap screws, which seem to follow a uniform class/rating/grade.

From the MSC Direct website:
--------
Socket head cap screws are not grade designated as are hex head cap screws. A standard inch series socket head cap screw is 20% stronger than a Grade 8 hex head cap screw and 50% stronger than a Grade 5 hex cap screw. The tensile strength is a minimum 180,000 psi for sizes 1/2′′ diameter and smaller and 170,000 psi for 5/8′′ diameter and above (Tensile strength may vary according to heat treatment and manufacturer.) Low head, flat head and button head cap screws are rated 10,000 psi lower due to the head configuration and are seen more in lighter duty applications.


As an alternative drive, Torx Plus (Star Head) screws offer more contact points allowing for a higher level of torque transfer and extended tool life. Additional benefits include faster tool engagement and reduced camout and end load.

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I seem to remember grades for metric and sae being different scales. I am not sure if those were merged. 12.9 seems to be applied to both metric and sae.

Phillips are great, as long as they don't rust in place.
As I said, SHCSs are rated in KSI....160-180KSI is typical of the size screws found in the XCR (for example, the 1/4-20 low profile head screw that retains the stock to the lower)....it's still a tensile strength rating, which is all the grades are.

And yes, I work in man rated space flight and worked on airframes where Torx are very prevalent. In spite of the claims of additional contact points, Torx in practice strip far more often then Hex do. One can most definitely assert that's due to operator/installer error, but I wonder how much tool wear on the smaller teeth of Torx bits is at play as well as installer error of not seating the tool fully to the bottom of the socket. It also appears Torx bits may be more shallow than the comparable Hex counterpart (though I haven't been able to confirm this via any engineering drawing on McMaster-Carr). If seated fully, Hex just outlasts Torx, IME.
 
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Sent an email in to RA about a KeyMod version of the Mid length upper....I'll post up what I hear back.
 
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RA is phasing out Keymod....

Everyone wants MLok.....

JFYI.
 

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These are popping up in my YouTube feed now since the Garandthumb review. Granted, I wasn’t really searching for any XCR reviews previously, but here are a few more I’ve seen in the last few days…and I haven‘t watched all of them…





Those video reviews all appear to have been up for a little while, but I hadn't found them before, and if you told me that there were a half dozen XCR reviews before the GarandThumb review, I would have said you were lying.

This forum might have a use for a video section.
 

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Those video reviews all appear to have been up for a little while, but I hadn't found them before, and if you told me that there were a half dozen XCR reviews before the GarandThumb review, I would have said you were lying.

This forum might have a use for a video section.
Yeah, all are from before GT. Same as you, I wasn’t looking for them, but would have thought someone was full of it if they told me all of these were out there. There are also a couple more I saw on the Tube that I didn’t post.
 

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RA is phasing out Keymod....

Everyone wants MLok.....

JFYI.
I was a keymod fan, and still have 2 ARs and my XCR in keymod.

It is very difficult now to get new quality stuff to fit keymod though.

I’m planning on swapping everything over to MLOK. Still not sure if I want to swap the XCR over though. Might be more trouble than it’s worth.


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I was a keymod fan, and still have 2 ARs and my XCR in keymod.

It is very difficult now to get new quality stuff to fit keymod though.

I’m planning on swapping everything over to MLOK. Still not sure if I want to swap the XCR over though. Might be more trouble than it’s worth.


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Yep....it was inevitable. I don't really have any need to attach anything new to my existing KM XCRs (or anything else that has KM for that matter)....so I'll leave them as is. The biggest issue lately has been finding good quality picatinny sections to attach.....but BCM is still making their KM stuff so that's generally G2G.
 

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Yep....it was inevitable. I don't really have any need to attach anything new to my existing KM XCRs (or anything else that has KM for that matter)....so I'll leave them as is. The biggest issue lately has been finding good quality picatinny sections to attach.....but BCM is still making their KM stuff so that's generally G2G.
That’s exactly what happened to me. I needed a rail section for my Owl and could only find the BCM for KM.


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