Quote:
Originally Posted by ThunderCactus
65 degree hardness what
Because if it's 65 rockwell B, it's pretty much as soft as steel gets. Leaded steel.
If it's 65 rockwell C, it'll shatter the first time the bolt hits it.
Vickers HV or Brinell HB, it might as well be a week old cheese.
Problem with hardening is you first need to know what kind of steel it is in the first place. Given that it's even actually steel to begin with.
Your standard 1018 low carbon steel comes in at 71 rockwell B. So this is either 10L18 (leaded) or something with even less carbon in it.
As you can imagine, leaded steels are gonna be garbage for hardening.
If you luck out and it's actually a carbon steel, and actually something that can be hardened, then the top end it going to be fairly low.
From back when I used to do it, I believe the top end of 1018 was about 110 rockwell B (quenching from 1550F into cold water), but for an impact component you'd want to temper it down to something between 90-95 rockwell B.
Hardest thing about heat treating a component, you have no freaking clue what hardness you're actually ending up with without testing.
What's really fucking hilarious, is that if it really IS rockwell B scale, then your bolt catch would be better off being made of 7075 aluminum, since it comes in at 87 rockwell B with the right temper. 6061, the traditional "aircraft aluminum", is around 60 rockwell B. So there it is, you might as well have an aluminum bolt catch lol
Is it magnetic? Or are they a bunch of liars?
Good idea, though. Probably worth trying if you can confirm it's a carbon steel.
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Thanks for your in depth analysis of the different steel scales. Indeed, I have no idea what hardness scale they are using as they only state '65 degree hardness'.
Yes, my biggest concern was how much carbon is in the steel they use to allow heat treatment to even work. While the bolt catch IS magnetic, there is no indication of how it would react to any heat treatment.
Here's some pics demonstrating a little clearer what the bolt carrier is doing on the bolt stop. I've also already ground down the protrusion on the arm so that it moves up further because of the upper receiver:
Looking from the top view:
Here's a pic of the stock bolt carrier when I shot about 5000 rounds through it completely stock, which then warranted the NEED for a new bolt carrier:
Here's the stock bolt carrier where the bolt catch caught - they had a hardened piece on there that completely sheared off along with some of the bolt carrier. It worked decently after this regardless.
And of course, the first bolt catch mod I did was to add the AEG shim to the bolt stop:
I saw a video on YouTube (user was MaximusMJG or something like that) that had received some test parts from RA-Tech, one of them was a heat treated bolt catch - not sure if they actually are selling this or if it's already being included as a spare part in their bolt carriers; in which case the metal is still soft enough to get chewed through.