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Posted: 9/15/2025 9:11:05 AM EDT
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I just purchased two new old stock MT6400s circa 2010. Both gas keys are staked to kingdom come and one staking on each bolt carrier exhibits torn metal. So, one out of four stakes on each is cracked only in the very middle. The sides of those questionable stakes are fine and solid. Attached are pics. Is this GTG or should I redo the gas key? I searched everywhere but could not find this specific circumstance, aside from LMTs stakes being cracked in numerous spots (MIM parts problem I think?) which was overall deemed a no go. Second question, Specialized Armament has NOS late 90s Colt carriers with the bold C stamping. If I were to pick one up as a "factory spare" that I didn't have to modify/reinstall the gas key on, is the Permatex sealant still good/viable after all this time?? Thank you all in advance for your time and opinions, it is much appreciated. Attached File Attached File Attached File Attached File Attached File |
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The is a most thoroughly staked gas key. It is fine. The metal has been well displaced preventing the bolts from walking out. Not really surprised that cold forging carbon steel produced such results, you could polish the surface which bothers you off, but there is little point to it. Again, it is fine. db |
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When you cold hammer mild steel, it will move without showing stresses like this. Gun alloys are durable, but have a carbon content. Hammering them hard enough, to do this, will produce such results. Those screws will not walk out. That is well above the steel that is doing all the work. If it is not pleasing to the eye simply remove it. It will never be stressed in such a way to cause it to continue to grow, but if you think it is a point of weakness once again, simply remove it as it is above the steel that is actually doing the work. db Edited to add a false dichotomy: Given a choice of visible but ineffective staking or this, which is better? |
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NJ, USA
| Thank you all for taking the time to respond. I definitely appreciate the insight and assurance. I was thinking along the same lines but I am no expert by any means so I was eager to see what you guys thought. The way things were described (especially with the content of carbon in the steel) makes sense and I will full send them both at the range. As I understand it, staking to this level with a carbon alloy may result in what we see here, and yes, I would rather have it this way than a visibly appealing but ineffective stake. And for those who read this and/or posted negating the general consensus indicating the BCGs being gtg, I am curious as to your reasoning? |
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Originally Posted By mark5pt56: Max height should not exceed .025 above the key surface, knock it down with a file if so, touch up if desired. This.^^^ Attached File |
"All welchers should be removed from the EE".-Aimless
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