New Sharps Relia-Bolt design using S7 tool steel.

[Cane55]

Ill post them after I give them a chance to make it right.

What happened, what side Sharps say? Could you post some photos of the bolt?

[vicious_cb]

Had a replacement bolt shipped the day I made the call. Excellent customer service. Going to run the new bolt they sent and see what happens. I hope it was just a bad batch. Sending the bolt back so they can see what happened.

Upper used was a 6920 barrel with a BCM Bolt Carrier. The bolt had approx 3.2k rounds on it when the lugs broke. Had to pull 2 big chunks of bolt lug out of my barrel extension when it happened, threw a spare BCM bolt in there and proceeded to fire another 200 rounds with out any problems.

[Tokarev]

Had a replacement bolt shipped the day I made the call. Excellent customer service. Going to run the new bolt they sent and see what happens. I hope it was just a bad batch. Sending the bolt back so they can see what happened.

Upper used was a 6920 barrel with a BCM Bolt Carrier. The bolt had approx 3.2k rounds on it when the lugs broke. Had to pull 2 big chunks of bolt lug out of my barrel extension when it happened, threw a spare BCM bolt in there and proceeded to fire another 200 rounds with out any problems.

Yikes.

So does the tapered bolt provide clearance in the extension for broken bolt lugs....

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[hk_shootr]

Wow....that’s a rather epic failure

[Cane55]

Had a replacement bolt shipped the day I made the call. Excellent customer service. Going to run the new bolt they sent and see what happens. I hope it was just a bad batch. Sending the bolt back so they can see what happened.

Upper used was a 6920 barrel with a BCM Bolt Carrier. The bolt had approx 3.2k rounds on it when the lugs broke. Had to pull 2 big chunks of bolt lug out of my barrel extension when it happened, threw a spare BCM bolt in there and proceeded to fire another 200 rounds with out any problems.

Thanks for the photos and reply. That’s a severe break. I’m sorry this happened to you, glad they are sending you a new bolt. Just curious, did you buy the bolt new? Did you buy it recently? I’m just asking because I’m curious if it could be one of the bolts from the bad batch two years ago. I wonder if this bolt is from the original bad batch or if it’s a design flaw that affects all of them.

[vicious_cb]

No, this was a new purchase circa May 2017

[Cane55]

No, this was a new purchase circa May 2017

That’s troubling to hear. I hope my bolts aren’t a time bomb waiting to break. I know it’s only a sample of one, but it’s troubling nonetheless. The older faulty reliabolts broke on the same lugs as yours, so maybe it’s a design issue, not a steel issue. I really want to hear Sharps explanation as to what they think the reason is this broke.

[BufordTJustice]

That’s troubling to hear. I hope my bolts aren’t a time bomb waiting to break. I know it’s only a sample of one, but it’s troubling nonetheless. The older faulty reliabolts broke on the same lugs as yours, so maybe it’s a design issue, not a steel issue. I really want to hear Sharps explanation as to what they think the reason is this broke.

With any steel, the heat treatment, stress relief, and method of shot peening (and the order in which those are conducted) is at least as important as the metal alloy itself. There is a specific "known recipe" for C158 AR15 bolts and for 9310 AR10 bolts. S7 is a different animal and they may still be trying to get the best ratio of a ductile core along with proper surface hardness....without, of course, increasing brittleness too much.

The only other steel which I know can be used successfully in an AR15 pattern rifle is the Aermet steel which LMT uses in their enhanced bolts. I believe, but could be wrong, that the KAC bolt is C158, just with a radically different geometry at the lugs, extractor, bolt face, and cam pin. But don't quote me on that.

[JG007]

I don't think that's right about kac bolts

[BufordTJustice]

I don't think that's right about kac bolts

It may not be. Various KAC sources have said it was another alloy and some have said C158. But the dimensional changes alone would provide massive strength and fatigue life increases. So a material upgrade on top of that would be an even bigger upgrade.


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