For Future Reference

[Spook]

http://www.ar15performance.com/home

Scroll down to " I.T.S. Superbolts "

Without inferring anything,You might want to think about bookmarking this...just sayin'
Really well made products and nice people to deal with.

[BWE Firearms]

Thanks for the tip. I bookmarked it as suggested.

[alorton]

I've been thinking about those for some time.

I had some correspondence with AR Performance after reading a long thread on M4carbine.net about the 9310 alloy bolts. The consensus on M4 was that the 9310 alloy was not as strong as Carpenter 158 (standard bolt steel) but that the design of the super bolt (more material around the cam pin hole, radius at the base of the lugs) was superior.

When I asked AR Performance about it they said that the tempering process they use to harden the 9310 makes it stronger than Carpenter 158 and that Harrison has really pounded on several of the super bolts without having any breakage issues. I haven't been able to locate any direct comparisons, most likely because the ammo cost to test two of them heads up would be too much for most folks (myself included).

[Spook]

Originally Posted by alorton

I've been thinking about those for some time.

I had some correspondence with AR Performance after reading a long thread on M4carbine.net about the 9310 alloy bolts. The consensus on M4 was that the 9310 alloy was not as strong as Carpenter 158 (standard bolt steel) but that the design of the super bolt (more material around the cam pin hole, radius at the base of the lugs) was superior.

When I asked AR Performance about it they said that the tempering process they use to harden the 9310 makes it stronger than Carpenter 158 and that Harris has really pounded on several of the super bolts without having any breakage issues. I haven't been able to locate any direct comparisons, most likely because the ammo cost to test two of them heads up would be too much for most folks (myself included).

Not being a metallurgist, ( but having stayed at several Holiday Inn Expresses ) I would conclude that you could reduce the cost of the comparison by reloading less ammo to higher pressure
Here's a hint, rather than test to failure, test for wear and or distortion.

I've really hammered a few of the .473 bolts/extensions (6 BRX,6.5 BRX and 30 BRX) and couldnt get anything to break.... attempting a 338 BR next.

[rsilvers]

9310 may be stronger than C158, but the bolts do not fail from not being strong - they fail from fatigue, cracking, etc.

So the question is - what material is BETTER for a bolt?

Answer: C158.

So why does not everyone use it? It is MUCH more expensive due to a minimum order quantity that smaller makers cannot swing.

[Spook]

Originally Posted by rsilvers

but the bolts do not fail from not being strong - they fail from fatigue, cracking, etc.

WTF? So they crapout beacause they are strong enough?

Sorta defies logic dont it?