Todays laugh!

[LRRPF52]

From what I have researched all the enhanced bolts that are made to fit the mil spec extension have experienced breakages, even Sharps new highly radius-ed bolt, without regard to the material. My preference would be for a hybrid that gives up some of the extensions inside radius for expanding the bolt's outside radius. Though I have never broken any bolt personally, what I have seen would indicate a weakness or a higher stress being applied on either side of the extractor. Physics tells me that if I double the diameter of the cartridge I will get 4 times the area or force at a given pressure. Why not build a better bolt?

That Relia-bolt proved to be one of the most brekage-prone bolts on the market, for a premium price too. The choice of steel was not really an appropriate one for starters. Upward learning curve on heat treating with S7 on such small AR15 lug geometry also seemed to contribute to the failures.

The only bolts I have broken in the AR15 have been in 5.56 chambered guns run on a tortuous firing schedule, CLGS, with a lot of M855 and Winchester White Box. The AR15 was designed at a time when the final SCHV cartridge had not been realized yet, and was built around .222 Remington with 50,000psi SAAMI MAP (Maximum Average Pressure or working pressure of the cartridge set by SAAMI).

Are you talking about increasing bolt body diameter, or outer diameter of the bolt lugs?

Knights Armament did a nice approach to this with their E3 bolt and extension.




LMT also uses Aermet alloy on their enhanced bolts, which is a good prescription for the 7.62x39 guns, but extractors still break with the .124" bolt face depth limitations on extractor lip geometry, and the enhanced LMT bolt extractors are proprietary lobster tail designs.