The first broken bolt catch I ever saw was on an ArmaLite AR-10T 24” gun running suppressed in Finland.
That huge BCG slamming into the bolt catch every time he ran to LRHO was just too much for the bolt catch, especially at accelerated cyclic rates from the suppressor.
1996-forward ArmaLites (Eagle Arms re-branded) are one of the best-engineered AR-10s on the market, with superior bolts, bolt carriers, sprung firing pins, and fitment of all the parts to almost everyone else. They are very reliable and accurate as a rule, but even they had problems with bolt catches breaking, as did KAC.
The challenge is that once you make the bolt catch more tough, it can then start peening the bolt lugs. It takes serious engineering and competent staff with a large budget to solve these and many other problems.
The companies that are worth buying from have run pyramid-testing with multi-million dollar staff and ammo budgets.
The companies that have not done this are merely using customers to find all the weak spots.
Most of them just replace the trash item with another piece of thrash, rather than investing in pyramid-testing because it’s too expensive.
KAC probably has the most experience with extensive testing across a wide range of conditions and customers who have demands that are not seen typically in the private sector.
LMT used lessons-learned from the SR-25 and AR-10, since Karl Lewis was involved with the ArmaLite AR-10 development and parts supplies to many other companies, and properly-engineered and tested the LMT MWS.
LaRue did excellent design work, research, and testing on the 7.62 OBR, with tight controls on production for the parts machined in-house, and very well-designed testing parameters and schedules.
Daniel Defense did excellent design work and pyramid-testing with their DD5 .308 and 6.5CM rifles.
Savage did Pyramid-testing with the MSR-10s when they were part of the Vista Group, so they bought ammo from Federal to run those tests. They took a laundry list of features that AR-10 enthusiasts had wanted and incorporated them into the design from the start.
DPMS pyramid-tested the GII prototypes until they ended up with the final models with the separate feed ramp inserts, the elastomer extractor, metallurgy for the bolt and extension, gas ports, etc., then handed it over to DPMS product management, who screwed the handguard SKUs, and production screwed the QC cranking out guns with ejection ports that wouldn’t even open. They had an awesome design, then ruined it somewhat in mass production and SKU configuration.
The companies that sell cheap receivers, outsourced generic BCGs and cheap nitrided barrels have not done any of this, which is why they are able to sell at such low price points. They literally don’t care about your shooting experience, as the main motivator for them is single sale, high-volume sales hoping you can’t afford to shoot much through their parts.
Even from the companies that I place in high regard, I would only want a parts kit from them so I can go over everything, fix what needs fixing, and then assemble myself.
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