YouTube channel that might be worth a look

[phishfood]

Ran across this channel the other day. He goes through AR parts, shows signs of different problems, etc. He sure does have a lot of specialized gauges.
https://www.youtube.com/channel/UCaUOYvl...M4w/videos

[Lemonaid]

Thanks for the link!

[Popeye212]

Thanks for the link

[CJW]

Thanks phish for the link, very interesting.

[PNWTargets]

A Gunsmith I know just got back from SOTAR. He did the two day course. Said it was good.

[BCG]

I was watching his videos last week of him inspecting bolt carrier. He’s very thorough.

[LRRPF52]

Great channel. If you follow any of his videos, you'll quickly see why those of us who have been chasing reliability and durability in the AR15 for so long will always say that most parts are not built to the Military Technical Data Package, and would never pass the basic inspections that the DoD requires for the AR15 family of weapons.

I started learning this the hard way taking non TDP carbines through high volume shoot schedules, and the Arctic/sub-arctic courses I've done over many years really showed what fails and why the US MIl-Std TDP is what it is.

Carrier bore dimensions, bolt materials, upper receivers, FCG parts, RETs, barrels, chamber dims, gas ports, flash hider materials and processes, gas tubes/alignment/carrier keys, detents and every part on the AR15 are just not the same when looking at companies that base their sales and margins off of volume and unsuspecting civilian customers (who they assume will never know anyway).

Anytime someone says Mil-Spec is just the baseline lowest bidder that most AR15 companies follow, then improve on, I know the person is not familiar yet with the reality of how hard it is to meet the TDP.

A number of years ago, some guys tried to compile a list of what to look for that would somehow indicate guns that were worthy of Mil-Spec and ones that weren't.

It didn't even scratch the surface of what is actually important, and called one one of the main things that actually makes AR15 bolts weaker that is part of the TDP (HPT non-destructive testing).

That's the main gripe several engineers and prominent AR15 manufacturers have voiced, including Bill Alexander.

The Canadian Colt engineers also said they use a different approach to making C7 bolts that are extremely durable, as does Knight's Armament.

Other companies that try to adhere to the TDP as closely as possible (minus select-fire lowers and FCGs) still use the HPT/MPI bolts.

I see a lot of companies make the claim that they improve on the TDP by using one of many different types of coatings or finishing processes on barrels and BCGs, while ignoring all the minute details that make a reliable AR15.

One thing you'll notice about Instructor Chad's videos is that he deals with severed carrier key fasteners and incorrect bolt carrier bores quite often. Gas leakage and short-stroke malfunctions are what initiated the diagnoses/"autopsy" as he likes to call them.

He'll very often find carrier kets staked with "YFS" fasteners and carrier bores that are too loose in the call-out IDs in the TDP. This doesn't allow sufficient gas to be contained in the chamber formed by the bolt gas ring flange and the carrier wall that the tail penetrates though.

The TDP calls for specific fasteners for the carrier key that are made from ductile steel with a certain heat treat. If the fasteners are too hard (brittle), they can break off under full auto or high volume shooting. There isn't anything wrong with the YFS fasteners for other applications that don't involve a lot of heat and repeated stress cycles in compressed time schedules, and they normally last long in AR15s that aren't subjected to tortuous firing regimens, but why deviate from the TDP that has been established and updated over the past 60 years?

[CJW]

Great post 52.

[sundowner]

Thanks for the link .