Reliability to the max: best AR internal upgrades for superior cycling?

[BallisticHarmony]

After reading several articles and threads about the Surefire OBC, I'm trying to piece together what the most "optimal" AR would look like under the hood. I'm thinking that some of the upgrades certainly worth considering would be:

KAC E3 bolt
KAC MOD 2 Intermediate Gas System
LMT Enhanced BC
Surefire OBC (and buffer?)
A5 Extension (and A5 buffer?)
Radian ADAC Bolt Catch Feature

I'm sure there are others that are in the running, but what I'm really unclear about is which of these upgrades work together, and which are too proprietary to coexist. Do they stack on top of each other in terms of improved functioning, or is it redundant? Would they counteract each other? Does a Surefire OBC even work in an SR-15? Would the Surefire buffer work with an A5 tube?

Just trying to get a grip on how all these different advances in the market can work together to make the ultimate build, which ones should be strongly considered, and which ones are unnecessary or overblown.

Thank you.

[Firefly]

All you need is an LMT Enhanced bolt and an H buffer

[Wake27]

I'm picky about a lot of things, but never understood this. Maybe its because I've never had an unreliable AR that wasn't defective from the factory (unless you count broken gas rings). If I manipulate it or it otherwise affects my shooting, I'm all about experimenting. But if it goes bang every time I want, why screw around with any of that? I'm still not really sure why I went all in on the A5 system.

[MountainRaven]

If we start with a 20" barrel, rifle gas, rifle receiver extension, rifle buffer weight... only one part would really be an improvement, and that would be the LMT E-bolt. Or the KAC E-bolt, if you got a KAC barrel extension. And I don't think that's going to give you an edge in reliability, so much as durability.

Everything else is pretty much intended to get full-auto carbines to run on par with full-auto rifles, and I'm not certain you'll see much benefit (possibly any benefit) in a semi-automatic carbine.

Maybe if you can test the dozens of hundreds of configurations across a couple dozen weapons with ten or twenty thousand rounds run through each, you might find something that pushes the carbine to be more reliable than others, but otherwise...

...it's just one dude tinkering with one (or a few) of their own personal rifles. Which is fine. But it's going to be a non-scientific test, statistically insignificant, the plural of anecdote isn't data, &c.

So, sure, maybe you'll be able to get a 14.5" barrel intermediate gas gun with some sort of E-BCG (SureFire, KAC, LMT, doesn't matter) and an A5 buffer system to run reliably and with great durability; But I feel reasonably certain that you would be unable to demonstrate that this hypothetical individual weapon is more reliable or durable than an LE6920 (or reasonable proxy), much less the Stoner-Sullivan Original™ AR-15/M16/C7 configuration.

So, yeah. An LMT E-bolt, if you have to. I don't think an H or an H2 buffer should even need to be mentioned.

(The above assumes the end-user wants a 5.56mm NATO rifle or carbine capable of running reliably a variety of ammunition types under a variety of field conditions, and is not trying to specialize the weapon for accuracy, multi-gun competition, 100% silenced/100% of the time, preservation of spent brass, preferred "recoil impulse," feel or any other specialized application(s).)

ETA: Probably the most, "optimized," fighting carbine that fits the above criteria - and actually has the testing to demonstrate it - would be a KAC SR-15/SR-16 upper on an LMT MARS lower. And the LMT MARS lower is just because the ambi bolt catch on the LMT is better than what the KACs come with. Just add the Geissele, KAC, LaRue trigger of your choice and done.

[MistWolf]

Just because it's rocket science, doesn't mean it's complicated. Proper gas drive, quality springs and correct reciprocating mass. Colt M4 has all three.

PROPER GAS DRIVE- Right gas port, gas system length and enough blow down time (distance from gas port to muzzle).

QUALITY SPRINGS- In my experience, the Number 1 killer of AR reliability is marginal springs. The Big Three are extractor, hammer and action springs. An action spring that's too stiff will also cause problems, but not like a marginal or weak action spring.

RECIPROCATING MASS- If the reciprocating mass is too great or too little, it throws the AR out of balance. AR carbines work best with buffers weighing between 4.6 oz (H2) and 5.3 oz (A5H2, Rifle).

Next, choose parts of a known quality and assemble with care. There are particular details to pay attention to that make shooting the AR a better experience (good trigger, comfortable furniture, preferred sights etc.) but don't do much for reliability.

[BoyScout4Life]

All you need is an LMT Enhanced bolt and an H buffer

And perhaps an SSA-E trigger....

[Goldorak]

I like the question. It drives some folks to push boundaries, to expand knowledge, to create new stuff. This is how most inventions and innovations happen.
As opposed to the "There is nothing left to be discovered" crowd.

Does it automatically guarantee something better? NO, but it should not stop us from trying.

[Sry0fcr]

Probably the only "universal" improvements will be the A5 and an enhanced bolt. Everything else will be situationally dependant.

You can't throw a bunch of "enhanced" parts at a gun and expect it to be "optimized'. A lot of these parts were designed to work within a specific envelope and may not work well with each other. If you don't know why you're doing what you're doing I suggest learning more about how the platform works before you end up with a Gucci build sheet and non-functional gun.

Sent from my Pixel 3 using Tapatalk

[JediGuy]

Clearly, the most important, simplest, and cheapest upgrade related to reliability in actual adverse conditions to ensure one has a bolt EDIT: “bolt carrier” with sand cuts. They are available at both DS Arms and KAC.

[Uni-Vibe]

Saw a guy at the range who had done exactly that. Took a rifle and put in a bunch of enhanced parts, polished plated bolt carrier, custom charging handle, I don't know what all. The muzzle device looked like a medieval mace. There was even a dust cover that said "F*** You." I am not making this stuff up. It failed to function. I think he only got a few shots off. I offered my bottle of CLP which he declined .

Meanwhile, my old unmodded Bushmaster A2 was cranking out the rounds merrily.