Home Forums Hunting & Shooting AR and Tactical Rifles Couple of lessons learned

I was a part of an AR class this week. Twenty students, a bit over a thousand rounds apiece. Couple of observations....

An Aero Precision home build had a lot of problems. Something in the trigger (somebody else looked at it and I forget what it was) broke and the gun went full auto on day two. The gas key staking was abysmal and the key worked loose on day three. And the extractor lost tension on day four. The extractor spring was visibly shorter than the new replacement by a coil length and could be compressed with moderate finger pressure. The BCG and LPK were both AP, those problems are on them. The gas block also came loose, that's the fault of the builder. Don't forget to loctite set screw gas blocks.

Every gun with extraction problems during the week had carbine gas.

Most people can shoot better standing than kneeling.

Once people understand how ARs actually work, they immediately buy into the idea of quality parts.

Edited to add:
Cheap Vortex optics continued their 100% fail rate. Every single one of their cheap red dots have failed over the course of a week. One Sparc2 lasted until lunch on the last day, then rattled loose from its mount.

Thanks for the update! Always appreciated.

Why anyone would put anything together without loctite, preferably 640 where the screw can then fall out and it still won't move, is kinda beyond me. I know if i ever get to building Carolyn and I a pair of vehicle guns, they sure won't be anything but solid.

You don't alwyas have to have the best parts, but you do have to know what to look for and how to assemble when building. And you do need to know which parts HAVE to be good. Extractors are NOT the place to skimp.

Keys will stay in place without staking if 640 is used...

Kneeling sucks UNTIL you kind of figure it out. There are some important parts to learn on kneeling or it IS worse than standing. Ball of the knee to ball of the elbow is one of the big killers.

A shame to know about Vortex, the binocs Carolyn has are just really good glass for what they are and what they cost. Never had an issue.

Have never bought vortex scope or dot, and you indicate why thats been a good decision so far.

Be interested to see if you contacted them and told them what you are seeing, if they would beef up and send you a few to torture test... it does happen as you well know.

Have a great weekend. Heat sucks already but what can I do... just keep dreaming of mile marker 1402.....

I've got a pair of their binos too, I think they're Diamondbacks. I've been very impressed with them.

I know a lot of guys who use the Razor line of scopes, specifically the 1-6s and they all love them. But I think Vortex relies on the popularity of their really good stuff to sell their really crappy stuff.

Yeah the heat sucks.... A/C went out last weekend, but I got a buddy deal and got it fixed for free and got the A/C hooked up and running on the addition.

Doesn't surprise me about the low end Vortex optics. I don't trust anything they make other than the Razor line, which is very nice. Even their PST scopes seem to have an abnormal amount of issues.

Thanks for the info, Blue.

Not too surprised at the Vortex failure.......... & I don't have any Vortex.

Also, mildly surprised at the AP's BCG failures, but I don't consider AP as anything more than lower mid-range product & other than a lower of theirs that I've used, I don't use anything else from them.

In the long run, using premium components doesn't absolutely guarantee success but I think it surely increases the likelihood of it by a significant amount so in the long run, less grief & not that much more money expended either. If cheaper parts have to be replace, likely the end cost or premium parts is actually a better bargain.

MM

Bluedreaux,

That is some quality information - Thanks. I am brand new to AR's and am trying to figure out which parts to use. After reading your initial post, I have quite a few questions:

What trigger were you using? What after-market trigger would you suggest for general plinking and possibly hog/deer hunting sometime in the future?

Whose BCG would you recommend? I have been leaning towards the Sionics NP3 coated unit but am open to another brand.

Do you recommend using Loc-Tite on CLAMP-style gas blocks? Seems like this attachment type is more secure than the set screw configuration.

Mid-length gas over carbine? I am going with the 277 Wolverine cartridge, so heavier bullet.

Whose LPK would you recommend?

What red dot would you suggest?

Thanks in advance.

I used a CMC 4.5# this week. For what you're doing, if you didn't want to just use a stock GI trigger, I'd get an ALG ACT, BCM PNT, or something similar. They run about $50.

My go-to for BCGs would be BCM. Look for an 8620 carrier and 9310 bolt. HPT and MPI is a sign that they're checking for quality. I haven't used any of the Sionics stuff, but the guys running Sionics know what they're doing and I've only heard good stuff about them. Even the Aero BCG that messed up this week would likely have been fine for a very long time if the spring and staking had been fixed before it was used.

I'd loctite either kind of gas block. With whatever loctite Jeff recommends. And I'd use a set screw over a clamp on style. They seem less prone to leakage and more stable / easier to line up if the barrel is dimpled.

Mid-length gas is usually a better idea. Most ARs are over-gassed. Mid-length systems can help that.

BCM, ALG, Colt for LPKs.

Aimpoints are the go-to answer for dots. I prefer an Eotech, but they can have problems. For your uses you'd be better suited with a 1-4 optic. There are several threads here on them.

Also, I'd really, really, recommend that you get a 5.56 gun. Wildcats can be problematic to gas properly and tracking down problems with loading and gassing isn't as straightforward because not many folks have experience with them. And in the field they offer very little real advantage. Figure out how to build and what you like with the 5.56 and then go from there.

Appreciate your thoughts on triggers. Had been looking at the basic single-stage Geissele but will give these others some thought.

The Sionics BCG is made from Carpenter 158 which, by all accounts, seems to be a high quality steel. The gas key will be staked from the factory but is there anything further I can do to reinforce it?

Probably does not matter but I am going with an adjustable gas block. Will use Loc-Tite.

Too far along with the 277 Wolverine at this point. The nice thing is that I can just swap a 223/5.56 barrel and shoot that ammo with no issues. The 277 is based off of the .223 and uses the same bolt, mags, etc.

Which Geissele are you looking at?

The Sionics will be staked fine. If it's not they'll fix it.

Besides what Blue has recommended, & especially since you are going with a wildcat, I'd also add that I strongly suggest an adjustable gas block & it doesn't get any better than SLR's version, IMO.

Gives you more flexibility if you are over gassed & I strongly prefer adjusting the gas than buying & trying several different spring & buffer combinations.

An H or H2 with a standard or enhanced spring & adjust gas as you need to.

JMHO

MM

Good info bluedreaux. I'm not surprised at all by the Vortex going to chit. My buddy had the Viper PST on a short mag and it didn't last very long. We both swore off the POS's after that... I have a question regarding the gas block: Aren't most of the good ones considered "bomb proof", where the barrel is actually drilled and a pin put in to hold the gas block in place, with the addition of the typical set screws??? My 3 ar's are built this way.. The other comments on Aero Precision are good to know as well, but I'm wondering if it was more of a novice builder mistake that anything else??

Pat Rogers used to keep track of this stuff and shared it so folks would steer clear of parts with a bad average.
Looks like nothing has changed.

Now wait for someone to say their brand x has never failed and parts is parts...

As for loctite, 640 is bearing retainer not thread locker. Don't use it on anything you wouldn't put a torch on for removal.

Yes, the best method is to install the gas block with taper pins. It's essentially a structural part of the barrel at that point and is as solid as it can be, short of welding it on.

The trigger, gas key and extractor spring are all AP's fault as far as I'm concerned. The parts just failed.

Was just about to post... but you covered my tail once again. 640 will come off eventually. Last front sight base I put on many years ago that I needed off, pulled the set screws, then heated with propane torch and between that and a 2x4 and a 3 pound sledge with the barrel clamped in a vice it came off again finally...

But if you use 640 I'd be WAY surprised if you ever had an issue with stuff coming apart. AMU units have used it for years due to this...

Blue, I have a Colt 6920 with carbine gas but most of my guns are DD mid length gas. Did you see Colt's or DD guns fail? I have two cheap SIG Romeo 4's I wish I had not bought and use these on guns that are not serious. Any scopes used and failed at the course?

To further this, which I"m often to much of a hurry to do...

IF you have NO clue how an AR works and how to assemble, then by all means buy the best you can afford with the best parts! Thats the only way to do it.

And RE the 640.. I use that on sight bases for years but used other either blue 242 or green something to set the screws with. The 640 went on the part. I would put it on carrier key screws though, the 640, if they were not staked. Certain things can benefit from 640 big time, other things if you need to take them apart, like a small screw later on, you'll likely just strip the head before the 640 releases.. unless you get it really hot first...

Just FYI on being careful with where you put 640... on a bolt gun, bases to gun probably ok, ring screws... nope, 242 has never failed me there and you may need to replace the scope at some point... hence no 640 for me on certain parts.

Sorry just re-read, any SWFA scope failures, Leupold, any others besides vortex red dots and scopes?

There was one home build with a DD barrel that ran great. About 8 factory Colts that ran fine (all carbine gas).

A Steiner 1-4 and Leupold VXR1.25-4 were used and there were no problems from either of them.

Both of the Vortex dots crashed. The Aimpoints and Eotechs were fine. One non-F-marked FSB had elevation problems because Bushmaster refuses to put proper parts on a gun.

Thanks for your information! That Steiner 1-4 keeps popping up!

Carbine gassed guns, built right, run just fine. Mid length guns with a larger than needed gas port will still be over gassed and be hard on parts.

I shot today with a friend who has a PSA mid length M4, I shot my Colt pencil barreled carbine gassed gun. We started out shooting offhand at 50, kneeling at 75 and prone using the magazine as a monopod at 100. M193 ammo, he shot a red dot, I shot my 1-6 FireDot on low power to keep it fair. His gun runs fine but throws brass at 2:00, mine at 4:00. Time will tell how his will hold up but it bugs him enough, he's ready to try an adjustable gas block. Extra power buffer spring and H2, even 9mm buffer didn't help.

True mil spec works.