Parts Is Parts? Small Parts Quality

[MistWolf]

There are things that make their presence known only by their absence. Often, it's an unexpected small thing, like an endplate.

Today, I swapped a carbine RE on Colt 6920 for an VLTOR A5 and reinstalled the carbine RE on another lower. A straight forward job that went without a hitch. Big deal, right? As it turns out, yes, it is.

My previous experiences with installing and removing REs involved generic brand parts. The problem I ran into was with the fit of the tongue of the endplate in the groove of the RE. The fit was loose and when tightening or loosening the castlenut, care had to be taken so the RE wouldn't spin. If the RE turns while tightening the castlenut, the RE will be off angle and the tongue will damage the threads of the RE. Both create a disturbance in my CDO.

My experience with removing and installing the Colt and VLTOR REs was different. The fit of the tongue of the endplate in the groove of the RE was much tighter. The fit prevented the RE from turning making it easy to install without damaging the threads and ensuring the RE was properly aligned.

Parts are parts but only if they are made to the proper specs. I thought the poor fit between endplate and RE was normal. If I hadn't worked with endplates and REs made to the right dimensions, I never would have known otherwise.

In case anyone is wondering, a Colt 14.5" Socom barrel will not lock back with a 5.3 oz A5 buffer. It will fire, extract and eject, but it won't lock back unsuppressed. It will lock back with a suppressor

[Kain]

Parts are parts but only if they are made to the proper specs. I thought the poor fit between endplate and RE was normal. If I hadn't worked with endplates and REs made to the right dimensions, I never would have known otherwise.

The bold is the damned truth.

I have personally run into the same issue with a DPOS lower and stock assembly. You'd have loved that one since they had to grind a notch into the front of the RE to hold the buffer detent too. Oh, and the FCG was jacked up too, which was all sorts of fun. The castle nut was another piece of special junk. Just goes to show, it is cheaper for a reason.

[Vegas]

I just torqued a DSG Arms castle nut to spec and turned 2 corners out of 3. Have a BCM castle coming to replace. That's what I get for buying cheap.

[ScottsBad]

You are absolutely right. Part of the reason I don't buy from PSA. My first purchase yielded a RE with out of spec threads.

But I've also bought a few things that were supposed to be high quality that were not.
Kits with improperly heat treated detents. BAD
Loose selector levers DD LPK
Receiver pins with a crappy finish. DD LPK
Ill fitting REs that had to be hand fitted. BCM

Generally, I buy quality stuff. But sometimes you have to buy generic parts.
I've had weak crappy crush washers.
Gas block roll pins some were too short.

Then there is the stuff that is consistently good.
ALG LPKs
Geissele LPKs
Most BCM parts
All LMT REs
Vltor A5 stuff
Vltor MUR
Noveske QD end plates
BCM QD end plates
Sprinco Tactical Springs
DD and BCM BCGs. They just work and seem to last

[ScottsBad]

Also, I thought I'd add that quality tools are important too.

My first castle nut wrench was a weak POS and broke totally screwing up the nut.

[Vegasshooter]

It won't lock back with your ammo, or with any ammo ? I only ask because it may not lock on PMC, but be totally fine with mil spec 5.56.

[tom12.7]

All parts are not equal by a long shot. Unfortunately, there's more garbage out there than good components. A long time ago, I made a jig to keep the RE properly aligned to the base receiver. There's many versions of these out there, and most aren't that hard to make. That doesn't make garbage in components non garbage for use, more of a tool for quality parts.
If real M855 does not properly cycle for you with the Colt barrel and with proper environments for that with that buffer mass, then you have some issues to look into.

[MistWolf]

It looks like I was shooting a mix of Federal 55 grain 5.56 ammo and Remington Freedom bucket 55 grain 223 ammo. I only had 40 rounds with me as it was a quick trip to function test the AR. I didn't realize the ammo was mixed. The ammo came from a 40 round mag that was partially loaded with the Remington ammo, then topped off with the Federal. I'd strip a round from the 40 round mag and test lock back in a Colt 20 rounder. At first, it locked back with no problem. Then, when I got down to the Remington ammo, it wouldn't lock back. Interesting.

I'm not worried though. The SOCOM barrel works fine with any ammo when using the factory H buffer (which is lighter than the A5H2 buffer), suppressed or unsuppressed. I can get lighter A5 buffers. I haven't been able to measure the gas port, but evidently it's right on the money

[556BlackRifle]

Yep, and there are a lot of companies more than happy to sell you junk (no name made who knows where) for the same price as properly spec'd parts. Some might not even know they're selling out of spec garbage because not enough people complain.

Good advice above from ScottsBad to stick with a known good company.

And I agree with what tom12.7 said. The buffer mentioned (5.3 oz) is an A5H2 which usually works with everything. I'm surprised it's not working with a 14.5" SOCOM barrel.

Edit to add: Just saw MW's response. Remington........ Nuff Said.

[RobertTheTexan]

On top of Scott's and Tom's & the other guys comments about quality parts, I have also learned to stay away from gimmicks. Even if it seems the company is GTG. Case in point the PWS ratchet locking RE tube and castle nuts. I initially thought, oh this is cool, no need to stake the castle nut. But after having a couple of A5 RE tubes ruined because of the improperly made end plates I learned that I had made a mistake trying to avoid a fairly simple process. I even had PWS send me some new end plates that were identical to the bad ones. Except the new ones had permanent marker used on them to cover the fact they were used. Point being, if it isn't broke, don't try to fix it. I ended up pulling the PWS parts off my RE tubes and going with a mil spec end plates & castle nuts and just doing it the tried and true way.
So through the course of my builds I have had some lessons hat cost me money, but at this point I'd like to think I have learned what company's I can depend on. For example I always use LMT BCG's, unless Km building a precision rifle and then I usually match barrel and BCG manufacturer. My optics mounts, I like LaRue, not everyone does, but they have always trued up for me. I imagine we all have our "go-to" guys, and that's the great thing about having friends who have figured out who has "the goods" and who doesn't, that has also saved me from learning things the hard way. Except for those times I get a knucklehead notion to try something like that PWS ratchet junk. My friend even cautioned me and in the end he was right. Stay away from the gimmicks.


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