AR15 Will everyones parts fit?

[luckyned7]

S! All

Looking into a AR and I'm searching thru all the options and makes and models. I think I want a RockRiver lower for the lighter trigger but than began to wonder if I can piece it all together from different companies? Afterall- currently I'm just looking to put alot of rounds down range for fun..so I just want short and light for my 50 yard plinking range but later I may want a long range shooter. Whatcha think? Is there one company that I need to stay away from parts or another that sells a upper to beat-up at a low price?

Thanks ahead~Ned

[JIMMYC308]

Can't go wrong with Bushmaster or Rock River. I also have been reading good things about Stag arms.

[TonyF]

I'm probably going to get flamed but here goes.

There are only two companies that possess the technical data package (TDP) to properly build an M16 / AR15 ............. Colt and FN.

Under terms of the government contract, FN is not permitted to sell AR15's on the commercial or open market so you can't get FN components.

All other manufacturers have basically had to reverse engineer most of the components they use in their AR's.

What does that mean?

It means that they had to purchase other manufacturers parts, measure them, dimension them, and then start fabricating them. Without the TDP, this approach cannot take into account how far from nominal those parts were, so in many cases *their* part has a different *nominal* dimension than the same Colt or FN part.

What does that mean?

It means that assembling an AR15 from parts from various Tier 2 and Tier 3 manufacturers *may* result in an overall tolerance stack that *may* lead to functioning and reliability issues. YMMV.

For these and other reasons my preference has always been Colt. We see all manner and types of AR's in our classes. And we know many other instructors who also see all manner and types of AR's in their classes. The brand that fails the least and has proven to be the most reliable is Colt.

Colt and FN are also bound by .mil government contract to higher QC standards which is why Colt AR's typically cost more than any other brand. For example, Colt and FN are the only manufacturers that magnetic particle test EVERY BCG.

Some criticize Colt for using non standard hammer and trigger pins. I think it was stupid for them to do that too. However, in regard to reliability, we have never seen a Colt hammer or trigger pin break (or any other manufacturer's for that matter). The fact that Colt has standardized on the smaller size pins for their entire commercial line as well as LEO models mitigates the problem of availability.

Bushmaster doesn't properly stake their carrier key.

Rock River Arms uses a non mil spec receiver extension.

Have there been examples of issues with Colt rifles in training classes? Yes. However, from a statistical perspective, the percentage of *bad* Colt rifles vs. other brands is almost immeasureable.

Granted, if you're interest is hunting, target shooting or plinking then paying for Colt quality probably isn't worthwhile. Worst case scenario is you *may* have nagging function and reliability issues. OTOH, if you intend to use the rifle for self defense, the few hundred dollars difference in price is well worth it IMHO.

Before anyone *corrects* me and points out that other manufacturers use some of the same subcontractors as Colt, recall the issue of Colt (and FN) being compelled to adhere to .mil government QC standards.

[danp]

I'm probably going to get flamed but here goes.

Not sure what there would be to flame, that was a super post! I definitely learned a few things.

[buddy7311]

That was probably the most concise explanation I have heard about the different manufacturers. Thanks

[GRoPA]

I have MEGA's and love them. The front of the mag well has a grip area on the front of it that looks like a meat tenderisor, the mag well has a good bevel for loading and they are just the blackest of black. They make everything else look gray.

[bloomautomatic]

I have PWA lowers for my AR's. From what I heard, that's who makes the Rock River lowers now.

I bought my parts kits from Sherluk. They told me that the parts were made by FN. I have no reason to doubt them.

Vince

[DPB]

Tony is 100% correct regarding the TDP issue. Some of my personal experiences, however, lead me to believe that this is not as big of an issue as some have made it out to be. None of this should be taken as bashing of Colt, FN, or Tony

At one point in my misspent youth, when I was younger and stupider, I was responsible for an arms room that was about 80% Colt M16A2s, and 20% FN M16A2s. The Colts had been in service for 8+ years, the FNs for less than 5, in a unit where they were shot more than average and exposed to wear factors that most would consider abusive.

Now these two sets of rifles had been held to the same USGI TDP, but the FNs were universally worse. Worse rate of breakage, higher rate of observable wear, you name it, terrible parts fit, they were no where near the standard of the Colts. One or two rifles, I would have attributed this to USGI BF&I (Brute Force and Ignorance), but it was true across the limited sample I observed.

Take from this what you will, but it tells me that adherence to the TDP does not insure a uniform quality of firearm, or even that every rifle that went through USGI QC was held to the quality of a major manufacturer sporting firearm.

One other thing. Colt and FN are held to the TDP for weapons that are bought by the US military. They are NOT compelled to meet this standard for weapons that they sell commercially. You are not necessarily buying a gun that came off of the same line, or went through the same QC, as GI Joe's M4.

Are Colt's the best of the mass produced guns, quite probably. The issues with Colt are availability (go look for one on the shelf), and price. While I agree, that higher QC justifies higher cost, and MPI BCG and barrel do not account for the fact that a Colt costs 150% what a BM does. You can look and see, the difference between an MPI and non MPI BCG is what, $20 retail. The difference in barrell depends alot on the manufacturer, but it's generally less than $100 for otherwise equal barrells. Locally, a BM 16" carbine goes for less than $900, a similar model Colt goes for $1300+.

I'm not saying Colt is causing this unaccounted for price difference but somebody, manufacturer, distributor, whatever, is getting some mileage out of the pony.

[phillyd2]

Flame Tony? Hell yeah, sign me up (just teasing)

Seriously, Tony got it right. I too own a Colt AR and consider them tops in every respect.

To expand on the caveat though: Some civilian Colts (not M16) use non milspec front pivot pins (.312" instead of .250") and Most Colts (correct me here Tony) use slightly larger fire control group (trigger & hammer) retaining pins (Standard milspec hammer/trigger pins =.1540 inch diameter & Colt = .1720 inch).

You can solve this issue by buying some extra Colt parts: Brownells part # for the .170 trigger & hammer pins is 160-305-101

So besides Colt, all other parts are interchangeable between AR makes.

Down side to Colt is the price. For me it was worth it but others may not agree.

[phillyd2]

Colt and FN are held to the TDP for weapons that are bought by the US military. They are NOT compelled to meet this standard for weapons that they sell commercially. You are not necessarily buying a gun that came off of the same line, or went through the same QC, as GI Joe's M4.

True, but I do think that they are all made on the same line with the same strict QC. Other may correct me on this one but it is what I have always "heard".