top tier ar-15 makers and testing of parts, questions....

jhb,
Fist off, mil spec only really guaranties parts interchangeability not highest quality available.
Explanation of Desirable Features in Commercial M4 Pattern Carbines
http://spreadsheets.google.com/pub?key=pwswheghNQsEuEhjFwPrgTA&gid=5

The link covers several areas equating to mil spec requirements which can vary from materials, dimensional tolerance, finish coatings etc. The actual list can be very long for a given component and not all as important as the next.
Don't place all your trust in the mil spec requirement. An example could be the fact that a milled billet upper receiver (not mil spec) will generally fit my forged mil spec lower much better with much less or NO apparent slop than any forged mil spec upper I've tried. Another might be the trigger group. Who would prefer a mil spec trigger group to just about any make of aftermarket unit?
Hope I haven't just confused the situation for you.

Stack said:

Who would prefer a mil spec trigger group to just about any make of aftermarket unit?

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Some of the guys who rapidly blast magazines full of ammo at man sized targets at close range.

Not my thing but that is what some guys consider fun.

Think of the "mil-spec" more as a set of minimum guidelines to try and minimize parts failure under hard use. Strict adherence to the "mil-spec" ensures that your gun meets the minimum requirements set forth by the military to be considered a legitimate battle implement. Because of the heavy demand put forth in military usage, it is comforting to a civilian to know that their gun has been built to standards much higher than they will likely ever need, or that parts failure may be minimized in case of a need to use the gun for self defense.

Still, there are times when mil-spec is not desirable. Those looking for accuracy should shun the mil-spec chrome lining in their barrel. Different buffers and bolt carrier groups than mil-spec may be desirable in certain usage scenario's. Also, some manufacturers go out of their way to exceed mil-spec and could be considered much more desirable than a standard mil-spec gun.

When buying an AR, the more tested and quality parts you can get on a gun, the better. Which mil-spec items are important to you depends on what you intend to use the gun for. Define your use, and match that to the manufacturer with the best materials and products for your needs. It will take a lot of time and effort, but will be worth it in the end.

Some of the guys who rapidly blast magazines full of ammo at man sized targets at close range.

Not my thing but that is what some guys consider fun.

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Uh, that is what they call serious use, and certain make rifles are not suitable for such rigorous activity.

Go for Daniel Defense and be happy.

JHB,

MILSPEC is for a particular purpose. So I will try to answer your questions as they relate to a military weapon for combat use. Obviously, if you are building an AR based long range precision rifle in 6mm PPC that will have a whole other bunch of specifications all it's own.

"...do the mid pack makers....meaning s&w, stag, rra, bushmaster, and various others....use inferior parts as far as materials......i saw in my research they don't test all their parts, rather batch test, but....."

Yes. When compared to milspec, some of the other barrel steels, aluminum alloys and coatings are not as tough, wear resistant etc. Even when the correct materials are used milspec requires that every one of certain parts be individually tested. this is done to reduce the chances of critical parts failure as much as is reasonably possible.

Batch testing, the use of inferior barrel steel etc are ways to cut corners so you can reduce price. For 95% of shooters it will never matter. For the other 5% it's life or death.

"does this mean these untested parts are any worse quality than the ones used by colt, noveske, lmt, etc, etc that are tested to mil spec requirements?"

"Quality" is part of "quality control" yes? Even if the part is made of the correct material, in the correct way, individual testing reduces the chance of an unseen flaw causing a critical failure at the worst possible time. For most of us that's at the range and is no big deal. If our improperly staked gas key starts to cause short stroking, our incorrect extractor slips and fails to extract every now and then or our uninspected bolt shears in half. we cuss and go get another one. For self defense, LEO or military situations its another story.

"does the mil spec mean it's the testing that seperates the parts in quallity or is it the actual materials used?"

It's both. to meet milspec you have to use the specific material in the specified way and test it as demanded.

What's so valuable about a milspec AR is that there's 40 years of experience behind the platform. everything that's going to wear out or break on it is a known quantity.

When you introduce non milspec materials, better or worse, you have an unknown quantity. While I have a piston AR with a nitrided barrel as a range toy I would hesitate to take it to war as that's not where i want to be a beta-tester.

An AR is like a Harley. You can build one as low end or as high end as you want to go. And high end as it exists today will get you past 2K real quick.

I never heard of Bushmaster being referred to as mid pack. Unless you are looking at the 2 or 3K very high end as some how better.

Random statistically correct testing has worked fine for manufacturing for years.

As you piece one together break out a spreadsheet and start adding up all the pieces. You will get a grand into one before you know it. You start paying insane prices for barrels and hand guards and target triggers and you will push into a very high priced rifle in no time.

Its always a good idea to ask what you are planning on using the rifle for. A basic RRA is a generally very fine weapon. You would have to search out some major junk to put together a really lousy AR. Most of the lowers are made by one of four companies and engraved for the distributors.

You read enough posts and you hear about this part or that part and then you start thinking you have to have all those parts and next thing you know a basic AR prices into the silly range.

Unless you have a very specific purpose in mind the parts you get from a Bravo Company or a Larue tactical will all build you a very nice rifle. You can put together a very nice rifle for under a grand if you don't get too fancy.

JHB,

I am also left handed. I remember back in Basic in the days of the A-1 receivers I had to use a plastic brass deflector or the empties would wind up in my face and down my shirt!

Today the A-2 receivers with the integral shell deflecting "bump" solve that problem. Empties wind up between 3 and 1 o'clock and are never a problem.

Colt, LMT, BCM are all excellent and proven choices in top tier (as close to 100% milspec as a semi auto AR can get) ARs.

My current favorite is BCM for the sweet spot between quality, reputation and price.

Currently, if I wanted a top tier AR at the lowest price then Spikes Tactical would get the nod. While not as established in reputation as BCM or Colt, their fully milspec (except the buffer which is upgraded) ST-15 LE Carbine At $799.95 is hard to beat. http://www.spikestactical.com/new/z...7.html?zenid=00756e515ab468912bf667176c1ccde0.

Especially when they include
* Detachable Mil-Spec Forged A2 Carry Handle
* 1 Magpul 30rd P-Mag
* Hard Plastic Carry Case
* Spike's Tactical Lifetime Warranty
to sweeten the deal.

The whole discussion is hogwash. There is probably no meaningful difference between any AR's. I realize that's heresy, esp to guys who've plunked down $1500 on one. But there you have it.

Define meaningful?

no meaningful difference

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For upper tier rifles, you are probably correct, outside of specific accuracy desires. Over the years though, IME the less than stellar rifles can really drive the owner nuts with poor cycling, lack of durability and mystery malfunctions.

As we have recently found out by trying to investigate what true "mil-spec" really is, there are only one or two major companies in the industry that really know. They have government contracts to produce rifles and their "mil-spec" tolerances are a closely guarded secret. One of the big things that I have been hearing on the internet is MPI and HP testing of the bolt carrier groups. That is one thing that sets apart a cheap component from a more expensive one. I am a firm believer in proper fit and finish on firearms.

Define meaningful?

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Anything that will noticeably affect overall performance.

Taurus 617 CCW said:

One of the big things that I have been hearing on the internet is MPI and HP testing of the bolt carrier groups. That is one thing that sets apart a cheap component from a more expensive one.

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The main difference is that if it is stamped "MPI" on the part, then that individual part has been subjected to Magnetic Particle Inspection.
Companies that don't stamp them will MPI a certain number of examples from a batch and MPI those, but not the rest. Just because it is not MPI stamped does not mean all by itself it is a defective or inferior part. It may be as good a part as any other ... it just hasn't been inspected individually.
In such occasions of course it is possible certain parts do get by with defects just because they weren't inspected. It is a statistics game involving keeping costs down versus quality control.

Some interesting numbers that nobody seems to have are failure rates of tested vs nontested parts. I think that would clear a bunch of the air in what seems to be an endless debate.

Well, I think I would say that while it would be nice if every part were appropriatly tested, OTOH if one had a non tested one, it doesn't mean one has to go around crying that they have a defective part. That's not a logical conclusion.
If you have a non inspected bolt carrier group, I'd just use it. Bravo Company makes good inspected ones that are not horrifically expensive and can be purchased as back-ups .... or you can use those and keep the uninspected one as back up.