AR-15 Q

[Guest big496]

I want a AR-15 so i have been looking and i have found they come with many different options i dont know where to start can someone please explain all the good and bad points to the different AR makers. and please explain all the different options.

thanks a bunch

dose the handle come off of a AR? can i make one with a handle a flat top or do i have to get a new receiver?

[John Wall]

What do you want to do with the gun?

There are many different ways to deploy this versatile firearm.

If you want a plinker, get the base model.

If you want a firearm for shooting past 150 yards, or if you do not have the best eyesight, get a scope for your base model.

If you want a firearm with dedicated optics, get a flat top.

If you want your AR-15 to shoot as accurately as most bolt action rifles, get the full size gun with a heavy barrel contour (HBAR)

If you want a precision long range rifle that shoots 223 and 5.56, get an accurized rifle built for the purpose with precision barrel, match trigger, full sized stock and such.

Figure out what you want. If you want the firearm to perform dual chores, say a precision rifle and a standard carbine, get the precision rifle and add a carbine upper.

You could even add a pistol caliber upper for cheap plinking, or for harvesting game, larger calibers such as 6.5 Grendel, 6.8 SPC, 7.62 Soviet, up to the 458 SOCOM (ballistics similar to the 45/70).

These are extremely versatile firearms.

[Smith]

I want a AR-15 so i have been looking and i have found they come with many different options i dont know where to start can someone please explain all the good and bad points to the different AR makers. and please explain all the different options.

thanks a bunch

dose the handle come off of a AR? can i make one with a handle a flat top or do i have to get a new receiver?

Those are questions that can't be answered that briefly. I would say go over to arf.com and just do some research.

My personal suggestion is to go to Guns & Leather and let them show you as they explain it. All the options are personal and objective anyway.

[Guest Mugster]

Yeah, go someplace they have a bunch on the shelf and have someone show you around. I could recommed hero gear. Dan or Joe would take an inordinate amount of time to show you what they have...and they have alot of AR's.

If you surf around here, you might get an idea of the lingo:

http://www.rockriverarms.com/

http://www.dpmsinc.com/

[The Average Joe]

The last line....it's true, it's so true.

[R1100R]

It looks like someone is about to contract the BRD.

[TGO David]

Here is a nice comparison chart of major AR brands, courtesy of the fine folks at www.m4carbine.net . If you haven't already signed up over there, I recommend that you do and (a.) lurk and read a lot and (b.) post only when you can't find an answer for your question by searching their forums. A lot of common questions have already been answered numerous times over.

Of course we here are willing to help you in most any way we can as well. The only thing more fun than spending your own money on a new rifle is helping someone else spend their money on a new rifle.

A full diagram of an AR15/M16 with all parts labeled can be found here http://www.fulton-armory.com/AR-15Diagram.htm

Bolt Carrier Group

The first six items listed on the new chart pertain to the bolt and/or carrier, commonly referred to as the "Bolt Carrier Group" or BCG. This is the part that moves back and forth in the upper receiver chambering fresh rounds, extracting and ejecting empty rounds, and generally ensuring that your rifle or carbine operates as it should. As such, in terms of reliability, the BCG is the heart of the gun, and having as high a quality BCG that is assembled correctly out of the correct materials and which has been properly checked for flaws is key to the continued reliability of the AR-platform firearm. The first four items refer to the bolt itself, while the remaining two deal with the carrier.

Shot Peened Bolt

There are many resources available online as to the exact process and how it affects the structure of the part at the molecular level, but essentially the goal is to increase the resistance of metal to fatigue. The bolt, in the performance of it's duties, is put under a considerable amount of stress as the gun fires. Ensuring that this part lasts as long as possible is key to the continued reliability of the firearm over time, and increasing the resistance of the part to fatigue increases it's service life.

More information on shot peening can be found here http://en.wikipedia.org/wiki/Shot_peening

High Pressure Test (HPT) Bolt

This is also sometimes referred to as "proof loading" or "proof firing". Essentially it is a test fire of the bolt (and barrel) in order to subject the part to a pressure that could cause it to fail in use. This is a preparatory step in order to prepare the part for the next step. Not all companies perform this step and prefer to "batch test" their bolts and barrels, or to test a representative sample of each batch.

More information on proof testing can be found here http://en.wikipedia.org/wiki/Proof_test

Magnetic Particle Inspection (MPI) Bolt

Like shot peening, there are resources available online as to what the exact process is and how it works, but the intended purpose is to check for surface cracks in the part that may not be detectable by the naked eye and that may have been caused by the HPT. Not all companies perform this step and prefer to "batch test" their bolts and barrels, or to test a representative sample of each batch. This is a crucial step following the HPT in order to observe the results.

More information on MPI can be found here http://en.wikipedia.org/wiki/Magneti...cle_inspection

Black Extractor Spring Insert

The crucial element here is, in fact, the 5-coil extractor spring which the black insert indicates as there is some debate as to the actual chemical or physical properties of the insert itself as compared to the rifle version which comes with the 4-coil spring and is blue. The shorter gas system of the carbine makes for a sooner an more violent operation of the BCG which can cause the extractor on the bolt to jump over the rim of the case and not properly extract the empty case. To some degree this can be mitigated by gas port size, but beefing up the spring tension to cause the extractor to clamp more tightly on the case ensures proper function.

More information on extractor springs and inserts can be found here http://www.m4carbine.net/showthread.php?t=14310

M16 Bolt Carrier

The M16 bolt carrier serves two functions. The first is that the firing pin is fully shrouded so that the hammer is cocked by the carrier and not the firing pin itself. The second is that the M16 bold carrier is heavier and therefore increases "lock time" (or the amount of time that the empty case after the primer is struck by the firing pin) which aids in extraction. The heavier carrier also reduces the felt recoil impulse which in turn reduces wear and tear on the other internal parts of the carbine.

More information on M16 vs. AR15 carriers can be found here http://www.m4carbine.net/showthread.php?t=14534

Properly Staked Gas Key

The gas key on top of the bolt carrier is the part that the gases (which have been re-directed through the gas port, then the gas block or front sight base, and into the gas tube) impact on in order to push back on the carrier, unlock the bolt and cycle the firearm. As such it is under tremendous pressure and is critical to the continued operation of the firearm. The key is held on to the top of the carrier by two screws, typically allen but sometimes torx, that are tightened to a specified torque. After tightening the metal of the key should be "staked" in such a way as to prevent the screws from loosening. In order for the staking to perform it's job properly it must deform the metal of the key sufficiently to make contact with, and perhaps even deform a bit, the attachment screws. Use of Locktite is not sufficient, as virtually all versions of Locktite are weakened by heat.

More information on staking of carrier keys can be found here http://m4carbine.net/showthread.php?t=6993

Barrel

The barrel rivals the bolt in terms of how critical it is to the long term reliability and functionality, as well as accuracy of the firearm. Clearly, accuracy may be sacrificed to some degree in favor of longevity in terms of a chromoly and chrome-lined barrel. The features that are included in the barrel section, the next eight items on the chart, are all related to the longevity of the barrel as well as the reliability of the firearm, with some features being somewhat optional as they pertain to use of certain projectiles and other shooter-defined needs.

Milspec Barrel Steel

No term used in the chart has elicited more of a negative reaction than "milspec". As such every effort has been made to remove it from The Chart wherever possible. In the case of the barrel, however, it remains. The short version of the story is that barrels are typically made from two grades of chromoly steel, 4140 and 4150, with the latter being a slightly higher grade that withstands heat slightly better than the former. The long version involves very specific types of steel, much longer numbers, and is in fact generally considered to be of little consequence. There are, however, other grades and/or types of steel that meet or exceed the properties of 4150 and are therefore acceptable.

More information on barrel steel can be found here http://www.m4carbine.net/showthread.php?t=7263

High Pressure Test (HPT) Barrel

This means the same thing, and is done for the same reason, as the HPT of the bolt.

Magnetic Particle Inspection (MPI) Barrel

This means the same thing, and is done for the same reason, as the MPI of the bolt.

Chrome Chamber and Bore

Chrome-lining of the chamber and bore serve to protect both from corrosion due to the heat of combustion of the gunpowder in the bullet as well as "neglect" in humid or other harsh environments. The chamber and bore are directly related to the accuracy potential of a firearm, and damage to either in the form of pitting will negatively impact the accuracy potential. The trade off is that chrome is often applied unevenly, at the microscopic level, meaning that it may negatively affect the accuracy potential in and of itself. The potential for damage due to other factors is generally considered greater than the small amount of uneven application, and so chrome-lining is generally considered desirable. No, it cannot be added after the fact as barrels intended for chrome-lining are first slightly overbored with the lining then reducing the internal diameter to the proper dimension.

5.56 Chamber

There is a common misconception that .223 and 5.56 are the same thing. They are not. 5.56 is often loaded to a higher pressure, among other things, which is the most critical issue. There are other dimensional differences pertaining to throat, bullet seat, etc. but what it comes down to in practical terms is that you can shoot .223 in a 5.56 chamber but the reverse is not a good idea. Generally speaking the barrel will be marked with one or the other but unfortunately those markings cannot always be trusted. If you think you may ever shoot 5.56 ammunition it is a good idea to get a 5.56 chamber from a maker that can be trusted.

More information about chamber dimensions can be found here http://www.ammo-oracle.com/body.htm

1:7 Rifling Twist

Another common misconception is that bullet weight determines the optimal rifling twist. This is incorrect in that it is actually bullet (projectile) length that should be used to determine the twist rate. Generally speaking, however, the heavier bullets are also longer so while technically incorrect it is common to say that a 1:7 twist is more desirable for the heavier 75 and 77 grain projectiles. Therefore, choosing a barrel twist really comes down to first choosing your projectile weight, and more correctly, length. If you work for a department that mandates or issues a certain ammunition then this should be your guide when choosing a rifling twist rate. A good rule of thumb is that 1:9 will stabilize bullets in the 45 to 62 grain range, and 1:7 will stabilize bullets in the 55 to 77 grain range. Like all things this is not a given, and any barrel should be tested with the intended ammunition to ensure the desired results are achieved.

More information about rifling twist and ammunition selection can be found here http://www.ammo-oracle.com/body.htm

M4 Feedramps

M4 feedramps refers to the feed ramps in the barrel extension being matched up to feed ramps cut into the upper receiver. The alternative is Rifle feedramps which stop at the end of the barrel extension and do not continue into the upper receiver. Longer projectiles, soft-point projectiles, and carbines with faster cyclic rates tend to benefit from the extended M4 feedramps. There are no known downsides to having the extended feedramps.

More information on feedramps can be found here http://www.m4carbine.net/showthread.php?t=193

"F" Height Front Sight Base

Front sight bases come in two basic varieties. One is the front sight base intended for use on carbines and rifles with fixed A2 uppers,the other (The "F") is intended for carbines with flattop uppers. In order to ensure compatibility with the various aftermarket rear back up iron sights, the "F" is more desirable. Not all "F" height front sight bases are marked with the "F" (LMT for example), and some that are marked are not true to the correct height.

More information on front sight bases can be found here http://www.m4carbine.net/showthread.php?t=14753

Taper Pins at Front Sight Base (FSB)

A minor issue, but taper pins hold the front sight base better and tighter than a straight pin. Some makers attempt to make up for this by using slightly oversized straight pins that can be extremely difficult to remove.

More information on taper pins can be found here http://en.wikipedia.org/wiki/Taper_pin

Parkerize under FSB

Parkerizing under the front sight base (or FSB) is done by very few makers. Most prefer to attach the base to the barrel and then parkerize the assembly as a whole. If parkerized as an assembly, both the outside of the barrel under the rings of the base and the inside of the rings themselves do not get the protective coating of the parkerizing process. There have been some reports of these parts rusting in the unprotected area, but it is unlikely that rust in these locations will affect the function of the carbine.

Double Heat Shield Handguards

Obviously this is not an issue of the end user intends to replace the handguards with an aftermarket part, but the proper M4 handguards are larger and contain a dual-layer of aluminum heat shields inside each half. The added diameter and extra shield serve to keep the shooter's hands cooler over prolonged periods of fire.

Receiver Extension

The receiver extension is the part of the rifle, often mistakenly called the "buffer tube" that extends out from the back of the lower receiver. It not only holds the stock on the rifle but also does act as a tube for the buffer and bolt carrier to move back and forth inside of when the rifle cycles. This receiver extension is held in place by a castle nut which also holds the receiver end plate in plate, which in turn holds a spring and detent in place inside the lower.

1.14" Diameter Receiver Extension

This is often referred to as the "milspec" receiver extension. The alternative to a "milspec" receiver extension is the "civilian" or "commercial" receiver extension. There is some debate as to whether or not the milspec extension is actually stronger or "better" than the commercial, but for most users the real choice comes down to availability of aftermarket stocks. Some companies, like Magpul with their CTR stock, offer versions for both extensions, but many do not. If you know that your intended stock is available for the commercial receiver extension or if you are happy with the stock your rifle comes with it is most likely not an issue. If, however, you want to change the stock or just keep your options open then the milspec extension is preferred.

Dimensions for a "milspec" receiver extension can be found here http://www.magpul.com/pdfs/buffertube-Milspec-M4.pdf

Dimensions for a "commercial" receiver extension can be found here http://magpul.com/pdfs/buffertube-civilian-M4.pdf

Staked Castle Nut

The castle nut is the nut that holds the receiver extension in to the lower receiver and prevents it from backing out. If it backs out, the buffer retainer spring inside the lower can come loose, which in turn can render the carbine inoperable. The best case scenario if your castle nut comes loose is that your stock becomes loose which is also not a good thing. Calling it a "staked castle nut" is somewhat of a misnomer as the part that is staked is actually the receiver endplate. The castle nut itself has small notches on the forward side, and large notches to the rear. The large notches are used for tightening, and the small notches are there so that the receiver endplate can be staked to displace metal into the notch on the castle nut, thereby keeping it from turning. With the proper castle nut wrench the staking can be easily overcome to change out the parts, but without the tool the nut will not come loose. Locktite, once again, is not a viable solution as this part can heat up and Locktite is weakened by heat.

More information on staking of castle nuts can be found here http://m4carbine.net/showthread.php?t=6994

"H" Buffer

The buffer is the weighted part that moves back and forth inside the receiver extension when the rifle cycles. It is held forward by a long spring called the buffer spring, and is kept from moving too far forward by the buffer retainer pin (which is in turn held in place by the receiver extension, see "staked castle nut" above). The buffer and spring provide resistance to the bolt carrier as it cycles and the spring then pushes the bolt and carrier back into battery after the empty case is ejected. A heavier buffer can increase lock time (see "M16 bolt carrier" above) which reduces wear and tear on parts and increases reliability in carbines. The heavier buffer can also decrease felt recoil. It is, however, possible to install a buffer that is too heavy which will not allow the rifle to cycle properly. Typically the "H" buffer is used on carbines with barrels 10-16" with carbine (7.0) length gas tubes.

More information on buffers can be found here http://www.m4carbine.net/showthread.php?t=5136

.154" Diameter Fire Control Group (FCG) Pins

Colt is the only maker of complete rifles that uses slightly oversized fire control group (trigger and hammer) pins to prevent the installation of M16 full-auto or burst parts from being installed in the lower. Virtually all aftermarket trigger makers (Timney, Geissele, McCormick, etc.) make trigger groups that utilize the larger pin size so finding aftermarket parts is a non issue. The odd-size pins do become an issue if you own rifles from Colt and other companies as the spare parts in question will not be interchangeable. In addition, finding the proper diameter pins, and the FCG parts they hold in place, for spares from any vendor other than Colt may prove difficult.

[Guest price g]

Or, you could go to a 3-Gun match and see every type of set up known to man.

[Guest bigbuck_tn]

Oh no. Not "the chart" here too.

All that is going to do is confuse the issue. 90% of the people reading the chart and talking about it haven't the faintest idea what they are talking about. Myself included.

I do however have extensive knowledge in manufacturing methods and machining and 1/2 of everything that you read related to that chart is baloney. Makes you wonder sometimes why they push it so much...

If you really want an AR just get a decent one. Armalite, Bushmaster, Rock River, S&W, etc... Ad Naseum

They are all in the same boat. They all get their parts from the same suppliers regardless of what "QC" checks they do.

My advice is to call/email a couple of tactical training schools and ask them what they recommend, if you are worried about durability or "mil-spec" on your defense weapon. Particularly some that aren't in the business of selling you a gun. That and think about who supports your rights and who doesn't....

If you are just getting if for fun or hunting get what you can afford and like.

By the way, those of us who have worked in the automotive industry get alot of good laughs out of MIL-STANDARDS...

[Guest bigbuck_tn]

By the way. Magnetic Particle Inspect is a fancy term for dip it in glowing kerosene and VISUALLY look for cracks......

Go to any local Mom and Pop machine shop / engine rebuild shop and they might even do it for you for free.

Or you could buy your own from McMaster Carr for a couple hundred dollars and even pick you ultraviolet dye color and then you too can buy BCG's and bolts and sell them online as Mil-Spec MP Inspected. And if you are really smart you will scratch MP on the bolt head and thereby induce a stress riser. Or better yet, buy one of the bolts that has MP machined into the bolts before they are tested.....

Hey, I've just thought of another sales gimmick...

I use "Mil-spec" Army Green dye that is more visible to the human eye....

[TGO David]

Actually none of the items listed on that chart confuse me in the least. If an item confuses someone, they should ask for clarification or guidance. If they are still confused or just don't see the merit in spending a little more (or sometimes even a little less) to obtain components or complete rifles that include the more desirable features, then I am sure that an "Armalite, Bushmaster, Rock River, S&W, etc... Ad Naseum" will meet their needs just fine.

Until something breaks, bumps, hiccups or otherwise fails to perform adequately or up to their own expectations or standards... at which time they can once again ask for clarification or advice.

By the way, as someone who has an engineering degree (me) and who has "magnafluxed" plenty of automotive parts over the past 20 years to search for cracks and stress fractures, and found plenty by doing so that were not otherwise visible to the naked eye, I can assure you that your casual dismissal of MPI is pretty narrow sighted.

But what do I know.

[Guest bigbuck_tn]

If you have used Magnaflux before then you are aware of it's shortcomings. It only detects surface cracks and those very close to the surface or those that are so large that their field distortions extend beyond the surface of the part so that the dye will align in the field. You should also know that Magnaflux is a VISUAL inspection which at BEST is an 80% effective measurement. So 20% of all failures WILL be missed, no matter how well your operator is trained. Even more so on a complicated part like a BCG or a Bolt that has lots of little nooks and crannies for cracks to hide in.

Magnaflux is a great tool for investigation not a very good tool for 100% inspecton during production.

I am not making a casual dismissal of MPI. It is a good tool and it seems to be a great sales gimmick to the uninformed.

Especially since all the AR companies use the same parts from the same vendors. Only a few of them make their own parts and they all sell to each other. Remember, until just a few years ago LMT was Eagle arms which turned into Armalite when Westrom bought it. Stag still is CMT. Bushmaster still is Qality Parts. And so on.

Hence the newest star on the block. Charles Daly....

My only complaint about "the chart" is that it is used as a marketing tool rather than information based on the way it is presented. Too bad they don't do a chart on AK's... See of they ar following IZMASH's TDP:D Gosh they don't use 4150 barrel steel and their bolts and carriers aren't MPI test 100%, they will obviously fail at the first opportunity...

I think we would be alot better served telling guys new to AR's to determine what they want to use it for and then call some guys that use their rifles that way for real and ask them what they recommend.

[Guest big496]

hey thanks for all the great info guys i think the chart rocks but i like to look at stats lol. i went with the S&W got it friday for $700 whoo hoo im on my way now i already have a list of goodys for it lol i got new grips friday and put them on that night cant wait to get my four rail. can anyone deer hunt with theres? is 223 ok or should i look for a 6.8 upper? ideas?

[Smith]

While technically/legally you can hunt with .223, I wouldn't recommend it. It is a little small for whitetail. I know, I know shot placement, but the 6.8 would be a better hunting round.

[Guest big496]

if i went with the 6.8 would i need to get a whole new upper or could i just go with a new barrel and bolt? and where is the best place to get a 6.8 upper anyone sell them used?