Mil spec

[Aegis]

Im selling a Milspec Walther P99AS w/ a Milspec OD Frame and Milspec High Capacity Assault Magazines.

ive got a Old School Milspec HK P9S too.

pretty sure ive got a Milspec PS3 around here somewhere too.

im gonna go have some Milspec Coffee, so I can stop being an ***

 

[NWSharpshooter]

I meant licenses to buy a full auto or three round burst like the military uses. Of course you don't need a license to but a mil spec buffer tube lol

I was unaware I needed a license to own full auto. I thought a tax stamp was enough? Who knew?

 

[Retread]

So an AR-15 is an assault rifle?
Got any assault rifles in 22LR or 9mm?

 

[NWSharpshooter]

So an AR-15 is an assault rifle?

No such term.

 

[Peacekeeper]

I get annoyed lately at people who say their ar's are "mil spec" and they are like dpms' or something. There are no real "mil spec" rifles available to civilians without proper licenses. As long as they are semi auto they are not "mil spec". I guess this ain't a big deal but anyone else feel like this?

I would bet there are maybe a million, maybe even a lot more than that, "mil spec" rifles owned by civilians.

 

[Teefman]

Im selling a Milspec Walther P99AS w/ a Milspec OD Frame and Milspec High Capacity Assault Magazines.

ive got a Old School Milspec HK P9S too.

pretty sure ive got a Milspec PS3 around here somewhere too.

im gonna go have some Milspec Coffee, so I can stop being an ***

Man, Milspec Coffee sounds good. I'm going to go get me some. lol Too funny Aegis!

 

[edzackley]

There are many features of the rifle that can be examined for MilSpec aside from the fire control group:

BOLT CARRIER GROUP

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.

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.

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.


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 quicker and 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.

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 remains in the chamber 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.

Properly Staked Gas Key

It is under tremendous pressure and is critical to the continued operation of the firearm, and must remain sealed in order to allow all of the gas pressure into the carrier to do it's job. 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.

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.

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 is applicable, and the specification is MIL-B-11595E or "Bar, Metal and Blanks, Steel (Under 2 Inches in Diameter) for Barrels of Small Arms Weapons". Specific Chemical Composition in Table 1 on page 3 of the specification as follows:

ORD 4150 ORD 4150 Resulfurized Chome- Moly- Vanadium

Element Percent Percent Percent

Carbon 0.48 - 0.55 0.47 - 0.55 0.41 - 0.49

Manganese 0.75 - 1.00 0.70 - 1.00 0.60 - 0.90

Phosphorus 0.040 0.040 0.040

Sulfur 0.040 0.05 - 0.09 0.040

Silicon 0.20 - 0.35 0.20 - 0.35 0.20 - 0.35

Chromium 0.80 - 1.10 0.80 - 1.15 0.80 - 1.15

Milybdenum 0.15 - 0.25 0.15 - 0.25 0.30 - 0.40

Vanadium 0.20 - 0.30


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.


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.


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.


"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.

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.


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.

LOWER RECEIVER

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.

Staked Castle Nut

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.

"H" Buffer

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.

.154" Diameter Fire Control Group (FCG) Pins

At one time, Colt was the only maker of complete rifles that used 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. This issue has been resolved on current-production Colt 6920s as they are now shipping with .154" diameter hammer and trigger pins.

 

[sovietak474u]

I meant licenses to buy a full auto or three round burst like the military uses. Of course you don't need a license to but a mil spec buffer tube lol

You don't need a "license" to buy a full auto either. You do need a tax stamp and a fat wallet though. There is no "class 3 license" if you can own a pistol you can own a machine gun.

 

[jwhited]

OK now let's argue about clips and magazines.

 

[tywest]

ive got several milspec rifles

century also builts many milspec rifles. You can in my opinion buy a "milspec" rifle..........id also caution you not to put top value on it either. Its a good solid reliable set of specifications but its not the peak of perfection. It does however.......like stated before......allow for some known compatibility between manufacturer B's part X and manufacturer F's part W. Kinda like on an AR you reasonably expect to be able to slide any like caliber BCG right into any upper..........if not for them following someones standardization you probably would not be able to.