So what does Mil-Spec mean???

[ZDL]

Not even close. They all use LARGE gas ports (.068-.073). Reason? Because they expect their customers to use the cheapest (read under pressured) ammo they can find and they don't want to get complaints about their AR's not cycling. The issue is that when their customers DO use Mil-Spec pressured ammo, they are beating the guns to death (breaking bolts, bolt override, hard recoil, etc).


C4

Geesh. Thats great info right there.

[Shihan]

Good thread!

[rob_s]

The terms get over-used in all kinds of discussions. I was recently participating in a discussion on another forum about the function of 9mm AR magazines and one guy mentioned that the mags will work fine in a "milspec upper and lower". AFAIK there is no such thing when referring to the 9mm AR.

[C4IGrant]

Geesh. Thats great info right there.

Thanks. I was under the impression that everyone knew that tier 3 AR's use large gas ports so they could feed crap ammo better. I guess I was wrong.

My favorite thing to see is when someone takes an AR with a large gas port and then puts a suppressor on it! Talk about some serious recoil. I often wonder how the buffer does not get blown out the back of the receiver extension.



C4

[Failure2Stop]

If we are going to look at just uppers, LMT and BCM are tied for position one (IMHO).

What about Colt, or are you omitting them because of availability?

From what I know I would think that if the respective manufacturers' bolt were used with the uppers than the leaders would be Colt and BCM, with the LMT being a close second (due to straight vs taper pins), probably right along with the Noveske N4 (due to blue buffer and batch tested bolts).

Not saying that you are wrong, just curious about your answer.

[deercop]

Grant,

I seriously wish there was some way you could have a "psychic moment" or something, and realize all the tidbits of information that you (or other's more knowledgable than I) take for granted, that lots of people may not know.

I've been around the AR/M platform for over 20 years (granted a large chunk has been with company guns), but I never had a clue about the different gas port sizes. Also, I recently learned for the first time about how you take the collapsible buttstock itself off the extension (until then I thought you had to remove the extension).

I would like to thank you for sharing that information, and encourage you to share any other tidbits such as that, that you may think "everyone knows".

Thanks again!

[C4IGrant]

What about Colt, or are you omitting them because of availability?

From what I know I would think that if the respective manufacturers' bolt were used with the uppers than the leaders would be Colt and BCM, with the LMT being a close second (due to straight vs taper pins), probably right along with the Noveske N4 (due to blue buffer and batch tested bolts).

Not saying that you are wrong, just curious about your answer.

Left Colt out as I only wanted to list companies that sell uppers (alone). We all know that Colt's complete AR's are king, but they do not offer just uppers.


C4

[C4IGrant]

Grant,

I seriously wish there was some way you could have a "psychic moment" or something, and realize all the tidbits of information that you (or other's more knowledgable than I) take for granted, that lots of people may not know.

I've been around the AR/M platform for over 20 years (granted a large chunk has been with company guns), but I never had a clue about the different gas port sizes. Also, I recently learned for the first time about how you take the collapsible buttstock itself off the extension (until then I thought you had to remove the extension).

I would like to thank you for sharing that information, and encourage you to share any other tidbits such as that, that you may think "everyone knows".

Thanks again!

Roger that. Working with these weapons day in and day out makes you think that everyone knows the same amount as you do. I also hate to talk down to people so I try not to cover/explain what I classify as the simple stuff as people will assume I am just talking to hear myself talk.

Here is a quick list of companies that I know for a fact that use the .063 (or close to it) gas port size:

LMT
Colt
BCM
Noveske (14.5 N4)
S&W (later models)

I would give the benefit of the doubt to Charles Daly as well as they know what they are doing.


C4

[jmart]

Regarding ammo, Mk262, M855 and XM193 are NATO-pressure level, so those loads should work hand-in-glove with the .063 sized port. But they beat the crap out of BMs/RRAs since they run larger ports.

Wolf is down on the pressure scale and it may have problems with these ports, but because BM/RRA/et al drill their ports larger, this ammo will work in those barrels.

Where does other ammo fall in line pressure wise? BH ball, Win White Box, Amer Eagle, TAP? Are those loaded to SAAMI spec, in which case that would be a better match for a BM/RRA than a NATO-spec load?

[Highway 55]

Here is a quick list of companies that I know for a fact that use the .063 (or close to it) gas port size:

LMT
Colt
BCM
Noveske (14.5 N4)
S&W (later models)

I would give the benefit of the doubt to Charles Daly as well as they know what they are doing.

I have been looking for that specific info for quite awhile.

Thank you!