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Discussion Starter · #1 ·
Given that I already have a Sig 556 with a 16 inch barrel, if I was considering buying another rifle in 5.56 mm, and (can't yet afford a Scar-16), would a rifle with a 20 inch barrel be a better choice in terms of wear on the rifle and reliability?

If so whch manufacturer should I consider? I don't thinkLMT makes a 20 inch barrel.
 

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I am not an AR fan, so let me begin by stating that. However, I actually was considering buying one just to have one and learn how to run it in case I ever do need to run one....

According to the AR15.com guys, based on a lot of reviewing on that site, Colt seems to be the manufacturer of concensus choice.

Also almost bought a Russian AK for the same reason...passed once I held it.

Right afterwards, I bought another SCAR instead...the black ones came out. But you ruled that out as an option.

I also bought another SIG P556, this time in a SWAT model, since I was contemplating buying a SIG factory SBR...decided to not go to NFA extremes.

I'm very happy with both choices, and glad I decided against the AR and AK....
 

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pk3 said:
Re: Direct impingement 5.56 mm with a 20 inch barrel?
pk3 said:
would a rifle with a 20 inch barrel be a better choice in terms of wear on the rifle and reliability?
..yes...absolutely...significantly better in "terms of wear on the rifle and reliability"...the origional Stoner design parameters are based on gas pressure levels produced in a rifle with a 20 inch barrel and a rifle length gas system to drive the weapon...ie... M16 series...not the M4 carbine with it's shorter barrel and the "short carbine length gas system"...

...for example..."one" of the M4's greatest deficiencies is that it has "hard extraction" issues which are not characteristic of the M16...that is...the shell is still "obturated" against the chamber walls due to residual pressure while the bolt is being forced to rotate and unlock...the lock time on the M16 is ~ 550 microseconds...on the M4 ~ 350 microseconds...the peak port pressure averages around 20,000 psi on the M16 whereas on the M4 it averages around 35,000 psi...likewise...the internal bolt pressure within the expansion chamber averages around 1000 psi for the M16 and around 1500 psi for the M4...consequently the linier and rotational shear forces and loadings on the bolt lugs are dramatically increased in a non-linier fashion...this increased "strain" is cumlative in metals ...resulting in a considerably shorter useful service life of the bolt and it's components...and also the cam pin...the caming area of the carrier...FP retaining pin..etc...the carbine has a greater probability of component failures as the round count goes up...including components of the FCG and recoil system and such...

...and "that's just the tip of the iceberg"...although the M4 "carbine" is an acceptable field weapon under most conditions...it is critical that it is serviced and PMed properly based on round count...especially the replacement of the bolt...extractor...extractor spring and ejector spring...cam pin...firing pin retaining pin...and gas rings...all of these components should be replaced ~ 5000 rounds in military use...the springs at ~ 3000 rounds....the gas rings and firing pin retaining pin possibly sooner...and the carrier "must" be carefully inspected in the caming area for any signs of cracking or uneven wear...it was designed to be subjected to loadings developed in the M16 rifle...not the increased loadings imposed upon it in the M4 carbine...since the metal is a little thin in that area...and that's just for starters...my intent here is not to go through the entire "carbine."..i'll just say that the M4 "carbine" needs "just a little" extra care and a watchful eye than a M16 ...

...when it comes to ARs...the rifle will be more reliable and less ammunition sensitive than the carbine...have a considerably longer service life...and is just "plain more pleasant" to shoot...

pk3 said:
If so whch manufacturer should I consider?
...i suggest you purchase an AR from one of the "major manufacturers" such as Colt Manufacturing...Armalite or Bushmaster...an A3 HBAR model with the detachable carry handle and a full A2 stock...and you'll be GTG...
 

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Another brand I'd give a hard look at, if I were buying a 20" DI AR would be Stag, which is now owned by S&W. Their QAQC is very good. The key to happiness with a DI AR (regardless of barrel length) is lube. Keep the bolt/bolt carrier wet and it'll run like a sewing machine.

Mike
 

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pk3 said:
Ullie, I'm thinking of putting a Colt on my wish list, but was wondering if the DSA AR-15 was a good buy? Thanks.
...if you want a professional grade AR 15...here is "one" option...a Bravo Company 20 inch barreled upper...

... http://www.bravocompanyusa.com/BCM-M16- ... gov-20.htm

... use a BCM full auto bolt carrier group and charging handle...see dropdown...and a BCM detachable carry handle...

...pin the upper to a LMT Defender lower with a fixed A2 stock...a factory LMT 2 stage trigger would be a nice add on...

... http://www.lewismachine.net/product.php ... 8aab7e4787

...when you buy the upper and lower seperately...you save the 11% FET on assembled weapons...

...if you want a super accurate AR 15...pin this 20 inched barreled upper to an LMT lower with an A2 stock and the optional two stage trigger...the Larue Stealth upper includes the FA BCG and rails...etc...read the descriptive...this is about as good as it gets...

... http://stores.homestead.com/Laruetactic ... bok?no=100
 

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Discussion Starter · #9 ·
Ullie, your response is appreciated. I should have been more specific about my goals. The "super-accurate" is out of my price range of $1500 or less. The " professional grade" looks more affordable, but I'm not up to building my own rifle.

In trying to learn more, I've read about "tiers" and "the chart" as well as numerous reports of personal experience with a variety of manufacturers. It's hard to see a pattern among the personal reports, and my extremely limited personal experience with government contracting has not convinced me that selection by a government agency necessarily correlates with quality.

I would define quality in terms of reliability, ease of maintenance, accuracy and cost. This definition has caused me to re-consider the FAL on my .308 rifle wish list.

I guess my question is, in your opinion, for a beginner, which AR-15 type rifle is most similar in terms of quality to a Sig handgun. You buy it and it works within reason to your satisfaction.

And perhaps you've already answered with Colt Manufacturing, Armalite or Bushmaster.
 

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pk3 said:
I would define quality in terms of reliability, ease of maintenance, accuracy and cost. This definition has caused me to re-consider the FAL on my .308 rifle wish list
...if i could only own "one" battle rifle...it would be a FAL...and DSA argueably makes the best FAL...


pk3 said:
I guess my question is, in your opinion, for a beginner, which AR-15 type rifle is most similar in terms of quality to a Sig handgun. You buy it and it works within reason to your satisfaction.

And perhaps you've already answered with Colt Manufacturing, Armalite or Bushmaster.
...the Colt...Armalite and Bushmaster are good guns...and will serve you well...

...but what i suggested is a professional grade weapon...constructed with the correct grade of materials and assembly protocols...LMT and "Colt Defense" does not produce a 20 inch AR15 with a detachable carry handle...Colt Defense only a AR15 A2...with the intragal carry handle...

...you buy the "assembled upper"...add the handguards...add the FA bolt carrier group...have Bravo Company check the headspace...an extra step i always do myself...almost nobody else does...don't forget the charging handle and BCM carry handle...

...then just pin the BCM upper to the LMT lower...

...you aren't building anything...you simply pin the upper to the lower reciever...just as you would a Sig 556...the BCM will be superior to an AR from Colt Manufacturing ( a different company than Colt Defense)...an Aramlite or Bushmaster...
 

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Discussion Starter · #12 ·
After spending some time trying to learn more about ARs, I have to give the guys who tried to condense an overwhelming amount of information into a "chart" or "tiers" alot of credit.
 
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