NEW Comparison Chart of Commercial M4 Pattern Carbines

**sinlessorrow** · 02-20-12, 23:33

question..how important is a 5 coil extractor?

my new DD MK18 upper came with a 3 coil extractor, oring, and extractor buffer

should i upgrade to the BCM 5 coil system?

**feedramp** · 03-20-12, 21:00

Thank you for the charts, they are very helpful!

I'm curious how Sig's 516 series measures up. I had my eye on a 516 Patrol but that was before reading the chart info.

Next time I get to look at one, I'll check to see if it has the staked key and carrier nut. Most of the other items would have to be answered by the manufacturer I guess.

Has anyone else contacted Sig to see whether they abide some/most/all of the items listed on the chart?

edit: these threads were helpful: http://m4carbine.net/showpost.php?p=...9&postcount=73 https://www.m4carbine.net/showthread.php?t=59700

**rob_s** · 03-21-12, 03:09

The 516 is an external-piston AR.

**machinegunbob** · 03-21-12, 13:52

Cool and very useful.

**SW-Shooter** · 04-19-12, 21:22

I haven't read through all of the posts so I'm not certain if it has been asked before.

Disregard, it's been asked before. With the current trend of PSA selling a whole lot of rifles I'm sure many would like to see how they stack up.

Thanks

**shootist1970** · 05-06-12, 13:27

16 inch m4 profile Chrome lined barrel and chamber, chrome lined bolt carrier group also. MP/HP tested bolt and carrier group, properly staked gas key, much better quality and parts fit than the newer Bushmasters even though built by the former owners and employees of bushmaster that Freedom Group screwed out of jobs. M4 feed ramps, heavy bolt carrier group fixed front sight base A2 style and comes with either a flip up rear or removable handle.D ring defender included under extractor.

Price payed: $954 including the PA sales tax.

Note: Well built , well fitted rifle for price, if bought at a Cabela's store a donation is made to the "Paralyzed Veterans of America, outdoors recreation fund" that sponsors hunting and fishing expeditions for disabled veterans.

Reasons for chosing this model over others: Better built than original bushmasters, supports veterans program, Former Bushmaster owner started this new business out of loyalty to his former employees and friends that Freedom Group abandoned when they took the name and not the employees to Remington plant in New York.

Don't have accuracy stats as i haven't been to the range yet with it.

**shootist1970** · 05-06-12, 14:00

As student of arms i will just say this as i haven't been around any "Piston" AR's:

The military when it adopted the AR platform as it's weapon in the Mid 1960's extensively tested the AR in diffrent climates, the technology existed to make a Operating rod AR which is what your piston system is BTW. The military saw no reason to do so.

The malfunctions in Vietnam M-16's wasn't carbon jamming it was Rust from carbon left by the military switching powders in the ammo without testing. Hence why the Modern M-16/AR guns have chrome lined parts. Troops didn't clean the guns carbon drew moisture , moisture causes rust, Rust causes failures to extract....PERIOD!

The Direct impingement system has been around for almost 50 years in the AR/M16 system weapons and yet the military did not see a problem that required fixing by incorporating a piston into the design.

I don't care if it craps where it eats, if you are any Gun owner, LEO or Soldier, Sailor, Airman or Marine worth the ammo you expend, you would be cleaning your gun REGARDLESS OF DESIGN OR MODEL(AR,AK etc.) religeously as your life depends on it, because it could!!

To me the Piston systems are an overcomplicated fix it gimmick to a non existent problem.

Just my two copper Lincolns, YMMV.