Comparison Chart of Major AR Brands

[jmart]

Don't know. If Randall will get off his ass and get molds of chambers, we wouldn't have to guess.


C4

Freakin' slackers........

[AR15barrels]

Don't know. If Randall will get off his ass and get molds of chambers, we wouldn't have to guess.

Patience grasshopper.

I'm going to chase down a small hotplate that I can use for cerrosafe out in the shop.
Then I will start taking some chamber casts and publish what I find.
This is going to take some time (read months) before we have a really good picture.

I have SEVERAL YEARS in measuring barrels to aquire 160+ discreet barrel profile drawings.

[BravoCompanyUSA]

Cool chart. Lot of good reference info.

As a practical matter, as soon as the chart is perfect.... things will change.
Large commercial maufacturers could not maintain production if they didn't vary on small issues. What you may find in todays product may be a little different in last months or next weeks.

Sorry if this has been brought up already, (I did not read all 10 pages)
FWIW, I would catagorize barrel steel by 3 different types: 11595E, 4150MOD, 4140.
That will cover about 99% of the OEM carbon steel products.

[Robb Jensen]

I'd also like it to be CL

From what I've been reading it sounds like Ned's reamer is built on the large side of the 556 NATO chamber. So if you had a smallish 556 NATO chamber that is still acceptable all you have done is removed your CL. Obviously if you are having issues and suspect it is the chamber then the reamer would be the way to go. But for a gun that is running fine with no signs of problems, it sounds like a solution in search of a problem.

Just some thoughts.

If it runs.........don't ream it.
If it's giving you trouble............ream it.

[Armalite]

Some of the info on the chart for our rifle is wrong. Here is the correct info if you could update the chart for everyone.

MPI Bolt 3
Pressure Test (HPT) Bolt 3
Shot Peened Bolt X
Black Extractor Spring Insert 3
Properly Staked Gas Key X
M16 Bolt Carrier 4
Milspec Barrel Steel X
Pressure Test (HPT) Barrel 3
Chrome Chamber and Bore X

1:7 Rifling Twist 5
5.56mm Chamber X
M4 Feedramps X
F Front Sight Base (FSB)
Milspec Dia. Receiver Extension X
Staked Castle Nut X
“H” Buffer X

Taper Pins at FSB
Parkerize under FSB X
Double Shield Handguards 6
Milspec Dia FCG Pins X

Lifetime Warranty X
Average Street Price

3. MPI and HPT performed as contracted, normal MPI and HPT verification
established by 4 gun 25 HPT RD/MPI torture test. Bolt bears patented
“load leveled” lugs.

4. M16 hammer cam on carrier

5. 1:7 inch rifling twist available on certain runs.

6. Double heatshield handguards used on 6 inch guards.
ArmaLite mid length handguards feature single heatshields

[AR15barrels]

3. MPI and HPT performed as contracted, normal MPI and HPT verification
established by 4 gun 25 HPT RD/MPI torture test. Bolt bears patented
“load leveled” lugs.

This is also known as batch testing or lot testing.
In order to get an "X" on the chart, you would have to be doing every single bolt and barrel.

4. M16 hammer cam on carrier

So you have a shrouded carrier, not an M16 carrier.
No soup for you.

[Armalite]

We have plenty of soup, and will share.

[AR15barrels]

We have plenty of soup, and will share.

And a sense of humor as well.
You'll do well here.

Welcome to M4Carbine.
Glad to have you aboard.

[rob_s]

I also received the above via PM from "Armalite" and replied there before I saw that this was posted here.

The things I requested were:

1) Photos of the carrier key staking, M4 feedramps, and castle nut staking.

2) Clarification as to whether or not every single bolt and every single barrel were tested.

3) Clarification of exactly what barrel steel Armalite uses.

Something I left out of the PM but also need clarification on is "Black Extractor Spring Insert 3". Either it's black or it isn't. I'm assuming this is a typo but would like to make sure.

[Shihan]

Something I left out of the PM but also need clarification on is "Black Extractor Spring Insert 3". Either it's black or it isn't. I'm assuming this is a typo but would like to make sure.

I called Armalite looking for supplies awhikle back and asked about extractor inserts and springs. I was told(they counted while I was on the phone) they use a 4-coil spring.
I asked about the extractor inserts and was told they were not black or blue(no pun) but clear. Here is a post I started awhile back about them.

http://m4carbine.net/showthread.php?t=6790