Difference between these two rifles

[DwnRangeKing]

Can anybody tell me the differences between these two rifles? I looked at them on-line and they seem very similar to me

Armalite AR-10 A4 Carbine
&
Armalite M15 A4 Carbine

Thanks!

[DefensiveCarry.com]

[Chooie]

M15 is .223/5.56, AR-10 is .308/7.62x51.

[DwnRangeKing]

I misquoted the model # for the M15...
It should be M15A4C-7.62X39 (that is how it is written on armalite's web site.

[snowdoctor]

7.62 x 54 is a .308
7.62 X 39 is slightly smaller, and used most commonly in the AK 47 and SKS...

[HahnsXD]

7.62 x 54 is a .308

Negative. 7.62x51 is .308.

7.62x54 was used in the Mosins, Dragunovs, ect.

[HotGuns]

The AR -10 has about some parts compatability with the AR-15 in7.62x39

Other than that, they arent even in the same league as far as ballistics go.The .308(AR-10) is a much better round with much more range and energy.

The 7.62x39 is comparable to the ballistics of a .30-30.
The 7.62x51 is comparable to a .30-06.

The 7.62x54r that Hahns talks about is very close to the .308 ballistically and is a another very good round.

[dukalmighty]

The AR10 upper is like an AR15 on steroids,the lower receiver parts are interchangeable and that's about it,the AR10 bolt is longer and heavier,I would suggest you stay away from a 7.62x39 upper since the base of the round is larger diameter than 223 and to adapt the bolt to fit 7.62x39 they ream the bolt face out bigger which weakens the bolt,after less than 1500 rounds thru my 7.63x39 upper I had an extractor that needed replaced and within another 100 rounds had one of the locking lugs on the bolt break off,new bolt $64.00.I'm gonna replace the bolt with a standard bolt and swap the barrel out for a 5.56,If I wanta shoot 7.62x39 I'll use my Mini 30.I really like my AR10A3 It's fun to shoot and more accurate than I am,When I bought mine it cost me $998.00 New about 6 years ago

[rocky]

Actually 7.62 X51 = .308 caliber , while 7.62X54 is = 300-06 caliber .
From Wikipedia :
Metric calibers for small arms are usually expressed with an "x" between the width and the length; for example, 7.62x51 NATO. This indicates that the cartridge uses a 7.62 mm diameter bullet, loaded in a case 51 mm long. Similarly, the 6.5x55 Swedish cartridge has a bullet diameter of 6.5 mm and a case length of 55 mm. The means of measuring a rifled bore varies, and may refer to the diameter of the lands or the grooves of the rifling; this is why the .303 British, measured across the lands, actually uses a .311 inch bullet (7.70 mm vs. 7.90 mm), while the .308 Winchester, while dimensionally similar to (but should not be considered interchangeable with) the 7.62x51 mm NATO cartridge, is measured across the grooves and uses a .308" diameter (7.62 mm) bullet. An exception to this rule are the proprietary cartridges used by U.S. maker Lazzaroni, which are named based on the groove diameter in millimeters, such as the 7.82 Warbird.[1][2]
Note this is not a standard size , the neck taper is different between .308 and 7.62 rounds.

[razor02097]

Actually 7.62 X51 = .308 caliber , while 7.62X54 is = 30-06 caliber .
From Wikipedia :
Metric calibers for small arms are usually expressed with an "x" between the width and the length; for example, 7.62x51 NATO. This indicates that the cartridge uses a 7.62 mm diameter bullet, loaded in a case 51 mm long. Similarly, the 6.5x55 Swedish cartridge has a bullet diameter of 6.5 mm and a case length of 55 mm. The means of measuring a rifled bore varies, and may refer to the diameter of the lands or the grooves of the rifling; this is why the .303 British, measured across the lands, actually uses a .311 inch bullet (7.70 mm vs. 7.90 mm), while the .308 Winchester, while dimensionally similar to (but should not be considered interchangeable with) the 7.62x51 mm NATO cartridge, is measured across the grooves and uses a .308" diameter (7.62 mm) bullet. An exception to this rule are the proprietary cartridges used by U.S. maker Lazzaroni, which are named based on the groove diameter in millimeters, such as the 7.82 Warbird.[1][2]
Note this is not a standard size , the neck taper is different between .308 and 7.62 rounds.

correct. the rimmed russian round is similar to the 30-06 round (they came from the same wars don't cha know)... the boxer primed reloadable mil- surp 30-06 is more accurate to shoot but you can pick up a 7.62X54R rifle for 100 bucks and find cheap (very inaccurate) mil-surp ammo

I know because I reload 7.62X54R