3 ms·

Is 7.62x39 a problem here too?

rolph 4y ago
no it wont even chamber, however there is a further nuance. most current AR chambers are .223 / 5.56 WYLDE chamber meaning both will fit and function. the problem comes from a straight up old school .223 being fed 5.56. the evolved gas pressure is higher for the 5.56 round, and will probably work for a while, will put extreme use on the rifle and will eventually malfunction probably with similar results to the .300BLK problem. a 5.56 can be forced to chamber in a 7.62 chamber, but is about 6mm too long so you will know theres a problem 7.62 nato of standard configuration wont fit the lede [ogive] of the 5.56 chamber unless you shove really hard with a mallet. what you may see is a lower receiver stamped for 5.56 NATO assambled with a 7.62 upper and barrel. this is proably fine for most aluminum lowers but i would stay clear of the polymer lowers or the skeletonized milled out lowers, for the 7.62
- walrus01 4y ago
  > what you may see is a lower receiver stamped for 5.56 NATO assambled with a 7.62 upper and barrel the last paragraph is not exactly correct, a lower receiver for 556 NATO STANAG magazines has a different length magazine well (AR-15 derived design, not AR-10) and cannot take the dimensions of an AR10 magazine/7.62 NATO magazine. you can mistakenly chamber a .300 blackout in a 556 nato rifle upper because the blackout is the same length cartridge as a 556 nato round and will feed. you cannot mistakenly shove a 7.62x51 NATO/.308 winchester round into a rifle lower/upper that is not an AR-10 derived design because there would be no way to even seat the magazine. even if you were to somehow mistakenly mount an ar10/762 NATO upper and barrel on an ar15 lower the only way you could try to get a round into the chamber would be to shove it in sideways through the ejection port
  - rolph 4y ago
    thats right you cant mistakenly do that, you would know something is wrong. >>what you may see is a lower receiver stamped for 5.56 NATO assambled with a 7.62 upper and barrel<< 5.56 magazine wells can be modified to fit 7.62 magazine there a couple examples on the range right now, also a .375 win magnum necked down to a .223 projectile. up here its common to ammo up with a full mag, +1 one in through the out door
    - walrus01 4y ago
      considering that a stripped designed for purpose AR10/LR308 lower is maybe $140 from a decent quality manufacturer it would be exceptionally rare for someone to hack up a AR15 lower and magazine well to accept AR10 magazines, I have never heard of anyone actually doing that. if you have a photo example of someone actually doing that on an ar15 magazine well i'd be very interested to see what the hack job looks like
      - rolph 4y ago
        you should check out modular lowers, hydra and i think viper-A [or vipera] have re thunk the lower into two pieces, result being exchangeable magazine wells to match the upper config. why would someone actually chop a lower? because its not available, or its a do something winter project to chase off the cabin fever.

no it wont even chamber, however there is a further nuance. most current AR chambers are .223 / 5.56 WYLDE chamber meaning both will fit and function. the problem comes from a straight up old school .223 being fed 5.56. the evolved gas pressure is higher for the 5.56 round, and will probably work for a while, will put extreme use on the rifle and will eventually malfunction probably with similar results to the .300BLK problem. a 5.56 can be forced to chamber in a 7.62 chamber, but is about 6mm too long so you will know theres a problem 7.62 nato of standard configuration wont fit the lede [ogive] of the 5.56 chamber unless you shove really hard with a mallet. what you may see is a lower receiver stamped for 5.56 NATO assambled with a 7.62 upper and barrel. this is proably fine for most aluminum lowers but i would stay clear of the polymer lowers or the skeletonized milled out lowers, for the 7.62

walrus01 4y ago
> what you may see is a lower receiver stamped for 5.56 NATO assambled with a 7.62 upper and barrel the last paragraph is not exactly correct, a lower receiver for 556 NATO STANAG magazines has a different length magazine well (AR-15 derived design, not AR-10) and cannot take the dimensions of an AR10 magazine/7.62 NATO magazine. you can mistakenly chamber a .300 blackout in a 556 nato rifle upper because the blackout is the same length cartridge as a 556 nato round and will feed. you cannot mistakenly shove a 7.62x51 NATO/.308 winchester round into a rifle lower/upper that is not an AR-10 derived design because there would be no way to even seat the magazine. even if you were to somehow mistakenly mount an ar10/762 NATO upper and barrel on an ar15 lower the only way you could try to get a round into the chamber would be to shove it in sideways through the ejection port
- rolph 4y ago
  thats right you cant mistakenly do that, you would know something is wrong. >>what you may see is a lower receiver stamped for 5.56 NATO assambled with a 7.62 upper and barrel<< 5.56 magazine wells can be modified to fit 7.62 magazine there a couple examples on the range right now, also a .375 win magnum necked down to a .223 projectile. up here its common to ammo up with a full mag, +1 one in through the out door
  - walrus01 4y ago
    considering that a stripped designed for purpose AR10/LR308 lower is maybe $140 from a decent quality manufacturer it would be exceptionally rare for someone to hack up a AR15 lower and magazine well to accept AR10 magazines, I have never heard of anyone actually doing that. if you have a photo example of someone actually doing that on an ar15 magazine well i'd be very interested to see what the hack job looks like
    - rolph 4y ago
      you should check out modular lowers, hydra and i think viper-A [or vipera] have re thunk the lower into two pieces, result being exchangeable magazine wells to match the upper config. why would someone actually chop a lower? because its not available, or its a do something winter project to chase off the cabin fever.