What makes an AR-15 Rifle,Carbine and M4 as far as buttstock/buffer springs

[ar15barrels]

i should probably tell my buddy this, he has been using an A2 RE with some spring out of his parts box that he doesn't even know where it came from, and a spikes T2 carbine buffer.

it seems to work but who knows

we'll have to take a look at his carrier lol

Does his charging handle sometimes pop out of the upper when he shoots it?

[Mossy Man]

Not that ive seen

[eth727]

I ordered the rifle length parts(tube,spring,buffer) and A1 pistol grip without finger notch. So I can now call this a AR-15 Carbine A1/A3?

[Jimi Jah]

I'm building a 20" with the A1 stock and rifle buffer. Can you use tungsten powder instead of the fixed weights inside the rifle buffer like the Spikes carbine buffer does? I use those in the carbine and like the softer cycle from them.

I don't recall anyone selling rifle buffers with the powder inside. They are also a longer shape so maybe that prevents it's use?