I see that my posts caused some confusion.
When I originally started this thread I didn't realize that the "ar-47" manufactured by Special Weapons Inc was actually just a AR lower that accepted AK mags and
was to be used with existing 7.62x39 uppers made by other companies. I learned something so all was not in vain

.
No. Please read my post above.
The AR47 cannot accept nor function with an “existing 7.62x39 upper”
The upper for the AR47 has some extra machining done
(at the upper receiver case and bolt carrier).
That machining is made so the upper receiver-case and bolt-carrier can accommodate
the wider mag (lips) of the AK mag.
If these mods are not done, then, you will be able (theoretically speaking)
to install that AR-15 upper on a AR47 lower,
you will even be able to safely fire it (if a round is chambered by hand),
but
you will not be able to install the AK mag under an un-modified AR upper because
the lips of the AK mag are too large for the un-modified AR-15 upper case and bolt carrier.
About magazines:
7.62x39 is known to work bad in a .223 AR-15 mag.
It does not feed well from those 223 mags because
the lips of the 223 mags do not exactly match the 7.62x39 cartrige.
Also, 7.62x39 kinda bulges the 223 mag body.
(but there are however exceptions:
-the ar15/m16/ar180 steel mags made by Sterling in UK (rare here)
seem to work well if not more than 5-10 rnds are in the mag,
-the SAS steel mags (Vietnam era), work very well, at least in my experience,
and maybe other steel mags.)
That is why you need to buy one of these AR mags especially made for 7.62x39:
They will fit an AR-15 lower.
Do not buy National Mag, since those guys were too cheap to re-engineer
the mag lips to match the 7.62x39 cartridge.
Contrary to what people might think,
in the AR-15 lower you will not be able to fit the AK47 mag
(even if you use a 10lbs hammer)
In my picture posted above
the AR-15 (on the LEFT side) does not use an AK47 mag
how you may believe. Sorry for the confusion.
It uses a
hybrid mag,
that is made basically from a AK47 mag body with a neck
made from a AR-15 mag (welded together).
If you take that mag out of the gun it looks sumpin like that:
Top row, left to right: MWG 10 round, Colt post-ban 5 round, Colt pre-ban 5 round.
Bottom row: Scherer 30 round, Gordon Technologies 30 round, USA 20 round, USA 30 round.
The hybrid mag is a very reliable mag,
it has been used for years in tac rifle matches
in Europe (Scandinavia) and not only.
But it is very hard to “make” that mag in your garage.
In Europe, in addition to Sherer, Gordon Tech and USA,
there used to be a military armourer in Finland
who was making them as a side business.
I do not know exactly what followers and springs were used.
Again, you cannot fit a regular AK mag in an AR-15 lower

Again, if you want to use regular AK mags,
then you need to use a special receiver (like AR47)
AND a modded AR upper.
There are also other receivers that are specially made to take the AK mags,
but they are very hard to find in here or very expensive.
There is also one company (MGI) that makes a modular receiver.
The front part (magwell) can be swapped so you can use other magazines (and cartridges),
but you NEED the matching upper and bolt/bolt-carrier, modded as I said above.
In addition to the removable magwell for AR-15 magazines,
the MGI modular receiver accepts the removable magwells
to fit other mags (like mags for Glock 21, grease-gun, AK, whatever).
This is the MGI removable magwell for the AK mag:
I hope that diffused some of the confusions created by my previous posts.
About the corrosive ammo making a mess in the rest in the gun,
yes, that is absolutely true.
As I said many times before, enjoy the advantages of the direct impingement system

Some people clearly did that when using corrosive Czech or Chinese 7.62x39 ammo
and they preferred the piston system for their AR47:
More 7.62x39 #### (both Ar-15 and AR47)
and pics shamelessly stolen from internet:
Colt R6830 and R6850DC
SR-47 was an old project of Knight Armament.
Initially it was intended as a weapon that
can use a mag and a caliber readily available on the battlefield.
Its price (5-6k) convinced the US military that if they want to use 7.62x39,
an AK is cheaper and more reliable.
A less known brand: Tactical Weapons Inc.
As I said, on the market,
Special Weapons Inc is considered to be the best AR47 money can buy:
Model 1 Sales barrel with M4-like ramps:
7.62x39 barrel. Not a lot diferrent on the outside:
AR47 upper: