While you can use a standard lower fire control group, I had multiple failures to fire that way. The heavier spring gave me 100% ignition.

As well, the Geissele Hi-Speed trigger works 100%.

from BSF: 10  with occasional missfeeds.
from HiramRanger: Uses 20 and 30 rounders with the old style followers... do NOT use green followes. Do not load to full capacity due to difference in taper of the rounds.
from RS39:  Runs about 25 rnds on black follower AR mags, round taper/stack tilt limits total and mandates no green anti-tilt followers.

from MOS2111: I have used HK, HK w/6.8 followers, and USGI with 6.8 followers. I can get between 17 to 26 rounds depending on the mag body. I have not found any "standard" mag body that holds a set amount. It seems to be a combination of body, follower and spring (surprise, right).  Most of the mags had no problems feeding and I only ran into problems on the last several rounds.  After I forced as many rounds as possible in the mag, and let them sit for 2 days until I could shoot. The only mag problems I ran into were failure to chamber, where the projectile and front of the case were "pinched" by the bolt.

Barnaul Arsenal in Russia is still producing today 5.56, 5.45, and 9mmMak using corrosive primers. TODAY. But, they use non-corrosive priming on commercial ammo for export. We hope. There is no way to tell with foreign ammo by simply looking at it. A test is the only absolute sure way.

Home test for corrosive ammo:
You will need to have FOUR controls for an accurate test:

Positive Control - A known corrosively primed round (I use 1940 dated 7.62x54R)
Negative Control - A known non-corrosively primed round (I use Remington .22LR)
Control - A clean piece of degreased metal
Test Control - The suspect round
First, pull all bullets, dump powder and discard. We want THREE primed empty cartridge cases here folks. Be safe.

Clean and degrease FOUR pieces of steel. I use old unusable M-16 Stripper clip housings (the steel piece, not the brass insert). I prep them by briefly touching the steel to a grind wheel to expose raw steel (this gets rid of the Parkerizing). Label each piece with a 1,2,3, & 4 with a marking (sharpie/permanent) pen.

Label each empty cartridge case with a 1, 2, or 3. Fire each cartridge case onto its corresponding numbered piece of steel. The fourth piece is placed with the others as a ambient temperature/humidity control. Place all four pieces in a shallow Tupperware container on top of your fridge near the back (this is an ideal warm humid place) UNCOVERED for 4-5 days.

Optional: If you are in a very dry climate, place a shot glass of water in the Tupperware to provide a small region of humidity. Unnecessary anywhere except desert regions or very cold dry climates.

After 4-5 days inspect the pieces of steel. Compare the suspect steel to the CONTROL piece (the one piece you didn't fire a cartridge on). Is it rusted more or less? Does it have strange colors? If yes, compare it to the POSITIVE control. Equal? It's corrosive. Does it look like the NEGATIVE control? Then it is likely that it is non-corrosive. But, still check after you fire the ammo for fast growing crud. The difference will be obvious, as a corrosively primed round will grow rust and strange stuff almost overnight. Sometimes, the Negative control piece will exhibit almost zero rust, due to the sealing effect the priming compound has on the steel. This is especially true if you use a .22 pistol to fire the empty cartridge, like I do.

This is not a perfect test, but it is one you can use at home with great accuracy. I have used it for over 10 years, for hundreds of suspect rounds, and I was wrong ONCE (verified by lab test). So, my success rate is still over 99.9% with this test.

I've been shooting corrosive ammo for the last 50 years. No big deal, it will not destroy your rifle or other firearms if you clean it properly.
To save money, and make your own cleaner you can use the following:
mix a 1/3rd part to part,
Clear Ammonia ( do not use sudsy type )
White Vinegar
Distilled water
When mixed and stored in a plastic bottle the mixture will last for about six months. Soak a patch with this solution,run it down the bore, and let set into the bore no longer than 20 minutes. ( 5 minutes is long enough )
Follow with a Nylon bore brush. Do not use bronze.
Follow with several clean patches. ( the patches will be green from the copper )
Oil as needed.
The solution will remove all of the salts,powder fouling,copper fouling and lead.
I use this solution on all of my firearms. From El-cheapo to my most expensive machine guns. It works,it's cheap and it removes all of the primers salts instantly.
I have never had a rusty bore from shooting corrosive primed ammo using this cleaner,ever.

Most surplus ammo on the market today is corrosive.  Usually the primer is the culprit, when fired it coats the inside of the firearm with corrosive salt residue. When the salts combine with moisture, damage starts to occur to the metal surfaces. Oils or petroleum based products will not break down the corrosive salts and therefore are ineffective in cleaning or neutralizing the salt compounds.
I have read that modern bore solvents will break down the salts and I have spoken with chemist friends that tell me that this is not true. Alkaline based solvents will break down the salts, as well as simple soap and water or just plain water. Ammonia will not break down the corrosive salts and can cause damage to the bore if left in too long. Ammonia will remove metal deposits such as copper from the bore.

I for the longest time mixed an ammonia and water based concoction that I used to clean the bolt, bore, and any other effected areas. I then spoke to a friend of mine that said to just use simple ammonia based window cleaner.