As you would guess, the 5.45x39 Russian round was adopted by the Soviets in 1974. AK-74 rifles began to be issued to the Soviet Army in 1976.
The military ball ammo is a 53 gr. bullet that resembles a 30-06 bullet to me. It is a longer, although slightly lighter bullet than the original 5.56x45 US military M-193 ball.
If you will allow me to gloss over - balistically speaking, this round is about 10% less efficient in fps and energy delivered on target than the US round. To me that is insignifigant but it might be important to some. I'd still hate to be hit by one.
Like original US M-193 ball ammo this round has excellent tumbling characterisitics and tempory wound cavity traits when used upon infantry, but produces poor performance on soft and hard barriers.
This round has a rather robust rim compared to the US 5.56 round which assures better cycling, extraction, and ejection in the AK rifles for which it was designed. It's rim is not only thicker but is also wider in circumference than the 5.56 round. Therefore whatever magazine is used for this rifle should take into account that the magazine should have an appropriate arc to it's body in order to cycle up the mag tube reliably. This aspect of magazine design is just as important as having a dedicated follower which also corresponds to the round.
Please accept some advice about using corosive primer original military ball 5.45 ammo in your rifles - especially in AR variants but the advice also holds true in AK rifles. The best way to clean these rifles if you want to use the corrosive primer ball ammo is the same way you would clean a black powder weapon. Use very hot soapy water first then dry thoroughly before either using a more comtemporary cleaning solvent or going straight to lubing before storage.
If you are using 5.45 ammo with non corrosive primers I don't think you will have any problems.
Good luck with your new rifles, gents.
I have 7 Colt AR-15 variations I have built and collected over the years and 10 Russian(only) variations of AK-47,AKM,& AK-74 rifles with many original(non full auto parts) Russian parts I've collected over the years.
I have studied both rifles extensively over almost 15 years and I am delighted to see some more interest in this round in the US.
The first AK-74 rifles were imported to the US via Romania in 1997. Prior to this, 5.45 ammo was almost impossible to find in the US and the "early" AK collectors had to modify brass from existing US cartridges in order to use their rifle.
Even 22 years later there is no US ammo manufacturer that I know of that makes this cartridge.
I am hoping that there are now a sufficient number of AK-74 shooters in this country that our domestic ammo producers might start making it if the ecomony improves and if the Feds ever decide to ban Soviet bloc ammo imports. US made ammo is produced under much more stringent quality control and generally better material than Soviet era military ammo. The Russians are not stupid, this is an area in which they could save on expenses. So they deliberately compromised on the ammo quality. They actually have a sterling history of barrel mass production that goes back to the early 1800s when the Russians decided it was important to become self sufficient in small arms production rather than having to rely on purchasing small arms and small arms designs from foreign countries. This goal was not entirely realized until after WWI.
The round is quite effective and the 10% less efficiency I mentioned earlier also means this round has slightly less recoil to it, especially when used with a Russian rifle and original Soviet designed AK-74 muzzle brake. In original configuration (AK) this is a very light recoil round and I expect it would also have very light recoil in AR-15 rifles.
HTH
