The video discusses the differences between .223 Remington and 5.56 NATO ammunition, as well as their compatibility with various rifle chambers. The speaker, Gavin, explains that while the two cartridges are similar, they have distinct differences in terms of pressure ratings, chamber dimensions, and bullet profiles.
Gavin notes that the 5.56 NATO cartridge has a higher pressure rating than the .223 Remington, but this is due to differences in testing methodologies rather than actual differences in pressure. He also explains that the 5.56 NATO chamber has a longer freebore and a slightly larger diameter than the .223 Remington chamber.
In terms of interoperability, Gavin advises that 5.56 NATO ammunition should only be shot in a 5.56 NATO chamber, while .223 Remington ammunition can be shot in various chambers, including 5.56 NATO. However, he cautions that shooters should be aware of the potential risks of shooting 5.56 NATO ammunition in a .223 Remington chamber, particularly with certain bullet profiles.
Regarding reloading, Gavin notes that the process is similar for both cartridges, but that reloaders should be careful to remove the crimped primer pocket from 5.56 NATO cases. He also advises using separate load data for each cartridge to ensure safety and accuracy.
Overall, the video aims to educate shooters and reloaders about the differences between .223 Remington and 5.56 NATO ammunition, and to promote safe and responsible handling of these cartridges.
Here are the key facts extracted from the text:
1. In the 1950s, the US Army outlined the requirements for their next-generation rifle platform through an organization called CONARC.
2. The requirements included a .22 caliber projectile, supersonic bullet velocity at 500 yards, a net rifle weight of six pounds or less, and a magazine capacity of 20 rounds.
3. The requirements also included select fire for both semi-automatic and fully automatic use, penetration of a US steel helmet on one side at 500 yards, and accuracy and ballistics equal to M2 ball ammunition.
4. The joint development of the .223 Remington ammunition and the AR-15 rifle platform was led by Remington Arms and Eugene Stoner and Armalite.
5. The US Army adopted the AR-15 rifle platform as the M16 in 1964, but specified a new ammunition specification called 5.56 NATO.
6. 5.56 NATO and .223 Remington are almost identical, but not exactly the same.
7. The exterior dimensions of .223 Remington and 5.56 NATO cartridges are the same.
8. The .223 Remington cartridge has a working pressure rating of about 55,000 psi.
9. The 5.56 NATO cartridge has a working pressure specification of about 63,000 psi, but this is due to differences in pressure testing methodologies.
10. The SAMI methodology used for .223 Remington uses a conforming line on the case, while the military uses a different methodology called EP V 80.
11. The chambers for .223 Remington and 5.56 NATO are different, with the 5.56 NATO chamber having a slightly larger base diameter and shoulder diameter.
12. The free bore diameter is about 2.5 thousandths of an inch larger in a 5.56 NATO chamber.
13. The free bore length is about 50 thousandths of an inch in a .223 Remington chamber, and about 100 thousandths of an inch in a 5.56 NATO chamber.
14. It is generally safe to shoot .223 Remington ammunition in a 5.56 NATO chamber, but not the other way around.
15. Reloading .223 Remington and 5.56 NATO cartridges requires careful case prep to remove the crimped primer pocket.
16. Load data for .223 Remington and 5.56 NATO cartridges is different, and it is safest to use the correct load data for the specific cartridge being reloaded.