For most shooters, most of the time, buy M193. It's range-friendly, works in almost every AR barrel twist, and is usually the cheaper case. Buy M855 when you specifically want its construction and your range allows it. Never assume a range allows it.
M193 and M855 are the two military-pattern 5.56 NATO loads that dominate bulk listings. They look nearly identical in the box, but they differ in bullet construction, and that difference decides where you can shoot them.
| M193 | M855 (green tip) | |
|---|---|---|
| Bullet | 55 gr FMJ, lead core | 62 gr FMJ with steel penetrator tip |
| Identifying mark | Plain tip | Green-painted tip |
| Twist preference | Stabilizes in most common twists | Prefers faster twists (1:7 to 1:9) |
| Steel targets | Generally fine at safe distances | Often banned; can damage steel |
| Indoor ranges | Commonly allowed | Frequently prohibited |
| Best for | Bulk practice, general use | Its intended construction; ranges that permit it |
Why So Many Ranges Ban Green Tip
M855's steel penetrator is harder than the lead cores most range backstops and steel targets are designed for. Ranges ban it to protect equipment and reduce sparks and ricochet risk. Some check with a magnet, since the steel tip makes the bullet magnetic. Check your range's rules before you buy a case of green tip. A thousand rounds you can't shoot anywhere near you isn't a bargain.
Twist Rate Matters
Heavier bullets need a faster twist to stabilize. Most modern ARs use 1:7 or 1:8 twist barrels, which handle both loads. Older or budget rifles with a 1:12 twist can struggle to stabilize 62-grain M855, which shows up as poor groups or keyholing (bullets hitting sideways). M193 runs well in nearly everything. If you don't know your twist, it's usually stamped on the barrel.
Performance, Honestly
Both are full metal jacket military loads, not defensive or hunting ammunition. Much has been written about the terminal behavior of each, and the consistent takeaway from published military and law-enforcement testing is that both depend heavily on velocity. Performance drops off from short barrels and at longer distances. For home defense or hunting, buy ammunition designed for that job, not surplus-pattern ball.
The Picks
Winchester M193 5.56 NATO 55 gr FMJ
Best for mostThe default bulk 5.56. Range-friendly, twist-tolerant, and widely stocked.
PMC X-TAC 5.56 NATO Green Tip (420-round can)
M855-type construction, packed in a reusable can. Confirm your range permits steel-core ammunition first.
Key takeaways
- M193 (55 gr, lead core) is the best bulk default: cheaper, twist-tolerant, and range-friendly.
- M855 green tip has a steel penetrator. Many ranges ban it, so check first.
- 1:12 twist barrels may not stabilize 62-grain M855; 1:7 to 1:9 handle both.
- Neither is a defensive or hunting load. Buy purpose-built ammo for those jobs.
FAQ
Is green tip ammo legal?
M855 is widely sold to civilians in the U.S. Local rules vary, and many private ranges prohibit it. Check your state, local, and range rules.
Can I shoot M855 in a 1:9 twist barrel?
Generally yes. 1:9 is commonly cited as able to stabilize 62-grain bullets. 1:12 barrels are where problems typically appear.
Why is M855 sometimes cheaper or pricier than M193?
Pricing follows supply, contracts, and demand, not construction alone. Compare cost per round on current listings when you buy.
Is M193 the same as .223 Remington?
No. M193 is a 5.56 NATO load. Fire it only in rifles chambered for 5.56 NATO (or .223 Wylde), not in .223-only chambers.