Lapua brass for AR15

[Gabe22BR]

People are going to hate this, but starline is the best I've ever measured.

556_Brassh20.xlsx

docs.google.com

Keep at under your hat-….

 

[r bose]

That last sentence is a falsehood that a lot of people believe. The bullet has to pass the gas port before gas is allowed to enter the gas port, by the time the gas reaches the bolt carrier and it begins to move, the bullet is already out of the barrel. If this were true, there would be a whole lot of gas being directed back toward the shooter, enough so that safety would be a major issue. The brass would be destroyed by the pressure. Neither happens. AR's have withstood some really extreme loads, far beyond what is considered safe to use. One guy I know put 30gr of Ball C behind an 80gr Sierra and the gun survived. How he managed to get that much powder in the case is beyond me! He forgot to put his reading glasses on when he was loading his ammo. In that instance, maybe the bolt was starting to unlock but, obviously wasn't fully unlocked or he wouldn't have had a face left.

I was incorrect. I meant to say bolt carrier. The carrier does begin moving rearward before the bullet exists the barrel. Point I was trying to make is follow thru is very important.


In a properly functioning AR-15 or similar gas-operated rifle, the bolt does not open before the bullet leaves the barrel. While the bolt carrier begins to move rearward after firing, it is designed to unlock and cycle only after the bullet has exited the muzzle.

Here's a breakdown:

• Gas System:
  The AR-15 utilizes a direct impingement gas system where gas from the fired cartridge is directed into the bolt carrier group.
• Bolt Carrier Movement:
  The initial movement of the bolt carrier is driven by this gas pressure, but the bolt itself is locked into the barrel extension.
• Delayed Unlocking:
  The bolt is designed with locking lugs that engage with the barrel extension. The bolt carrier's rearward movement unlocks these lugs, allowing the bolt to rotate and begin its rearward travel.
• Bullet Exit:
  The unlocking and cycling of the bolt occurs after the bullet has already left the barrel.