Here's what happens when you load pistol powder in a .223 AR

[nmmi9100]

http://www.thefirearmblog.com/blog/

also at

http://www.ar15.com/forums/topic.html?b=3&f=118&t=533885&page=1

Bad deal.  Keep only one powder on the bench at a time and NEVER reuse powder containers with other powder put in them.

Stay safe.

-David
Edgewood, NM

[Nickle]

Back when I was about 15 years old, two guys walked into the shop, both had 7mm Rem Mags (this would be about 1970). One had a Remington 700, knocked the bolt handle off the bolt trying to open it. The other was a lefty, owned a Savage 110. The Savage he left at home, all 26 pieces of it (other than what the docs took out of his face).

I talked to the both of them, they were using handloads they had made. They told me the data, they were supposed to be made with IMR-4831, but the load was STILL over max.

I pulled a bullet on one of the cartridges, and lo and behold, Alcan shotgun powder, and it turned out to be AL-5 (can ID by the colored flakes in it). This powder is pretty fast burning, about the middle of the shotgun scale, more to the slow end of the pistol scale.

We ended up sending the rifle to Remington, told them the cisrcumstances. Remington estimated the pressure at 175,000 PSI (normal working pressure is about 55,000 for that caliber), and even replaced the barrel, bolt and reciever for the guy for free. Of course, they also knew full well the guy and his friend were going to tell everybidy they knew about how well he got treated by Remington.

How the powder ended up wrong was they had bought bulk powder, which was placed in a different container, and the idiot that sold them the powder grabbed the wrong stuff. Add the fact that they didn't even remotely know what IMR-4831 powder looks like didn't help matters. AL-5 is a flake powder, and IMR powders are extruded stick powders. A mildly experienced reloader could have picked up the mistake with nothing more than a quick glance, let alone adjusting the measure.

[Old Dog]

I'm amazed (regularly on arfcom) by the folks who say an AR15 is stouter than a M700 Remington.  Those M700 are TANKS compared to most standard rifles these days.

If you're going to reload, be double d..n sure you know what you're doing.

[Nickle]

Hee hee, Old Dog, they ain't got a clue.

AR's are tough, for sure, but I only know of 2 other actions that are, for sure in the strength class of the Rem 700. One is the Winchester Model 70, the other is a special proof Arisaka (usually 6.5 Jap). Parker Ackley blew the barrel out the front end of an Arisaka (on purpose, mind you) 3 times, wrecking the reciever THREADS the 3rd time. It didn't blow.