Lage says no. But what’s the reason why?

Anyone here shoot steel cased ammo thru there lage uppers?

I've shot as much Tula and Wolf through my MkII upper on my M10/9mm as I have brass.

No issues.

Shoot it. Replacement barrels are cheap compared to the price of of the ammo needed to toast a barrel.

I reccomend avoiding ALUMINUM cases though. I get a lot of bullet setback with aluminum and My Mac generally splits the cases too. You can see flame and fire from some rupturing alumin cases while shooting it. I think it’s cause the Mac is blowback with no real recoil locking mechanisms.

Open bolt guns like the m10 and m11 are tough on brass as it starts to detonate before the casing if fully seated. Many recommend not reloading it, others say only a few times and you need to really go over it well.

I also agree with not shooting aluminium ammo but that is just in general.

As far as steel case ammo goes, my understanding its due to many of the options being crappy ammo overall and stuck cases being another. That being said I've run steel cased wolf in my m10 with lage upper without issue. I had a bunch of it sitting around from a previous ammo scare that I had stocked up because I was shooting IDPA at the time. My gun ran it fine.

My Lage upper (45 ACP) won’t run steel case. With brass case it runs like a top and brass is undamaged and can be reloaded multiple times.