Steel cased bimetal bullet barrel wear.

[stchman]

OK. I've heard of a lot of people on a lot of forums state that steel case bimetal bullets will ruin a barrel in 5-6K rounds. They keep referencing the Lucy Gunner AR torture test. Mind you this was a torture test for ARs, I don't think that this applies to every gun ever made.

I also hear a lot of people say that they have 60K-100K rounds through their guns and the barrel looks fine(I assume NOT shooting bimetal bullets).

So is it believable that bimetal bullets are 20X more abrasive than non-bimetal bullets? Are people just making stuff up to sound like they are knowledgeable? I have met a lot of steel case ammo haters that have never even shot steel case or only shot it in an AR. I fully realize that ARs can have issues with steel cased ammo.

I've been shooting polymer steel cased ammo for years with no issues. I see no appreciable barrel wear, but I don't shoot that often.

 

[stonecutter2]

It comes down to the metal on metal contact of the various rounds.

Brass and copper are soft metals, softer than a steel barrel for sure, and softer than the metal parts in the extraction/ejection systems in weapons.

This means that on a per round basis, the brass will be far more forgiving on the parts and copper on lead will not wear or affect the barrel as severely as a steel jacketed bullet would.

A "bi-metal" bullet (interesting as lead and copper are "bimetal" too heh) is just lead covered by a steel jacket, flashed with copper. That copper flashing is usually pretty thin, and I'd imagine once it first contacts the grooves in a barrel, it's rubbed down pretty much instantly to where there's steel on steel grinding against each other at high speeds for a good portion of the barrel, until the bullet exits the barrel. I believe the flashing is just applied for additional corrosion resistance until the round is fired. Same with the polymer coating on the steel cases.

So, my opinion is that yes - bimetal bullets with steel cases can be much harder on a firearm than brass and copper (or lead) counterparts.

The wear would only occur after several thousand rounds. Your best bet for a resource is probably a sport shooter, as with practicing and competing in competitions, they go through thousands of rounds and replace barrels accordingly...and can probably provide opinions on "usual" wear vs accelerated wear.

For recreational shooting, steel cased stuff is probably just fine. If you're going through a lot of rounds, you will see wear from shooting steel cased bimetal faster than brass/copper FMJ without question.