We had a guy on here recently and on other forums trying to get his SIG to run steel cased ammo.
He insisted that he should be able to run steel cased ammo in his SIG.
I sent an email to SIG asking for their official position on using steel cased and here it is...

We do not advocate steel cased ammunitions for several reasons. Primarily ammunition must meet SAAMI standards. Sig Sauer recommends the use of only newly manufactured ammunition meeting SAAMI (www.saami.org) and/ or NATO specifications. SAAMI is Sporting Arms and Ammunitions Manufacturers Institute. For information on their regulations or to see if your ammunition selection is SAAMI compliant, please go to http://www.saami.org. Secondly, steel cased ammunition is very hard and can cause excessive wear or damage to components. Brass is a softer material and will result in far less damage or wear to the firearm.

I had heard before that steel-cased ammo was to be avoided; that confirms it. Thanks for posting that!

I spend good money on my guns and cleaning components. So it stands to reason that I'll feed it quality ammo.

Another issue with steel cased ammo is that most often, the bullet head is steel with a copper wash over it. STEEL BULLETS HITTING STEEL BACKSTOPS MAKE SPARKS! UNBURNED GUNPOWDER IS FLAMMABLE! INDOOR RANGE IS ONE BIG PIPE BOMB! (Yes, I know that's a reach, but it gets the point across).

I've personally seen a small fire from a spark igniting unburned powder, and video of a large flare-up that I hope to never witness in person. The private range I'm a member of has a magnet in the Ready Room so that you can test your ammo if in doubt.

Not that I’ve ever used steel cased ammunition, but steel cases aren’t necessarily loaded with steel bullets. And this question inevitably results in the “steel cases aren’t as hard as the steel in slides and extractors, so they can’t cause any wear” responses. That is probably true, but steel, any steel, is harder than the brass or aluminum used for other cases, and a substance doesn’t have to be harder than another to cause friction wear on the other.

On the other hand, sparks can be caused by hitting steel even if the bullets don’t contain any steel. I was firmly convinced that was impossible until I started conducting low light shoots using a steel target and witnessed it myself. Steel on steel is probably worse, but that’s not the only way it occurs.

I don’t care in the slightest what other people shoot in their guns as long as they don’t blow up while standing next to me, but anyone making a decision should understand simple facts.

Thanks for that statement from SIG. I had not seen it before.

Some of the steel cased ammo is loaded with a bullet that's a very soft steel, that's almost iron. (I can't recall the name for it). They are copper washed as a gilding metal over them.

Steel cases don't have the elasticity that brass does, they don't spring back down as much after firing as brass, which leads to harder extraction, which can cause function issue, but it's also harder on the extractor. Harder because it's harder to pull the case out and harder because the cases are steel and literally harder, causing more wear.


When I worked at the range I saw all sorts of trouble caused by steel cased rifle ammo. One particular note was the awful 710 bolt action rifle Remington made. (we called them the Bic lighter of rifles) People who bought these inexpensive rifles would naturally tend to buy cheap ammo. I saw 3 or 4 people break these rifle's bolts trying to get steel cased ammo to eject. (and "good" quality sporting ammo too, not Chi-com machine gun ammo or anything)

The only steel case ammo I use in for my 1992 Norinco AK. That rifle is almost indestructible.

If Sig recommends brass cased ammo then I would say that it would be wise to follow that recommendation.

It may be worth while to confirm if your guns can function with steel cased ammo in the event of a ammo shortage.

For my personal use, I run brass cased ammo in all of my high value and collectable firearms, but steel cased ammo in my other guns. To date, I've ran about 4,000 rounds of steel cased .223 in my Rock River HBAR AR15, and about the same number in my Gen 3 Glock 19. The only parts I've ever changed on these gun are recoil and buffer springs.

A good friend of mine has run thousands of rounds of steel cased 9mm through his Sig 320s and Glock, and never had any issues. I ran about 250 rounds of steel cased .45ACP through my G21 and had a couple of FTE problems. I was thinking about buying a case of steel 9mm for my faux-Glock (P80), but for $20 more I found some Federal brass range ammo and bought that instead.

I don't know who wrote this statement, or why, but it is not factual.

Might be an uninformed Customer Service rep injecting their personal opinion or misheard thirdhand information. We've had many examples over the years of members here getting wrong information from Sig CS reps spitballing answers...

Or it might be a blanket stance that Sig has adopted because they're tired of dealing with less informed customers complaining to them about having reliability problems while using cheap steel ammo. Which is a result of it being cheap ammo, not of it being steel... Cheap brass ammo can have the same reliability issues. While much of the cheap ammo out there is steel, not all cheap ammo is steel, and not all steel ammo is cheap. Hornady, for instance, offers high quality steel cased match ammo and hunting ammo.

Or there could be various other factors/considerations involved.

Similarly, Sig also says to never store a gun that is loaded, and always store your firearms separate from your ammunition. It's a CYA thing, not the gospel. Consider how that blanket stance would impact things like home defense guns, patrol rifles, etc., if strictly adhered to.


Commercial steel ammo is loaded to SAAMI/CIP specs (American and European equivalent), just like commercial brass ammo. Whoever wrote that is apparently unaware of this fact.


And the mild steel used in steel cases is not "very hard" as erroneously claimed. It is a similar hardness to brass, and significantly softer than the hardened steel use in the gun parts themselves. Brass does not result in "far less damage/wear" than mild steel, as it is only slightly softer.

The hardened steel used in barrels and the like typically has a Rockwell hardness value of around C25-C35, which is equivalent to about B100-B110. Mild steel that is used in cases is around B70. Brass used in cases is around B60.


Mild steel cases have been used in military and commercial ammo cases around the world for over 100 years, and continue to be used. Brass is a slightly better material overall, but steel is perfectly safe and will not cause excessive wear to your gun. Even brass cases cause wear, after all... This is why many gun parts are wear items, designed to be replaced throughout the gun's lifespan.

Besides, the cost savings of steel vs. brass can be significant if you're a high volume shooter. More than enough to cover the replacement cost of parts like the extractor/ejector/barrel/etc., if it were true that steel wears them out "far more" quickly. Thus rendering the entire argument moot.

This message has been edited. Last edited by: RogueJSK,

Well the guy that was complaining that his P320 would not cycle steel case came back and finally posted SIG's response to his questions :

Thank you for contacting Sig Sauer



SIG SAUER recommends the use of only newly manufactured ammunition meeting SAAMI (www.saami.org) and/or NATO specifications. SAAMI is Sporting Arms and Ammunition Manufacturers Institute. For information on their regulations or to see if your ammunition selection is SAAMI compliant, please go to http://www.saami.org. +P ammunition manufactured to SAAMI/NATO specifications is fine to use as a defensive round or for occasional range use, in any of our firearms. Continual use of this round will make it necessary for more frequent service on the pistol. We do NOT recommend the use of any +P+ round. This, and the use of remanufactured or reloaded rounds, may void your warranty.



SAAMI and NATO specified ammunition will always be brass cased. Aluminum casings are too soft and expand so much to the interior of the chamber that when the slide and extractor attempt to remove the casing, the aluminum resists and adds extra drag, slowing down the slide speed. This can cause erratic and inconsistent ejection and failures to cycle. Steel cased ammunition can rust, so on all steel cased rounds is a thin layer of lacquer to protect the ammunition. The lacquer when heated leaves a sticky residue that will cause failures to feed and cycle as the residue builds in the chamber. We make our pistols with very tight chamber tolerances as compared to many manufacturers. Steel cased ammo expands differently than brass does and will grab the chamber with a lot of friction that will leave more deposits behind and will also slow down the slide speed which will eventually produce failures.

I don't know. I've ran a bunch of steel pistol ammo through various pistols. Guilty: I usually buy cheap ammo. I haven't had any issues so far for what it's worth.

quote:

Steel cased ammunition can rust, so on all steel cased rounds is a thin layer of lacquer to protect the ammunition.

Yes, steel can rust and must be coated. But all steel ammo isn't lacquer coated. Most steel cased ammo nowadays is now coated with polymer, not lacquer. This isn't due to any actual issue with lacquer, but was adopted by many manufacturers to placate the interweb keyboard commando backlash in response to this widely spread urban legend:

quote:

The lacquer when heated leaves a sticky residue that will cause failures to feed and cycle as the residue builds in the chamber.

Nope. Doesn't happen. It's been thoroughly tested and debunked, but yet the urban legend persists. (Like steel cases, lacquer coatings have been used by various militaries on their ammo for 100+ years.)

The residue that builds up in the chamber with steel ammo isn't melted lacquer. It's fouling due to the fact that steel doesn't expand to seal the chamber quite as readily as brass, plus the fact that cheap steel ammo tends to use cheaper, dirtier powders.

This can happen even with poly coated steel ammo.

This generally isn't an problem, unless you've fired a very large number of rounds without cleaning. This issue is further exacerbated if you swap back and forth between steel and brass. For example, if you shoot a bunch of rounds of steel ammo and the chamber starts to get fouled, and then immediately switch to brass ammo, the extra expansion of the brass combined with the excess chamber fouling from the large amount of steel ammo can cause some of the brass cases to stick in the chamber.

quote:

Steel cased ammo expands differently than brass does...

The first half here is true; it expands differently than brass as discussed above...

quote:

.. and will grab the chamber with a lot of friction that will leave more deposits behind.

...This second half doesn't even make sense.

Rogue is right and I seriously call bulkshit on the OP. I’ve got 5 320’s. I would lay a crisp 100 dollar bill on the table and a box of Tula. Or Wolf. If the gun is a standard unmodded firearm in good repair that gun will run that box (and many more) without fail.

Internet nonsense. Lies. Folderol. Name it what you will. I personally have shot 10’s of thousands of rounds through glocks, plastic Sig’s, metal sigs, cz’s, Dan Wesson’s, S&W’s, etc.


Sum total? Saved enough money to buy multiple entire guns. Parts breakage? Zero. No one ever posts the pictures of all these worn out extractors. Shot out barrels. And for fucks sake where are you getting steel bullets out of steel cases handgun ammo? Granted I only shoot Tula and Wolf but never had a steel bullet with light copper wash. I have seen idiots at the range say they are because they ran a magnet next to the case and said, “yep, steel”. Fuck.

Liars and internet. Any proof to stake your claim? Anything? Like I said. Hundred bucks OP is full of shit and the gun runs perfectly on steel. Shoot more bullshit less.

If he's merely copying and pasting the replies from a Sig CS rep, it's not the OP that's full of it... It's the CS rep who would be the one in the wrong.

As I mentioned in my first post, wouldn't be the first or last time a CS rep was talking out of their butt to a forum member.

Point taken. Reading his post again, it wasn’t even his gun. CS reps can be as stupid as gun store clerks. I still hate the spreading of bullshit internet lore. Oh and quoting the manual too. They quote something out of manual like it Moses with stone tablets. They ignore all the other gems in that same manual. As you stated. Don’t store loaded. Keep ammo separate. Never shoot your reloads. Void your warranty. Oh brother. It’s like arguing with the spring guys. That spring from the factory is the perfect spring. It was sent from JMB himself. Never never ever change spring weights. They are the experts. Of course those self Saale experts can’t explain why the geniuses at Sig put a red DAK mainspring in a 225a1 and not in a 228, 229, etc. They had a bin full of springs and put them to use. Yea, straight up geniuses.

Whoever claimed his 320 wouldn’t run on steel. If true which I doubt then something is wrong with your gun. Or it’s a lie.

100 bucks, I supply the steel cased ammo, if it won’t shoot you win a hundred bucks. If it runs I win a hundred bucks. Pretty simple and no one would be dumb enough to take this bet.

People can say what they wish. I’m going to keep shooting it whenever I want to. The evidence of the claims that are always presented just are not there.

My P365 eats steel, aluminum, and brass cased ammo with regularity.
I prefer the brass stuff, just cause that's what I was weaned on. But have had no ill effects on the gun or shooter when I run cheaper stuff through it.

The lacquer melting and causing steel cases to stick is a myth. I recall a thread a while back where someone used a blow torch on a steel case and nothing melted.

Just so I am Crystal Clear, I posted responses from two separate SIG CS reps.
The original guy who was complaining that his P320 wouldn't run steel, said that he sold that P320 and bought an M&P.

I shoot steel case all the time in my guns. My thought is if it breaks my extractor I've saved enough money to buy a new one and swap it out. So far in my 229 I've ran about 3000 rounds of wolf with no issues.