This question crosses my desk with increasing frequency every year. Like a lot of things, if you need to ask . . . the answer is normally no, it is not a good idea. If a shotgun barrel is not tested with, or designed for steel shot, you are needlessly putting your barrel at risk. Maybe you do not care if you damage your barrel; in that case, blaze away.

Long-term use means you will likely have to buy a barrel. Not so with lead, where many thousands of rounds have no effect on a shotgun’s bore. When you use steel (today’s steel loads are normally Chinese made) you are using a product that is harder than old barrels and nearly as hard as modern barrels. Eventually, you will get some scoring and scuffing in your bore. Ammunition manufacturers have fought to try to find ways from keeping steel and other very hard no-tox products from embedding themselves into the wad and contacting the bore through wad slits. Their success has been limited. Buffering helps, reducing velocity helps, lowering shot size helps. Large non-compressible pellets slamming into your choke at 1200 – 1500 fps is a huge amount of stress to expect your barrel to absorb over time. There are handloading techniques, such as the use of Mylar wrap that work well. The problem is that they are not easily used in high-speed production of shotshells.

Steel is so much less dense than lead that larger shot sizes and higher velocities are the only way to get it to perform acceptably. This is the exact thing to which we don’t want to subject our barrels. The problem is more pronounced with good stack barrel and side-by-side shotguns, which use thin wall barrels to save weight.

Steel is not a huge safety issue, but there are some concerns. Steel rusts and attempting to shoot a welded together mass of pellets through your gun could mean a ringed barrel. Steel is also a problem if you bite into a pellet at mealtime, a boon to dentistry. Steel pellets embedded in trees have not found great favor with the timber industry, either.

Browning has this to day about steel shot damage:

“DAMAGE: In not all, but a number of instances a very slight ring will develop about 1-1/2" to 3" rearward of the muzzle. This ring is about .005 of an inch above the plane of the barrel, completely encircling the barrel. From our tests, we could determine no adverse effect on pattern or shot velocity because of this ring. Our conclusion is that the most significant objection, the slight ring, is entirely cosmetic. This 'ring' effect does not affect the function or safety of the firearm.”

I cannot speak for other individuals, but I know I have no interest in buying or shooting a shotgun with a ringed barrel, cosmetic or not. Steel and fine shotguns do not mix well; steel and vintage shotguns do not mix at all, as far as I’m concerned.

With the intermittent, unreliable availability of bismuth, there are only two viable choices for those seeking to protect vintage barrels while using no-tox shot today. They are Kent Tungsten-Matrix shotshells and the recently introduced Hevi-Shot “Classic Doubles” loads. Of the two, the Kent loads are closer to lead in density, 10.8 g/cc (lead considered 11.0 g/cc, showing as 11.35 g/cc on the periodic table). Both shotshell types are reviewed elsewhere, with the Kent shells being the current best of breed.

This is not meant to dissuade you from steel shotshells in modern screw-choked shotguns specifically designed for their use. Hopefully, it should give you a little food for thought before stuffing steel shotshells into an older, fixed choke shotgun that you want to keep in top condition.