More Information Needed

For safe, accurate and reliable information about a gun’s proof marks, email the proof house in the country of the gun’s manufacture.
For safe, accurate and reliable information about a gun’s proof marks, email the proof house in the country of the gun’s manufacture.

These days what my reader correspondence principally boils down to is communications from individuals who need more information. Evidently they can’t get it anywhere else. But often in trying to help them, I find myself the one needing more information, because many of their communications are so sketchy that they leave out many important details that I need to give them an accurate answer. This is exacerbated by those communicating via super-short cell phone emails and especially texting. It then takes several back-and-forth emails to dig out the information I need. And these individuals basically want all of this time on my part for free. 

One of the biggest areas involves contacts from readers who own or recently have purchased, inherited or been given so-called vintage shotguns. By definition these are shotguns that are more than 75 years old, with many not having been manufactured in the US. Most of the readers want to know what US-made shotshells are safe to shoot in such guns. To help these individuals, I need to know the particular gun’s name and country and date of manufacture. I also need to know its gauge, chamber length and actual bore diameter and what kind of steel it contains. I almost never get all seven of these pieces of information, because the readers simply don’t know. 

And so here is my basic answer: Shooting modern US factory-made shotshells, especially hard shot types like steel or HEVI-Shot, in old shotguns is a recipe for gun damage and/or personal injury. Vintage shotguns, which in the science of metal fatigue are actually classified as antiques, were never designed to handle the peak chamber pressures and the quick rise over time to those peaks created by today’s modern smokeless powders. I don’t care if such firearms were nitro-proofed many years ago for smokeless-powder loads. The smokeless powders and internal ballistics are no longer the same. And neither are the velocities. Older loads basically produced lower pressures and were much slower than current ultra-high-velocity US shotshells. And if the antique shotgun in question was never nitro-proofed, it absolutely must be in order to set the stage for the possible safe shooting of modern shotshells in it. 

Now, despite these facts, the love that some shotgunners have for very old shotguns, especially those with Damascus barrels, results in them abandoning risk management and shooting modern loads in the guns anyway. And that’s why nearly every year I’m consulted for my expert-witness services in cases where vintage shotguns have ruptured or blown up from shooting modern loads in them.

If you want accurate information about your shotgun and safe ammunition for use in it, I advise that you go directly to the manufacturer and/or the gun’s owner’s manual. If you want proofing information and the gun was made overseas, google “CIP” and you can find information about the proof house in the country where your gun was likely proofed and where to send the gun to be re-proofed, if needed. A particular country’s proof house is an excellent source of information on safe ammunition practices for specific shotguns. Never rely on word-of-mouth information, no matter who it comes from. Get details from the manufacturer or proof house directly. 

The second big area in terms of requesting information involves readers asking for my interpretation of proof symbols stamped into shotguns, modern and vintage. Many such inquiries begin by the reader telling me his/her interpretation of the proof marks. Well, I certainly don’t claim to be an expert on the myriad proof marks out there on the different guns of foreign manufacture. I have found most readers’ interpretations of proof marks to be incorrect, because they’ve originated from assumptions and/or hearsay. Big mistake. My advice is to never self-interpret proof marks. For safe, accurate and reliable information, email the proof house in the country of the gun’s manufacture. 

A third big area of inquiries is in regard to reloading recipes. Almost all of the questioners assume that I have recipes for them for free. This is likely because there is free reloading-recipe data published by powder companies. There are also free recipes available in chat rooms and forums on the Internet. The initial problem is that while the powder-company recipes are completely reliable, the recipes bandied about in chat rooms and forums are decidedly not. That’s because the latter typically have not been fact-checked, are relayed as hearsay and/or have been plagiarized—often incorrectly—from copyrighted sources of reloading data.

Many shotgunners simply do not understand or appreciate all of the time and expense necessary to work up reloading data in accordance with SAAMI procedures and methodologies to yield statistically reliable results concerning velocities and pressures. We’re talking about thousands of dollars of electronic testing equipment, thousands of dollars of components—to purchase and store—and thousands of hours of time to assemble loads and empirically test-fire them in correct sample sizes in SAAMI-compliant testing equipment. Given all this, I cannot—nor can anyone unless they’ve won the lottery—afford to work up and provide non-plagiarized reloading data for free. The powder companies can, since they get back the costs of data development by selling powder, as do certain reloading-component mail-order suppliers. 

A less-frequent—and frankly frightening—request for reloading information comes from those who have decided to work up their own reloading data using only a chronograph to test velocities. Big, big mistake! The velocity of a shotshell load cannot be interpreted as an accurate indicator of chamber pressure. Anyone working up a reloading recipe using only a chronograph and assuming that if the recipe measures a reasonable velocity it must also possess a safe chamber pressure is absolutely playing with fire. The first big problem is that most home chronograph setups do not accurately measure shotshell velocities; they are designed for measuring single projectiles, as in bullets, not the foot-long shotstrings of shotshells. Second, there is no relationship between how velocities are measured and how pressures are measured. 

Always be safe. If you want to go the DIY route for shotshell-reloading data, go to for publications listing the various testing equipment needed, how to correctly set up and operate this equipment, and supply sources. 

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SSM 2309

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1 Comment

  • I agree completely Tom. I have spent many hours at the Birmingham England Proof House. I am not aware of any US loaded factory shotshells that pass British Proof. I have contacted one US manufacturer of a very popular 1 oz 12 gauge target load, that is commonly used by owners of older British side by sides, and was informed by the ballistics engineer that pressures of the load commonly reached 12,000 PSI. Basically a Proof load for old British guns. Obviously this is a very dangerous combination.
    Keep up the good work.
    PS. I frequently shoot nitro reproved British hammerguns from the late 19th century using powder manufacturers load data in the 4,000 to 5,500 PSI range. They are incredibly beautiful and effective, on both game and clays.

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