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Old Guns and Pressure by Ron Jones

The low–pressure RST ammunition in this photo is equal or superior to all the other 20th–century ammunition in the photo… and it performs at minimal breech pressure, which is optimal for vintage guns.

ou, and you alone, must take total responsibility for your decision to shoot an old gun, and for the selection of appropriate ammunition. Do not shoot the gun if you are not willing to assume all risk. Selecting low–pressure ammunition does not automatically guarantee shooting it in your unique old gun will assure a safe outcome. Aging guns undergo a certain amount of metal fatigue, and no one can determine with absolute certainty that critical parts will not fail. If you are not willing to assume all risk, do not shoot the gun!

You’ve finally decided to take granddad’s old gun out of the safe and shoot it… or maybe you spotted an old Remington, Browning, Winchester or Savage in the used gun rack at “Endless Guns” and wondered whether it would be safe to shoot. You’ve heard all the stories about old guns blowing up, maybe even read Michael McIntosh’s proclamation it is not whether a Damascus gun will blow up but when! Old guns were either designed for black powder or for smokeless–powder loads in paper cases with cardboard and fiber wads. Since that ammunition hasn’t been available for decades, maybe you should just make grandfather’s gun into a wall display in the den or just forget about buying that old L.C. Smith, Fox or Ithaca Double.

I’m not here to proclaim any gun safe. Only a trusted gunsmith can make an educated guess as to the safety of a particular firearm. And even then, there is some likelihood, however slim, he/she may miss something. The ultimate responsibility is yours. Even if the gun was made after 1900 by a reputable manufacturer, was not abused by the previous owner(s), and your gunsmith proclaims it safe to shoot with appropriate ammunition, you still must be aware you alone bear all the responsibility for an injurious event.

Appropriate Ammunition

The overwhelming cause of catastrophic gun failure is a barrel blockage, and the ultimate responsibility for preventing that occurrence always resides with the shooter. If the gun was made during the first half of the last century, I’m sure you are aware the manufacturer intended it to be used with paper–cased, smokeless–powder ammunition. If the gun was made in the first quarter of the last century, it very well might have chambers shorter than 2¾″.

Ron and Abby

Here I am with my dog Abby on the marsh with a vintage gun and low–pressure ammunition. Abby will attest none of the misses were the fault of the gun and ammunition.

Since you’re reading this article, you may already be aware of the dangers associated with shooting today’s plastic ammo in some early guns. While writing a review of the Remington Model 10 pump–action shotgun made between 1908 and 1929, I discovered Remington had some reservations about shooting heavy charges of nitro powder in barrels made with their standard “Remington Steel.”

According to the 1909 catalog, Remington recommended the purchaser invest in the optional “Ordnance Steel” barrel at an additional cost of $6.75. The catalog states “…the tensile strength of the ordnance steel is 110,000 lbs, and the elastic limit 60,000 lbs. This being greatly in excess of any strain to which shotgun barrels are subjected with reasonable loads of nitro powder.” If Remington was suggesting there might be some safety risk associated with shooting heavy charges of paper–encased nitro–powder loads in their standard barrel and if other manufacturers of repeaters were using a comparable steel in their guns, would it not be prudent to use low–pressure ammunition in all of these guns?

Another concern I have is not knowing whether a previous owner may have shot that old 1925 gun with high–pressure, full–length shotshells or, even worse, a 3″ magnum. They could have stressed the gun to the point where it is no longer safe to shoot. Is it even worth taking the chance?

Dealing With The Issues

I own a number of guns made in the last two decades and, for the most part, they reside in the back of my gun safe. I enjoy shooting guns made in the first half of the 20th century, and most of mine were made before 1942.

If I have any doubt whatsoever about how the gun may have been treated in the past, I have a gunsmith check the integrity of the barrel(s) and action. There can be surprises not obvious to the casual observer. If the gun passes the gunsmith test, I select or handload low–pressure ammunition appropriate for the age of the gun. Choosing appropriate ammunition does not guarantee a barrel or breech bolt will not fail, but it reduces the odds.

Unless you were a subscriber to Double Gun Journal over a decade ago (Vol. 13, Issue 2, Summer 2002), you may not have been aware of a series of research articles by engineer and vintage gun enthusiast Sherman Bell. Sherman liked to hunt waterfowl with his old guns and was perplexed by all the claims and counterclaims being made by noted authorities regarding their safety with available ammunition. His primary concern centered around the safety of shooting smokeless– powder loads in guns intended for black powder, but the results are instructive for all of those shooting vintage guns. Sherman also looked at the dangers of shooting long cases in short chambers.

Let’s look at chamber pressures first. Some claimed even if smokeless powder produces the same breech pressure as a black–powder load, the smokeless–powder load raises pressures farther up the barrel where the barrel walls are thinner and more vulnerable. Others claimed just the opposite. The first camp claimed low–pressure smokeless–powder loads would “blow your forend hand off,” while the second camp claimed they would “blow your nose off.”

Sherman also looked at shooting 2¾″ and 3″ smokeless shells in guns with short chambers. Presumably, this practice would blow off both your fingers and your nose. Sherman was an engineer with a bent for research, so he teamed with Tom Armbrust of Ballistic Research Labs to set up their own pressure tests. What Sherman discovered changed the way many of us look at using low–pressure smokeless–powder loads in old guns with both Damascus and nitro–steel barrels.

Sherman concluded all of the powders he tested, including black powder and an assortment of quick, medium and slow–burning smokeless powders produced peak pressures very near the breech. In fact, the best smokeless loads produced pressure curves that were safer than black powder at all distances from the breech. With these 12–gauge tests, Sherman had no problem duplicating black–powder breech pressures with an assortment of Hodgdon, IMR and Alliant powders.

When testing long cases in short chambers, Sherman concluded if the load in a 2¾″ case was otherwise safe to shoot in a 2½″ chamber, the slight pressure increase he measured (approximately 1,000 p.s.i.) due to the short–chamber effect was not significant enough to pose a safety issue. He wasn’t able to find a load that demonstrated a pressure increase exceeding 1,000 p.s.i. until he shoved a buffered bismuth 1½–ounce 3″ magnum handload into a 2½″ chamber. That load ripped the crimp area from a few of the cases and actually raised pressures from about 11,500 to 12,950 p.s.i. Not nearly enough to damage the gun but an increase of some significance nonetheless.

That revelation would never convince me to shoot 2 ¾″ or 3″ ammunition in guns with 2 ½″ or 2 5/8″ chambers, but it does provide some solace knowing if a previous owner had unwittingly ignored chamber length, and gun was otherwise safe to shoot with modern ammo, the experience did not place catastrophic stress on the firearm.

Factory Fodder

Damascus side-by-side

A lovely, fast–handling Damascus-barreled side–by–side and a box of soft–shooting shells like these from RST can create some beautiful memories.

If you are a subscriber to Shotgun Sports, you most likely are aware of RST Ammunition, as they are regular advertisers in this journal. This American company makes all their shotshells at their home in Pennsylvania, and they regularly pressure test to assure the ammunition you buy meets their pressure specifications. Their “Best Grade” product is made in 2½″ cases, so short chamber issues are addressed. If your gun doesn’t have short chambers, nothing is lost, because patterns will be equal to those produced by full 2¾″ cases. Their prices are reasonable, and they can have a case or two shipped right to your door.

I’d be remiss if I didn’t tell you Polywad also makes low–pressure ammo in short cases, so you may want to give Jay Menefee a call to get the specs and a quote on his products.

Many old guns will safely shoot modern plastic ammunition without a hiccough, so why not use the stuff that is lower–priced and readily available at the big box stores? You certainly can do that, but it’s my belief low–pressure ammunition will reduce the stress on a gun that is already 75–100 years old. It makes sense to me a gun hammered with 11,000 p.s.i. breech pressure will be stressed more than one coddled with 7,000–p.s.i. ammunition.

Low–Pressure Loads

“Okay, Ron, you’ve convinced me I probably should be shooting low–pressure loads in any gun made before 1942, maybe even before the introduction of plastic cases and plastic wads circa 1960. So, what pressures should I be looking for?”

I use black–powder pressures published in my old Lyman handbook as a benchmark. Those were l.u.p. pressures recorded in a muzzle–loading barrel, but they can serve as a benchmark. Sherman Bell’s black–powder 12–gauge test loads in Federal Paper cases with card/fiber wads were a 3–dram, 1 1/8–ounce light load and 3¼–dram, 1¼–ounce field load. The first generated 4,700 p.s.i. at the breech, and the latter fire–belching charge gave a reading of 5,900 p.s.i. That is consistent with the old Lyman pressures at similar velocities.

Typically, I look for pressures between 5,000 and 7,000 p.s.i. It’s easy to find 12–gauge smokeless loads in that range, not too difficult to get 16–gauge loads that satisfy that criteria but a little trick finding 20–gauge loads with pressures below 7,000 p.s.i. I bought a mixed case of 16 and 20–gauge ammo from RST over a year ago, and they were good enough to give me the pressures of loads I wanted to purchase. I’m sure they would do that for anyone who calls. In 16 gauge, they have a 7/8–ounce load at 1,125 f.p.s. in a plastic case that produced 5,800 p.s.i., a 1–ounce load at 1,150 f.p.s. in a paper hull that produced 6,200 p.s.i. and a 1–ounce load in a plastic hull at 1,200 f.p.s. that produced 6,800 p.s.i. I’m sold on the paper–cased load, as it put down pheasants out to 35 yards with impunity and probably would do it farther downrange, but I never shoot that far away.

In 20 gauge, their Paper–Lite 7/8–ounce load at 1,150 f.p.s. produces a pressure of 6,700 p.s.i., and their 7/8–ounce plastic–cased load at 1,125 f.p.s. produces 7,200 p.s.i. Both employ modern plastic, one–piece wads. I find it instructive that RST’s Paper–Lite fiber–wad load produces 8,800 p.s.i. compared to 6,700 p.s.i. for the same cartridge loaded with a modern plastic wad. The Paper–Lite/plastic–wad loads were effective on pheasants in my Stub–Twist Flues inside 30 yards. The old Flues must have thought it had died and gone to heaven! I didn’t inquire about 12–gauge loads, but they must have multiple options in my recommended breech–pressure range.

Will these low–pressure loads kill waterfowl with bismuth (or an equivalent non–toxic) and large game birds like pheasants? The old market hunters took waterfowl by the boxcar with guns delivering muzzle velocities near 1,100 f.p.s. and breech pressures at or below the equivalent of 6,000 p.s.i. ’Nuff said!

New Products

I bought a bag of Claybuster’s CB0175–12 Winchester–style ¾–ounce wads and was delighted to discover the bag labeling actually is a four–page leaflet containing about 75 loads for this low–capacity 12–gauge wad. There were 55 loads for Remington cases and nine each for Winchester and Federal empties. I found 11 Remington listings below 7,000 p.s.i. using Extra–Lite, Red Dot, Clay Dot, Titewad and Clays powders. Seven of the Winchester AA/HS–case loads were below 7,000 p.s.i. using Clay Dot, Red Dot and Extra–Lite. Eight of the Federal Gold Medal loads dipped below 7,000 p.s.i. using the same three powders as listed for Winchester. That gives low–pressure reloaders recipes using Winchester, Federal and Remington primers.

Vintage skeet

An occasional round of Vintage Skeet with a classic gun can be special. Just keep the shot charge light, the velocity close to 1,100 f.p.s., the pressure below 7,000 p.s.i. …and don’t keep score!

I also grabbed a bag of CB1075–20 ¾–ounce Winchester–style Claybuster wads to see how they would perform. The loads on the back of the bag label included 20 offerings for Winchester 20–gauge AA hulls and 27 offerings for Remington RXP, Premier and STS hulls. Unfortunately, 8,000 p.s.i. was the lowest pressure listed in the two categories. There was one offering in a Federal case using Unique powder listed at 7,400 p.s.i. and two offerings in a Remington Unibody hull using 20/28 powder listed at 7,100 and 7,400 p.s.i.

If you’re looking for 16–gauge loads, I mentioned in a previous article you need look no further than Ballistic Products. In their The Sixteen Gauge Manual, 6th Edition, I counted 16 loads listed at 6,900 to 7,700 p.s.i. Most were a little higher than I would prefer, but you could make the argument I’m splitting hairs.

Another recent source of wads for low–pressure, light 16–gauge loads is Downrange (DR) Products. Their ¾ to 7/8–ounce wad, combined with Hodgdon loading data, makes very low–pressure loads in this gauge a reality for handloaders.

Semi–Automatics

Aware that classic humpback semi–autos produced before World War II were regulated to cycle paper–cased shotshells loaded with nitro cards and filler wads, I was optimistic when I ventured to the gun club to test my Remington Model 11. I positioned the friction rings in my 20–gauge long–recoil Remington for standard loads and fed it RST’s Best Grade paper and plastic 7/8–ounce shells. It cycled the rounds and spit out the empties like it had been tuned for these low–pressure offerings. I suspect it was.

I was somewhat less optimistic when I fed it my ¾–ounce Claybuster low–pressure handloads in Federal, Remington and Winchester cases, but the old Model 11 couldn’t tell the difference. These same loads would have turned my Beretta Teknys into a jam–o–matic, but America’s homegrown pre–war auto handled them with ease. Operating at 6 degrees Fahrenheit and a breech pressure as low as 7,400 p.s.i., the Classic Remington ejected casings with authority. Granted, spring tensions in the old guns can vary, so not everyone may be as lucky as I was.

Damascus Guns

I’ve discussed this in other articles, but it bears repeating. Those of us who shoot Damascus or stub–twist steel barrels do so knowing we are at somewhat greater risk of a barrel rupture than those shooting nitro–steel barrels. It is a risk we are willing to take, but we must use extreme caution in selecting appropriate ammunition with documented low breech pressures in short cases.

It’s good to remember pressure figures are averages taken from a test barrel with a particular powder and primer lot. There are an infinite number of variables in the shotshell–loading process that can impact the true pressure generated by your load in your particular gun. Ammunition or recipes listed as low pressure may, in fact, produce much higher pressures in your gun. That being said, I still like to know the ammo I’m shooting has the best chance of treating my vintage pump, auto or double shotgun with kindness.

Low pressure does not equate to low recoil. In truth, a low–pressure load using a heavier charge of a more progressive–burning powder may actually increase theoretical recoil slightly if the weight and velocity of the projectile (shot charge + wad) remain the same. Most low–pressure loads, however, achieve that end by reducing the weight and velocity of the shot charge. Both of these variables have a significant impact on recoil.

Is it breech pressure or recoil that causes old actions to shoot loose and the ribs on old doubles to separate at the braze? If you are concerned about the stress chamber pressure or recoil puts on aging steel parts, you just might want to consider shooting low–pressure, light–recoiling loads in guns more than half a century old. They also put less stress on aging body parts! Always keeping safety in mind, you can enjoy using your old guns.

Ron Jones is a retired pharmacist of 49 years who confesses his first love after family and God are shotguns and hunting. His first shotgun experience was his grandfather’s 1911 Ithaca Flues 20, and that experience nearly caused him to look for more pleasurable avocations. He admits to missing all 50 targets his father threw with their Remington hand trap, and the experience resulted in a headache which wouldn’t quit. But his love for guns, particularly vintage scatterguns, has remained with him in the ensuing 60 years. Our heritage is important. Preserving and embracing the values and traditions which our forefathers have handed down will enrich the experiences of those who follow. In some small measure, Ron hopes to contribute to that body of knowledge the younger generation embraces.

CAUTION: Read the notice and disclaimer on page 4 of this magazine. Always consult comprehensive reference manuals and bulletins for details of proper training, requirements, and procedures, techniques and safety precautions before attempting any similar activity.

NOTE: Pressures are often listed as “p.s.i.” or “l.u.p.” values. You may find different pressures listed for the same load in different handloading manuals. They are not the same. In general, p.s.i. values will be about 1,000 units higher than l.u.p. values. This applies to lead–shot loads only. There are often considerable differences between the p.s.i. and l.u.p. values with steel–shot loads. Also remember there can be differences in how loads act in various test guns and equipment that can also affect these readings and the values published.