Editor’s be aware: Nick Charney is an engineer by commerce and a self-taught shotshell maker. He works with Apex Ammunition, serving to to construct their TSS, metal, and TSS-steel blended hundreds. This text was compiled by Charney with assist and experience from the shotshell engineers at Apex.
Attributable to its density—18.1 g/cc (grams per cubic centimeter)—TSS (tungsten tremendous shot) is an environment friendly killer of turkeys, waterfowl, upland birds, and predators. The heavy weight of TSS is leveraged to make use of smaller pellet sizes than lead, bismuth, or metal, delivering denser patterns downrange whereas growing penetration and vitality on the goal. The smaller pellets additionally scale back wind resistance, which causes all shot to lose velocity, and vitality. The result’s a pellet that maintains its vitality longer with out dropping its form (as a result of it’s so laborious), creating extra constant patterns and clear kills—assuming shooters maintain up their finish of the discount.
In fact, the lethality of TSS comes at a price. At the moment the worth per pound of the non-toxic shot is round $45 in comparison with $36 per pound for Hevi-Shot (12 g/cc), $15 to $20 for bismuth (9.7 g/cc) and $2 for lead (11.34 g/cc) and metal (7.8 g/cc). It’s the most costly shot ever engineered: you may pay over $10 per shell. However its effectiveness is the ultimate. And there are steel-TSS stacked hundreds which are a way more inexpensive (round $1.40 per shell) means for hunters to shoot tungsten.
The Primary Constructing Blocks of TSS
A normal rule of TSS load growth is to take a lead pellet and scale back the shot measurement by two to 4 sizes relying on the quarry. For instance, a No. 2 TSS pellet will be an efficient predator spherical as in comparison with a BB lead load, and No. 9 TSS is a typical alternative for turkey hunters in lieu of a No. 5 or 6 lead. There are lots of efficient TSS shot sizes for all authorized recreation, however whenever you start constructing a tungsten load, that is the primary hurdle to clear.
Climate and area of the nation, in addition to the seasons for which animals can be most outstanding, is a predominant think about load growth. For turkeys, producers choose a pellet measurement from 7½ to 10, though 9s are the most well-liked. Waterfowl fall inside the identical pellet vary, however the simplest load depends upon the scale of the hen and time of yr (waterfowl develop down feathers later within the season, making pellet penetration harder). Upland birds may also be taken with the identical shot sizes. For predators, the commonest shot sizes are BB, 2, or 4, though 2s are the most well-liked. For hogs or anybody who run canine on deer (the place authorized), BB is the commonest attributable to its large knockdown energy and skill to penetrate disguise and bone.
To offer you a greater visible of the effectiveness of TSS, I ran some frequent pellets sizes for capturing TSS, lead, bismuth and metal on waterfowl, turkeys, and upland birds by way of a ballistics software program program. Pay shut consideration to the column “Vitality Density on the Goal” above. (Vitality density is vitality divided by the cross-sectional space, or floor measurement.) Basically, it lets you evaluate the vitality delivered on the goal as if all of the pellets within the desk had been the identical measurement. The U.S. Fish and Wildlife Service carried out a research the place they shot greater than 4,000 mallards with varied hundreds in a managed surroundings and decided that an vitality density of 235 ft/lb./inch squared killed geese over 95 % of the time. (Sadly, that research just isn’t printed on the web, so I can’t share a hyperlink to the outcomes.)
For penetration, the hundreds within the desk had been examined in 10 % ballistics gel (10 and 20 % are normal ballistic gel densities). It takes about .5 inches of gel penetration to kill a dove. For geese, it’s 1.5 inches, and a couple of.25 inches for geese. In fact, that may be subjective from hen to hen, relying on quite a lot of elements. However typically, these penetration depths lead to a deadly load.
Balancing Bore Diameter with Shot Dimension
The subsequent variable for ammo makers is to find out what gauges the shotshell can be accessible in. Smaller gauges carry smaller payloads, but in addition restrict the shot sizes that can be utilized attributable to bore diameter. When too massive of a pellet is utilized in a smaller bore, an impact often known as “bridging” can happen the place two or extra pellets turn out to be interlocked as they journey down the barrel. When this occurs with pellets as laborious as or tougher than the metal barrel (metal shot, TSS, and nearly all tungsten shot alloys), it may possibly injury the gun or choke tube. For shot softer than metal, resembling lead or bismuth, the lead can deform or the bismuth can fragment, creating inconsistent patterns. To maintain TSS hundreds protected, BB is the biggest shot measurement utilized in 10 and 12 gauges with No. 2s in 16 and 20 gauges, and 4s in 28-gauge. Within the .410-bore, it’s troublesome to ship a viable payload with something bigger than 7½s. However when you completely stack them on high of one another so bridging can’t happen, bigger pellet sizes might be used within the .410. The important thing takeaway? Balancing bore diameter with shot measurement and accessible payloads creates the premise for the event of a viable TSS shotshell.
Which Shotguns Can Be Used with TSS?
Since TSS is such a tough pellet, it can’t be shot by way of Damascus metal barrels, or older weapons not manufactured with trendy low carbon metal (solely bismuth and Kent Tungsten-Matrix are protected for such smoothbores). Whereas many weapons from the Forties on had been constructed with the sort of metal, they don’t seem to be marked for metal shot as a result of lead was nonetheless authorized. It remained the dominant pellet materials attributable to density, value, and availability, and there was no must mark the barrel for metal use. Most firearms produced after the lead ban are marked for metal use or “proof.” Nonetheless, many weapons made previous to that period can safely shoot metal and TSS.
With any firearm, it’s essential to evaluate the situation, most payload it may possibly deal with, and its constructed supplies to find out whether it is viable to be used with TSS. A main instance is the unique Browning Auto-5 and whether or not it has a Belgian- or Japanese-made barrel. The latter was made from a stronger metal alloy able to dealing with tougher shot materials. As a precautionary measure, it’s best for older firearms to be inspected and evaluated by your native gunsmith prior to make use of.
Along with assessing older weapons, modern-day firearm manufacturing is taken under consideration based mostly on gun tolerances, in addition to the kind of motion used (single shot, break-action, pump, or semi-auto). There are quite a few firearms producers that construct shotguns. Every one has its personal design and specs, so when ammo makers are mass producing a shotgun shell, we should guarantee that it’ll cycle by way of as many of those weapons as doable. For instance, the corporate I assist construct TSS shotshells for, Apex Ammunition, predominately roll crimps their rounds for a customized shell size, due to that, we have to assess whether or not the shell size of an expended hull will reliably eject from right this moment’s semi-autos.
Balancing Payload Dimension with Smaller Pellets
The core density of TSS can energize smaller bore weapons such because the 20, 28, and .410, however there are limitations to payload weight and shot measurement. Smaller TSS pellets might be packed right into a 3-ounce-plus load in a 12-gauge or over 2 ounces within the 20. However it might lead to a slowed muzzle velocity (between 700 and 900 fps) and will in the end injury inner steel parts of the gun, just like the recoil spring and the bolt, as a result of weapons aren’t designed to deal with the excessive chamber pressures that may be created by firing such heavy payloads. Bigger shot sizes in smaller bores can’t obtain the identical cost weight as a result of the pellets are so large. That creates more room between pellets, so the general pellet depend suffers as properly.
Weighing the Payload Makes TSS Extra Efficient
With smaller TSS pellets, resembling 7½s, 8s, 9s, and 10s, ammo makers must be extra exact of their measurements attributable to pellet settlement. Pellet settling creates a possible for extra voids between pellets. The voids can throw off your shot cost, making a heavier payload, which may exceed SAAMI strain requirements, degrading patterns and probably damaging your gun. There is no such thing as a extra correct technique to loading shot costs than a scale. Most trendy business loading is finished by volumetric measurement utilizing a pneumatic in-line loader. Nonetheless, small TSS pellets can settle in another way (so can metal, lead, and bismuth) below the amount loading technique, probably leading to inconsistent shot costs. The burden-based technique gives a level of accuracy inside plus or minus one pellet each time.
How TSS Shotshells Are Manufactured
Roll crimping TSS shotshells permits for a customized tailoring of the shell size to the payload. Fold crimping reduces the necessity for an overshot card (positioned on high of the shot cost earlier than roll crimping) however wants a precise quantity of parts contained in the shell to crimp it correctly. You additionally should think about crimp depth. When you crimp the shell too deeply, it may possibly trigger the chamber strain to extend as a result of the cost should push open additional plastic. Utilizing a hand-trimmed hull permits for a clean roll crimp and customized size to make sure correct biking in semi-autos and pumps. It additionally higher protects stray pellets from escaping the wad and contacting the barrel throughout the firing course of.
Since TSS is the toughest pellet materials in shotshells, the barrel and choke want safety from it to stop scoring and injury, simply because it does with metal shot. To perform that, a high-grade wad should be used. It may well stop the pellet from contacting the barrel, and ought to be versatile sufficient to soak up the influence of the pellets hanging the wall of the wad in order that they don’t penetrate it. The wad additionally should create an hermetic strain seal contained in the barrel to attain the correct velocity. The tradeoff is that these wads are a lot thicker and heavier than those utilized by softer metals like lead and bismuth. TSS wads create increased chamber pressures as a result of there’s extra friction between wad and barrel. As a result of the wads are additionally heavier, TSS shells should both have diminished payloads, velocities, or various powders to regulate the burn price.
Why Some TSS Hundreds Want a Polymer Buffer
Small TSS pellets—7s to 10s—have to be buffered to carry out correctly. TSS is tough, so not like comfortable lead shot, it received’t take in the vitality of one other pellet because the payload travels down the bore of a shotgun and out the muzzle. Relatively, the pellets bounce off each other. Think about throwing a handful of bouncy balls down a hallway—that’s what unbuffered TSS seems like exiting the muzzle of your shotgun. Bigger TSS shot doesn’t want a buffering agent as a result of it’s so heavy.
Controlling the Burn Charge of TSS
The powder, or propellant, is one other key part within the design of TSS. Shotshell powders are primarily small flakes or balls, they don’t seem to be extruded like rifle powders. How briskly powder burns impacts chamber strain and shotshell velocity. There are two kinds of powder: single base (which accommodates nitrocellulose) and double base (nitrocellulose and nitroglycerine). Most trendy shotshells use double based mostly powders, that are both ball or flake type powders that improve vitality. The ratios of those chemical compounds enable the powder to be tailor-made to a particular burn price. The scale of the granules, and their relative floor space have an effect on the burn price as properly, making a managed explosion to make sure consistency with every ignition. The result’s a payload, shot sort, inner parts, and burn price that come collectively to create a viable velocity (1,050 to 1,500 fps for TSS, relying on what sort of recreation you’re looking) whereas additionally balancing chamber pressures (roughly 10,500 to 14,000 psi) for a protected and efficient spherical. Too scorching of a powder burns too rapidly and creates extreme chamber strain; too sluggish and the specified velocity can’t be achieved.
Primers all sometimes comply with the identical design however ignite a flame at various temperatures. Waterfowl hundreds use a warmer primer as a result of they’re typically shot in chilly environments and should burn sooner to extend velocity for main transferring targets. Cooler primers are used for turkey hundreds attributable to hotter spring temperatures, and for a slower burn as a result of the payload is heavier (as much as 2½ ounces). You additionally don’t want as a lot velocity since you’re aiming at a longbeard, not main a mallard.
Learn subsequent: Lengthy-Vary Turkey Capturing Actuality Test: Right here’s What TSS Patterns and Penetration Actually Look Like at 70 and 90 Yards
Balancing primer ignition temperature impacts each how the propellent is ignited and the speed at which it burns. That may drastically have an effect on chamber pressures by hundreds of psi. The hull and base wad design may affect burn charges, but it surely’s minimal. Excessive brass (16mm or bigger) bases are sometimes paired with magnum hundreds as a result of powder cost they create.
How TSS Hundreds Are Examined
Creating any product requires thorough testing. That is very true of shotgun shells. As soon as a shell is created, it undergoes a sequence of evaluations to ensure it’s 100% protected and constantly performs to the specified stage. A method it’s security examined is by using an impartial third-party evaluator to measure chamber pressures and velocities (there are skilled firms that conduct these assessments). Chamber pressures will be measured utilizing a piezoelectric gauge—which makes use of a crystal to emit {an electrical} cost—drilled into the aspect of a barrel and mounted flush with the barrel wall. A sequence of 10 shotshells are fired to show the common chamber strain doesn’t exceed the SAAMI requirements and verifies the speed falls inside a protected vary for the gauge. Any time a number of supplies change in parts, this course of is redone to make sure there are not any variances in efficiency and high quality. Counting on an out of doors get together to confirm the information provides one other layer of security testing. It additionally ensures the shotshell’s outcomes are constant in several areas and capturing environments.
After the shotshell is developed and examined, it’s patterned. Testers sample shells from a bench, capturing a stagnant goal at varied distances from 20 to 50 yards with quite a lot of totally different shotgun and choke mixtures. The purpose is to supply a sample that drops not more than 10 % each 10 yards from 40 to 70 yards. They’re additionally verifying that as every sample begins to open, it holds a uniform two-dimensional dispersal. If the sample doesn’t meet these requirements, engineers return to the drafting board.
If it passes, it’s on to the penetration check. That is carried out utilizing an FBI-grade ballistics gel block that fashions tissue injury of animals as shut as doable (there isn’t a substitute for capturing wild recreation). The shotshell is fired right into a block at varied distances to gauge wound channel sizing and penetration in comparison with its examined velocity. With TSS, particularly within the bigger shot sizes, you may obtain anyplace from 3 to six inches of gel penetration or extra.
As soon as all the event and testing are full within the lab, it’s time to take it to the sector and assess efficiency below looking situations. No product is full with out rigorous area testing within the situations through which will probably be relied upon. As talked about earlier, the environmental elements can play a considerable function, particularly with the number of hotter or cooler burning powders and outside temperatures. Most sluggish burning powders utilized in heavy magnum turkey hundreds don’t function properly below extraordinarily chilly temperatures (that is subjective based mostly on the primer and powder of the shotshell). For waterfowl, a warmer burning powder is used with a smaller payload to fight chilly.
Retailer Your TSS Hundreds for Optimum Efficiency
If it’s going to be extraordinarily chilly at evening, it’s all the time smart to carry your shotshells inside when you’ve got the choice. That helps defend the efficiency of your TSS. At Apex, we run a frozen load check, putting rounds within the freezer in a single day and firing them to make sure the primers ignite. Hundreds are additionally distributed to pick out hunters for in-the-field testing previous to launch. A number of personnel in various climates and areas will put them to the check in essentially the most excessive environments. Afterward, suggestions is integrated from the workforce and ultimate changes are made earlier than the primary pallet is shipped.
