Gunsmithing: Shotguns. Patrick Sweeney
Читать онлайн книгу.automatic ejectors and shells we would recognize today. Or, for the real technology buffs, pumps and semiautomatic shotguns. And all the newest technology used smokeless powder. Reloaders had to try to keep up, switching from black, to semi- to high-bulk to smokeless powders.
Proper testing meant using a known ammunition. This Boulange chronograph that Fabrique National used to use is now on display. It took a crew of technicians to use this, test the firearm, and record and calculate the results. It's much easier today. Hooray for electronics!
One legacy of the change from black to smokeless is so puzzling and arcane that many shooters don't even try to follow it: the “Dram equivalent.” Many shooters simply go by brass height. “I need low brass” or “Pheasants take high-brass shells” and go with what they learned as kids. The convenient measure of black powder for shotgun was the dram. Certain combinations of powder and shot were found over time to most efficient, and the ammo makers settled on them. The “Three dram” load was 3 drams of black powder (obviously) and l-⅛-ounce of shot. If you think the choices today were vast, you should look into the catalogs of a century ago. It was common for hunters then to have the ammunition factory custom-load their ammo. If you ordered the minimum number (500, 1,000, 1,500 shells) you could have any safe combination of powder and pellets size and weight. If you thought that 3-½ drams of powder and 1-¼ of No. 4 shot was death on ducks (it was and still is) you could have the plant custom-make you enough to get you through the season.
When smokeless powder showed up, you couldn't just shovel three drams of it into a case or you would blow up any gun it was fired in. So the ammunition plants came up with the transitional “Dram equivalent.” By explaining the power of their shells in the language familiar to their customers, the ammunition makers planned to move completely out of the black powder business. What measuring scale was supposed to replace it? I'm not sure anyone knows, because the “transitional” measuring system is still with us over a century later.
And what a century it has been. Some things haven't changed much at all. Hunters still don't lead racing ducks and geese enough, and agonize over shot size and pattern density. Other things have changed radically. A pair of duck hunters camouflaged to their eyebrows, launching a duck boat from the trailer at the back of their SUV would be akin to men from Mars if seen by a duck hunter a century ago. And the radio-controlled paddling decoys? Wondrous stuff.
One good thing about the transition to smokeless powder was that it left us with a high-capacity hull and compact propellants. By using the extra space for cushioning, the shot-shells of today give their pellets a smoother ride than shotshells did back then. With the excess space that used to go to black powder freed up, the wad could be re-designed to protect the pellets. It also made possible larger payloads, which used to be devoted to extra pellets. Before the switch to steel shot, shotgun shells could be had with nearly 2 ounces of shot in them. Now, with the bulkier steel, payload weight is back down to what it was a generation or two ago. Again, the capacious hull gave designers, hunters and reloaders the room to work with.
When the Army adopted shotguns for use in the trenches, they adopted a new finish, Parkerizing, and full-length brass shells. Both the guns and the shells are now prized collectibles.
Oh, and the low and high brass? Another holdover, from the days of paper shotshells. Shells used to be assembled from paper tubes, base wads and crimped-on brass rims. The higher brass was for one of two reasons. The optimists held it was to keep the hull together under the higher pressure of a hotter hunting load. The pessimists felt it was simply a sales gimmick to get people to pay a lot more money for shells that only had a little more shot and powder in them. Today shells are made of plastic, and are molded or formed from a single piece. The brass (actually brass-plated steel) is there solely for the extractor to hold on to. Each type of hull made by a manufacturer has the same strength, regardless of how high the brass is. Some don't even bother with a brass rim, and have a plastic hull with a steel washer inside as support. If you are reloading, use what works and what the reloading manual suggests. If you are reloading but aren't using a reloading manual, get one and read it.
In the time before plastic the only way to ensure a water-tight cartridge was to make it from brass. The all-brass cartridge (left) is very expensive. For most uses, paper (2nd from left) worked just fine. Then came plastic. The high base is a factory indication of high velocity or heavy payload.
CHAPTER 3 Tools, A Place, and Practice
“Give me a place to stand and a lever long enough, and I can move the world” Archimedes
Give me a comfortable bench and enough light and I can take apart any shotgun and fix it. If you are going to work on your shotguns with any comfort you are going to need a place to work. Something a little larger and more sturdy than your lap is required. I have disassembled, cleaned, repaired and inspected shotguns with no more than a shop apron spread over my lap, but it wasn't by choice. You bachelors out there, do not get too attached to using the kitchen table. As soon as you find someone willing to put up with you, the kitchen table will become forbidden territory for gun work. Besides, do you really want the lubricants, solvents and powder residue working its way into your food?
Your workspace must be well-lit. The overhead fluorescent light gives good tight, and the white watt next to the bench adds an even reflection. The dehumidifier next to the bench is a good idea in some climates. Arizona residents need not bother.
First, there should be light. You can't work in the dark, and you can't work very well in the typical gloom of a basement, garage or spare room with only a centered ceiling light. A fluorescent fixture over your bench will fill the area with even light, without being too bright or hot. You'll need additional light, in the form of a flexible desk lamp. The desk lamp can be positioned and angled to shine directly into an area as you're working. Rather than fish around inside a receiver by Braille, you can shine the desk lamp into it and see what's going on.
You need a sturdy bench. The bench can be in a spare room or large closet, in the basement or the garage. It should be solid wood, not particle board. You can build a bench from lumber or heavy-duty steel shelving. One of my workbenches is made from lumber. It came as a ready-to-assemble kit from one of the “big box” stores. I also used shelving rated for 1,500 pounds per shelf, and stiffened the tops of both benches by laminating plywood to them. The particle board shelving that came with the steel frame is sturdy enough to hold things, but not sturdy enough support a vise. You should have a vise. A solid vise holds parts securely while you are filing on them, measuring them or using a tap or wrench on them. A good vise is a more solid arrangement for holding parts than the strongest person you know, and you don't have to worry about missing the part and hitting your buddies hands if the part is in a vise.
In addition to the overhead light, a flexible desk lamp adds light just where you need it. Notice the fire extinguisher on the end of the bench. Keep it close at hand when soldering.
Bench height and vise height are important. The bench should be high enough that its working surface is a couple of inches above your wrist when you stand next to it. If you have to bend over to grab something off of it, it is too low. Vises are designed to stand on top of a bench of the proper height. Depending on your height, you may have to vary the height of the bench when you assemble it. At the proper height, you do not have to bend over even the slightest to pick something up off the bench, or to file something in the vise. The easiest way to find the correct height for YOUR bench is to work on a bunch of different ones and see if they