Swaging tool design

Cat Whisperer, I believe Mr Corbin's early work with radial compression for swaging didn't prove out. Too much effort/cost to achieve the same result as with the axial technique. While it's true grease groves can be installed this way, there are dependable canneleur tools that will do this task at much less cost, I think. Also, there is the paper patch technique that by-passes groves entirely. As to casting a bullet and then swaging it, there is that basic fact that you will be "swaging up" a few thousandths. Its a mite difficult to cast a .358 lead bullet and then stuff it into a .358 swage die body as is: you would have to size it 'down' first. An extra step (as is using a cannelure tool). Another thought is velocity: why do you need high speed lead bullets? Keeping rifle lead under 1500fps and pistol under about 900 fps solves beaucoup problems. For greater speed, go with full jackets. I think, too, that each barrel throat is different and that requires, for those most demanding target shooters, a chamber cast of the 'neck-throat-initial land/grove area' be taken to use as a guage in designing the proper bullet ogive and cartridge OAL specifications. For the proper bullet weight/length, that will depend upon several other factors such as powder, bullet hardness, number of groves, type of lub, and so forth. The swager can only contol part of this "formula".
I reread those Corbin books every year or so and learn and relearn a lot each time. Some of his points slide by your attention until you run into a situation where you say to yourself " Hay. Why am I struggling trying to solve this problem by myself... didn't Dave have something to say about this somewhere?" I've found that spending 2 hours finding his words save days trying to reinvent the same wheel. On the otherhand I have used my equiptment to find alternative ways to skin the same cat, but rarely have improved upon other's work. I've never attempted to make dies thou, as I don't have the skills or capital equiptment for that exercise. A lathe and mill is just a start. 8)

Tim, Base Guards (BG) is a Corbin Product. They are moderately thin (.015" aprox) brass washers that are formed into a very slight cone shape so that when they are swaged onto the bottom of the bullet they become flattened and theryby expand outwards a few thousandths, making a bit better scrappers than the older type zink washers. Dave Corbin wrote a piece in one of the past isues of Handloader Digest (I think) on the equiptment, technique, and results. They are used in his 'regular' dies (you will need a BG punch, however), as an option, and he sells them by the bag, or he'll sell you strip copper and the BG maker kit so you can make them yourself.
I think that after you make a few bullet dies and punches and use them awhile you'll really appriciate the decades of development , and current availability of the broad range of supper accurate tools that are being offered by the Corbin brothers, and perhaps by 1 or 2 other places. The costs will appear high until you attempt to duplicate the capability. Then you'll see that those purchaced tools are quite worthwhile. But, there is nothing like first hand experience, and the resulting pride, in developing your own. 8)

You put the BG with the high side towards the lead core. The BG punch is flat faced, with an indent in the center of the face a few thousandths larger than the hole in the BG, and about 1/8" deep. As the BG is flattened downward during the swaging process to make the core into a bullet, a little lead is squirted thru the GB center hole, and is trapped by the indent in the punch's face forming a brad that holds the BG to the bullet's bottom. The size of the BG hole and the indent in the punch face depends upon the bullet caliber, but the .45's BG hole is about 1/16" or there abouts... it's not a big hole at all. The biggest benefit of BGs is that there is no need for lub, or lub groves. While the bullet can be pushed a little faster there is really no need for that benefit most of the time.
Concerning other older swaging tools on the secondary market: beware! some aren't worth your money or time. Always ask specific questions such as "what is the brand, when was it made, is the firm (person)still in business, Have YOU made any bullets with the set, are their ANY defects with any part (and if so what are they), is a certain type press needed, are you sure it's the caliber you stated, will you take it back if it doesn't pass my hands-on inspection?). Ebay, Gunbroker, and Auction Arms are sites to see what's available on the 'net. Gun list is a good place to see what's advertised in hard copy. Of course, Both Richard and Dave Corbin list some used equiptment on their sites thou neither really get very involved directly in this business of used/prior owned stuff. And, I've never seen an offer to sell (or buy) any swaging equiptment on this site YET. There have been many folks making and selling swaging tools since 1942, but very few exist today. In many cases the designs were flawed. Several of these poor sets are still floating around and those who own them now have no idea what they are really worth. On the other hand there are a few quality sets for sale, but don't assume anything befor putting your good money on the barrel. Unlike bullet molds, you can't afford to 'take a chance' when it comes to the much more expensive swaging tools. 8)