· Stick the short rod into the shortened case and chamber it, keeping the barrel elevated so that the rod doesn’t slide down the barrel and out the end.

· Cut off an appropriate length of lead wire — more on that later — wipe it lightly with oil and drop it down the barrel.

· Slide the long rod down the barrel.

· With the rifle’s butt pad on a solid surface (ideally, on a piece of carpet on a concrete floor), use your off-hand to hold the rod centered at the muzzle.

· Using good mental focus, hit the end of the rod with the hammer, being sure to strike the rod as straight-on as possible. Use mild blows because that’s all that’s needed and because they won’t flatten your hand if you miss. After each blow, re-center the rod in the muzzle with your off hand. The rod will proceed a bit further down into the bore with each blow. For most calibers, it’s easy to choose a rod diameter that is nearly a slip-fit into the barrel. Even with a slightly loose fit, there is no force applied to the rifling. Try it and you’ll see.

· The casting is completed when the rod no longer moves down with each blow and the rod tends to bounce upwards — the lead has filled all available voids and the long rod is now springing back in an elastic response.

· Unchamber the case and short rod, then tap on the long rod to remove the casting. Do this with the rifle flat on a rug, with ejection-port downward. This prevents the delicate precision casting from being damaged through a free-fall when it comes clear of the throating. Once it is free, just push it on down further until it falls out of the ejection port.

· If the casting is too short (e.g., stops prior to the end of the leade-cone), then do another with a longer piece of lead. It’s hard to give you a good starting point, given the variety of lead wire diameters and calibers. Play with it. It takes very little time, and almost no money, to make another casting using more wire. Always discard your rejects into the lead bin before trying for a replacement.

Rule — You really should have a 6" stainless steel machinists rule graduated in 10ths and either 50ths or 100ths of an inch. These are available from your local machinists’ supply store or from MSC at 800-645-7270 [Starrett #C303R-6 and MSC #86412731 @ $12.54 for the 10ths and 50ths rule or Starrett #C305R-6 and MSC #86412822 @13.26]. They are pretty hardly to do without for lots of jobs you’ll face as a reloader and caster.

Blade Micrometer — Although you can do some of the measurements with a regular micrometer, about the only way to measure the land-to-land diameter (down in the grooves of the casting) accurately is with a blade micrometer. These are also wonderful for load development for higher pressure loads (measuring free casehead expansion). In case you want one, try Sun Coast Tools at 800-872-2281 [Chicago Brand 1" mikes # 9950075 @ $147.35].

The next step is to make a sketch of the throating. It doesn’t have to be to scale, but it helps if it is at least roughly proportioned so that you can visualize the actual special, diametric, and angular relationships involved. The sketch should: show the measured chamber neck diameter; if there is a transition step from the caseneck to the rear of the throating, show its steepness and note its measured length; if there is a cylindrical portion prior to the leade-cone, show its measured length and diameter; show the leade-cone’s length; and measure and note both the land diameter (grooves in the casting) and groove diameter (major diameter on the casting) just ahead of the leade cone (if the rifle’s seen much use, the land-to-land diameter should be larger in diameter than those portions further toward the muzzle, but it is this rearward-most portion that your bullet must fit). Also measure and note the barrel’s bore and groove diameter closer to the muzzle, as described below. If you keep your sketch on a piece of paper about the size of a postal card, then you can use it as a protective wrap for your casting.

You’ll be able to get most measurements with a set of regular micrometers and your machinist’s rule, but there are four situations in which the blade mikes are a just the bee’s knees.

· Measure the Eroded Land Diameter — Your sketch should show the land diameter both ahead of the leade cone and from further up the barrel. That’s a snap to measure with your blade mike — it’s the down-in-the-valley diameter on the casting, forward of the leade-cone. To get the bore diameter closer to the muzzle, use a soft mallet (aluminum, brass, rawhide, or plastic) to pound a buckshot (#0 buckshot = 0.320" diameter works for 30 caliber) or other lead ball of suitable diameter into the muzzle end and then push it back out with a cleaning rod from the rear. Measure and record both the land and groove diameters at both the muzzle and just ahead of the leade-cone. Typically, the groove diameter will be unchanged or (ideally) gets slightly smaller in the forward direction, whereas the land-to-land diameter will be larger in the rear (from erosion caused by powder gases) than in the front. However, I have one near new bolt action rifle where the muzzle shows a 0.002" belling of the bore diameter, as compared to that just in front of the leade-cone. That’s a good thing to know BEFORE spending lots of time trying to get a rifle to shoot.

· Locate Front of Leade-Cone — You’ll face this challenge with nearly every casting. The leade-cone’s front end location is only obvious in steep-leade-cone chamberings like the standard 30-30 Winchester. For the others, it is rather subtle, so the best approach is to insert your mike’s thin non-rotating blades down into the opposing "grooves" of the casting and take repeated bore-diameter measurements as you move rearward. At some point, the diameter will start to increase. That is the forward end of the leade cone. Mark it, then use your machinist’s rule to measure its length;

· Grooves Larger than Throat Cylinder — Sometimes, you’ll have a chambering with a throat cylinder that has a diameter that is a bit less than the rifle’s groove diameter! In that case, you’ll be able to SEE the darn grooves tracing their way back along the throat cylinder portion of the casting (raised slightly above its surface), but you won’t be able to measure it on the casting unless you have blade mikes. In this case, without blade mikes, try various sizes of CBs (base-first) until you get a slip fit. . . measure and mark your sketch accordingly. Note, too, that this type of situation will not give you reasonable CB accuracy unless you use an expanding base check, like a V-Chec or P-Chec, or a C.F. Ventures wax check. Another trick for this is to size your drive bands to a slip-fit diameter but size the Hornady gas check to a diameter larger than the groove diameter, using a Noze-First top punch, as described in my #4 War Horse article on the 8mm Mauser. This is another example of how having an impact throat casting in-hand can really help guide your load development work. Don’t run blind! SEE your throating, then THINK about it, and THEN ACT.

· Grooves Larger than Leade-Cone — In K98 Mausers chambered for the 8mm Mauser, you have a throating that is all-leade-cone and whose rear end ends in a very sharp transition to the chamber neck. In some cases, the groove diameter will be larger than the leade-cone’s rear-end diameter. If so, you’ll see that the "ridges" on the casting (the bottoms of the grooves) proceed beyond the rear of the leade-cone and terminate on the transition cone to the chamber neck. In a case like this, blade mikes are about your only good bet for obtaining the cone’s rear diameter, given that it will terminate down between the "ridge" prints of the rifle’s grooves and will also be hard-up-against the step to the chamber neck.

If you have only one or two rifles in a given chambering, then you can keep each rifle’s throat casting (wrapped in its sketch paper), the shortened case, and the short rod right in the sizer die box for that chambering. Otherwise, you’ll need to figure out something else. Just make sure they are both protected and handy. For long-rod care, see the next section.

You can order your drill rods in 36" lengths from MSC [1-800-645-7270]. Here’s a list of calibers and appropriate rod diameters, in relatively inexpensive water-hardening or oil-hardening alloys (we don’t care about the alloy, so long as it’s steel; we just want the precision-ground diameter), including the MSC part number. Just call them up and order one rod for each of your favorite calibers. If you have many chamberings in a given caliber, a single rod will usually give you at least four short rods and still leave enough long-rod length to do the job on barrels 24" and less in length. Here are the rods:

22 caliber, use 0.2120" rod: #06008031 @ $2.64;

6mm.243 caliber, use 15/64" rod (0.2344"): #06000152 @ $2.36;

25 caliber, use "D" rod (0.2460"): #06019046 @ $2.60;

6.5mm caliber, use 1/4" rod (0.2500"): #06010169 @ $1.52;

270 caliber, use 17/64 (0.2656"): #06000178 @ $2.46;

7mm/284 caliber, use "J" rod (0.2770"): #06019103 @ $2.77;

7.7mm, 30, 303, 32, & 8mm calibers, use 19/64’ rod (0.2969"): #06000194 @ $3.03

338 caliber, use 21/64" rod (.3128"): #06000210 @ $3.36;

9mm/35 caliber, use 11/32" rod (0.3438"): #06000228 @ $3.43;

375 caliber, use 23/64" rod (0.3594"): #06010235 @ $3.74;

41 calibers, use 25/64" rod (0.3906): #06010250 @ $4.13;

44 caliber, use 13/32" rod (0.4062): #06010268 @ $4.10;

458 caliber, use 7/16" rod (0.4375): #06010284 @ $4.10.

Typically, your rods will be of rustable steel and some are very similar to each other in diameter. Therefore, when you get your assortment of rods: first, mark each rod (permanent felt-tip marker) with the caliber(s) for which it will be used; then give them all a light coating of paste wax as soon as you get them from the supplier. Store them together in a dry corner, clearly marked as being for special use, so that nobody grabs several for use as a tomato stakes. Mah!! That way, they’ll still be nice and smooth whenever you are ready to use them (e.g., every time you get a new rifle).

It took you a while to read this. However, once you have the supplies and tools, you’ll find that it is takes VERY little time to make and decipher an impact casting. I hope that you get as much use out of this little trick as I have.

wosikae@dgweb.com