Having usable bullets, however, is only part of the battle. You also need to be able to seat those bullets in the appropriate brass, which means getting dies that are right for your particular rifle. As mentioned, the .40s are notorious for their variations. Both RCBS and Redding make dies for different diameters of the same cartridge (.406, .408, etc.). You need an expander plug that will leave the neck the right size to accept the bullets you require. In extreme cases, this means having a plug machined by your friendly lathe operator.

With barrels that have an even number of grooves and lands, bore diameter can be measured using a caliper.

It is entirely possible that you will go through all this only to find that your apparently perfect cartridge will not seat in the chamber of your rifle. There are various explanations. Most common is the practice, with black-powder rifles and handguns of all kinds, of making the chamber undersize, knowing that the soft lead bullet will be bumped up in diameter by the ignition of the black powder. Smokeless powder is less abrupt in its ignition, so bumping up does not occur. Nor, of course, does it happen with jacketed bullets, regardless of the powder. Therefore, you have to use bullets that are full size to begin with, and they might not fit in the chamber.

Sometimes, reaming case necks will remove enough material to let a snug cartridge fit. At other times, more drastic measures are needed, such as reaming out the rifle chamber. If that is the case, you need to make a decision whether firing Grandad's rifle is worth it to you. More than one lucky heir has decided to hang the rifle over the mantel instead.

Going back a few steps, let's look at brass. Cases in .40-65 are easy to find nowadays, but such was not the case even 10 years ago. It has staged a comeback because of black-powder silhouette shooting. Even had it not, .40-65 can be readily formed from .45-70 cases, and the whole .45-70 family is relatively standardized.

A cartridge like the .40-70 Straight Sharps is another matter entirely. There were variations among original rifles and cartridges, and cases from one manufacturer or another might be the wrong length or have rims that are too thick (in which case the cartridge won't seat) or too thin (resulting in headspace problems).

Shooting Grandad's Gun
Bullets, Brass and Dies
Hawk Bullets. Hawk makes bullets from pure copper and pure lead and will produce bullets with custom cannelures and nose shapes, in various weights and diameters. If you want to shoot jacketed bullets in an older rifle, Hawk is your best bet. www.hawkbullets.com
Huntington Die Specialties. This is the first place to look for specialty brass or bullets, and Fred Huntington always has good advice for the loader of odd calibers. www.huntingtons.com
MidwayUSA. This is a good general source of all conventional loading components and equipment, as well as specialty items such as the Meister Slug Your Bore kits (available in .308-.32, .35, .375, .40, .42 and .458). www.midwayusa.com
Old Western Scrounger. OWS is a good source of ammunition in obsolete or obscure calibers, as well as brass for same. www.ows-ammo.com
RCBS. RCBS features loading dies for virtually any old cartridge. It will also make dies to special dimensions to accommodate odd bullet diameters. Its Cowboy dies are specially made to accommodate lead bullets. www.rcbs.com
Redding. Redding offers a wide variety of top-quality specialty loading dies in virtually any cartridge you can name. Since its market is the serious target shooter, including black-powder cartridges, it offers varied dimensions to accommodate different bore diameters. www.redding-reloading.com

In the early stages of reloading for a vintage rifle, do not attempt to reduce costs or labor by going for volume. What you want to do first is create two or three cartridges as prototypes. In fact, it never hurts to do your first few as primer-less, powder-less dummy cartridges, created solely to determine what fits your chamber and feeds through your action.

A few years ago I acquired a .500 Nitro Express and made the mistake of assembling about a hundred rounds of ammunition. They were within SAAMI specs for the cartridge but steadfastly refused to chamber. I had to pull them all apart and start over. Now I make sure I have a couple of fully functional cartridges to use as templates before embarking on mass production.

Most of the foregoing dimensional discussion involves diameters, but with lever-action rifles with tubular magazines, length is equally critical. Generally speaking, there are constraints with levers that simply don't exist with bolt actions. Naturally, with a tubular magazine you are limited to either flatnosed or bluntly roundnosed bullets to ensure that recoil does not cause a cartridge in the magazine to touch off the one ahead of it.