Pros: Simple; Inexpensive; Works for both large and small cartridges
Cons: So simple and effective, it can be hard to find at times
For those not familiar with the nomenclature, a primer is that little round 'button' at the base of a centerfire cartridge. The primer is, essentially, a 'cup' filled with a tiny amount of explosive. When the cartridge is loaded in a firearm, the firing pin strikes the primer, the explosive goes off, providing a 'spark' that enters the cartridge through a small (flash) hole in the case, under the primer, igniting the powder within the cartridge, and the resultant pressure from the expanding gas is what drives the bullet down the barrel to the target.
When reloading ammunition, once a case is sized, prepared, and cleaned, the first step in loading those parts that actually go "Boom" is to seat the primer. Again, the primer contains a tiny amount of explosive. Once a cartridge is discharged, a small amount of carbon residue is left in the primer pocket; i.e., the cavity in the bottom of the cartridge case left when a primer is removed. Thus, a critical step in the preparation process, prior to seating a primer, is to clean the primer pocket.
Bear in mind that not everyone fully cleans their brass every time they reload. The reasons for this are myriad; some good, many questionable. Either way, the carbon residue must be removed prior to inserting a new primer. There are two, basic reasons for this. First, any material lodged in that 'flash hole' in the bottom of the case through which the 'spark' passes can impact the consistency with which the powder ignites. In fact, if there is too much material blocking the hole, the amount of spark entering through the hole may be insufficient to properly ignite the powder - IF any passes through at all. While there are tools which easily clear the hole as part of the case preparation process, the objective is to minimize the possibility that such material will build up in the first place.
The second reason is even more crucial. While some primers are 'dirtier' than others and may only take a single firing, if left in the primer pocket, the carbon residue left after two or more discharges may be sufficient to impede proper seating of a new primer. There is little margin for error. A primer must be seated at least flush with the bottom of the case and, preferably, slightly deeper than flush. On the flip side, if a primer is seated too deep, then it will essentially be 'crushed' and not provide a consistent ignition or no ignition at all (misfire). How deep is "too deep?" According to the instruction sheets with my priming tools: "Correct seating depth is .003 inches to .005 inches below the case head." That means we're talking about a margin of .002 inches in terms of the range of proper seating.
Essentially, there are two types of tools for cleaning primer pockets - a brush or a scraper. Sized to fit small and large primer pockets, a steel wire brush such as those made by RCBS will loosen the residue and may even remove all of it. I like to start with this, but don't consider it to be sufficient by itself. Call me a creature of habit, paranoid, or just plain cautious, but I like to get in there and scrape out as much as I can.
At an MSRP of $1.98, the Lee Primer Pocket Cleaner is probably the most economical 'scraper' for this purpose on the market. By way of comparison, Lyman makes a set of cleaners with nice, wooden handles, they cost $9.95 each and, if you load both large and small pistol/rifle, then you must buy two - one large and one small. Likewise, Hornady makes Primer Pocket Cleaner Heads for $5.45 ea. (large & small); but, you'll also want the Universal Accessory Handle they screw into at $3.61. So far as I can tell, RCBS now only offers Primer Pocket Brushes, at $17.95 for the combo pack of small brush, large brush, and accessory handle.
Weighing approximately half an ounce, the Lee Primer Pocket Cleaner is 1 1/2" long and double-ended; one end for large primer pockets, the other for small. The 'scraper' is, for all intents and purposes, a Square-Tip screwdriver blade; i.e., one made for recess screws. Just don't get the idea it's simply a matter of grabbing the square-tip screwdriver you have in your toolbox. These blades are designed to fit the primer pockets on most large and small cartridges. In addition, they won't damage the primer pocket or flash hole.
All it takes is grasping the knurled center of the tubular cleaner between thumb and forefinger, inserting the blade into the primer pocket, and giving a light twist. As I mentioned earlier, I like to start with a light brushing, hit it with the Primer Pocket Cleaner, then tap the case lightly to knock out any loose residue or hit it again, lightly, with the brush. That's it. You're done. If you don't think you've removed enough residue, then simply set the case aside for proper tumbler cleaning.
I recently went down to a local outfitter store which stocks reloading equipment. They didn't have the Lee Primer Pocket Cleaner on the pegs. I asked the clerk, he asked the manager, they ordered six of 'em. The item in question came in about a week later and, naturally, they forgot to pull one for me. I just happened to be in the day they put them out. I grabbed two; at a price of $2.99 each. The other four were gone in less than a week. I guess the store figured they didn't need them as a stock item since they sold too fast; i.e., I haven't seen them replenish yet.
What I'm getting at is: A.) Shop around a bit on the price. Remember, MSRP is $1.98 on the company's website and (B.) Grab one, or two, when you seen them. Lee Precision makes some good quality reloading tools. They also operate on the philosophy that you shouldn't have to break the bank to purchase their stuff. Unfortunately, there can be a bit of bias with some 'outfitting' stores where the philosophy is that the customer feels like they got more because they paid more; even if they didn't need to. Thus, it is too often the case that Lee Precision's products can be tucked into a corner, 'hidden behind' the more expensive 'name' products; e.g., usually the corner where the store's employees actually do their shopping.
In this instance, the "marketing phrase" that Lee has on the blister pack for their Primer Pocket Cleaner probably sums it up quite nicely:
"Costs so little. Works so well."