Why? Why not just buy a bullet for the application?
Here's a whole thread on the subject in one of the long-range forums, explaining some reasons others say they do it:
https://www.longrangehunting.com/threads/berger-prep-for-terminal-performance.236995/. Take a look. Watch the video at
to see a motorized meplat trimmer used by target shooters. If you read my document, you'll see I cite an article by a terminal-ballistics expert employed by the U.S. Army and many police forces suggesting to those agencies the possibility of drilling SMKs precisely to improve terminal ballistics, after he himself experimented with the practice and found it effective. It's not as crazy as it sounds, if you know what you're doing.
As for why not buying a bullet for the application, I can give you three reasons.
(1) Even "hunting" bullets such as the Berger 156-grain .264 EOL sometimes don't expand nearly fast enough to have effective terminal ballistics. (I mention this case in my post and document, and cite a Barbour Creek video that shows you how slowly that "hunting" bullet expands. I built a custom 264 Win Mag around this bullet. I had to figure out how to make it expand, if I wanted to hunt it knowing it would expand as quickly as most Berger hunting bullets do.) The drilling/trimming operations can change that dramatically. That EOL went from expanding at around one foot to expanding after 1.5" (like most Berger hunting bullets) after I drilled and trimmed it. The difference was night and day. (You see a variant of this argument in the forums: some say bullet tips sometimes come out of the factory clogged, and one can use a drill bit to unclog the tip, which the posters report makes the bullet expand more reliably.)
(2) Some folks are committed to hunting with a particular open-tip target bullet (especially certain Bergers and the Sierra MatchKing). With a bit of work, they can have their cake and eat it too, so to speak. (If you can't talk them out of using the target bullet, help them make the bullet behave more like a hunting bullet on impact.) I have found that the 220-grain SMK, modestly drilled, is
terrific on stout game such as nilgai. (My guide on the King Ranch said the same thing. Nilgai are famous for running when shot. Both of mine dropped right where they stood. Terminal ballistics were perfect. He was impressed.) Why folks are committed to hunting with target bullets may have to do with accuracy, high BC, or availability (see below).
(3) Especially during the pandemic, there were whole
years where I couldn't get the hunting bullets I wanted, because they were sold out--or hunting bullets in the weight and style I wanted didn't exist. For example, I wanted a 180-grain 7mm Berger hunting bullet, but it was always sold out; and I wanted a 190-grain Berger 7mm hunting bullet, but Berger doesn't make one. They do make a dandy target bullet in that weight, and my experiments concluded that bullet can be made to expand like a hunting bullet, with a very little drilling and trimming. (A variant of this reason is, someone buys a few hundred target bullets, perhaps on bad advice about their suitability for hunting, and doesn't want to waste or replace them.)
As I wrote at the start of this thread, I'm not recommending the practice. I'm reporting my experience and research, in case someone finds it informative. If you think drilling and trimming are a dumb idea, for heaven's sake don't do it. I did this research because I am a trained engineer, and the research reflects how I approach technical problems. Years ago I stumbled onto the idea and wanted to try it with a bunch of SMKs I had left over from my early days of long-range hunting, after a bad experience with a factory SMK hitting an elk in the heart/lungs region but not killing it. I studied the idea very carefully, experimented very carefully, and eventually arrived at some great results. (In retrospect, I wish every SMK I ever shot at an animal had been drilled and trimmed.) I also read reports of very mixed results by folks hunting with undrilled/untrimmed hunting bullets, especially SMKs. I thought perhaps my experience and research might lead someone to a more humane way of hunting.
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