Thanx boomer I knew you would come up with a big long post.
For me the simple facts are X bullets give a smaller diameter wound channel. I like a bigger one. A .280 SD and higher Hornady in popular calibers at 2900 down to 2300 Fps impact have always given me both adequate penetration and wound channels on every deer I have shot. At the upper velocity's I can penetrate from last rib forwards through to far shoulder with 7 and 30 cals, in the lower velocity ranges I have penetrated nearly full length on some of the smaller whitetails. That is more than enough penetration for me.
The whole inadequate penetration boogie man that started on the Internet 12+ years ago came from guys shooting African game. I bought into it for a while shooing really heavy for caliber bullets with heavy construction on deer untill I realized they did not do the job as well as some of my old standards. I had been a light for cal at high velocity guy before and now have settled more towards that end and the middle. I find the best results for deer are from higher velocities, middle of the road bullet construction and high SD.
I have stated what I believe to produce border line or unsatisfactory results in the wound diameter department. (X bullets especially from small cals) I would love to hear from you guys what you feel to be border line in the penetration department. (without quoting some kind of John Barsness's "standard cup and core under 2800fps" mantras that eveyone seems to be regurgitating without thought).
You are a youngster if you think concerns about bullet failure only go back a dozen years. I've read articles concerned with bullet failure on North American game from the 1940s, actually earlier if you take into account the stuff written by Elmer Keith, Ned Crossman, and Stewart Edward White. Why do you think John Nosler got into the bullet business in the 1940s? Because domestic bullets were failing on domestic game. The problem for quite sometime has been the premature failure of bullets impacting game at high velocity. Whether you choose to use them or not, the X family of bullets answers the question, as do other technologies.
SD! What do you think the value of SD is once the bullet begins to expand? A 140 gr 7mm bullet with a frontal diameter of .60" has a pretty poor SD don't you think. It works out to .056! SD is a reasonable way to compare non-expanding bullets, and non-expanding bullets have their place, but for best performance their design and construction is critical.
If you choose to use Hornady bullets, thats great. They work, although I think their cores are too hard. I shoot many more Hornady's in a year than I do Xs. If you don't like heavy for caliber bullets, you should love the Xs because their performance is balanced in favor of light weight. Heavy for caliber bullets work well in medium game, but if you choose a bullet with a heavy jacket you've chosen the wrong bullet. The only reason for them not to open properly is if the bullet is in yaw at the moment of impact, and the hollow point is closed off and unable to open. Granted this will not happen with a lead core bullet, but the lead core bullet will expand grossly to one side and straight line penetration will be lost. Granted, both cases represent a failure. If this is a problem that occurs repeatedly, a switch to a shorter bullet or a barrel with a faster twist is in order.
The choice of the X bullet is particularly useful for those who use very small bores for big game. There is no other .224" bullet that can perform well enough to make me comfortable using a .223 or a .22-250 for big game, yet across the North caribou and even moose are routinely killed with .223s loaded with 55 gr Remington Coreloks. Check out the articles on South Africa's GS Custom's website concerning the use of .22 caliber mono-metal expanding bullets on big game. GSC's line of mono-metal bullets I think predates the Xs. They have experimented with a .22X63, essentially a .30/06 necked down to .224 and they have broken 5000 fps with this thing. Anyway when they test their bullets they test them on game. The carcasses are cleaned hung and photographed so the results can be seen. According to GSC, a hyper velocity impact from a 40 gr X type bullet kills deer sized antelope about as well as a 100 gr .243.