Here's a piece by John Barsness. I like John - he's a no-nonsense, "just the facts mam" sort of writer (of course he is, he's from Montana). I've used copper mono's on and off since the 1990's. Mostly I stick to lead core bullets. I've absolutely found they kill quicker than mono's. Apparently John has found the same thing to be true. However, I think the case for lead-free is compelling and I keep an open mind. For your consideration:
"Here's Chapter 20 of my Big Book of Gun Gack III, which is a longer version of an article I previously wrote for Handloader magazine:
Non-Toxic Hunting Bullets
While the term “non-toxic” sounds somewhat weird when applied to hunting bullets, the recent lead-free trend keeps increasing. Some hunters believe the concept to be an anti-hunting conspiracy, but it’s happening because lead isn’t good for animals—including humans, the reason we developed lead-free gasoline, paints, and plumbing pipes, and many indoor shooting ranges ban lead bullets.
Some skeptics point out that lead occurs naturally on Planet Earth. That’s true, but lead primarily becomes a problem after being mined, smelted and used in various products, adding to natural levels. It can affect all organs of the body, resulting in symptoms from exhaustion and hearing loss to seizures and miscarriages. These don’t necessarily happen immediately:
Lead tends to first accumulate in bones, and can be released months or even years later.
From 1960-70, Americans had average lead blood-levels of 60 micrograms per deciliter, while for many years five micrograms per deciliter was considered “safe.” (All lead levels cited here will be micrograms per deciliter.) Recent studies, however, suggest any lead-level can result in damage to humans, particularly in children. Thanks to the elimination of many lead sources, since 1970 the average level in Americans has dropped considerably, in 2012 averaging five.
How much eating wild game taken with lead-based bullets affects humans, however, is debatable. One large-scale study in Germany and Switzerland found adult hunters had about the same lead levels as non-hunters, perhaps because hunters tend to live in more rural areas, instead of cities where lead pollution is more prevalent. A Spanish study found elevated levels of lead in the meat of deer and wild boar, and stated, "Mining sites in the region can influence the results, but they alone do not explain the extremely high levels detected in some samples."
Another study in North Dakota found hunters, and people who eat game provided by hunters, have lead blood-levels 50% higher than non-hunters. However, the levels were very low, .84 for people who didn’t eat game, and 1.27 for people who did—far less than the average for all Americans.
Another, less general “study” took place in our own household, when for a while my wife Eileen’s blood had to be tested annually for a medical condition. Despite our living almost entirely on game meat, her lead levels were also far lower than average for adult Americans.
However, during that period we started using more and more lead-free bullets. I took our first big game animal with a non-toxic bullet in 1995, and during the next decade we put a total of 55 big game animals into our freezers, 23.6% with non-toxic bullets. Over the last five years we’ve put 21 big game animals into our freezers, 15 of them (71.4%) with non-toxics.
We started using more non-toxic bullets not because of concerns about eating lead fragments, but because “monolithic” bullets ruin less meat in smaller animals like pronghorns, and penetrate deeply in larger animals like elk. The lead-free bullets used during the past five years included Barnes TTSX’s, Cutting Edge Raptors, Hornady GMX’s and Nosler E-Tips, and normally tore up noticeably less meat than lead-core bullets—though there have been occasional exceptions.
Velocity and shot placement also affect meat loss, and one rare exception was a mule deer buck Eileen took in 2014 with the 100-grain Barnes TTSX at 3150 fps from her NULA .257 Roberts. Despite shooting behind the shoulder as the buck stood broadside at 100 yards, the bullet still ruined a lot of shoulder meat. On the other hand, some of our moderate-velocity lead bullet loads result in very little meat damage, especially the .35 caliber, 180-grain Speer Hot-Cors Eileen handloads to 1900 fps for her old German 9x72R combination gun, and any of the lead-cored 286-grain bullets I use at around 2400-2500 fps in various 9.3mm cartridges.
We also personally butcher all big game going into our freezers, and trim bullet-damaged meat very carefully. Still, lead fragments can travel a long way from blood-shot areas. A Norwegian study found leads fragments as far as 29 centimeters (about 11 inches) from bullet entrance holes, but hunters who cut up their own animals trimmed at most 20 cm (8 inches), and often less than 10 cm (4 inches). The same study also noted that controlled-expansion lead-cored bullets result in far fewer lead fragments than cup-and-core bullets, but all lead-core bullets left “a cloud of lead particles in the meat around the wound channel.”
A British study on gamebirds taken with lead shot indicates cooking can increase how much lead enters human bloodstreams. Tiny pieces of lead normally pass quickly through the human digestive system, but cooking allows some lead to be absorbed by the surrounding game meat, especially when vinegar’s used in the recipe.
Concerns about lead poisoning aren’t only about humans but various sorts of wildlife, especially birds. The lead shot ban for hunting waterfowl in the U.S. occurred because ducks and geese picked up lead shot while feeding in ponds and lakes. Their gizzards ground the shot, sometimes resulting in lead poisoning. The same thing occurs with carnivorous birds scavenging gut-piles or varmints shot with lead-core bullets, the reason for lead-bullet bans where rare California condors have died from lead poisoning. (Condors also live in parts of Arizona, but their game department only requests that hunters use lead-free bullets in those areas.)
However, even after lead bullets were banned in the parts of California where most condors live, their blood-lead levels didn’t drop, and in 2019 lead-based bullets will be banned throughout the state.
Eagles, ravens and other scavenging birds have shown elevated lead-levels in areas where big game gutpiles or varmint carcasses are common. Studies also indicate that (like human children), young birds in the nest are far more affected by eating lead fragments. I know a ranch-owner here in Montana who only allows non-toxic bullets for shooting prairie dogs on his place, though he doesn’t ban lead-core bullets for hunting big game, and uses them himself.
However, scavenging mammals may not have the same sensitivity to eating lead, perhaps because (unlike humans) they only eat raw carcasses. A 2010 study of wolves, coyotes, mountain lions, and black and grizzly bears around Yellowstone National Park found some animals had higher blood-lead levels than others, though almost all were lower than five.
Only grizzlies had lead levels approaching those considered unsafe for humans, but no lead fragments were found in their droppings, so the reason couldn’t be determined. Mountain lions and wolves don’t scavenge carcasses very often, and their lead levels were often too low to be detectable. Perhaps the most significant finding of all, however, was that in all the animals tested, “blood lead levels did not increase during the autumn hunting season when potentially lead-tainted gut piles are available.”
So once again, the evidence is mixed, but non-toxic bullet regulations keep increasing, one reason so many companies now produce lead-free bullets, along with ammunition loaded with lead-free bullets, including rimfire ammo. The major concerns for American hunters, of course, are price and effectiveness.
Prices continue to drop as more companies make lead-free bullets, but in general non-toxics still cost more, because lead’s one of the cheapest, most easily formed metals available. However, in 2018 monolithic big game bullets cost about the same as most “premium” lead-core bullets, and less than some. The only lead-core hunting bullets that are substantially cheaper are the cup-and-cores the Norwegian study found disperse the most lead in game meat.
Many big game hunters consider the terminal performance of monolithic big game bullets superior to almost any lead-cored bullets, for the same reasons Eileen and I use so many: They destroy less edible meat, and usually penetrate deeper than lead-cored premiums.
On the other hand, because monolithics destroy less tissue, on average they don’t kill as quickly as lead-cored bullets. In an analysis of my big game notes since 1995, rib-shot animals taken with monolithics have traveled an average of slightly over 50 yards after the shot before falling, while the fastest average kills come from lead-cored bullets that fragment considerably—and the more they fragment, the sooner animals drop. The average distance big game shot with Berger hunting bullets, for instance, has only been 18 yards, and the percentage of instant drops from rib shots is also higher.
