I though I'd relate performance of factory 300 wby 165g sp loads the last two seasons. My first use was on a 2004 Wyoming mule deer. The shot (probaby illadvised) was on a large bodied 26" buck at approx 200yds on the run. The animal was hit quartering away sharply through the right hip. The bullet did not exit but penetrated to the vitals. The buck went 40 yds and piled up. I could not find the bullet.
My 2004 Montana buck was a small bodied but mature deer (28" 5X4). He was shot quartering away at 311yds. The bullet entered just behind the shoulder and exited through the neck. As would be expected, he dropped at the shot.
My 2005 Utah Antelope was shot at 292yds broadside. The bullet hit a rib going in and left a 4" entrance wound. A small piece of jacket or lead exited through the neck (this really was a broad side shot). At the shot, the goat simply collapsed. The core and jacket compeletly came apart and pieces were found through out.
My next use was on a 2005 Wyoming buck which was the biggest bodied deer I've ever seen. The 61/2 year old 30" wode 3X4 buck weighed 300+. This buck was shot at 287 slightly quartering away through the ribs. The bullet hit a rib going in and left a 3" entrance would. The bullet did exited in front of the opposite shoulder. This buck made it 25 yds before piling up and left a 6" wide blood trail that even this color blind hunter could follow.
My 05 Montana buck was also 61/2 years but only 200lbs or so. This buck was shot slightly quartering away at 327yds. The bullet entered just behind the shoulder and exited just in front of the opposite shoulders. This buck collapsed, got up and stumbled forward about 10yds.

Continued . . .
My observations after two years are as follows. This is an excellent long range load on medium game but only if shots could be picked very carefully. I would not want to hit a big bodied buck through the shoulders at close range--the 3350fps muzzle velocity is simply too much for these bullets. I've stuck with the load for this long simply because the factory loads shoot so well--1/2" groups are routine. I spent last winter working up loads for 150 lazerheads, 165 partitions, 165 interbonds, 165 tsx, 180 tsx, 180 partitions, 180 ballistic tips and 180 accubonds. While I could get 180 partitions with the same accuracy, it was saddly with my last supply of MRP. The tsx would routinely shoot 2 shot groups that were touching. However, the third shot always opened up to 11/2" plus no matter how cool or clean the barrel was. I was able to get 180 partitions to shoot into an inch with 7828 at good velocity, but I could never do any better. The other bullets simply would not group well with 7828, RL22or RL 19. This rifle started out as a long range deer rifle and for that it suffices. However, it is far from ideal with the hornady soft points. I expect exit wounds on deer sized game with broadside or slightly quartering shots. While 180 partitions at 3200+fps which group into an inch is more than andequate, I'm disappointed I couldn't do any better accuracy wise. Isn't it funny how extraordinary accuracy can change/dissapoint expectations? I may try the 180 interbonds this winter to see if they wont shoot any better. They've proven to be very accurate for me over the years and this gun shows a definite preference for flat base bullets. Any thoughts (other than I'm being too picky)? I'd post some photos but haven't figured out how to do so on this site.

I nearly lost a 110 pound whitetail buck using 180 grain soft point bullets with my .300 Weatherby. The only shot I had at him was while he was running, quartering away from me at about thirty yards, and I made a less than perfect shot (hit him in the right thigh). There was some considerable amount of blood at the spot where I hit him, but the blood trail quickly disappeared. I kept following him, jumped him twice more, and then finally had a broadside shot at about 80 yards. He dropped at that shot. When I examined him, I found that the first shot had not penetrated very far at all. Apparently the bullet simply exploded on the surface, leaving a cratar like wound that probably wouldn't have been fatal. I didn't find the second bullet either, but did find a few fragments of jacket in the chest.
I quit using the .300 for deer shortly after that and started handloading better quality bullets. I use it for larger game now, and have taken two moose, three caribou, three elk, a bunch of mule deer (while hunting elk), four bears, and ten african animals with it. Nearly all were one shot kills. I have recovered a bunch of bullets and all have good expansion and held together. the bullets I have used are trophy bonded 180 grain, Barnes X 165 and 180 grain, and Kodiak bonded core 200 grain.
The .300 is my favorite rifle for larger game, but I won't waste my money on cheaply constructed bullets for it. I learned my lesson on a Pennsylvania whitetail. I am convinced that if I had used a stronger bullet I would not have had to chase that buck all over kingdom come. A Barnes X bullet, for example, would have gone through the ham and through the body cavity and would have done enough damage to put the deer down for keeps. I am convinced that the .300 is way too much gun for whitetails. Since then, I have taken a whole bunch of deer using my .257 Roberts and Sierra Game King 117 grain boattails.

I have (had) two very close friends over the years that both hunt with 300's. Both were very proud of their rifles and were happy to point out that their rifles were the most powerful 30 cals. out there (many years ago).

The first friend had the luxory of hunting on private land most of his life. I only hunted with him a few times, out of choice. He would bang away with that rifle and yes he would take some very large bucks (30+" 's) many times, but almost always he would destroy half the animal in the process. At that time he didn't handload and used factory 180's, their would be an entrance hole and half the animal would be missing on the far side. He only laughed and said, see it didn't go any where. It also didn't fill the freezer either. I stopped hunting with him, still a very close friend, just couldn't stand to see the waste.

The second friend (best friend for life, sadly he passed away a few years ago) allowed me to load his Weatherby after he developed a very bad "flinch". He missed alot... He didn't understand reloading, all he knew was that he was shooting a "Weatherby". I started loading "down" to 30'06 velocities and also went to 165gr Grand-Slams, about 2900'/sec using IMR-4350, I think. It's funny how his "flinch" disapeared and he started hitting animals where they needed to be hit. He used that load for deer and elk. Just before he died we went on a "premium" elk hunt in Utah's BookCliffs, he was able to make a wonderful 300yrd shot across one of the canyons and took a great 6x6. The bullet entered as the elk stood facing (quartering) us, it fell forward and down the hill about 20yrds. It never knew it had been hit. He never did figure out that he was shooting a very nice 30'06, and was Happy all his life with his "Weatherby". I still miss him very much, there wasn't a week, that we didn't go either hunting or fishing for nearly 30 years. I will never find another "PJ".