Re: .416 Ammo
wilb,
Congrats on getting your gun sorted out (it is a big boost once your are done worrying with that and can just practice I know!), and I am sure you will have a great hunt. It sounds like a good rifle and optic setup. I have some comments on the process having setup a .375 H&H (with Swaro Z6i 1.7-10x42 in talley QD rings) and a .416 Rigby (with rail and Aimpoint T1 on LaRue low QD mount...return to zero verified multiple times) for someone over the last two years (two hunts, total of 1 buff and 3 elephants down...currently hunting in Botswana). I think the .416 caliber is an excellent choice for an all-arounder when including the larger dangerous game animals.
1. I would highly reccomend that your two ammunition choices be the Barnes X 400 gr. load (provided it shoots well) and one of the 400 gr solid loads (if your gun shoots the 400 gr DGS load well then you are in business as it works well and is less expensive!). The buff mentioned above was taken with the .375 and 300 gr barnes X, the Elephants with .416 400 gr DGS rounds (x2) and one with the .375 and the 300 gr DGS Superformance (excellent solid...gives the .375 almost a caliber step up in energy!!).
Having solids is a very good idea for all those tough critters in Africa, and I am sure your PH will be happy knowing you have solids to backup the Barnes X stuff. Nothing against the Bear Claws which are excellent bullets in most cases, but they are a bit soft for a dangerous game bullet in my opinion when compared to the Barnes X (see the post of "APA in Africa" here where they test fired a .375 TBBC into the leg of a dead Buff and it failed to penetrate). Three shots were put on the Buffalo (menitoned above...not the APA one), and all three had excellent full penetration, with two of the bullets recoverd in the offside hide, one after smashing through a shoulder and the heart, the other on a quatering shot through parts of the stomach/rumen, heart/lungs, and the other shoulder. Both recovered bullets looked like the "picture perfect" example of a 100% expanded x-bullet with 100% weight retention.
The shots on the Elephants were all heart shots with the animals down within 20 yards of where they were hit (all solids). Final note, I would not want to take a head shot/anchoring shot/dangerous shot with anything but a solid for max penetration and straight tracking.
2. Definitely practice with the round/rounds you plan to hunt with. I would check zero/groups at 100 and see if one or the other groups significantly better then stick with that one. Know your Zero with both loads (hopefully it is close enough to not matter from 0-100 yards). If there is a radical difference I would honestly just zero for and shoot the solids only. If your gun has irons those should be zeroed/verified also, although hopefully you don't have to use that useful but inferior system.
Glad to hear you are practicing with the sticks...I think having your own set of sticks to practice and hunt with gets you a huge leg up on understanding the type of shooting you will be doing and helping you eliminate a variable/know your limits so you can focus on just the shot. I second the idea that grabbing some stick and some rifle, and putting some forward pressure into the setup/"leaning in" is the most stable method for most, and helps with recoil control versus just "laying" the gun on the sticks. A little offhand practice from 50 and in should round out the practice regimen and give you full flexibility/confidence (though if you have time for the sticks, always try to use them).
Don't forget to immediately cycle in a new round after following through briefly on your shots, even in practice (in other words don't admire your work or look for your hit for too long with an empty gun...you may only get a little bit of time to get a second/insurance shot on the animal in question if needed/available). A well placed and executed first shot is critical, sets the tone for calm and confident 2nd/follow-up shots, and eliminates almost all worries of dicey follow-up scenarios. Plus your PH and trackers will love you ha!
3. While practicing, at least a few times shoot with the mag box completely full (if you haven't). Also, at least a few times shoot every round in the gun when loaded to max capacity (full mag plus one over the top) without reloading (checking feeding/extraction). As was mentioned in the thread, if not setup properly there is an increased risk of the floorplate popping open on the heavier calibers when loaded full, which is obviously not the best thing to have happen. Definitely make sure your gun feeds well from the first round to the last with your chosen ammo/loads.
I am not so sure about the idea to reduce the power of your magazine spring for an extra round down for fear of feeding issues (thought I would defer to mrfudd for more commentary on this since he made the comment and apparently uses it like that with no issues?).
3+1 should be plenty, and beyond that your PH should be shooting while you reload (if needed). On that note don't forget to have your ammo pouch/catridge belt sorted out, and practice loading from empty, and loading to "top off" before moving on after shooting so there are no suprises there.
I do not mean for any of the above to be condescending towards your shooting experience, practice routine, or ability. Your experiences and other peoples actual experiences may vary from mine. These are just the common themes noted in my limited experience preparing the rifles and the shooter for two safaris, (obviously with feedback from both). I would not be suprised if you have all of the above nailed down already (100+ rounds of practice with the actual rifle and loads is a fair bit more than most I would wager), but since it was fresh in my mind I thought I would just put it out there. I am sure you will have a memorable and successful hunt. Make your own luck!