Welcome aboard to the best website for all things hunting Africa. many experienced folks here.
I have owned and reloaded for two different .416 Rigby's, a CZ 550 and a Ruger RSM over a 10-year period with about 400 rounds downrange. Great cartridge. You will become aware of a new realm of rifle cartridges, and there is good reason the Rigby is a classic.
What rifle do you own?
What dies are you using?
In answer to your questions:
- Yes, always full length resize to SAAMI specs. Unless you are just long-range shooting for elk, etc. the 416 Rigby is a dangerous game cartridge. 100% reliability of your rifle and loads are the first priority. I always full length resize my hunting cartridges. The design of the Rigby case reduces case stretching.
With the big Rigby, proper lubrication of the case is important. Some spray lubricants are okay, but Imperial Sizing Die Wax is your friend. Apply a very thin coat with your fingers over the whole case, especially at the neck and lower base area. Do not put too much, as a dented neck may result. You will develop a feel for this. Just enough that you can feel the lubricant, but you can't see any. Keep the dies clean. When working with the big Rigby case, there is a lot more surface area of brass. More buildup of residue, lube etc. I clean my dies every 100 rounds or so, with a bore cleaner, then wipe them dry. I have used RCBS and Redding dies with great success. I prefer Redding dies for the big cases, but that is just me.
- Regarding powders I have used H4350, IMR4831, and Reloder 22. Mid to upper range book loads of H4350 worked well (source Hodgdon Reloading Data Center). I preferred H4350 because accuracy was good, but especially the lower powder charge, compared to larger charges of slower powders, made for noticeably less recoil. Recoil is important to me for accurate field shooting. There are some good threads here on powder charges, and recoil, especially in the Double Rifle section.
- Primers- I have used CCI 250 LR Magnum, Fed 215, and Winchester LRM primers. Federal 215 Large Rifle Magnum primers is what most big bore shooters use. Nowadays, primer availability trumps everything else. The key with primers is consistent ignition. I have experienced erratic ignition (a very slight hang fire, but noticeable) with a starting charge of Winchester 760 and CCI 250s. I read up a bit on this, and large charges of ball powders can sometimes be difficult to ignite consistently in cold weather.
I prefer extruded or flake powders in big bore cases. You are igniting about 30-50% more powder than in a 300 WM. Of course, ANY TIME A COMPONENT IS CHANGED, start back at minimum powder charge, and slowly work up, looking for any sign of erratic ignition, pressure, etc.
Hope this help. Ask more questions, and you can get some very good advice on tips, techniques, and experiences.
AH members offer excellent advice in helping you spend more money for big bore rifles.
We all do it.
![Giggle :giggle: :giggle:](https://cdn.jsdelivr.net/gh/twitter/twemoji@14.0.2/assets/72x72/1f60a.png)