For all the visitors and folks reading this lets put this whole thread into a little perspective.
Of all the 416 Rigbys built and used around the world today, all can achieve 2400-2500 FPS with factory loads using hunting qualtiy 400 grain bullets in a standard length barrel in roasting hot sunshiney weather.
There is one claim that an old siamese rifle can achieve this with some magic load using about 1/2 the powder and the same bullet weight. safely I might add, even in 100 deg plus weather! Although living in Tacoma Washington there was probably not more then one 100 deg day in the last 50 years and even considering Eastern Wa. temps there are few and far between 100 plus days there as well. Lets suppost that the wheel of fortune landed on a hundred degree day during his testing. So what we have here is the claim that one rifle and magic 1/2 capacity powder load drives a 400 grain bullet to 2400 fps. I'm afraid this carnival act must have been done with some disregard for common safety. and should not be attempted by anyone with any common sense.
An interesting thought on this too. Al Arpin, Craig Boddington, Finn Aggard, Terry Wieland, and Gary Minton all say it cannot be done safely. Not just with common rifles but with some carnival act Siamese mauser either. These folks whote a book together called "Any shot you want" It's a Book on Hunting rifles for serious hunters which address all the best rifles ever made for hunting and Reloading. It is packed with more information on Pressure and formulas and on and on. There has never been a book written like this that so thouroughly covers how things really work inside a rifle shell and what can be expected as a result of both factory and reloaded ammo. The text on pressure, and the engineering of rifles and shells is unsurpassed in any book written today on hunting rifles. They did not miss a beat in this huge document. The graphs on pressure and temps and the graphs on pressure from hot loads compared to factory loads is just a work of art!
They started with the tiny .22 hornet and discuss every aspect of the cartridge and the various rifles and handloads that can be used in it. They don't stop there either. Aside from the normal everyday cartridges used today there are some unusual cartridges that they examine completely for hunters and reloaders: 6mm PPC, .25 souper, 7.62X39 Russian, 300 pegasus, .338 excaliber, all the metric 9.3mm cartridges, .375JRS, 400 pondoro, .416 gerlach, .425 express, all the old doubles, up to 600 nitro express and even the 105X608mm too! As I said they did not miss anything regarding the hunting rifles of the world. They discuss the best rifles and reloads that can be achieved with each one.
The 45/70 is not even in the book, it's not safe to tinker with!
Can you imagine the experience and test facilities these gentlemen have access to? Can you imagne the resources that they have at their fingertips? Al Arpin is a master gunsmith and inventer, that has an enormous shop and was the fella responsible for listing the 338/06 as a factory cartride with SAMMI. These folks are the real deal they are part of the core of American gun knowledge where firearms and hunting loads are concerned.
Yet in this huge book of guns with all the obscure cartridges they wrote about. .........There is one missing,........ not even mentioned in the book the 45/70.
Why is that? Did all of them forget it exists? Did the editors miss it? Was it a little joke they decided to play on LMG?
Do you folks know of a man named Ken Waters? He wrote the bible of all handloading and was the editor of Handloading Magazine. He has a two book set called "Pet Loads" which is a compilation of all the research of handloads done with about every cartridge made. This research was done using the most advanced pressure measurement equipment available and multiple Chronographs. Every concievable powder and bullet combination and rifles and handguns of many different makes and barrel lengths.
He lists loads for the Siamese Mauser and states directly that these loads should only be used in a Ruger #1 or a Siamese Mauser. NEVER in the Marlin!
Here are some spec's and quotes from his excellent book on the subject:
The Highest velocity load we tested was a 300 grain Hornady at 2228fps.
The Best we could get with the 350 grain Hornady was 2020fps.
Our Speer 400 grain bullet was at Maximum pressure at 2027fps and had poor accuracy. We managed 1972 FPS with another load and bullet but it too had very poor accuracy. The poweders used were IMR 4198, 3031, and H4895 H4831 and many many more. No powder charge exceeded 57 grains.
Note here that the highest velocity load tested with the 45/70 in the dozen or so pages of test data published was 2228 FPS with a Siamese Mauser and only a 300 grain bullet. This by a recognised expert in the field who's testimony would stand up in court as an expert witness!
There is good reason, you cannot load a 400 grain or 500 grain bullet to hunt Dangerous game with in that old shell and get enough velocity to use it safely. Especially in the high southern African climate. The liabilty to anyone publishing hot loads with a 45/70, or the lack of responsibility to people who post this non-sense is absolutely off the charts bad behaviour and in very poor taste.
However as visitors you should be able to read the kinds of things that are possible even in the fantasy world of some posters. Maybe we should step back and be grateful that LMG has done this testing. He brought that old cartrige to the functional edge of it's limits and lived to tell about it. A true Pioneer. Like space travel, deep underwater exploration, land speed records, air shows, and medical experiments and testing all being high risk so was LMG's testing of this cartridge.
Good job LMG, ............I do think you can get 2500 though, you really should push that envelope and see if you can squeeze in just a bit more powder, Use a shoe horn!
