Are RS40, 52, 60, 70 and another one or two grades single or double-based? That depends on your definition of single v double. The key word is 'base' - ie does the main recipe that makes the mix that is rolled and cut / extruded nitrocellulose only or does it have other inflammable ingredients added at that stage? All smallarms rifle ball powders and a few extruded grades have both nitrocellulose and nitroglycerin at that initial stage - hence double-based. Many extruded powders only have nitrocellulose (and that's how it stays until poured into a case) and are single-based.
BUT ... then you have those RS powders and the Viht N500 series that start single-based and after the kernels have been formed / cut some fancy process sees them partly infused with nitroglycerin. As Malxwal correctly says they fall into a category or their own - 'High energy'. To a chemist or propellant scientist this late addition of nitroglycerin doesn't change them from single to double-based. Hence what it says on Reload Swiss's website - technically correct, but IMO highly misleading. To the average shooter (and his or her rifle barrel) what counts is specific energy level and flame temperatures and as a general rule adding nitroglycerin by whatever method increases both - although the powder companies claim that additives they introduce into their recipes to reduce flame temperatures ensure no extra barrel wear.
So we have true double-based powders such as the Bofors manufactured Norma grades most of which have less than 10% nitroglycerin by weight incorporated - several have less than 5% .... and we have Viht N540 with ~40% nitroglycerin content, but 'officially' single-based. I do notice Nitrochemie is careful not to divulge the nitroglycerin content of its RS powders. I suspect given what we see of their performance and users' emerging experience of barrel-life that they vary considerably in this respect. RS52 seems to give excellent results without being a barrel-burner; RS60 is something else if run at full pressures. It is one helluva performer though if run at full throttle.
Let's look at this (RS60) from the other end of the telescope. This powder has been frequently documented as giving >200 fps MV in cartridges it really likes, in particular the 6XC with heavy bullets. Plus 200 fps is around 7% additional MV over a single-based powder in the 4350 class's performance. Forgetting powder type for a moment, if you have a similar cartridge - let's say 243 Win with around 55gn case water capacity and you want to increase MVs around 3,000 fps by 200 fps / 7% through use of a larger cartridge with greater case capacity at the same maximum pressure, the rule of thumb is that an X% capacity increase gives X divided by 4 percentage increase if everything else (bullet weight, pressure, barrel length) remains constant. So we'd need something with a 25-30% larger case to get this improvement with conventional powders, or ~68/69gn capacity. Now it just so happens that this figure is only a grain or two of water more than the 284 Win case that in days of yore was the basis of a popular hotrod 6mm wildcat the 6-284, its case holding 65-66gn water. The 6-284 is a notorious barrel burner, so much so it rarely turns up these days. In benchrest use, 600 rounds was usually a barrel's lifespan. So, if you get something approaching 6-284 performance from RS60 and ~1,200 rounds barrel life instead of the usual 2,000, it's actually a bargain.
All this tells you is that there are no free lunches in the laws of thermodynamics no matter what route people choose to get extra performance, so it's no good their happily accepting RS60's usually impressive MV increases and then wingeing later in the year as they start telephoning their favourite gunsmiths for expansive rebarrel jobs! You could also run your loads at proof pressures too to get similar MVs and kill your barrel just as quickly (but also maybe yourself into the bargain - but that doesn't stop a few people trying it).
BUT (again - gets boring, this!) ...... there is more to RS40/60/52/70 than just nitroglycerin however it got their and no matter how you categorise / classify the result. The other half of the RS performance story is, as again mentioned by Malxwal, Nitrochemie's cunning patented secret 'EI' deterrent infusion process. 'Deterrents' are the chemicals that modify the early burn in this case slowing (deterring) it so that pressures are kept down to match the cartridge's internal ballistics characteristics and bullet weight. Normally they're applied as ultra-thin surface coatings and when they burn through the burn really lets rip. EI sees it infused into, ie inside, the kernel so the kernel has to burn down further before the deterrent effect is burned out. In other words, if you look at the pressure / time / bullet travel curve, it extends the initial peak over a longer period of time during which the bullet also travels further. As the energy imparted to the bullet in the form of MV is directly related to the area of space enclosed by the graph line that gives a large increase.
Wow! Great! Sooper! (for fans of Reggie Perrin remembering CJ's two office sycophants) - something for nothing surely. What's not to like? Again, though there's no free lunch. Because it's peak heat + pressure that erode barrel steel and because the period of both time and bullet travel under these conditions are extended, a longer section of barrel is exposed to these conditions for a longer time period. Faster wear! It's not just powders that do this - run a heavy bullet at the same peak pressure as light one in any cartridge and the barrel life will be reduced, often considerably, irrespective of powder type. That's because the heavy bullet with its greater inertia starts moving later and accelerates down the barrel more slowly than its light cousin and so the throat and rear section of the barrel is subjected to peak pressure and heat for longer ( a slower burning powder used to avoid excessive pressures).
The following RS powders are high-energy / EI types:
RS24 ......... RS40 .......... RS52 ........... RS60 .......... RS70 ............ RS80
The following are true single-based non-EI grades:
RS30 ......... RS50 .......... RS62
So far as 'equivalents' go - a term to be used only in the widest possible terms with great caution and it does NOT mean uses same charge weights
RS50 is very close indeed to Viht N140 in both charges and performance. (Before Nitrochemie set up the UK 'Reload Swiss operation' it was sold here at a bargain price as 'TR140' with the advice to use Viht's data for N140. RS50 users say that they can safely 'push' it a bit more than the Viht product. Although I did a side by side test of the pair in 223 and 308 with otherwise identical components and got MV results so close they could have been different production lots of the same powder, I wouldn't like to be associated with endorsing RS50's use with higher charges. It is an excellent and flexible powder though and a true alternative to N140 should it bed easier to obtain than the Finnish powder - just work up loads again if switching, please.
RS52 is the best replacement for H. VarGet I've found to date and with the likely exception of matching VarGet's exceptional temperature insensitivity, I'd consider it superior to the ADI / Hodgdon powder. I've tried it in three cartridges / bullet weights where VarGet is regarded as exceptional to date and found that it is a more flexible performer producing higher MVs if needed. Do not use VarGet's load data of course and also DO NOT TRUST QUICKLOAD's DEFAULT RS52 SETTINGS as the program usually (grossly) underestimates pressures and MVs and you risk overloading the cartridge.
RS62 is usually an excellent alternative to IMR and H4350. It works very well in the smaller 6.5s which use the 4350s - Creedmoor and 260 Rem, not always in 6.5X47L where some rifles will prefer RS52.
What is lacking in the true single-based RS range is a grade that replaces IMR-4831 and more importantly H4831sc. Nitrochemie has been made aware of a European demand for a - to give it a name - 'RS72', and promised samples of such in early 2018, but so far nothing has appeared
