reloader swiss 52

[banus02]

looking for start and max loads for my 20" 243 1in10 twist using rs52 powder   70gr nosler b/t /85/87gr and 95gr bullet if any one has any information or can tell me where i can find any .i have tried reloader swiss but they dont show any bullets in the 80/95gr area.many thanks. ihave other powders i use but want to try rs52.

[Laurie]

Use Hodgdon VarGet starting loads as a guide to the RS52 starting load and work up from there. You usually find you can use the VarGet maximum and sometimes a little more.

I'd say you're starting to become marginal with this burning rate powder with the 85/87gn weight. At 95, it is too fast burning. It'll likely still work using H. VarGet loads which some sources quote, but you are by then running with such low charges that the case fill-ratio is in the low 80%s and you lose more than 100 fps compared to  slower burning powders better suited to this bullet weight in the 243.

To give an idea of starting loads using the Varget figures, the new Lyman 50th edition manual loads are as follows:

Remington brass / Rem 9 1/2 primer

70gn Sierra MK HPBT match ..................... 37.5gn starting 3,301 fps 47,900 psi (Max VarGet 41.7gn 58,700 psi)

85gn Sierra HPBT Game King .................... 35.2gn starting 2,991 fps 46,800 psi (max VarGet 39.0gn 58,900 psi)

95gn Nosler Partition ................................ 32.0 gn starting 2,714 fps 50,200 psi (max VarGet 34.5gn 56,400 psi)

I've quoted the VarGet maxima to give an indication of where you might end up, but you'd have to decide exactly where that is with RS52 through pressure indications on the case and primer. Work up in modest charge increments - 0.4gn initially, 0.3gn or 0.2gn as you approach the VarGet maximum.

(With the 95 Nosler, Ramshot Hunter, Alliant Re19/22, IMR-4831, Viht N160, H4831 all give 120 fps or thereabouts higher MVs, a lot!)

Also, 243 is said to be very case sensitive, different makes having a large range of internal volumes and hence producing significantly different pressures from any given charge. Remington (used here) and Winchester are pretty thin. If PPU, Lapua, Federal, Norma, or Sako brass is used, drop these loads by 1.0gn. (Speer is so exercised by this issue that it says its loads are only valid in Winchester brass and mustn't be used in any other make.)

Normally, I'd give a QuickLOAD based suggestion, but unless the new QL v. 3.9 upgrade changes its base properties' values for RS52, I would suggest being wary of its results. My (v. 3.6) version often overstates safe loads of RS52 by 1.5-2gn in cartridges of this size. I've blown a few primers and scrapped a few cases with QL and this powder, and now always use VarGet instead as a safer option.

[banus02]

good evening and thank you laurie.i will do as you say.manythanks for your very helpfull reply,i know i can trust your findings.