'Palma' brass has the 1.5mm dia. flash-hole as per 220 Russian / PPCs; the BRs; 6.5X47 Lapua.
'Things' (powders and primers) seem to have changed over the last 30 or so years from when many handloaders experimented with Remington 308 Win UBBR cases in as made .308 form rather than smaller reformed designs such as the BR. As it was the US Palma teams which initially requested Lapua to make up some lots of experimental small primer / small dia. flash-hole cases, subsequently adopting the type as the norm for Palma ammunition, this subject was covered in considerable depth, several topic threads / many pages / some thousands of words, on the US Rifle Teams Long-Range Forum. Despite everything the Palma team captain said about the success of the trials with the then experimental cases, right down to placing small-primer ammunition in a domestic fridge overnight and taking it to the range in an insulated container to shoot chilled, many forum members were adamant this was a bad move that would end in tears based on their 1980s/90s experiences that only saw the genre work reliably if the flash-hole was reamed out to the standard 2mm / 0.080".
At some point or other, Palma brass loads are affected by low temperatures - hence Lapua saying officially in its product description that it is unsuitable for hunting use. My own tests (in 308 Win) when these cases first went on general sale were to see if they worked for UK FTR and TR shooters as we shoot all year round in our chilly but temperate islands and much winter season use will see ambient temperatures a little above freezing, typically 4-10 degrees C (40-50F), but potentially on the freezing level, if rarely below during daytime. Viht N140 and N550 loads seemed to be adversely affected at and below 4-deg C, but H4895, VarGet, Viht N150 not at all at this temperature level. Surprisingly, given the received wisdom that ball powders are hard to ignite, H414 performed superbly with the 185gn Juggernaut even at temperatures well below 10 C / 50 F.
I recently necked a box down to 7mm-08. Our Kiwi and Aussie friends have used necked-down Palma brass for hot 6mm, 260 Rem, and 7-08 loads long before anybody else with reported excellent results - but they don't get many frosty days 'Down Under'. So far, I've only had time to try a single loading, 162gn Hornady A-Max, IMR-4007ssc, and CCI-BR4 against the same in prepped / batched Winchester brass with the F210M and got identical 100 yard (OK but not outstanding) groups. I haven't had the chance to chronograph the small primer based loads as a comparison. I've changed my powder choices anyway for 7-08 from my initial thoughts and will move to slower burners, so the brass comparison will become more meaningful at that stage, especially as our Lapua / Viht importer has only recently received supplies of new Lapua large primer 7mm-08 cases allowing a closer comparison.
