I shot a lot of N150 / 155 rounds with my first proper F-TR rifle back around 2009/10. While I used Lapua brass, F210M 185 Juggernaut and N150 for long-range and GB league matches, I used 1980s thin-wall Norma brass F210M, 155.5gn and later the 155gn Dyer HBC VLD over N150 for short/mid range club matches.
The thin-wall Norma brass in my chamber had 0.4gn greater fireformed water capacity than Winchester (57.4gn v 57.0gn) and the throat was cut for the long 155gn Lapua Scenar seated at a bit under a calibre which fortuitously turned out about right for the 185 Juggernaut when it appeared. The barrel was a 1:10 Broughton and I tried anything and everything in in it up to the 210gn Berger BT and 208gn AMax, the uber-heavies of the time.
With the 155.5 BT, I ran test loads up to 48gn N150 in the old thin-wall 160gn weight Norma cases. This brass was known as being 'roomy', but not as the strongest around. (UK 'Match Rifle' shooters who shoot some horrendously long-throat chamber and high pressure 190-220gn 308 loads had dallied with them but abandoned them as case life was very short to nil!) The (optical) chronograph said 2,985 fps at 48gn. I got better groups at 47 though and adopted that. When the 155 HBC bullet appeared in the UK at a steal of a price back then, I tried it and found that 47gn N150 gave 0.3" or better 100 yard 5-round groups and 2,950 fps, still in the thin Norma brass and with the Fed 210M. I used this combination in club matches up to 600 yards and had some very good scores and a few wins, some of them highest score of the day beating all F/O competitors. (Times were very different in 2010 - not a chance today!)
Having just run 47 and 48gn through QuickLOAD in 57.4gn water capacity brass, the program underestimates MVs by the best part of 100 fps. I was told at the time that Broughtons were 'tight', but I've no idea if that was true or not, but if so that could account for some of the discrepancy. QL also calculates very heavily compressed fill-ratios of up to 112% with this combination - which is way out. (I find this a perennial issue with Viht powders in QL - it believes I run everything with 110% ratios or higher.)
As I said, the brass wasn't renowned for longevity and to get up to those MVs, QL says I had to be running right on maximum SAAMI pressures calculated at >61,900 psi for 2,985 fps with N150 and ~59,000 psi for my 2,950 fps match load, but I got several firings out of the cases, no leaking primer pockets or anything and they'd be retired after half a dozen cycles when primer pockets just started to feel slack - same as I was getting from Lapua brass at the time with slightly higher MVs. So I don't believe I was running really high pressures. No case-head marks or any other excessive pressure signs.
I wouldn't try N540 in your shoes. We in the UK did back in 2009 with the 155gn Scenar at 3,074 fps in Lapua brass from a 30-inch slow-twist Bartlein in my rifle and two friends with the same barrels from a single order running a bit hotter at just over 3,100 fps. Their barrels failed at 1,100 rounds, mine was nearly kaput at 1,500 - still performing but the borescope said it wouldn't for much longer, and I wanted to go to a faster twist anyway to try 185-210s. After a season or two of F-TR, GB shooters went 'off' this particular powder in a big way - and we pair shoot here as you know, and it's generally a lot cooler than in the lower 48, so it'd be a real barrel-killer in US F-TR.
