What you are reading is people’s satisfaction with their Swedish rifles but don’t get carried away with the enthusiasm. Your rifle should be perfectly safe with Swedish service ammunition, it should be perfectly safe with ammunition loaded to Swedish service rifle pressures but Swedish service rifle ammunition is not that hot. I don’t know if anyone is selling a +P 6.5 X55, but just in case, don’t let fans convictions about “Swedish Steel”, its supposed strength and durability fool you into sticking hot loads into your rifle. It was not designed for it and its pre WW1 metallurgy may not support it. People just do not understand how primitive process controls and metallurgy were back than and these old plain carbon steel receivers will break with the sort of abuse that would only damage a modern receiver.
I am certain that the owner of this receiver took too literally claims of “Swedish Steel” being superior and hot rodded his rifle.
These are velocities of Swedish service rifle ammunition from a couple of my rifles. These loads are absolutely fine as is.
M1896 Infantry Rifle 29' barrel Carl Gustafs mfgr 1903
17-Aug-06 T = 85 °F
143 gr FMJ 1986 Swedish Ball
Ave Vel = 2610
Std Dev = 14.38
ES = 45.59
High = 2633
Low = 2587
N = 8
M38 Infantry Carbine 24" barrel
28-Oct-94 T ≈ 60 °F
143 gr 1986 Swedish Ball OAL 3.065" 47.4 grs powder average
Ave Vel = 2427
Std Dev = 22
ES = 62
Low = 2395
High = 2457
N = 10