I used to believe the larger the bore, the more efficient. Since these tests, I have no clue what's going on lol I "believe", a .338 Federal would be more efficient than the .308, and a .358 Win would be more efficient than the .338 Fed.
I don’t know what’s going on either, but it’s certainly an interesting topic and testing results that blows everything I was led to believe out of the water! But, I think there may be more unidentified variables involved, since OPs here are reporting different results? Just don’t know?
I hope by getting my hands on RL17, I can show bigger velocity windows between the Alaskan and African.
I just took this pic from my Hornady manual. Either your loading your Rigby over max or my manual is too conservative?
Rl15 should be useable but with a lot of research and caution. I have used AR2206H (H4895, IMR4895) in my Rigby. NOTE this was with cast bullets and I obtained the info from a mate who ran different loads through the Quick Load program.
These would, I suspect, be in a fast barrel. My manuals say the 4350 powders 94 grains for 2450fps, remembering AR2209, H4350 and IMR4350 are the same powder, manufactured in Aust as AR2209 and sold as the 4350 powders in the US. The 4831's are AR2213sc.
That particular 308 of mine-I have sold that one- would get 2680fps with a 150 grain projectile and very flat primers and sticky bolt lift. I now have a Browning XBolt and Steyr Scout in 308. Yet to velocity test in the Steyr. The Xbolt is very close to those figures with a 155 grain projectile.
That’s a big jump from Hornady’s H4350 @ 90.5gr max and Hodgon’s 96gr max? If/when I can ever find some H4350 I think I’ll start with a milder charge and go up from there? Might have to use some filler to keep the powder against the primer when the massive case is horizontal in the magazine and chamber?
I have some IMR4350, and (in my .375 Ruger) I couldn't get a 300gr TSX seated on 79 grains. The bullet pushes back out. I have no earthly idea how'd you get 96 grains in it.
Yeah, I don’t know? I load my .416 Taylor with 70.5gr of RL15 for a moderate load. I think 74gr is max.
In the Rigby case 96 grains AR2209 is a conservative load. You can load it up to near 416 Weatherby velocities with about 110grains of AR2209 or 120 grains of the AR2213SC. However my shoulder agrees with the rest of me that the 96 grains of AR2209 will do nicely.
I started with the ADI recommended min of 89 grains of AR2209 and no need for a filler, use magnum rifle primers. From memory I was getting just below book velocities about 2300fps.
@TOBY458 uses a 21” Sako. Ask him.
I was getting 2750 fps with 270gr TSX. 2550 with 300gr Swifts and TSX. Barrel length 21 1/4".
I would not go shorter than 20" and that would be a pushing it. Not because of velocity loss. I had the unfortunate experience on 2 occasion os sitting at a bench next to a bloke with an 18" 375H&H. He also had a break on it. Every time he fired I had plenty of unburnt powder landing on my bench-lucky I had eye protection on- and my Chronograph would give an unburnt powder velocity. I say this as each reading was around the 1000-1200 fps mark.
