Getting out of the comp world and figure on having fun shooting up all my left over "stuff". I have lots of HEAVY 30 cal stuff I'd like to bang steel with at LR/ ELR. 208, 210, 215, 220, 230 and 245 Bergers, 240 SMK's. 230 and 250 A TIPS, etc...... Problem is that my old 300 WBY tubes are 11 twist with one 12 twist and one old10 in the mix. Looking at picking up a 1.25 straight taper 8 or 8.5 twist 32ish inch long 30 cal and chamber it in a boomer on my BAT 1.55 M. I already have the standard and magnum bolt for it and will get a Lapua bolt face also if needed.
Thinking of the following..... which are at the top of the food chain as far as eating powder.....
300 ULTRA
30-338 Norma standard or Improved
30-338 Lapua standard or improved
30-378 WBY
Don't know much about the newer offerings like the 300 PRC or the 30 Nosler.
I have lots of RL 25, RL 33, Retumbo, H1000, H4831, and faster and faster powders and lots of Fed 215 M primers
Single shot...my 300 WBY LOADS with a 215 Hybrid is 4+ inch OAL, so looong freebore.
I have steel out to 1500 with flash bangs and places to shoot twice that far.
I know that there is a point of diminished returns.....do you see that point on this list?
Just thinking out loud,
Tod
On diminishing returns, figure every 100 fps moves the target 75 yards closer and costs 1/4 to 1/3 of the barrel life. Barrel life isn't a single number for each cartridge, it'll depend on your string length, rate of fire, single vs. double base powder, pressure level, and especially retirement criteria. If you wait for an ELR gun to open up groups at 100 yards to retire the barrel, you'll be stunned at the improvement the next time it's shot past 2500 yards.
1500 yards isn't really that far for a 30 caliber magnum, those bullets, and someone with competition shooting/handloading skills from a game where those bullets are leftovers. That doesn't mean it isn't very entertaining, but it'll be difficult for the "best" of your list to differentiate itself from the "worst". It's a treat to have a range that far so accessible but the "home range" effect will eventually set in. It'll be in full effect when you don't bother to calculate a fresh firing solution for this trip.
I suggest the cartridge question start with logistics and capacity. Logistics is what you already have and/or what is readily available or cheap. Starting with case capacity:
300WM - 92 grains of h20
300PRC - 96
30 Nosler - 98
30/28 Nosler - 100
300 Norma - 104
300 Norma Imp - 109
300 Lapua - 113
300 Ultra - 116
The reported case capacity varies with brass manufacturer, fired vs. unfired, and individual chamber. If your pet case has been slighted in some way, it wasn't intentional and probably is not relevant.
From factory ammo data, 300 Norma picks up about 120 fps over 300WM. QL gives similar numbers if the pressure for each is held the same and the powder optimized for velocity with each. H1000 for the 300WM, Retumbo for the Norma to keep it within the same powder line.
So, let's call it 100 fps for 10 grains of water. Some other fuzzy numbers for perspective are 10,000 psi peak pressure is 100 fps and switching from single to double base powders is 75 fps. Lengthening the barrel from 26 to 30" is also about 100 fps with these cartridges. There might be 40 fps in the next 2" but it'll more likely be closer to 30 fps. I used to order 32" from Bartlein because that was where the per inch price break was. I'd order 2, when the second one was chambered, I'd order 2 more. Now I order 30" from Bugholes because that's what is stocked.
So, more or less, kinda sorta, 10 grains of additional case capacity will cost about 1/4 of the barrel life. It doesn't seem to matter much how the additional velocity is gained, case capacity, pressure, or powder type; it all costs pretty much the same. The lesson I've taken from this is the smart guys use soft loaded larger cases instead of trying to be a hero and making a smaller case something it's not. Those meticulously prepared cases last so much longer and the resulting loads are much less sensitive to conditions and pure magic.
I started ELR with a 1:10 32" 300WM shooting 230 Hybrids. Needed every foot of the 3000'+ DAs I shoot at and a liberal definition of minimum twist rate to work. It won the first URSA match at 2050 yards in 2015. I can exceed the performance of that gun with a factory barreled 300 PRC. I've shot both in the same match several times. The big difference is the 230 ATips the 1:9 twist allows
and I load much better ELR ammo 10 years later.
I bought a bunch of Lapua manufactured 338 Lapua cases for 80 cents each when Barnes canceled a contract during the Remington bankruptcy. As a result, I shoot 300 Lapua. The 300 Ultra would probably be a better fit for you because of the bolt face you already have. It is ridiculous overkill for 1500 yards. Mine go ~500 rounds before they're done for past 2500 yards. The throats wear and start affecting the BC spread, killing the vertical past 2000 yards. At 1500 yards, it might not be noticed. Looking at barrel life as a cycle rather than 1 number, if both barrels have 500 rounds on them, the 300 PRC will start outperforming the 300 Ultra at 1500 yards and beat it with more in the turret but better vertical dispersion at 3000 yards.
Hot loads of N570 did in my first 300 Norma barrel for ELR use in 550 rounds. The 300 Norma is pretty much the most 30 caliber performance that can be fed from an AICS magazine. 3.85" is the outer dimension, the cartridge OAL needs to be below about 3.75". With a single feed gun that you already own a magnum bolt for, there is no incentive to use the Norma case.
The only gotcha I see in your plan would be wearing the barrel with free bullets at 1500 yards enough that when you make that trip for the 3000 yard shot, the barrel is working against you. If you're looking for a reason to build a boomer 30, just do it and get it out of your system. If you want to learn the cold hard business of ELR shooting, I suggest you set up 2 barrels. A 300WSM (~82 grains of h20) for high volume practice with the lighter bullets at 1500 yards and the 300 Ultra with the heavy bullets for the bucket list 3000 yard trips. That'd also split in half the bullet location in the neck / jump with multiple bullets problem.
