What do you think of a 458 Lott necked down to hold 375 bullets? This is an improved H&H case I guess, slightly shortened.
A fellow contacted me to design a 375 caliber cartridge that could better handle the 350 grain Woodleigh bullets with all standard 300 grains as a secondary use projectile. Well, it took most of an hour to put this together as I was in the throws of loading up some 458 Lott ammo. I simply ran a 458 Lott case into a 416 then a 375 WSM die to give the neck length I wanted, made some measurements and adjustments, a reamer was ordered the next day.
The 458 Lott is the H&H case straightened out and trimmed to 2.800" from the max of 2.850" for the 375 H&H or the older 458 Watts. The Lott is a very good design for a 458 caliber. By shortening it .050" we can use the 500 grain bullets made for the 458 Winchester and crimp in the cannelure and maintain the established max overall length of 3.600". This length also works for the 350 grain, longer bullets of the 375 caliber. By removing the taper (actually using Lott brass there is very little taper) this gives us additional powder space to allow the 350 to be pushed to 2500+ fps, gaining almost 50 grains of bullet over the H&H.
This is probably one of the easiest case forming operations to do. I had annealed 40 cases and necked them down in one pass. I did also do ten more cases in two steps without annealing the necks. Of course this wildcat is not much different form the 375 Weatherby or the 375 Ackley improved ballistically but it does have the shorter length which could be an advantage for some applications. Besides, I think Jack Lott should have a 375 named after him.
I did consider using a full length straight H&H case, (called belted basic brass) such a case would be used for the 470 Capstick cartridge. This basic brass is more expensive and blowing out the taper and shoulder of the existing H&H or 416 Remington would require more work and 458 Lott brass is available and quite inexpensive by todays standard. The 458 Lott is currently a caliber factory chambered by a few makers and Hornady is on board with good brass and ammo. This gives us a supply of good brass to form into our wildcat at lower cost in terms of effort and money. Also, I think down the road we can get brass headstamped "375 Lott" for a reasonable charge. This brings the number of wildcats to five that I've designed in the past 18 months. I'm running behind. Does any one have need of a new caliber?