I attended a short range br match this weekend and shot with a guy that had an interesting cartridge sitting on the bench with him. I noticed it and recognized it from articles in the Varmint Hunter. I asked the guy where he got his cartridges and he replied that he invented them. I asked, "aren't these the round shoulder cartridges M.L. Mcpherson designed?" He said, "no, I designed it. M.L just advertises them."
At first I thought he was kidding me. But then he introduced himself and told me the story behind the development of these cartridges and how they got their name. The "S" in SMC stands for Smalley which was his last name. He is the founder and patent holder for Superior Ballistics INC. He worked in rocket building for several defense companies including Morton-thiokol which builds the Saturn rockets that take the space shuttles to space. In other words, this guy knew his internal ballistics!
He said he simply applied rocket building techniques and shapes to small arms cases and $75,000 later, he had patents for the rounded shoulder. This shoulder is reported to give much higher velocities while keeping the throat cooler. It also gives better standard deviations and extreme spreads.
There is a whole line of calibers in the SMC line, but the one he was shooting this day was the 20 caliber version based on the 6br case. He claimed that is was launching 50 grain Berger VLD's at 3950 from the 30" barrel with 32 grains of powder. That is roughly 150 fps faster than a 204 ruger will push a 39 grain bullet with 28 grains of powder. If true, that is pretty impressive performance. I had a chronograph in my truck and I really wanted to chrono it, but there was a BR match I was shooting in and didn't have time to mess around with it.
I did however get to spot for him while he got it on paper and I can honestly say that his bullets were hitting the burm at 300 yards at least three times faster than the bullets from all our 6ppc's so I know it was haulin' arse.
Anyhow, brass can be bought from Norma (or Lapua-I forgot) and rifles can be special ordered from Savage. Barrel twists are properly set up for heavy for caliber bullets. This might be a good way for a poor man to have a semi-custom long range hammer without going to much trouble. Anyhow, I thought it was interesting. Here is a pic of the ammo: