It's been interesting reading this thread. I'll share what I know to clear up a few misconceptions;
Boots Obermeyer did not "invent" the 5-R rifling pattern. He got it off the Russians. When the AK-74 was introduced by the Russians, Boots was asked by the gubmint to produce barrels to T&E the 5.45x39 ammo that was captured. He produced barrels in multiple configurations all with the 5-R being the most consistent. The "R" in 5-R is "Russian". Boots being a match shooter adopted it for his highpower and long range barrels where they did well. When the Army was developing their M-24, a 5-R barrel was spec'd. Mike Rock who apprenticed with Boots and whom Boots taught how to cut the compound angles of the Russian pattern produced the prototypes. When the M-24 was adopted and put into production, Remington elected to part ways with Rock and invested in the hammer forging tooling to produce their own 5-R barrels.
I don't know if a 5-R barrel is inherently more accurate but they're certainly not a detriment. I believe that the execution in producing the barrel probably has a greater influence, and Boots is/was one of the best so naturally his 5-R's shot. Boots would says that the 5-R pattern produced less stress on the bullet jacket when you were pushing a bullet hard.
There's more color and detail to the story, but this is what Boots had shared with me during our conversations. Fascinating man. I hope ole Barret J recovers and returns to barrel making.
Last edited by ChrisF; 03/31/18.
