Re: RELOADING RL-15 175GR SMK OUT OF M14 SAFE MUZZLE
LC M118LR is loaded to 2580 fps, which is what's needed to keep the 175 SMK supersonic at 1,000 under normal atmospherics. This isn't muzzle velocity. Like most military ammo, it's instrumental @78 feet, which corrects back to a MV of around 2620-2640 fps, if I recall correctly. The RL-15 you're using was the normal powder used in this round for the past decade or so, so you should have no problem in reaching this. One minor change you can't duplicate is the primer; LC uses their M43 primer for ther M118LR loads. The M34 primer you have is the standard military Large Rifle primer, and would roughly equate to a commercial Large Rifle Magnum primer. Unfortunately, the M43 primer isn't produced or sold commercially. You'll have to do some work ups to avoid issues from the hotter primer, but it shouldn't be any real problem for you.
When loading for LC certifications, I normally used somewhere between 41.0 and 42.5 grains of RL-15, depending on the lot I had on hand. Yes, it really can vary that much, and there is no "set" load that LC uses. It's dependant on the velocity, pressure and accuracy, and each individual lot gets its own work-up when they begin a run. The process gets repeated if they have to make a change of lots. Nature of the game, no way around this part.
The whole op rod issue centers more around using powders that are too slow, rather than too heavy a charge of an appropriate powder. Good to see that you're concerned about this, but you should be just fine with the RL-15 if you stay within these parameters.
