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Hornady recommends 2.750" COL (69.85 mm) for that bullet in .308 Winchester. The soft points bang up easily, though, so don't be surprised if the bullet lengths vary by .2 or .3 mm, causing your COL to vary. If you cover 2/3 of the crimp cannelure with the mouth of a case trimmed to 2.005" (50.93 mm), then the COL will be correct.
Hornady shows RL-15 never below 35.3 grains (2.29 g) and not above 44.3 grains (2.87 g). However, this is in the Hornady/Frontier brand case. .308 cases vary a lot from brand to brand, and I don't know the volume of your Norma cases. If you can provide the weight of one, we can estimate. It is best to take one that has been fired in your gun and weigh it and fill it with water level with top of the case (no meniscus) and weigh it again to see how much water it actually holds. That is what loads should be based on.
Anyway, in the M1A/M14 action, I would not use less than 40 grains (2.59 g) to start in the Hornady/Frontier case. If your case turns out to be similar, then we can adjust that.
QuickLOAD does show the RL-15 and 203B to be very similar and having the same starting burn rate.
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