bladeracer wrote:
One thing SFP can do that FFP can't is give you variable subtensions, as I explained about the holdovers changing with magnification. My reticle has holdovers out to 15.4MoA (for a theoretical zero at 600yds with a specific .223Rem load) at 18-power. If I'm shooting a load that requires say 31 minutes (heavier bullet, reduced velocity, a blunt hunting bullet, or simply a different cartridge - like .22LR) I can wind the scope back to 9-power, hold on the same "600yd" sub tension, and voila, I have a 31 minute holdover. Printing a dope card of the variations throughout the magnification range is no harder than any other dope card.
You can also range targets the same way, by adjusting the magnification to fit the reticle to the target, read the magnification, and read the dope. For example, you set out 150mm gongs (roughly the size of a non-helmeted head) at random distances. I'm using a 150mm target simply because it fits easily in metric or imperial ranging, 150mm is roughly 6MoA at 100yds and 5MoA at 100m (so I don't need a calculator for this example, I'm doing this on my phone). My scope has holdovers at 1.7, 4.4, 7.6, 11.4, and 15.4 minutes - at 18-power. At full mag, I put my reticle on the first target and it covers about three-quarters of the height to the second (or 4.4MoA) dot, about 3.3MoA, so I already know the 150mm-tall target (5MoA@100m) is around the 150m mark (at 200m the gong is 2.5MoA remember, so at 150m it's 3.33MoA). If I want more precision, I can adjust the magnification to fit one of the marks as neatly over the target as I can. I can't make the reticle "smaller", so I wind the mag back until the 1.7MoA gap "grows" to cover the target, then read the magnification. In this case it's 9-power, making the subtension actually 3.4MoA. So our 5MoA@100m gong is at about 145m. As my scope has 1MoA dots, I can do the same to make a dot fit over the target instead of the gaps between the holdovers.
It sounds complex, and takes a long while to explain what is not very complex, but with practice it becomes second nature, you can roughly estimate the range as soon as you put the reticle over the target, without having to adjust the magnification, regardless of the type of reticle you use. The most rudimentary version of this is learning the fields of view in your scope at various magnifications, mine goes from 63MoA (roughly one degree) at 18-power to 230MoA at 4.5-power. This is one reason all my scopes are identical, including the reticle - I am familiar with how large things should appear in my scope. Calculating it merely gives you a more accurate range estimate, but if you need precision use a laser.
Take your 150mm target ranging example and with a FFP mil scope just do this on any magnification
Like you said though much easier and precise to just use a laser as unless you know the actual target size and are measuring it correctly it's basically just a guess.
bladeracer wrote:But the primary reason to prefer SFP for precision shooting is the fine reticle, whether you're at 4-power or 24-power. You can see the difference in the picture I posted. You can also see how the holdovers change as magnification does.
My FFP reticle thickness is a constant .054 mils (5.4mm @100m) regardless of magnification.
Your SFP with a reticle thickness of eg .125 MOA on max power 18x (3.64mm @100m) is actually 3 times thicker than mine at minimum magnification of 4.5 power (16.37mm @100m)
I think we have come a long way from your original intent though and everyone is free to use what best suits them.