Hi Just Macca,
ILya said it well, optically the 3-15M and 3-15P are identical. The differences are of course the tube diameter, turrets/total travel, tool-less adjustment and weight. Between the 2 I actually prefer the P for the turrets and overall "feel", but really there is no way to argue against the M in almost all cases. Lighter, plenty of travel, excellent turrets (though not quite as fast or comfortable as the bigger ones if dialing constantly/quickly) and the same optical performance. I suppose if outright durability was a heavy concern that the P may also be more robust, but I wouldn't doubt the toughness of the M.
Compared to the 5-25, the image quality is the same technically I would imagine (and they are both just jaw-droppingly good) minus the larger objective and magnification. I would assume the 5-25 is generally going to be the best image you get from a TT, but it seems visually the same minus the power to me. As well, since the 3-15P is on the heavy side for its class, jumping the extra 4 ounces to the 5-25 might make sense if you prefer that power range etc. Note they are very different packages in terms of overall size and balance on a rifle though despite the modest weight difference.
For the reticles:
I think the G2MD is perfect in the 3-15 M/P (through the whole power range) and the Gen 2XR is perfect in the 5-25P. The G2MD actually has smaller subtensions in the important first .5 mil as it has the .28 mil per side floating cross as the center of the reticle. It is of course easy to visually split both reticles, but I just find the weight, appearance and utility of the gen 2 mil dot to be preferable in the 3-15. Of course this means I prefer to primarily dial elevation (those sweet sweet turrets) and typically only use elevation holds if they are small/quick or necessary for whatever reason.
In the 3-15 the inner lines of the reticle are also heavier in the G2MD (.15 mil vs. .025 mil) as well the full mil dots help beef up the visual profile. Depending on the lighting and color of the target the inner reticle on 3x can appear as a thin duplex/reference, or it can be visible enough to make out the subtensions. The illumination is just the inner .56 mil cross, which I also prefer and works well if you need it to reference center in very low light.
Sidebar: the center cross being .28 instead of .25 is a little weird (I'm sure there is a reason)...but in application it still works great and isn't worth getting worried about.
All that said I believe the main factor contributing to the increased reticle visibility on 3x is the presence of all 4 heavy outer bars (where on the Gen 2XR the bars are not only thinner but the bottom bar is further away at 10 mils). This really helps draw you to and bracket the center of the reticle. I think the G2MD will still be the best on 3x as the MSR2 for example only has two heavy bars and they don't start until 10 mils out (instead of 5). Of course we will have to wait and see what it actually looks like if it does show up in the TT scopes.
Keep in mind that it is still an ffp reticle at 3x, so it is still relatively small...but definitely visible enough to work well. Also keep in mind that as early as 5-6x I find them both very useable...so it really depends on how much you value the 3x use and also which reticle you prefer overall.
Hope that helps, the other posters here have made excellent points and posts as well. I am also definitely interested to see what new reticles show up in the TT scopes (whenever that may be). Have a good one!
-TSean
P.S. The pics above are good...nice work Wjm308!
