Thanks for all the info on these. With the price seemingly pretty close to Eotechs, What advantage would I get with this style close range over the holo's? They may be a little too budget for what I'm looking for, but what's the difference between the bushnell TRS-25 and TRS-26?
not sure what "this style close range" is, but a holographic weapon sight uses a prism and several mirrors to split and recreate a pattern from a laser diode, in theory allowing for a parallax free image that has a consistent size and relative position regardless of the viewer's position. a more typical emitter and refractor arrangement will appear to change size and position as the viewer moves their head.
the TRS-26 is a product improvement over the TRS-25 incorporating an Aimpoint T-1/H-1 compatible mount, additional adjustment settings for brightness and zero, and improved battery life, but at the cost of much higher weight. the TRS-25 is both less expensive, less complex, and lighter.
I figure I should specify more details and ask some questions: AR is currently rockin a A2 front post which I would prefer to 1/3rd co-witness, but I feel like realistically for close-medium range that may be ridiculously high with the A2's height. The reason I'm being a little anal about it is because my goal is to build a second upper that will be more prioritized to something like a low power scope.
co-witness is usually more about your ability to not be distracted by your back up sights than the optic choice itself. some prefer 1/3rd co-witness to remove clutter from the field of view which others prefer consistency with their stance and presentation and opt to ignore or remove/fold their back up sights away. the optic choice has very little to do with it unless it is difficult to get a mount for it at the height over bore you need to achieve your desired co-witness.
I will say I am curious that almost everything mentioned has be "true red dots", aka tube style. I am concerned about the ability to have good field of view while using it, and my understanding is that reflex/holographic are much friendlier is this regard, but it sounds like a true red dot is not as bad as I thought? edumacate me guys.
"true red dot" is an interesting way to describe them. the "tube style" is a consequence of the emitter technology started by Aimpoint for their refractive lens system. while it's true that a reflex optic (one that has a purposely thin bezel to minimize the "tube" effect) generally does provide a wider field of view, unless you are not properly focusing on your target through the optic, the optic itself should become nearly transparent when shooting as your other eye will compensate for the optic being in the way and your brain will superimpose the image, creating a ghost effect for the otherwise solid tube.
this is a hold over from how ghost ring sights work, and is illustrative of occluded "optics" as well, which is sometimes still used (have an illuminated dot in an optic and put a lens cap over the end so it cannot be seen through, then aim "through" the occluded optic with both eyes open and focus with the non-occluded eye, the red dot is also superimposed in your vision.
you generally should not use any sort of unmagnified optic with only one eye, which would be the primary cause for a bad field of view. some magnified optics can also be used both eyes open (Bindon aiming concept) for target tracking, but generally require an illuminated center dot and a relatively small eye relief / eye box where the effect works properly (Trijicon ACOGs use this design) and you should switch focus (but not close an eye) when it's time to shoot.
holographic weapon sights can be reflex or "tube" style. the difference is how the reticle is generated and made visible (laser diode and prism).
you might be better served with altering your shooting technique than focusing on a specific design of optic. if you don't want to do that, reflex optics will give you the larger field of view you want.
At what point is the ammo just too far gone to bring back? And are there any things I can look out for while inspecting to signify a particularly dangerous round?
generally any bulged, cracked, significantly dimpled or dented cases, or obvious signs of stress at the base or web (where the the case just meets the rim), or the shoulder are cartridges that might fail or induce a failure and be unsafe. corroded ammunition with verdigris (a cerulean corrosion via oxidation of brass) or rust (for steel cases) that is textured to the touch and isn't removed with scrubbing with a bit of steel wool and some oil is likely to cause a malfunction from scraping chamber walls or being weak or brittle from oxidation. discoloration or surface rust that is easily removed is unlikely to be a problem though. cartridges should also weigh nearly the same, so that's something else you can check for consistency.
very old or improperly stored cartridges can have issues with the primer or the propellent as well, with the primer losing percussive sensitivity with age as the priming material has hardened, or the powder separating over time as some of it oxidizes or was contaminated. when shooting a few safely with a remote trigger, listen to the sound volume given by the shot and ensure there isn't strangely loud or quiet reports, and that any visible muzzle flash is of equal brightness.
you can also just get a cheap bullet puller and take apart a few randomly selected cartridges and if you have a representative sample size that appears fine, the ammunition is likely to be also be in good condition, merely dirty.
Price indicates the 510 is "better" but what's the reality?
they aren't really "better", simply different in many ways. the HS503 is a more traditional enclosed red dot optic, which ruggedizes it in harsh weather and for some people, they prefer the option to use the red dot vs the compensated ring reticle without further complications. the 503 also has a few model variations for controls or a small solar panel to reduce reliance on the battery. the HS510 is an open reflex red dot optic, meant for fast target acquisition and is traditionally used in relatively clean environments that prioritizes an open field of view. while both sights can do this with effort, for some people, they find the reflex design easier to use in this fashion. the 510 also has variations with a solar panel and some reticle and control options. the mounts for the 510 are a bit harder to come by, as the HS503, being an evolved HS403, can share certain mounts.
choice between the two with boil down to budget, intended use, what the optic is attached to (some would prefer a lighter optic in place of a heavier one), and your abilities as a shooter.
