Optic Selection for 12.5

[a1madrid]

The reticle trijicon makes for the 14.5 barrel will be close enough that you can easily make it work for a 12.5 with suppressor. If you're starting to tell yourself that's not precise enough....then LPVO it is. MHO.

I completely understand what you are saying and I’ve been flip flopping between the two options for months now. I like the weight savings, simplicity, and efficiency of the ACOG though.


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[a1madrid]

Attachment 68310
Fed XM193/12.3” barrel that is a little on the slow side, due to age. That’s hits all day out to 500, with a little holding at 600, where wind and precision will be screwing with you, anyway.
You definitely want Strelok. Once you figure out how to use it, it definitely helps a lot with figuring out BDC reticles, which are frequently not quite as advertised for bullet weight and velocity. Helps for deciding which one to use.

I bought Strelok Pro and this is what I got with Federal XM193 using chronographed data I found online. I zeroed in inch low at 100 using a TA31RCO (made for a 14.5 shooting 62 grain green tip). The XM193 did very well to the reticle when I zeroed it an inch low at 100. When I zeroed it right at 100 it actually slightly outpaced the reticle by a little more.


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[Eurodriver]

I would not get too hung up on the reticle.

I have used the A4 and M4 TA31s on A4 and M4s with M855 out to 500 yards. I have literally never had one match. In fact, for the A4 in particular, it's usually shooting high by about 2+ FEET at 500 yards.

The only real way to know where the stadia lines end up is to shoot your gun with your ammo in your environment. M193 at sea level out of a cut rifled SS 12.5" is going to fly vastly different that M193 in Denver out of a button rifled nitride 12.5"

ETA: I would put an ACOG on a 12.5".

[ExplorinInTheWoods]

I put a 1-8 credo on a 12.5, I have not put the offset dot on it yet. I’ve only shot it to 300. It was boringly accurate. I run a 1.7 badger because I think 1.93 should only be on dots. Higher scope mounts are not great in my opinion because of the trend in ffp optics, they have worse eyebox es and now you’re taking away a consistent cheekweld by going higher. If you want the high dot get a normal scope mount and add a 12 o clock dot. Streklok is awesome and very useful, keep in mind the height over bore is mis labeled as optic height so it defaults to 1.5 but you end up adding like .95-.97 for actual bore to rail height.

[danieljmaunder]

Height from center boreline to top of pic rail in the measurements I've done on 5.56 guns is 1.2. Add in scope height say 1.5 standard height mount and you get 2.7 fot your actual height over bore. I typically run 1.5 mounts on a .5 riser, comes out to about 3.2. That works well for me being 6'5 and a big ass neck. Also completely clears the IR laser. Fore most people, running a 1.7 height on a 12.5 with an lpvo will be fine. For the shorter guns I really prefer RDS with magnifier but thats just me

[Pappabear]

Do you have StrelokPro and a chrono? One thing I never understood (granted my knowledge base on dope, holds, etc is close to zero) is putting something with minimal stadia on an SBR. The reduced velocity from a shorter barrel would tell me that you need a reticle that’s has lots of drop because the round is going slower. I don’t know which ACOG you’d be looking at but something to consider, same thing goes for a JM-1 Razor.

I like the dot+mag more and more. I’ve only consistently shot out to 200 with mine but on 8” plates or smaller. Another thing I don’t understand is when someone picks an arbitrary distance they want to shoot at but no target size. I assume man size, but there’s a big difference between that and a massive steel rectangle. Man size at 500 with a dot and mag would be pretty difficult IMO. Again something to consider is the reticle, you have to be very practiced to know your holds when the only thing your optic gives you is one dot. I’ve really gotten to liking the EXPS 3-2 reticle for up close and it seems reasonable on paper at distance, though I haven’t stretched it yet. Keep in mind that holosun makes an Aimpoint micro size dot with a ACSS reticle that has elevation holds.

Personally, something like the Razor GIII 1-10 or probably the new PA Platinum Compact 1-8 make a lot of sense to me. Both are lighter than the Credo and have significant reticles that would compensate for the decreased velocity/increased bullet drop. Initial reviews of the PA have its 1x performance rivaling the Gen II Razor 1-6 while being lighter and having a more useful reticle plus 2x higher, but at the cost of brightness. The 1-10 Razor won’t sacrifice on brightness and is in between the weights of the Credo and PA but at the price point of the Credo or higher.

As far as offset, a T2 sounds like overkill. I ran a 507c for a little while to include during some 3-gun where the rifle was getting dumped and it did great. Pretty big weight savings over the T2, and the RMR is even lighter. Again though, offset or top mounted is a bit unorthodox So having a dot with more reticle may help finding it in some circumstances. I’m currently experimenting with the ACSS Vulcan 507 for that.



Obviously not a 12.5 but I love this so far on this gun and would really like to build a 12.5 with the same optic setup.


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Nice gun Wake, that is the optimal solution but if he didn't want to goto that extreme, RDS with 3X would work just fine. An ACOG with RDS up top or 45 would be nice. As always, a lot of good options and nothing perfect. Good luck with your 12.5

PB