One optic I was looking at for my 300 BO build. Is the Primary Arms 1-6x24 with the KISS reticle.

https://www.primaryarms.com/pr...minated-kiss-reticle

The sub-tensions are in 1 mil it looks like. I'm just wondering how this would correlate or line up with Supers or Subs in 300 BO. 10.5" barrel.

quote:

Originally posted by myrottiety:
The sub-tensions are in 1 mil it looks like. I'm just wondering how this would correlate or line up with Supers or Subs in 300 BO. 10.5" barrel.

The subtensions are not all that usable IMO. Furthermore, the elevation turret moves in increments of MOA -- not the mils that are used in the reticle. I see that as a reticle mainly for use at the zero distance, not other distances.

The flight ballistics are radically different between subsonic and supersonic ammo. Subsonics drop like a rock in comparison, and it is noticeable at only 50 yards.

quote:

Originally posted by fritz:

quote:

Originally posted by myrottiety:
The sub-tensions are in 1 mil it looks like. I'm just wondering how this would correlate or line up with Supers or Subs in 300 BO. 10.5" barrel.

The subtensions are not all that usable IMO. Furthermore, the elevation turret moves in increments of MOA -- not the mils that are used in the reticle. I see that as a reticle mainly for use at the zero distance, not other distances.

The flight ballistics are radically different between subsonic and supersonic ammo. Subsonics drop like a rock in comparison, and it is noticeable at only 50 yards.

Yeah the rifle will be used for goofing off with steel plates. Maybe take a deer hunt 1 a year.

By the looks of this chart. (If I even did it right.) For 110 gn round It would get me within a 1.5" from 25 yards - 150 yards.

http://www.shooterscalculator....chart.php?t=e3b4d097

For a scope like this it wouldn't bother me the clicks are MOA and reticle mils as I wouldn't be dialing anything.

OP, run the loads through a free online ballistic calculator like JBM https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

You might get lucky and find that say a 100yd zero with supersonic corresponds to a 100yd zero at the 2 mil mark with a sub.

If the marks just don't really match anything useful on the trajectory of either then I'd skip this reticle.

quote:

Originally posted by Strambo:
For a scope like this it wouldn't bother me the clicks are MOA and reticle mils as I wouldn't be dialing anything.

OP, run the loads through a free online ballistic calculator like JBM https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

You might get lucky and find that say a 100yd zero with supersonic corresponds to a 100yd zero at the 2 mil mark with a sub.

If the marks just don't really match anything useful on the trajectory of either then I'd skip this reticle.

That's kind of where I am. I wouldn't ever dial this thing after I settled on a zero. I'm just wondering if there is a effective zero of either 25m or 50m or ??m that would make this effective.

I'm not sure I'll ever make a shot long enough for it to matter frankly. Unless I'm just hitting 300m steel using the 2mil mark. It'll likely be a 100 meter and in gun for all intensive purposes %99 of the time.

quote:

Originally posted by myrottiety:
It'll likely be a 100 meter and in gun for all intensive purposes %99 of the time.

You need to consider the flight ballistics for various 300blk ammo, as the bullet weights and velocities are so different. I have an 11.3" barrel blackout -- the following drops are pure drops from a 0" sight height over bore calculation. Drops are rounded to the nearest inch. This may sound odd, but once you shoot subs and supers from the same gun without changing an optic's zero, you'll understand. Trying to get the two types of ammo to work in one holdover-type reticle can be an interesting challenge.

110 Hornady Vmax -- 2196 fps MV
1" -- 50 yards
4" -- 100 yards
9" -- 150 yards
16" -- 200 yards
40" -- 300 yards

125 SMK Aussie Outback -- 2046 fps MV
1" -- 50 yards
4" -- 100 yards
10" -- 150 yards
19" -- 200 yards
46" -- 300 yards

150 FMJ American Eagle -- 1890 fps MV
1" -- 50 yards
5" -- 100 yards
12" -- 150 yards
22" -- 200 yards
51" -- 300 yards

208 Hornady Amax -- 1103 fps MV
4" -- 50 yards
15" -- 100 yards
33" -- 150 yards
60" -- 200 yards
137" -- 300 yards

And yes, subsonic ammo does impact 11" lower than supersonic ammo at 100 yards, using the same zero.

Just found this article: https://www.gunsamerica.com/di...ns-300-aac-blackout/

Though these are for high end scopes, both the ACOG and Leupold reticle photos show both sub and supersonic ballistics so it at least provides a visual of the trajectory differences when a 100yd zero is used for the supers. Doesn't look like the subs would correspond to anything meaningful on the scope in the OP, maybe a 50yd zero at the bottom of the chevron and 100 at the 2 mil mark.

This one cost more but looks like the ticket: https://www.primaryarms.com/pa...or-762-reticle-black

I think I may have found the ticket.

Once again it'll be a 100 yard & under rifle. So holdovers likely won't really be necessary on the shots I'll take. Unless I'm lobbing them at steel like mortars way off in the distance.

Also I want to make it clear. Only reasons Subs will be shot if for a giggle "look how quiet it is session" with the can.

Anyone have experience with the Vortex HD LH Line?? :
http://www.vortexoptics.com/pr...32-g4-bdc-riflescope

Looks like they are discontinuing them possibly. But they are Razor HD glass for $400'ish is you shop hard for it. That looks like a hell of a lot of glass for the money.

To each his own, but this question of supersonic and subsonic loads is a good illustration of why I am no fan of reticles that are calibrated for specific loads. I much prefer—and find no disadvantage in—zeroing a scope then preparing a trajectory chart to tell me how much to adjust the sight or to hold off for different distances or different loads. Any scopesight that’s calibrated in milliradians or minutes of angle can be used for the purpose and isn’t limited if I later want to change the zero distance or the ammunition.

As I’ve pointed out before, using a “bullet drop” reticle is also less precise unless shooting at the round number distances marked on the scale (100, 200, 300, etc.). For example, if the target is at 250 yards, where do we hold? (No, it’s not half way between 200 and 300. That may be close enough, but it’s not exact.)

quote:

Originally posted by sigfreund:
To each his own, but this question of supersonic and subsonic loads is a good illustration of why I am no fan of reticles that are calibrated for specific loads. I much prefer—and find no disadvantage in—zeroing a scope then preparing a trajectory chart to tell me how much to adjust the sight or to hold off for different distances or different loads. Any scopesight that’s calibrated in milliradians or minutes of angle can be used for the purpose and isn’t limited if I later want to change the zero distance or the ammunition.

As I’ve pointed out before, using a “bullet drop” reticle is also less precise unless shooting at the round number distances marked on the scale (100, 200, 300, etc.). For example, if the target is at 250 yards, where do we hold? (No, it’s not half way between 200 and 300. That may be close enough, but it’s not exact.)

I am just the opposite for a general purpose rifle.

For the purposes and target sizes of IPSC rifle, 3-Gun, etc.... you do hold just between the stadia of 200 and 300 for a 250 yard shot. Close enough is good enough when you are shooting offhand at a target that is 263 yards away and you are breathing hard because you just ran 100 yards and your shooting glasses are fogging up due to sweat. At that point precision isn't the name of the game and whether you are bracketing the target between the 200 and 300 stadia or if you have a perfect dope card for a true MIL reticle, your ability to make an accurate shot is going to be about the same. Similar situation if you are in a tree standing twisting around to shoot a deer that came out at a weird unexpected angle.


I like a MIL reticle for my precision rifle but a well designed BDC for 223 works great for everything from 50gr to 77gr, with a little careful thought to zeroing distance.

It is true that a BDC doesn't line up perfectly for all ammo, but neither does a strictly MOA or MIL optic.



300 BLK is a unique animal because the ability to use supers or subs and the wide spread in ballistic performance between the two.

Either way, you will need a dope card if you plan to stretch the legs of a cartridge. While I certainly acknowledge the utility inherent of a good MRAD reticle I think some of the negative attitudes towards a BDC reticle are born more out of theory than practical application.

Both certainly have their place and I think it largely depends on the end use of the shooter.


So yes you might still need a dope card with a BDC but if you are shooting that far you are going to need one for MIL or MOA as well.

^^^

For a shorter range cartridge and general purpose shooting the BDCs can work very well. For example, I have a TA33 ACOG on a 14.5" 5.56 AR. I took it to a 500yd range and was able to get 2nd round hits on steel (then nearly 100% hits once I had the hold) in what I estimated to be 7-12mph winds first with 75g ammo, then 55g. Steel was 12" and 24".

So, a 300 BLK with a BDC would be lots of fun and good enough out to any reasonable range. The advantage is speed which is why they work well for M4s/M16A4s in combat as well. Now for a precision or even semi-precision DM type rifle, I'm with you 100%. A mil reticle with mil adjustments and custom chart all the way.

Thanks for the perspectives of both of you.