Trajectories at various distances with 25 yard zero

[Charging-Handle]

I'm brand new to the 300 BLK cartridge and brand new to this forum as well. The reason I chose 300 BLK is because it performs very well from short barrels and I wanted a short, maneuverable gun for home defense. That said, I come from a 5.56mm background and know very little about 300 BLK trajectories across various distances. I have somewhat settled on using a 25 yard zero because as a home defense gun, I want it optimized for shorter distances. But I am also curious where my shots would end up on target at 50, 100, 150 or 200 yards using that zero.

I know some of you folks here are a whiz with those ballistics calculators (having browsed the forum before joining), so if anyone could run the numbers for me I'd really appreciate it. These are my details:

10.5" barrel
Hornady Black 110 gr VMAX ammunition
25 yard zero
Holosun 510C red dot optic (similar to EOTech) with an absolute co-witness mount

I'm really curious to see what the +/- would be on this specific gun and ammo/optic combination with a 25 yard zero from 0-200 yards or thereabouts.

[steven11b]

Hello and welcome to the caliber and forum. Do you have a chrono? If so chrono the rounds and tell us your elevation. With that said, a Ballistic program will benefit you with every caliber as it will tell you exactly what you just asked.

Using basic info and a velocity of 2200fps, sea level and 25yd zero-


oyds -1.5"
25yds 0.0"
50yds +1.0"
75yds +1.5"
100yds +1.5"
125yds +0.9"
150yds -0.4"
175yds -2.3"
200yds -4.9"

With a 25yd zero its very usable out to 200yds on any size target without changing point of aim.

[dellet]

Hello and welcome to the caliber and forum. Do you have a chrono? If so chrono the rounds and tell us yuour elevation. With that said a Ballistic program will benefit you with every caliber as it will tell you exactly what you just asked.

Using basic info and a velocity of 2200fps, sea level and 25yd zero-


oyds -1.5"
25yds 0.0"
50yds +1.0"
75yds +1.5"
100yds +1.5"
125yds +.09"
150yds -.04"
175yds -2.3"
200yds -4.9"

With a 25yd zero its very usable out to 200yds and any size target without changing point of aim.

I think you have an extra decimal place in there.

[smustian]

You need to plug in muzzle velocity, center of sight above bore measurement, bullet weight, BC of bullet into a ballistics calculator to get a ball park of what the POI's will be. The only real test is to then go shoot and verify what the calculator said.

[smustian]

Standard sight height above bore for an AR style weapon is 2.6" not 1.5.

[steven11b]

Hello and welcome to the caliber and forum. Do you have a chrono? If so chrono the rounds and tell us yuour elevation. With that said a Ballistic program will benefit you with every caliber as it will tell you exactly what you just asked.

Using basic info and a velocity of 2200fps, sea level and 25yd zero-


oyds -1.5"
25yds 0.0"
50yds +1.0"
75yds +1.5"
100yds +1.5"
125yds +.09"
150yds -.04"
175yds -2.3"
200yds -4.9"

With a 25yd zero its very usable out to 200yds and any size target without changing point of aim.

I think you have an extra decimal place in there.

Good catch! Fixed it

[Charging-Handle]

Thanks for all the replies. Here's some additional data that has been mentioned....

Elevation: 837 feet
Height over Bore: 2.6 inches (estimated)
Muzzle Velocity: 2200 fps average is about right (I've seen variations from 2150 to 2250 fps from this barrel length with this load, depending on conditions)
BC: .290 per Hornady website

Either way, using the previous rough calculations it appears this ammo/gun/zero combination will be capable of doing what I hoped it could do....be able to keep hits in a saucer size circle from 0-200 yards holding dead on. That is all I could ever ask from this specific gun.

[steven11b]

Using 2.6" sight height and your elevation, youd be better off with a 50yd zero. The POI would be similar to the 25yd, 1.5" and sea level.

[smustian]

Using 2.6" sight height and your elevation, youd be better off with a 50yd zero. The POI would be similar to the 25yd, 1.5" and sea level.

Agreed. Much flatter trajectory with 50 yd zero.

Use this simple calculator:

https://www.hornady.com/team-hornady/ba ... lculators/#!/
or
http://www.jbmballistics.com/cgi-bin/jb ... mp-5.1.cgi

[Charging-Handle]

Yeah, after plugging the numbers into that Hornady ballistic calculator, the 50 yard zero definitely seems preferable for what I am looking for. So I'll just go with the 50 yard zero instead. Thanks for all the help.