Recently someone mentioned Battle-Sight Zero (BSZ) for the 300 BLK cartridge. In its subsonic form, it has a rainbow-like trajectory. The supersonic form is less so. The key to getting a BSZ of 300 yards with this cartridge is zeroing at shorter distances.
With the right equipment and conditions, you could theoretically have BSZ of 300 yards with this load if you zero at 25 yards https://www.hornady.com/ammunition/rifle/300-blackout-110-gr-v-max-black#!/ . This is based on a ballistics calculator and not real-world experience. YMMV I am sure there are other loads that would work even better.
In no way am I endorsing this cartridge for shooting at a Known Distance event using BSZ I am just pointing out that sometimes you have to change your zero to something besides 25 meters if you want to shoot BSZ. There are much more dramatic examples if you increase the bullet weight (18 yard zero with 120 grain Federal copper cartridge).
For anyone interested, this Hornady load zeroed as above drops 24.8" from 300-400 yards.
Quote from: Tennessee Beast on July 08, 2020, 01:07:22 PM
For anyone interested, this Hornady load zeroed as above drops 24.8" from 300-400 yards.
Could you lay the target horizontal on the ground and just "lawn-dart" it?
Quote from: Sheepdog87 on July 09, 2020, 10:14:10 AM
Quote from: Tennessee Beast on July 08, 2020, 01:07:22 PM
For anyone interested, this Hornady load zeroed as above drops 24.8" from 300-400 yards.
Could you lay the target horizontal on the ground and just "lawn-dart" it?
If you read the long range trials of the 45-70 in 1879 at the beach at Sandy Hook, they certainly could have done so. The bullets were hitting at 45-50 degrees. http://www.researchpress.co.uk/index.php/firearms/long-range/sandy-hook-1879
While Shooting out to 300 with subsonic 300 blackout isn't impossible, I'm not sure you're student understands the concept of of a BZO
5.56 @ 500m has 90-100" of bullet drop
300 blackout "supers" have 90-100" of bullet drop at 450m
The biggest benefit to 300 blackout is that you have a round that can reach out to distance and touch something, and with a mag change you have a sub gun that is whisper quiet with about a 2" deviation from super to sub. Considering your effective zone 2" will still get you where you need to be.
I've been running almost exclusively 300 blackout out of an Ar platform teaching personal defense classes with it for some time so if you have any questions about 300 black feel free to send me a PM
Quote from: SSG Platz on May 04, 2021, 08:11:21 AM
While Shooting out to 300 with subsonic 300 blackout isn't impossible, I'm not sure you're student understands the concept of of a BZO
I don't remember who asked, so I can't comment. I'm pretty sure it was someone who understood BSZ fairly well, I just don't think they had ran the math.
Everything I've read and seen point to the most common supersonic loads being very similar to 7.62x39 trajectory. Sounds like a good place to start.
Quote from: 509gman on May 05, 2021, 04:49:28 AM
Everything I've read and seen point to the most common supersonic loads being very similar to 7.62x39 trajectory. Sounds like a good place to start.
Yes, but typically the Russian round is zeroed at different ranges due to firearms it is chambered for. One would zero an AK (is that an oxymoron?) or an SKS with iron sights differently than an AR due to sight height.
As OP, my point was that a 25 meter zero doesn't work for all cartridges if you want to have a BSZ of 300 yards. You may want to experiment a little to find the sweet spot.