Am I Doing This Right - Noob 300BLK Build

Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.

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VegasSirk
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Am I Doing This Right - Noob 300BLK Build

Post by VegasSirk »

Hi Guys,

Nice forum you got going on here. I just found the site today. I recently undertook my first AR Build and decided I wanted to go with 300BLK set up since I love my Bulgarian AK and thought it would bring some of the punch over to the AK platform (only had an RRA 556 AR in the past).

With that said I wanted to get some feedback on the build so far. Here is the current list of parts:

-Sharp Bros Warhog Lower, with Sharp Bro Upper and 10" Handguard
-American Trigger Adjustable Gold Trigger
-Radian Talon Safety and Radian Raptor Charging Handle
-Aero Precision BCG
-Ballistic Advantage 10.3" 300BLK Hanson barrel with pinned low pro gas block
-Q Cherry Bomb muzzle brake w. Q Whistle Tip
-Magpul UBR Gen 2 stock, Mag pul MIAD Type 1 grip, Magpul MBUS Pro Sights, Magpul 300BLK 30 round mags
-Form 1 Tax Stamp

The goal was also to add a suppressor and optics to make a Recce Rifle set up. The first question is do you think this combo is a solid combo for a Recce Rifle setup? It seems like Recce Rifles are used up to 500 yards roughly and wasn't sure if the 10.3" barrel + suppressor + 300BLK would be a good fit? Second, for those of you with Recce set ups, what optics are you using? I see Primary Arms seems to be the only company with a 1-6 30mm scope with a 300BLK specific reticle, is a 300BLK reticle really needed? Any recommendations for a 1-6 or 1-8 optic that I could combine with an SRO?

Appreciate any help you guys can send my way. I'm new to this so still trying to learn everything I can.
ReadyAimDuck
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Re: Am I Doing This Right - Noob 300BLK Build

Post by ReadyAimDuck »

I'm not entirely sure what a reece rifle is, or what one would be used for, but if you're looking to shoot out to 500 yards you're probably not going to enjoy the results out of a 10.5" 300 AAC. That bullet is going to be very low energy and with terrible wind resistance and dropping like a brick at that distance. I just ran some quick numbers on a very popular hunting load and the bullet drop at 500 yards out of that barrel would come out to about 104" at 500 yards. But if you look at the difference between 475 yards and 500 yards, the difference is about 26". That type of trajectory at that distance makes just about any kind of realistic shooting impractical, at my skill level anyway. 10 yards miscalculation in distance is coming out to 8" difference in point of impact, and a 5 mph crosswind is pushing the bullet more than 25" off course.

I think your build is an excellent close quarters setup. But I think you're going to be disappointed if you intend to shoot it practically at longer ranges.

As for the reticle, its hard to find one that matches up with the 300. There are so many loads and so many popular barrel lengths that make for a very wide range of trajectories. My advice is to find a reticle you like, work up a load that your barrel likes, and learn where the different holdovers are for that load. It may not be 300, 400, 500, for example. It may be more like 285, 315, 335, but you can figure out what works for you and figure out how to memorize it or write it down somewhere handy. I use a 5.56 reticle thats inteded for 300, 400, 500. But my setup has MPBR of around 260 yards. So beyond that, I have to start using the holdovers on the reticle. Since the 300 BLK has a different trajectory than the 5.56, I just match how many MOA down each hash mark is to how many yards out that correlates to where the bullet is going to drop in its trajectory. And I usually tape a card with that info on the stock or the side of the scope.
BJK
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Re: Am I Doing This Right - Noob 300BLK Build

Post by BJK »

'Duck, I didn't know how to help him so I remained silent, but recce is short for reconnoiter. At least that's how I understand the words usage.
ReadyAimDuck
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Re: Am I Doing This Right - Noob 300BLK Build

Post by ReadyAimDuck »

I think you're right. I just read an article about it. Seems like a really neat concept. The one takeaway I'm getting from it that stand out though is that it is a rifle intended to bridge the gap between a standard issue M4, and a sniper rifle. And it seems that they originally were designed on the 5.56 platform and settled on an 18" barrel instead of the 20" barrel that some originally had hoped to run. The 400-500 yard requirement does come up. We need to keep in mind though, that the 5.56 out of the 18-20" barrel is going to have a lot flatter trajectory than the 300 AAC out of an SBR length setup. So, I think the build in the OP is an awesome set up for a lot of things. It just doesn't seem like it fits the 500 yard rifle setup very well. It seems that if there was an intention to build a recce rifle out of a 300, it would utilize every inch of barrel it could possibly get for the added velocity.
noname
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Re: Am I Doing This Right - Noob 300BLK Build

Post by noname »

Recce rhymes with "Becky". Out to 500 yards would not be practice with subs. My PointBlank Ballistic v2.0.92 ---Bullet wt 125 grs, 2375 velocity, altitude 500 ft, zeroed at 200 yds. temp 59 degrees, sight ht 1.50 inches over bore.

3 inches high at 100 yds, 11 inches low at 275 yds. 24 inches low at 350 yds.

Sounds like your gun would work out to 200 yds.
Previously known as hardcase. Moved lost internet connection for 1+ years.
noname
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Posts: 92
Joined: Tue Aug 27, 2019 8:55 pm

Re: Am I Doing This Right - Noob 300BLK Build

Post by noname »

ReadyAimDuck wrote: Sat Mar 20, 2021 2:44 pm I think you're right. I just read an article about it. Seems like a really neat concept. The one takeaway I'm getting from it that stand out though is that it is a rifle intended to bridge the gap between a standard issue M4, and a sniper rifle. And it seems that they originally were designed on the 5.56 platform and settled on an 18" barrel instead of the 20" barrel that some originally had hoped to run. The 400-500 yard requirement does come up. We need to keep in mind though, that the 5.56 out of the 18-20" barrel is going to have a lot flatter trajectory than the 300 AAC out of an SBR length setup. So, I think the build in the OP is an awesome set up for a lot of things. It just doesn't seem like it fits the 500 yard rifle setup very well. It seems that if there was an intention to build a recce rifle out of a 300, it would utilize every inch of barrel it could possibly get for the added velocity.
Yes. What I learned is recon was popular during and after WWII before the advent of satellites and the airplane called the Blackbird. Awesome spy plane. None have ever been shot down. If needed, they fire-walled the throttle and outrun missiles of the era.
Previously known as hardcase. Moved lost internet connection for 1+ years.
VegasSirk
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Joined: Wed Mar 17, 2021 6:56 pm

Re: Am I Doing This Right - Noob 300BLK Build

Post by VegasSirk »

ReadyAimDuck wrote: Fri Mar 19, 2021 10:04 pm I'm not entirely sure what a reece rifle is, or what one would be used for, but if you're looking to shoot out to 500 yards you're probably not going to enjoy the results out of a 10.5" 300 AAC. That bullet is going to be very low energy and with terrible wind resistance and dropping like a brick at that distance. I just ran some quick numbers on a very popular hunting load and the bullet drop at 500 yards out of that barrel would come out to about 104" at 500 yards. But if you look at the difference between 475 yards and 500 yards, the difference is about 26". That type of trajectory at that distance makes just about any kind of realistic shooting impractical, at my skill level anyway. 10 yards miscalculation in distance is coming out to 8" difference in point of impact, and a 5 mph crosswind is pushing the bullet more than 25" off course.

I think your build is an excellent close quarters setup. But I think you're going to be disappointed if you intend to shoot it practically at longer ranges.

As for the reticle, its hard to find one that matches up with the 300. There are so many loads and so many popular barrel lengths that make for a very wide range of trajectories. My advice is to find a reticle you like, work up a load that your barrel likes, and learn where the different holdovers are for that load. It may not be 300, 400, 500, for example. It may be more like 285, 315, 335, but you can figure out what works for you and figure out how to memorize it or write it down somewhere handy. I use a 5.56 reticle thats inteded for 300, 400, 500. But my setup has MPBR of around 260 yards. So beyond that, I have to start using the holdovers on the reticle. Since the 300 BLK has a different trajectory than the 5.56, I just match how many MOA down each hash mark is to how many yards out that correlates to where the bullet is going to drop in its trajectory. And I usually tape a card with that info on the stock or the side of the scope.
Thanks for the info. Huge help. I was thinking with a silencer which would add another 6" to the barrel length that it might allow for longer distances, but now I'm thinking of just keeping this set up an SBR and running the EOTech 300BLK Holographic sight on it and then building out a .556 specific Recce rifle with a 14.5" barrel and silencer instead.
VegasSirk
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Posts: 5
Joined: Wed Mar 17, 2021 6:56 pm

Re: Am I Doing This Right - Noob 300BLK Build

Post by VegasSirk »

Also for anyone interested here is a great video on what a Recce Rifle is:

https://www.youtube.com/watch?v=JQc-z8MVhvY

Buck Doyle who is the go to for Recce rifle training is only a couple of hour ride away from me so its why I was basically last minute trying to convert the build over to that type of setup, but I guess you can never have too many guns so just another reason to build another rilfe. :mrgreen:
ReadyAimDuck
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Re: Am I Doing This Right - Noob 300BLK Build

Post by ReadyAimDuck »

One of the great things about the AR platform is that all you need to do is build another upper. And you will have both an SBR setup and a recce rifle setup. Swap on whichever one you want depending on your application.
VegasSirk
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Joined: Wed Mar 17, 2021 6:56 pm

Re: Am I Doing This Right - Noob 300BLK Build

Post by VegasSirk »

ReadyAimDuck wrote: Mon Mar 22, 2021 3:19 pm One of the great things about the AR platform is that all you need to do is build another upper. And you will have both an SBR setup and a recce rifle setup. Swap on whichever one you want depending on your application.
That's actually a great idea of just building an upper.
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