Best AR15 Round for 14.5” Barrel

[VIII]

Been a lurker for a while but have a question for the internet and am thus forced to make a post. I recently lucked my way into a new ar15 upper/lower for cheap and want to put together a new build. My goal is a lightweight, short, hunting rig capable of dropping deer sized game out to 300 or 400 yards, barrel will be 14.5” (pin and weld), and the ability to find factory ammo. I know there are a dozen calibers fit for that list, but which one will perform best out of a 14.5” barrel? I’ve been reading that the .224 Valkyrie is the cats ass with fangs, but I hear it’s best served out of a 18-20” tube. The .300 blk also sounds like it might fit the bill, but maybe not considering I’m married to the 14.5” barrel length and that seems a bit long for a caliber designed for pistol length. I have a 6.5 Grendel in a 16” barrel which I do enjoy, but finding factory ammo for that here in WV is a royal bitch. For calibers that will fit into a mouse frame I’m seeing ammo locally for the 6mm ARC and .224 Valkyrie. Any of you having good luck with either of those calibers out of a 14.5” barrel? Another thing of note, while I know a 14.5” barrel isn’t the foundation for precision, I do appreciate accuracy and I won’t take something out into the woods if it isn’t at least MOA. If you’re having luck with something in the above mentioned barrel length at those distances, please share your experiences.

 

[Avonac]

I’ve killed a lot of stuff with a 14.5 and shorter AR, but I think 3-400 is a bit of a stretch for the caliber and velocity you are gonna get. I’m a big fan of bonded bullets and the 62-64 gr gold dot and Winchester ranger have worked well on hogs and deer but at a much shorter distance. I think switching to the 6.5 Grendel or 6mm ARC answers your distance problem.

 

[Formidilosus]

Been a lurker for a while but have a question for the internet and am thus forced to make a post. I recently lucked my way into a new ar15 upper/lower for cheap and want to put together a new build. My goal is a lightweight, short, hunting rig capable of dropping deer sized game out to 300 or 400 yards, barrel will be 14.5” (pin and weld), and the ability to find factory ammo. I know there are a dozen calibers fit for that list, but which one will perform best out of a 14.5” barrel? I’ve been reading that the .224 Valkyrie is the cats ass with fangs, but I hear it’s best served out of a 18-20” tube. The .300 blk also sounds like it might fit the bill, but maybe not considering I’m married to the 14.5” barrel length and that seems a bit long for a caliber designed for pistol length. I have a 6.5 Grendel in a 16” barrel which I do enjoy, but finding factory ammo for that here in WV is a royal bitch. For calibers that will fit into a mouse frame I’m seeing ammo locally for the 6mm ARC and .224 Valkyrie. Any of you having good luck with either of those calibers out of a 14.5” barrel? Another thing of note, while I know a 14.5” barrel isn’t the foundation for precision, I do appreciate accuracy and I won’t take something out into the woods if it isn’t at least MOA. If you’re having luck with something in the above mentioned barrel length at those distances, please share your experiences.

There are zero issues with killing deer (and elk) cleanly at 400 yards with a 5.56 and 77gr TMK’s. This Thread will answer a lot of questions.

Having extensively shot every cartridge mentioned above in barrel lengths from 5.75” to 26”, the 5.56/77gr TMK is the winner by a long shot. After that, the 6 ARC.

 

[robtattoo]

There are zero issues with killing deer (and elk) cleanly at 400 yards with a 5.56 and 77gr TMK’s. This Thread will answer a lot of questions.

Having extensively shot every cartridge mentioned above in barrel lengths from 5.75” to 26”, the 5.56/77gr TMK is the winner by a long shot. After that, the 6 ARC.

^^^^^^
This, right here.

.300blk is awesome inside of 150, but it falls short after that. The 6.8 would stretch that a bit, but not as far as you'd like (not to say either won't get there, they just don't make bullets to suit the low terminal velocity) Same goes for .350 legend. I have no experience with the 6 ARC, although a friend shoots a 12" suppressed (I think it's a Honey Badger?) and kills stuff at silly ranges.

The 5.56 77tmk however, I do know. Nowhere near as well as Form, but my tiny sample size mirrors his massive sample size. If they hit at anything above 1800fps (I prefer 2k, but that's just me) they just downright work. And they punch WELL above their weight.

 

[JFK]

I’d put a 16” 1:7 barrel on it chambered in the standard 5.56/.223.

 

[robtattoo]

Read this.

.223 for bear, mountain goat, deer, elk, and moose.

DON'T HAVE TIME TO READ 176 PAGES? HERE'S THE CHEAT SHEET. “Bullets matter more than headstamps.” “Spent primers offer the supreme tutorial”. I’ve read it here and elsewhere online. It got my attention. I started digging and asking questions and listened. The 77gr TMK delivered by a .223...

www.rokslide.com

Eighty-some-odd pages of the 77gn tmk killing everything up to the size of a moose, up to 800yds.

 

[cod0396]

There are zero issues with killing deer (and elk) cleanly at 400 yards with a 5.56 and 77gr TMK’s. This Thread will answer a lot of questions.

Having extensively shot every cartridge mentioned above in barrel lengths from 5.75” to 26”, the 5.56/77gr TMK is the winner by a long shot. After that, the 6 ARC.

Are you saying that 6 ARC has been LESS effective than the 77TMK/5.56 combo? I just want to make sure I'm understanding you correctly. I wouldn't be totally surprised given how potent the 77gr TMK is, but I would have assumed that something like a 108gr ELD-M out of a 6 ARC would outperform it.

 

[cod0396]

Been a lurker for a while but have a question for the internet and am thus forced to make a post. I recently lucked my way into a new ar15 upper/lower for cheap and want to put together a new build. My goal is a lightweight, short, hunting rig capable of dropping deer sized game out to 300 or 400 yards, barrel will be 14.5” (pin and weld), and the ability to find factory ammo. I know there are a dozen calibers fit for that list, but which one will perform best out of a 14.5” barrel? I’ve been reading that the .224 Valkyrie is the cats ass with fangs, but I hear it’s best served out of a 18-20” tube. The .300 blk also sounds like it might fit the bill, but maybe not considering I’m married to the 14.5” barrel length and that seems a bit long for a caliber designed for pistol length. I have a 6.5 Grendel in a 16” barrel which I do enjoy, but finding factory ammo for that here in WV is a royal bitch. For calibers that will fit into a mouse frame I’m seeing ammo locally for the 6mm ARC and .224 Valkyrie. Any of you having good luck with either of those calibers out of a 14.5” barrel? Another thing of note, while I know a 14.5” barrel isn’t the foundation for precision, I do appreciate accuracy and I won’t take something out into the woods if it isn’t at least MOA. If you’re having luck with something in the above mentioned barrel length at those distances, please share your experiences.

I echo what others have said in this thread. 77gr TMKs out of a 14.5" 5.56 will perform excellently out to 400 yards. That setup is also one of the best possible home defense setups you can own, if you plan on using your AR for that purpose.

 

[Formidilosus]

Are you saying that 6 ARC has been LESS effective than the 77TMK/5.56 combo?

No, terminally the 108hr ELD-M is very good. However, for a 400 yard AR15, 233/5.56 is the way.

 

[h2so4]

If you want factory loaded ammo, you’ll have to venture away from the TMK at the moment. It’s probably easier to find the 6.5G than tmk’s.
77gr OTM on the other hand, has a small supply that continually trickles.