AR build: Suggested caliber?

[cartmanfan15]

Looking for suggested calibers for a new AR. Getting a PSA stripped lower, DD lower parts kit, and a Magpul CTR stock. Have always shot 223/5.56 but since I have recently gotten into reloading I thought I might try and upgrade to a bigger round. I'm leaning towards 6.5 Grendel or 6.8 but I do not know much about these rounds. Any info/suggestions would be most appreciated. I have no interest in .22, 308, or a pistol round.

 

[sgreen3]

300BLK!!!!!!!

 

[cartmanfan15]

What is the big deal with 300 blackout lol? I have seen them everywhere. Seems a little hard to get ammo for it to reload.

 

[lucky4034]

Its sub-sonic so it can be suppressed and it has a lot more range and punch than a sub-sonic pistol caliber.

The best part is that you don't have to modify a standard 5.56 receiver any, all that is required is a barrel change.

The .300 BLK is a heavy .30cal bullet in a necked down 5.56 cartridge which means they will stack nice and neat inside standard 5.56 magazines.

The only downside being that ammo is a little salty if you don't reload.

 

[jayhawk]

What is the big deal with 300 blackout lol? I have seen them everywhere. Seems a little hard to get ammo for it to reload.

Mainly that it works well sub-sonic for use with a suppressor.

 

[cartmanfan15]

Hmm. Interesting. See I have no interest in suppressing so it would not be a huge deal for me, but a bigger round is what I'm interested in. Anyone have any experience with the 6.5 or 6.8 round? I know these have been played around with to replace the 5.56/.223 as a bigger round with more knockdown than the 5.56 round.

 

[sloughfoot]

Here is several different choices for the AR platform.....6mm AR Home Page

 

[Mr Evilwrench]

.300BLK is available in subsonic and supersonic both. It would be necked UP from a .223 (7.62 vs 5.56) but it does fit the 5.56 mags. So, however, do the 6.8SPC and 6.5 Grendel. From what I've seen printed, 6.5 Grendel has the advantage; it fires like a 5.56x45 but hits like a 7.62x51, at least out to a few hundred metres. ALL OF THEM are going to be hard to come by commercially, so you'll probably want to look into reloading. Note all of this is opinion derived from second hand research, but it converges, so I don't mind throwing it out here.

 

[sgreen3]

Any caliber other than 5.56/223 would be a good idea to look into reloading. 6.8, 6.5, 300BLK, ect... Would all be tough to get ahold of in most stores. Plus reloading is going to save you money.

 

[esrice]

I would also vote .300BLK.

https://www.indianagunowners.com/forums/long_guns/171036-ar_15_in_300blk_300_blackout.html

 

[ZbornacSVT]

I have built both a 6.5G and a 300BLK. What is your intention for the rifle?

 

[Hoosier45]

Good luck finding a DD lpk. They are currently using all of them in house for full builds. I called for future availability and was told maybe sometime in 2013. I ended up going with a Geisselle SSA trigger and finished it out with a PSA lpk.

 

[malern28us]

Honestly, I have a 6.8 SPC. Ammo is VERY expensive. Not a plinking round. I would suggest 7.62x39. Ammo is cheap and it is a THUMPER out to 250-300 yards

 

[U.S. Patriot]

If you are wanting an SBR (shot barrel rifle), and have plans of suppressing it. I would suggest the 300 BLK. If you are wanting a round that is more affective at longer distances. I would suggest the 6.5 Grendel. If you have plans of hog hunting, etc. I would suggest the 6.8. That's my opinion.

 

[cartmanfan15]

I have built both a 6.5G and a 300BLK. What is your intention for the rifle?

I only use it at the range. Like my 5.56 setup, but figure if I am building one may as well get a bigger round. Very interested in the 6.5 and 6.8 round.

 

[cartmanfan15]

Good luck finding a DD lpk. They are currently using all of them in house for full builds. I called for future availability and was told maybe sometime in 2013. I ended up going with a Geisselle SSA trigger and finished it out with a PSA lpk.

Already getting one . Will have it soon on a trade.

 

[ghuns]

.458 SOCOM, go big or go home. Plays nice with suppressor and a legal deer rifle to boot. Hope you reload. Otherwise having your brain go $3, $6, $9, $12, $15...as you pull the trigger takes a lot of fun out of it.

 

[Hoosier45]

Already getting one . Will have it soon on a trade.

Nice find for you!

 

[cartmanfan15]

Thanks. Got it in a trade just waiting for it to come in. Just need to decide what to make the rest of it. I am leaning toward 6.5 or 6.8, but have only heard a little bit of feedback on both. The 6.5 Grendel round looks a little goofy, but if it shoots better than the 6.8 may have to look at it. Really just wanting something beefier than the 5.56/.223.

 

[melensdad]

My personal choice is the 6.5 Grendel. I currently have 2 rifles chambered in that caliber, I had 3 but 2 were so similar that I sold off one of them. I also had a first generation 6.8 SPC and was totally underwhelmed by that round, it was over-hyped and totally under delivered in actual life. The newer 6.8 SPC II chambers with slower twist rate barrels are much improved but still, when compared to the 6.5 Grendel, comes up lacking as I make comparisons between the 2 rounds. Some others will disagree.

Here is what I see, out of a short barrel and for short to medium ranges the 6.8 SPC has a VERY SLIGHT advantage. However if the barrel length is 18" or longer then the 6.8 SPC starts to seriously falter. Also, as ranges pick up then the 6.8 SPC shows its weaknesses.

For hog hunting someone above mentioned the 6.8 as his choice. I don't know why. I'm not saying its a bad round, its not. Its roughly a modern 30-30 and its hard to knock the 30-30. But it is clearly inferior to the 6.5 Grendel at every range when terminal energy is the deciding factor.

My favorite 6.5 Grendel rifle, which will be going on my next hog hunt, sports a 19" barrel and the bullets hit targets like a flying brick. It also has the amazing AR-Gold Trigger system and can easily shoot one hole groups from a rest while delivering TWICE the energy of the 6.8 SPC II round at moderate distances.

Ballistics comparison of several rounds:

As for costs per round you can buy the Wolf Gold, reloadable brass cased, 120grain MTP rounds for about 70 cents a round. If you can find the 123grain Wolf Gold Soft Point ammo that is about a dime less. I mail order my ammo in bulk to get the best prices. Premium ammo from Hornady and Lapua are in the $1 range.