Here's the situation. I have a stripped upper and lower that I have been slowly accumulating parts for. I feel like I am now at the point that I need to decide what I am doing before I go any further. I am torn between a 300 BO pistol, a 6.5 grendel pistol, (12" barrel), or a 16" 6.5 grendel rifle. I currently have bolt actions in 308 and 3006 and a 223 AR. What seems to make the most sense to round out the herd. I have an 11 year old and a 14 year old that are hunters. The 308 is set up for long range fun, 3006 for regular central and east Texas hunting and the 223 is set up for hog blasting with a red dot. Sound off and thanks!

300 BO is my next build so I will say go with the 300 BO. 6.5 Grendel would be fun in either but the 300 BO is a better option in my opinion. But then again it’s all about use and what you lean towards the most.

I've always heard that it's better to start a lower as a pistol, then the lower can be used as a pistol or rifle, but if you start it as a rifle, then change it to a pistol, it's considered a short barreled rifle (SBR) and then needs to be registered.

Pistol in 6.8 SPC or 6.5 Grendel.

I ran the numbers several months ago, even in short barrels they both hit the hardest out of any cartridge that will fit in the AR-15, out to 150 yards. Same case as in longer barreled AR-15's out to 300+ yards.

edit: I did not check numbers for the fat cartridges like .458 SOCOM and .50 Beowolf.

I was in the exact same mindset and even the same rifles owned already as you. I'll spare you the the pro's and con's that I think you already know. To me it looked like a dead heat but what pushed it over the edge was the long distance ability of the 6.5g. I'm not talking about for hunting purposes because I figure I rarely take shots that long anyways and I always do have my 30-06. The hunting capability of each seemed like a wash especially if you factor in bullet selection. I just figured the grendel would be much more fun for paper punching at longer distances.

I recently bought a 300 BLK upper for my lower. It is a rifle, not a pistol. I am very impressed with it, and would recommend the 300. My 9 year old boy likes to shoot it too, and it is great out to 200. I went with the 300 because it uses the same magazines and bolt carriers that I already have. I only have one lower and 2 uppers, so I just switch them out, and viola! Just gotta make sure you've got the right cartridge in the magazine.

Nothing is 300 bo ever

16 Grendel

I absolutely love my 300 Blk Out pistol in 10.5" barrel. 2630 fps with a 78 grain LeHigh CQB fragmenting projectile is hard to beat for self defense!! The blk out will get the most speed in a shorted barrel in comparison to other calibers. It does not give up as much velocity when the barrel gets short. It has to do with the faster burning powders that the blk out uses, compared to other rounds that use a slower burning powder.

But a 6.5 Gren or 6.8 is also nice in an AR when 16" or longer to get the speeds up.

Thanks for all the input guys. Based on the comments from Fireman, the 6.5 pistol would kind of be the best of the options as far as filling multiple rolls. The only thing that keeps me from committing to that direction is the thought of not setting up as a rifle and taking full advantage of the legs on the 6.5 g round!

I had a 300BLK once. Then I bought an AR10, sold the 300BLK, never looked back.

300 BO in 8.5-10.5" or 6.8 in 12.5". I've killed plenty of hogs and a deer with my 8.5" 300 BO. A lot of people put the smack down on hogs with a 6.8 in 12.5" barrel.

I'd do the one with cheap plinking ammo available, and in a carbine for the boys to use on game.

I was thinking about the ammo thing today. Checked my local Academy to see what was on the shelf, no 6.5...., they have it occasionally but I wouldn't be able to depend on it as a source. I would have to order ammo if I wanted to have a dependable source.

6.5g has been hard to find lately. Seems like 6.8 is more plentiful.

I am not a fan of AR pistols at all. It’s either SBR or 16”+ barreled rifle, IMO. AR pistols appeal to a lot of people, but once you shoot one they aren’t as much fun as you would think; plus they aren’t easy to hunt with (given the lack of stock to comfortably shoulder), especially for a kiddo. I know you can shoulder a pistol with a brace, but it’s still not great.

If you want a short barrel (SBR or pistol) and you don’t plan to shoot suppressed subs, I would go with a 12.5” 6.8. You get substantially more punch than a 300 BLK, and a little bit more punch than a 6.5 at the ranges one tends to shoot a pistol/SBR. You also have better ammo availability than a 6.5.

If you decide on the 16” route, a 6.5 is the best choice if you plan to consistently shoot 300+ yards. If you plan to shoot mostly 200 yards and in, which I would guess is the case for most people, the 6.8 is again the best choice. A 16” 300 BLK will be significantly outperformed by either the 6.8 or 6.5. If price of ammo is a major factor and you don’t reload, keep in mind 6.5 has the cheapest ammo of the three since wolf makes steel cased ammo for the 6.5. Wolf steel cased 6.5 ammo can be found for 30ish cents per round, where the cheapest 6.8 and 300 BLK is typically 50 cents per round and up.

Only scenario in which I would choose the 300 BLK is if you decide you want to shoot subs through a suppressor. I personally have a suppressed 8” 300 BLK SBR, and it sure does put a smile on the face of anybody who shoots it.

Best all-around rifle for hunting, IMO, would be a 6.8 with a 16” barrel. If you do decide on a 6.8, buy a barrel from ARP. They make both 12.5” and 16” barrels. https://ar15performance.com/6_8_barrels