AR build. 6.5 Grendel vs .300 Blackout?

[PNW_Steve]

Hey Everyone,

I have developed a problem. Like an alcoholic taking his first drink, I bought my first AR. Now I can't stop....

I am wanting to build my next one and have conflicting wants.

I started out gung-ho for .300 Blackout and the idea of running surpressed. Did my form 1 research and started looking around at kits & components to build a suppressor. My thought is to go with a 10.5" barrel and a pinned and welded suppressor 8"-10" long. That will keep me to a single form 1. The best part would be casting my own subsonic boolits

Then I read an article on the 6.5 Grendel. I have always wanted a good long range rifle. This cartridge really has my attention. A nice billet upper, Criterion 20" barrel, Timiney trigger etc. would make a great long range target rifle. Maybe a second lower with a trigger better suited to hunting? The big question is can I reasonably shoot cast bullets, at reduced load, and expect good 100-200 yard performance?

Surpressed fun or a long range tack driver?? Which way would you go?

[downzero]

6.5 Grendel is obsolete. 224 Valkyrie is what you would want instead. Ballistically, the 6.5mm diameter needs more powder capacity than the Grendel creates. The 6.5/6.8 and related cartridges are all related to each other and similar, including 224 Valkyrie.

I experimented with a modified 6.5 Grendel called 6mm Fat Rat. It was the most amazing semi-auto I ever had, shooting 2.5" regularly at 600 yards. It had .308 ballistics with 107 SMKs at every range. The problem was that the magazines are unreliable garbage. Its parent case is 7.62x39, which really was a poor choice as it doesn't stack well in the magazines (case is tapered a lot compared to American cartridges, probably because it's made from steel a lot). In short, Grendel feeds like crap and everyone I talked to at shooting matches agree. If you are okay with it being an unreliable ***, go ahead and get yourself a Grendel or other Grendel-based cartridge. But if you were thinking that what you wanted was something with 5.56 AR level reliability, I'm sorry to be the bearer of bad news.

300 blackout fits in normal AR mags and uses a normal AR bolt. Between these two, I'd want that.

I sold my mags and Fat Rat barrel and bought a 20" .223 barrel and I've been amazed at how much fun it is. With an 8 twist, it shoots 53 grain bullets at over 3200 fps and 77s at 2700+. They don't quite have the BC of the Fat Rat but they are fun at 600 yards and even more challenging at 800.

How far is "long range" to you? I would definitely not mess with the Grendel. For your use, you might enjoy the Blackout. If j words are in your future, there may be another better suited option.

[RU shooter]

Yeah the suppressed thing might be fun but it's shorter range . Me personally that gets boring after a while . I'm with Down Zero if you want something accurate at longer ranges just get a 8 twist 223 barrel from a company that makes good accurate barrels and build it how you want it . Or get both .

[nawagner]

Have to disagree on the Grendel. I built one as my first AR build and I have had zero problems with it. Including feeding or magazines. I did my research and bought the parts that are known to work with the Grendel platform and made the adjustments to magazines as needed. My gun is a tack driver with factory ammo. So I haven't even had to work up a load for it yet. I'm very impressed. I have not shot cast through it so can't answer your question there.

I was in the same boat as you trying to decide. I was thinking long range shooting and thinking about an AR10. I then started looking at and researching the Grendel. I'm happy I went that route and it's a lot of fun to shoot. I learned a lot more about AR design and building than I probably would have with a 223/5.56 or Blackout.

Go check out the Grendel forum for all the good and bad. 65Grendel.com/forum

[Boolit_Head]

I would not do a pinned and welded supressor. They are like crack, once you get one you will want to use on on more barrels.

[Earlwb]

Adult Legos comes to mind with ARs and building them up yourself. yeah they are addictive.

I would agree the .224 Valkyrie is a good long range round for ARs. But the 6.5 Grendel still works really well. The .300 Blackout is still lots of fun too. I would build them all.

[PNW_Steve]

I would not do a pinned and welded supressor. They are like crack, once you get one you will want to use on on more barrels.

ATF might get a little snarky with me if it is not pinned and welded to my 10.5" barrel with no SBR form 1.

Regarding .224 Valkyrie, I cannot hunt with it. Nor can I hunt with my .223's. The only legal hunting rifles in my current collection are a bolt action .243 and a 9mm AR. While legal here the 9mm is not an appropriate cartridge for hunting here. The 6.5 and the .300 are both reasonable deer and elk guns. The .300 would likely be a 150 yard gun. The 6.5 holds good energy well beyond that.

Yeah.... I had fun with my .225 bolt gun and my .223 AR but I am looking for something that I can legally hunt here and would be a good choice for a job hunt in Texas this Fall.

[downzero]

ATF might get a little snarky with me if it is not pinned and welded to my 10.5" barrel with no SBR form 1.

Regarding .224 Valkyrie, I cannot hunt with it. Nor can I hunt with my .223's. The only legal hunting rifles in my current collection are a bolt action .243 and a 9mm AR. While legal here the 9mm is not an appropriate cartridge for hunting here. The 6.5 and the .300 are both reasonable deer and elk guns. The .300 would likely be a 150 yard gun. The 6.5 holds good energy well beyond that.

Yeah.... I had fun with my .225 bolt gun and my .223 AR but I am looking for something that I can legally hunt here and would be a good choice for a job hunt in Texas this Fall.

If you're willing to deal with the magazine issues and can't hunt with a 223 diameter, the 6mm Fat Rat isn't a terrible choice. It certainly shot lights out in mine, I just wasn't going to deal with the capacity/feeding issues.

[adcoch1]

ATF might get a little snarky with me if it is not pinned and welded to my 10.5" barrel with no SBR form 1.

Regarding .224 Valkyrie, I cannot hunt with it. Nor can I hunt with my .223's. The only legal hunting rifles in my current collection are a bolt action .243 and a 9mm AR. While legal here the 9mm is not an appropriate cartridge for hunting here. The 6.5 and the .300 are both reasonable deer and elk guns. The .300 would likely be a 150 yard gun. The 6.5 holds good energy well beyond that.

Yeah.... I had fun with my .225 bolt gun and my .223 AR but I am looking for something that I can legally hunt here and would be a good choice for a job hunt in Texas this Fall.

I have both the 300 and the 6.5 grendel, and neither is acceptable on western Washington and Oregon elk. Yeah they may kill one at 30 yards, but neither pack enough wallop to reliably anchor 1000lb animals in most hunting situations. BUT, both are great for deer, and cast should be fine from the blackout, don't know about getting cast to work in an autoloader 6.5 though. I actually just finished powdercoating the boolets for my first attempt at cast in the 300, if only I could find a correct sizer in stock somewhere!

[adcoch1]

Oh, and on the barrel length thing, just build it as a pistol with an sb3 or sb4 brace.

[303Guy]

Is there a reason to not go with an over-barrel suppressor and a longer barrel?

[dimaprok]

If you don't care about subsonic, another option to look in to is 300 HAMR or it's predecessor 7.62x40 WT. It's stronger than 300 Blackout and has ballistics of 7.62x39 / Win 30-30 and quite accurate with cast bullets while using regular .223 AR parts, except barrel. I am using NOE 6 cavity HTC 130gr mold, powder coat and gas checked and it's cheap way to shoot, converting cases is pretty much same as 300 blk and I use range picked up LC cases. With jacketed bullets it shoots MOA or better, speer has cheap 125gr bullet that's perfect as well as soft point hunting bullet, I've also tried Hornady 150gr SP. Magazines if you want to load more than 10 you need de-ribbed ones just like 300 blackout, Wilson Combat sells them, in fact when they were on sale cheap I picked up four 20 rounders. With newer 300 HAM'R it's been added to SAAMI, so you can buy factory brass from Starline and at least 3 manufacturers make dies. I am getting about 2333fps with 137gr cast bullet, using Accurate 1680 but other powders work too, 4198, Shooter's World Blackout and Heavy Pistol and CFE BLK and 5744 (need to test)

[dimaprok]

I've been thinking about 6.5 Grendel too, but it's not as cast friendly in my opinion as 30 caliber and jacketed / copper plated bullets also not as cheap. For example in .308 I picked up some plinking bullets copper plated for about 11 cents each, round nose 120gr, it shot sub-moa in my 7.62 x 40 WT with Shooter's World Heavy Pistol powder, it really surprised me as it didn't perform this well with other powders. Speer bullets are cheap too and there is 20% rebate but it ends tomorrow. They had same rebate last year, the jacketed bullets were about 13 cents after rebate, can't beat that and there are ton of options in 30 cal not so much in 6.5mm, also gas checks for 6.5 are odd thickness compare to 30 cal ones I make from Home Depot aluminum. If I end up getting 6.5 Grendel it's probably going to be CZ bolt action and I'll order some custom mold so I can use thicker .010 aluminum for gas checks. Will need to purchase brass though, even though it can be converted from 7.62x39, I found less than a dozen in 5 years at ranges.

[am44mag]

Hey Everyone,

I have developed a problem. Like an alcoholic taking his first drink, I bought my first AR. Now I can't stop....

I am wanting to build my next one and have conflicting wants.

I started out gung-ho for .300 Blackout and the idea of running surpressed. Did my form 1 research and started looking around at kits & components to build a suppressor. My thought is to go with a 10.5" barrel and a pinned and welded suppressor 8"-10" long. That will keep me to a single form 1. The best part would be casting my own subsonic boolits

Then I read an article on the 6.5 Grendel. I have always wanted a good long range rifle. This cartridge really has my attention. A nice billet upper, Criterion 20" barrel, Timiney trigger etc. would make a great long range target rifle. Maybe a second lower with a trigger better suited to hunting? The big question is can I reasonably shoot cast bullets, at reduced load, and expect good 100-200 yard performance?

Surpressed fun or a long range tack driver?? Which way would you go?

The case taper of the 6.5 Grendel doesn't mean much. I have a 7.62x39 AR, and it is 100% reliable. You just need the right mags for it. The 6.5 Grendel is far from obsolete, and is a great little round. If you want a long range AR, it will fill that role very well.

[Lloyd Smale]

well ive got both. 3 blackouts and one Grendel. I shot 5 deer with the bo last year. Furthest shot was 200 yards and I used 110 barnes x bullets. Damage even a 200 was impressive. So lets call it a 150 yard deer round. The Grendel I haven't killed anything with but it will push a 100 grain bullet to 2800 fps so its pretty much equal to a 243 so we can call it a 250 yard deer gun. Grendel obsolete?? Id bet it hands down outsells the Valkyrie. Valkyrie shoots flatter but you cant eat paper. For actually killing something the Grendel is hands down the better choice. Unreliable?? I use Grendel mags and my gun has about 2k through it. I know that isn't much but its more then most on here will ever put through a gun and it hasn't missed a beat and its just a cheap psa gun. Where the bo beats it is obviously if you want to shoot sub sonic. It also is cheaper to shoot. Brass is about free if you make it from 556 yourself and still half the price if you buy it made or once fired. Add to that it operates at 2000 fps instead of 3000 so its a lot more cast bullet friendly. Plus finding Grendel brass once fired is like, well finding 224 valkyrie brass. Theres a few other choices. Some were mentioned here but still the best selling HUNTING round that fits in an ar15 platform that has more range then the 300 bo is the Grendel. HANDS DOWN. OBVIOUSLY if you want to hunt something the size of an elk you need to walk, NO RUN, away from the ar15 platform. Step up to an ar10. But start getting in shape because hauling one of those around up and over the hills is a workout. That said I doubt theres a deer alive that would walk away from a boiler room hit with a 6.5 Grendel at 250 yards and probably even a bit further. OBSOLETE!! I heard one know it all at the range one day trying to tell me the 308 is obsolete ever since the creedmore hit the market. You got to wonder how I manage to hunt with rounds like the 250 sav. 257 roberts, 280 and 300 H&H???? Buy yourself 500 rounds of brass and who cares if nobody wants to make ammo for it 20 years from now. Figure if you get 4 shots per piece of brass that's 2000 deer. Heck by then ill be dead and burried before 20 years goes by anyway.

[Greg S]

I've got a few in 223 and one 50 Beowulf. If I was going to go somewhere inbetween, I'd go 6.5g in an 18-20 for hunting and long range. The BO from my understanding is a 200m cartridge with most of the costs associated with reloading 308. 6.5 bullets are alittle cheaper.

[1006]

A little off the tread’s line of thought, but I have been crunching the numbers that matter to me.....price of an upper, ammo, reliability, Cheap and easy to reload ammunition, accuracy and power out to 200yards. I keep finding the 450 Bushmaster at the top of my list. I have a 300BLK Ruger American Ranch, and I like it for all the same reasons, but I do not think it is enough gun after 100 yards. It may be enough, but I feel more confident with something bigger.

[downzero]

The case taper of the 6.5 Grendel doesn't mean much. I have a 7.62x39 AR, and it is 100% reliable. You just need the right mags for it. The 6.5 Grendel is far from obsolete, and is a great little round. If you want a long range AR, it will fill that role very well.

The 6.5 Grendel was obsolete the day it was created. It should have been a 6mm in the first place.

Couldn't disagree more about the mags. The shorter ones were maybe 80% reliable, and the longer ones were absolute garbage. I tried every brand of Grendel mags there were. Granted, I was using a 40* shoulder cartridge, but I can't imagine they would have been much better with pure Grendel. There's a reason AK mags are curved as much as they are.

[Texas by God]

I've yet to see a review of any .224 Valykrie rifle that turned in acceptable accuracy at 100 yards. The Grendel and 7.62x39 are about the best performing, most versatile cartridges that will fit in the AR envelope. For under 150 yards, the .300 Blackout is a dandy cartridge that is cheap to shoot.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[am44mag]

The 6.5 Grendel was obsolete the day it was created. It should have been a 6mm in the first place.

Couldn't disagree more about the mags. The shorter ones were maybe 80% reliable, and the longer ones were absolute garbage. I tried every brand of Grendel mags there were. Granted, I was using a 40* shoulder cartridge, but I can't imagine they would have been much better with pure Grendel. There's a reason AK mags are curved as much as they are.

Just because you don't like something, does not mean that it's obsolete. I do not care for 270 Win, but I'm not going to call it obsolete, because it's not. I'm using 30rd mags in my 7.62x39 AR, and am again, getting perfect reliability. Yes, they are curved like an AK mag. For my Grendel, I do use shorter mags because I built it as a target gun. I don't want/need long and heavy 30rd mags hanging off the bottom of that gun. It's heavy enough as is, and they interfere with the bipod when shooting prone or off a bench.

As Lloyd said, I'm sure the Grendel has far outsold the Valkyrie, and it has it's advantages over the Valkyrie. Especially to the OP since he apparently can't use .22 cal rifles to hunt with in his state.

Out of curiosity, do you have any experience with the 6.5 Grendel, or just the wildcat you mentioned that's based off of it?