Dumping .308 for 6.5 Grendel?

RichS

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Minuteman
Nov 16, 2001
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PG County Maryland
Ok,
So I've been (slowly) working on an Aero M5 build. However I've been thinking alot about the 6.5 Grendel, and I think LRRP's posts on Arf may have pushed me over.
I'm weighing pros and cons, and I'm now having a hard time justifying the .308.

To me, the biggest Grendel pros...
- AR15 sized. HUGE bonus as there's tons of manufacturers and parts out there that are built to an established and accepted spec. I don't have to worry about a bunch of different makers all making parts that are incompatible with other makers since there's not really an industry standard spec...at least not equivalent to the AR15/M16.
- Ballistics. Not that I need it, but from everything I've read, the Grendel ballistics are as good if not better than the .308 (at least the 168 or 175), but better when you consider it does it in a smaller, lighter, and less recoiling package.
- Cost. I don't reload, and from just casual internet surfing, it looks like Grendel match ammo costs less than match .308
- Ammo Availability. It seems to be getting more popular and available.

Grendel cons
- Confusion between makers and their designations of Grendel I, Grendel II, etc. and the ensuing confusion with .136", .125". However, it seems to me that if you stick with known barrel makers that use SAAMI spec Grendel chambers you should be fine. Right?
- Ammo Availability. Unlikely to find it in my local B&M store. However, the only time I buy ammo at a store anymore is when I go to Cabela's to visit my folks in PA. Otherwise, I order just about anything I could want for better prices online.


.308 pros
- High quality parts are everywhere. Even if you do happen to get some parts that don't fit or are incompatible, you'll still be able to find what you need.
- Ammo is everywhere. You can go into just about any backwater sporting goods/hardware store and find .308

.308 cons
- No real industry standard. .308 ARs have a HUGE variance in parts from different manufacturers.
- Heavy. Not that I'm going to be humping the rifle around, but it does usually end up being a heavy bitch.
- Expensive. Parts/ammo cost more.

So, am I crazy for thinking of selling my .308 stuff and just going with the Grendel? What are your thoughts? At this point a gasser in 6.5 creedmoor doesn't interest me as much since (from what I've read) they can be a bit more "fussy" than the .308.
 
Have you looked at a .260 Rem instead?

The .260 will let you shoot heavier bullets and there is more and more match ammo available in .260.

Are you stickong with an AR 10 or AR-15?

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I had the same pros/cons list as you and went Grendel. I wanted 308 or slightly better performance in a small package and I got it. If you want to really smoke 308 you'll have to keep the AR10 and the weight/size that goes with it.
 
I guess that's kind of the issue; I'm not sure if I want to commit to the AR-10/LR308 platform if there's something available that will "scratch the itch" in the platform I already have. Since I don't reload, .260 isn't really an option for me. I have more than a few AR15 rifles/receivers/parts. As for the .308, I have the assembled lower but the upper is just a stripped upper at this point, but that's it.

I bought it in Oct during the "oh, shit....HILLARY, buy it while you can" panic.
 
I'm not dumping my 308, but I have been seeing this cute little 6.5 grendel lately. Don't get me wrong, I still love my 308, but she's kind of a "big girl" and a can be a drag to hump for any length of time. That said, when I lay her down and finger her trigger, she and I get it done.

Now, the gendel is a lot of bang in a small package. She's everything the 308 is not, and everything it is too. Smaller, shorter, lighter, generally less expensive to feed. Less recoil, easier to manage, nearly equivalent balistics, good energy on target (hunting or ringing steel...). Fits in a "take down" shotgun case. Don't think that's not a huge plus.

My goal with the 6.5 grendel was to equal the 308 in ballistics with a shorter and lighter gun. I think I have achieved that.

I've got a lot more time with the 308 than the grendel, so it is still my go to gun if weight is not issue. But, for carrying around the field and moving from vehicle to hike to blind and back again, I'll be carrying the grendel a lot more. And, it will be my primary range toy for the foreseeable future.

But, I just loaded every piece of 308 brass I have in the house, so the 308 is here to stay. We've got an open relationship...
 
I shot a Grendel and a big advocate for the Grendel. If I were to build an AR10 it would be a 18inch 6.5 Creedmoor but the issue I have heard is that the factory ammunition is a little to hot for a semi.
 
I guess that's kind of the issue; I'm not sure if I want to commit to the AR-10/LR308 platform if there's something available that will "scratch the itch" in the platform I already have. Since I don't reload, .260 isn't really an option for me. I have more than a few AR15 rifles/receivers/parts. As for the .308, I have the assembled lower but the upper is just a stripped upper at this point, but that's it.

I bought it in Oct during the "oh, shit....HILLARY, buy it while you can" panic.

I wouldn't throw out the .260 just because you don't reload. There are quite a few smaller ammunition manfacturers making good ammo in .260. And, Hornady has some loaded ammo with their ELD bullets.

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I just built a grendel for similar reasons. I wanted a light weight hunting rifle with more energy that a 5.56 but less weight than a AR10. Rainer has the Carbon Fiber Christensen barrels for $500 and I snagged a 18". I will post some pics soon but so far its what I was wanting. Its under 9lbs suppressed and is still paintable. Truth be told I would probably SBR it and do a 13" next time.
 
Can't speak to dumping the .308 but I'm very happy with my decision to get into the Grendel - JP SCR 11 shooting factory Hornady - super accurate and fun to shoot.
 
I will always have my 308 but I am exploring the 6.5 Creedmoor world. Pressure is not so much an issue if you use the JP rifle length plus 2 gas system. Gives the bolt a little more time to unlock and in conjunction with an adjustable gas block it is an awesome round in the AR platform. If I was to build another AR15 type weapon, I would look real hard at the 6.5 Grendel
 
For me, I will always keep a 308 no matter what just because it's such a versatile round. However, I have been shooting my 6.5 grendel a lot more lately. Love it for all the reasons as stated above but the only thing that bugs me about it is the lack of good muzzle velocity compared to 308, 6.5 C, etc... Mine has a 20" barrel and I'm thinking if stepping up to a 24" in the future. For now though, it's accurate, it'll drop a big mulie, and i have a blast shooting it...
 

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I say go for it. Nothing to lose, the Grendel has been shot by many and seems to be well liked. It is always fun starting a new project anyways. Hell a Grendel is up on my list as well.
 
.308 16" barrel can be built very light, and is pretty tough to beat for all around kickass. 6.5 grendel or 6.8 spc both do very well in the small platform out of shorter barrels. Creedmoor or .260 are good if your shots will need to be 800yds plus. But shooting heavy .223 out of an 18" or 20" barrel will keep up out to 800-1000 yards. Really the choice breaks to pick your most likely target and build accordingly. I say build them all and sell the ones you dont utilize, or make a fort with them.
 
.308 16" barrel can be built very light, and is pretty tough to beat for all around kickass. 6.5 grendel or 6.8 spc both do very well in the small platform out of shorter barrels. Creedmoor or .260 are good if your shots will need to be 800yds plus. But shooting heavy .223 out of an 18" or 20" barrel will keep up out to 800-1000 yards. Really the choice breaks to pick your most likely target and build accordingly. I say build them all and sell the ones you dont utilize, or make a fort with them.

I like the cut of your jib.
 
I think at this point the only real advantage for the 6.5G is you get long range in a lighter package. We now have bullets in .308 diameter that will get you as far and nearly as high BC as the 6.5's. Pushing the high BC but light 6.5 bullets is less of an advantage now for the 6.5 Grendel. It's still an advantage though. So, if you want to jump up in performance, get a 6.5 Creed or .260 to boost performance over a .308.

That said, I very much like my Grendel. And have liked the ones I've owned. There is still really only one magazine company that builds reliable mags, C-Mag. None of the polymer magazine manufacturers offer them yet for the 6.5G/.264LBC/6.5Sport.

As noted, the only cartridge you can pick up at a mom and pop store is the .308. But, that is a lost cause if we ever hit a panic buy again. .308 was off the shelves for years. Making all things kind of equal. You have to reload if you want it. That means stocking up on components.
 
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I've shot a lot of .260 over the past nearly two decades, and the prospect of shooting a 6.5 with just over half the case capacity simply does not appeal to me, no matter what the platform. I shoot the 260 because of the excellent bullets that are available, but you just have to get them up to a decent speed to make the whole thing worthwhile, guy...

Also, not handloading, seems like you're painting yourself into a corner...

DPMS LR-260, Prime Ammo, no brainer. Upper...?

Guy.
 
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I kind of felt the way greg did until last year. I built a 308 to shoot a DMR match last spring. After the match I started looking at other cartridges with the thought of matching or surpassing the 308 and I kept coming back to the 6.5 Grendel. On a whim I put one together and now it has become an addiction. Not only because it matches (and in some cases surpasses) my 308 loads but also because it is so much easier to shoot well compared to the large frame 308 AR. The fact that it is nearly 5 pounds lights is also a plus as is the bolt rifle like precision I am getting at distance.

Will I dump my 308, no. But I will say I have not shot my 308 AR in a year since the Grendel came into my house.
 
I shot a .264 ARP barrel for several months, the factory 123gr Amax could be put in the same hole. Once I started shooting longer ranges, the hits on steel were not impressive. I sold it and shoot a 6.5CM now for long range work, less recoil than a .308 and awesome drop/wind numbers.
 
I have a lightweight 18" Grendel that I really like as well as 308 & 6.5cm semiautos. I think it real comes down to what distances you will realistically plan to shoot at. For within 500 yards 90% of the time, with some shots out to 800 yards, a 6.5 Grendel is great. For beyond 800 yards, look at a 6.5 Creedmoor.
 
I tried the Grendel and didn't like it, disappointing velocity and accuracy. I was only able to get 2450 out of a 20" barrel and while I don't blame my lack of accuracy of the caliber, it still left a bad taste in my mouth. I have gone back to .223 shooting heavies and have been very satisfied with the performance.
 
I would go 6.5 Grendel, I love that little round! It's light and accurate as all hell. I don't own a semi in 6.5 Creedmoor or .308 but I have plenty of bolt guns. The Grendel is still my favorite round to shoot . I built a 18" Grendel just for hunting and have a 24" for precision work. It has performed extremely well. I would say go Grendel.

My wife thinks I only have 3 guns

 
I've owned 3 different AR10s/LR-308s, and 2 different LR-260s, one DPMS factory, one custom GAP-build that I still have, got out of all the .308 Winchester stuff after spending time with .260 Rem and 6.5 Grendel. I initially got into 6.5 Grendel as a fun toy, lightweight little AR15 that maybe I would consider for shooting certain matches that involved a lot of movement in field conditions.

What happened over time was that I shot the Grendel more and more, especially after the Hornady 123gr AMAX was introduced as a factory load. I started hand-loading for it, but quality, affordable factory ammo made it even more easy to shoot with. It gained SAAMI approval after that, and more factory ammo started to come online from various sources.

Now there are 42 factory loads, including 4 new ones from Federal. The 90gr TNT does ~2900fps from my 17.6" Lilja 318 barrel. It's advertised at 3000fps from a 24" pipe. They also announced and had 130gr Berger Hybrid OTM Federal Gold Medal Match at SHOT Show, which is a big deal. There are only a few cartridges that have ever had FGMM support.

My .260 Rem sits in pieces currently, and had been that way for a long time. I plan to change that now that Hornady introduced the 130gr ELD-M factory .260 Rem load, which will finally make .260 Rem affordable to shoot. The big difference between the 6.5 Grendel AR15 and .260 Rem large frame guns for me is utility. There is only one thing my .260 Rem is good for, and that is shooting from solid positions like prone or bench, maybe some tripod. Carrying it around (14lbs+ with just optics) is not fun at all, and is difficult to shoot from kneeling, standing supported, and modified positions.

Recoil is really not that different from a .308 for me of the same build/barrel weight. I personally do not see a huge difference in recoil between .308 Win., 7mm-08, and the 6.5-08 cartridges, unless you use really light bullets to compare one with the other. They all work at similar pressures (60ksi-62ksi), and push similar weight bullets, with the 175gr .308 and heavier obviously exhibiting more recoil.

The 6.5 Grendel, even from a rifle that weighs sub 8lbs, has noticeably less recoil, and is easier to point on target, and keep pointed on target. Getting into a Grendel is much easier than the other options especially in a gas gun, with the simple switch of an upper and mags.

Trajectory and wind drift between 6.5 Grendel and .308 is very similar. I find that the better 123gr bullets pretty much fly like a 175gr SMK for drop, but seem to have a little less drift, and again...50% less recoil. That means I can get a lot more trigger time, without any concern about recoil, and shooting from positions is much easier so I don't feel compelled to ride the prone, and can venture out a lot more from the comfort of prone or bench.

The most important thing though, is that I now have a rifle system that does many things very well, not just marginally. It acts as a great close-in defense rifle that blasts through cinder block and windshields like Swiss cheese. It then functions perfectly as a hunting rifle, capable of taking game much larger than you initially would think, including elk and moose. It then turns around and allows me personally to shoot not only Long Range, but ELR up here at altitude, with predictability that I never would have imagined it was capable of.

I know of no other rifle/cartridge combination that can do all of those things, especially in the 7-8lb range, with such low recoil. It's become my go-to system as a result.

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I tried the Grendel and didn't like it, disappointing velocity and accuracy. I was only able to get 2450 out of a 20" barrel and while I don't blame my lack of accuracy of the caliber, it still left a bad taste in my mouth. I have gone back to .223 shooting heavies and have been very satisfied with the performance.

That's the speed I and many others get with 16" barrels with 123gr SST or AMAX. 18" gives many different barrels I have chronographed 2460-2500fps with a 123gr.

In higher temps, I have seen 2520fps from 123gr Scenar from my 16".

2450fps is really slow for a 20". We normally see 2530-2600fps with factory loads.

With hand loads, you can drive a 123gr to 2580fps with CFE223 from a 20", and still be just under 50ksi. Keep in mind that these pressures are way under the 62ksi working pressure of the .308 Win.
 
I like the AR-15 platform. I picked up a used Alexander Arms Overwatch 6.5 Grendel w/ 24" barrel last summer. Added a PRS stock and Wilson Combat Drop-in Trigger.

1st range day ... laser bore sighting at 25 yds,
(2) 3-shot groups at 100 yds ... AA 123gr Lapua Scenars ... sub-moa
(1) 5-shot group AA 123gr Lapua Scenars at 200 yds ... center mass ... .625 moa
(1) 5-shot group Hornady 123gr Amax Match at 200 yds... center mass ... .5-moa
10-shots Hornady 123gr Amax Match at 200 yds... headshots ... just to be a dick

I'd buy the gun
 

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My expirience: I had been using the 5.56 for head shots on hogs, or quartering shots to the vitals but lacked confidence in my 77gr smks busting a shoulder (actually upper leg for the heart). My 308 would do the trick but was way too heavy for my kind of hunting which involves around 4 miles of walking. I built up a light weight 6.5 Grendel and have not looked back. It doues everything the other two did in in most cases better.

 
I think it comes down to the OP's planned use. Are you planning on using it in a match? For a range plinker? Run the .308 and shoot cheap ammo all day. Dog hunting? 6.5 will get the job done at the same ranges of the .308, and with less weight. Deer hunting? Lighter weight is a nice plus, unless you simply want a slightly bigger hole. Is it anything that your bolt guns can't accomplish or is this simply a "want"? The hard part is you can't go wrong with either one.

I originally built a Grendel so I could plink 5.56 all day and then pull two pins and be able to hit dogs at range with confidence. I never got a chance to push it at range, and recently sold it. A heavy .223 pill will any job I need done within 400 yards. If I have the need to reach out farther or hit harder, it is obviously not a plinking situation so I will grab the bolt gun and hit what needs hit. Then I can go back to bulk ammo plinking. If I do build another semi in the future, it will most likely be a short and light Grendel.
 
Purely from a ballistics standpoint, the Grendel will always be a little behind a 308 with equal length barrels. I had a 24", then sold it for a 16" which is now cut down to 12.5". At 12.5" it still shoots factory 123 Amax at 2350, which is all I need for hunting out to 300 or so. I didn't lose much velocity SBR'ing it, and it pretty much made my 300 BLK SBR obsolete. While I have a place for a 6.5 Grendel because it maximizes the AR15 platform, there are better choices in the AR10 platform. 6.5 Creedmoor would be my first choice.
 
308 is the Chevy 350 of the cartridge world and every needs 1 or 2.
I built a Grendel with an 18" 5R AR15 Performance barrel and matching bolt. The Grendel is a very accurate midrange cartridge that is great for punching paper, ringing steel ,or hunting anything up to deer/ hig size game in a light weight package. What's not to like?
 
I have an 18" Grendel, and a 20" .260. Wish I would have gone with a 22" on both. .260 weighs 12 pounds loaded. Grendel 8 lbs. So when whatever I'm doing dictates beyond 700 yards, .260 comes out. You've mentioned a lack of ammo. For .260 both Prime 130's and Hornady 130 ELDM are what you need. Both great factory rounds, and will get you out to 1k no prob with better ballistics than .308. I have found that the .260 Hornady ELDM ammo is the SAME price as Black Hills Grendel loads. So consider what you want to do, and choose accordingly. If you do try hand loading then make sure you setup your large frame for the Flatline 121gr bullets from the beginning.. I hope to be testing that bullet in my .260 in the coming months. I'd like to extend range a bit more without buying a new barrel.
 
I think at this point the only real advantage for the 6.5G is you get long range in a lighter package. We now have bullets in .308 diameter that will get you as far and nearly as high BC as the 6.5's. Pushing the high BC but light 6.5 bullets is less of an advantage now for the 6.5 Grendel. It's still an advantage though. So, if you want to jump up in performance, get a 6.5 Creed or .260 to boost performance over a .308.

That said, I very much like my Grendel. And have liked the ones I've owned. There is still really only one magazine company that builds reliable mags, C-Mag. None of the polymer magazine manufacturers offer them yet for the 6.5G/.264LBC/6.5Sport.

As noted, the only cartridge you can pick up at a mom and pop store is the .308. But, that is a lost cause if we ever hit a panic buy again. .308 was off the shelves for years. Making all things kind of equal. You have to reload if you want it. That means stocking up on components.

I really think Sand nails it on the head, if you're dead set on something smaller/lighter by all means go Grendel in the AR15 platform. But if weight isn't an issue go with an AR10 in 308, 260, 6.5 Creed, 6 Creed or 243. Seriously
 
Hey just to give you an update, Kel tec is also coming out with an RDB in 308 win, and also may be selling barreled assembly and bolt for other cartridge conversions on the same rifle. How they got away with what is the actual firearm on the RDB is anyone's guess (it's the steel piece that's on top that's is just the top cover and it joins the front and bottom together) no working parts are mounted in it or to it????
SB
 

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Old thread but this issue comes down to one thing for me and that's recoil.

For hunting or energy on steel it'd be 308. You can kill deer with grendel but I'd rather keep it under 400Y, for shooting steel with light recoil I'd pick the 6.5G.

Now with 224V coming shortly, used for steel at long range and normal hunting distances, I pick this.

Large frame AR's never grew on me. I tried a couple and didn't like the weight or the big ole BCG rocking the gun.

I have a 6mmFatRat that is a sweet shooter. As the saying goes, punches above it's weight, no factory ammo though.
 
Went through same considerations. Have excellent but very heavy 308 precision rig (18lbs) that have used for many years, but got tired of humping weight around. 300BLK AR Pistol was getting heavy for night ops at 11lbs with accessories. Wanted to try and bridge the gap between the two. Considered 6.5 Grendel but in the end went with 6.5 Creedmoor. Beats my 308 hands down, and used F1 receiver and lightweight components (Faxon 16" bbl) for overall weight at 6.5 lbs for AR10 platform. With all the other shit I've put on it I'm humping 11.5lbs now but still much better and balances very well. Shooting factory Hornady Precision Hunter 143 ELDx at 2650fps (+/- 15fps) and couldn't be happier on steel to 600 and critters to 315 so far (only 85 rounds total). 1MOA less drop to 600 and 1/2 the wind (was shooting 165 Sierra HPBT at 2720fps, fairly light loads in 20" barrel).