Opinions on AR10 caliber

[IHFarmer07]

I’m gearing up for a ar10 build and I’m not sure what direction I want to go on caliber.......I think either a 6.5 creed, 7mm08, 7mm Saw. I REALLY like the idea of doing a 7mm08 for being the middle row of knock down and range. I’ve always wanted a 7mm08 something, so what do you all think?

 

[tuckybill]

Good time to build. Parts and ammo have never been more plentiful or cheap! Ok now that that is out of the way......The AR10s are a bit finicky even with .308 ammo. I wouldn't build one in one of those calibers unless it is strictly to be a range toy. If that is the case go for the 7/08!

IF your thinking a all around AR10 just get it in the boring .308 and handload. The 308 is lots less boring if you load 155 gr palmas or tipped match kings in it. Or 110 barns. Or 180gr bear claws. Or sub sonics. Or........

 

[Slevin182]

I'm either 308 or 6.5 because I already reload them, the ballistic capability is well reflected in barrel life, and lots of companies make barrels for them.

 

[7mmFanBoy]

7mm-08 ar10 18" 1-10 my velocity are on the low side " could be my barrel / chamber" . OAL length issues getting into 162 > along with pressure increase. Cheaper and more availability bullets in the 120-150gr Bc is lower vs 6.5. Resizing 308 brass is EZ + LC brass more pressure which you can also do in 6.5 process takes longer. Run faster powders in my 7mm-08 which are also more available. I give it an edge over 308 hard to beat 6.5 in any barrel length

 

[KYAggie]

I have both 6.5 creed and 308; neither are finicky. Adjustable gas blocks are a must so you can tune to your load, even more so if you run a suppressor. I think the reputation for AR10’s being finicky is a little outdated with the parts now available and made worse by people trying to run them without the ability to adjust the gas system and a lack of understanding of how that whole system works. A 7-08 should be no different, but I would stick with a 6.5 creed over the 7-08. If you want something cool, run a 338 Federal, it’s made for shorter barrels and hammers within typical “hunting” ranges.

My 20” Faxon fluted match runs Barns 127 LRX at 2930 fps with RL16. 6.5# without optics. Lots of titanium in that one.

 

[CrabsandFootball]

6.5 and its not even close for cheap and plentifull ammo, as well as bullets like the 130AR designed to shoot from an AR at mag length.

.308 has seen its day, its like buying a car with a carburetor. Anything you can do with it can be done better with 6.5.

Just make sure you buy a quality barrel and check the port size.

 

[deersniper]

6.5cm. Better ballistics. Cheaper match ammo


308s only saving grace is longer barrel life and availability of cheap plinking/surplus ammo. Oh and you can load AP bullets

 

[Odysseus1911]

6.5 cm does NOT have better ballistics than 7mm-08; they are actually identical, but the 7 carries more energy from muzzle to 1000.

6.5cm does have much better factory match ammo selection.

I'd go 7mm-08

 

[BikePilot]

I think 7-08 would be pretty cool. I’m not reloading now so I’m currently sticking to stuff that’s more readily available from the factory.

 

[IHFarmer07]

Good time to build. Parts and ammo have never been more plentiful or cheap! Ok now that that is out of the way......The AR10s are a bit finicky even with .308 ammo. I wouldn't build one in one of those calibers unless it is strictly to be a range toy. If that is the case go for the 7/08!

IF your thinking a all around AR10 just get it in the boring .308 and handload. The 308 is lots less boring if you load 155 gr palmas or tipped match kings in it. Or 110 barns. Or 180gr bear claws. Or sub sonics. Or........

Yep it sure is.....little late to the party right!? I’m in no hurry with it because of those reasons but I’m keeping my eye out for deals on parts.

 

[IHFarmer07]

6.5 cm does NOT have better ballistics than 7mm-08; they are actually identical, but the 7 carries more energy from muzzle to 1000.

6.5cm does have much better factory match ammo selection.

I'd go 7mm-08

yeah and barrels are plentiful too for the 6.5cm. Idk I got time, let things settle back down and go from there. Kinda one of those last minute decisions right at the wrong time but it’ll be ok.

I think 7-08 would be pretty cool. I’m not reloading now so I’m currently sticking to stuff that’s more readily available from the factory.

I agree, I like different, one off deals......idk time will tell.

 

[IHFarmer07]

I have both 6.5 creed and 308; neither are finicky. Adjustable gas blocks are a must so you can tune to your load, even more so if you run a suppressor. I think the reputation for AR10’s being finicky is a little outdated with the parts now available and made worse by people trying to run them without the ability to adjust the gas system and a lack of understanding of how that whole system works. A 7-08 should be no different, but I would stick with a 6.5 creed over the 7-08. If you want something cool, run a 338 Federal, it’s made for shorter barrels and hammers within typical “hunting” ranges.

My 20” Faxon fluted match runs Barns 127 LRX at 2930 fps with RL16. 6.5# without optics. Lots of titanium in that one.

Honestly I’ve considered the 338fed. Just not sure if it’s out there enough to get ammo off the shelf if need be. I reload but there’s sometimes where you just don’t want to reload for certain chambering if you don’t have to.

 

[CrabsandFootball]

6.5 cm does NOT have better ballistics than 7mm-08; they are actually identical, but the 7 carries more energy from muzzle to 1000.

6.5cm does have much better factory match ammo selection.

I'd go 7mm-08

2 words.

Mag Length.

Its why nobody is shooting 7-08 out of AR10/SR25's.

 

[trdjohn]

2 words.

Mag Length.

Its why nobody is shooting 7-08 out of AR10/SR25's.

when I was putting together my large frame AR, I thought about 7mm-08 as pretty cool was to go for ballistics, but then the mag length popped into my mind and went with 6.5 creed instead haven't looked back since

 

[IHFarmer07]

Thanks all, I’ll look into all the possibilities, likely 6.5 creed, but you just never know. I’ve got some of the parts at home, some are ordered and on the way. Think all I need is barrel, bolt, (gas tube, gas block) if these don’t come with a barrel, hand guard, magazine. Who knows someone here might have a deal on what I’m looking for but as for tuckybill’s smart ass response, ......it’ll be ok, you look around and there are parts/items out there!! I might not get this done this year, who knows, AR’s are expensive to build!!

 

[j-dubya]

2 words.

Mag Length.

Its why nobody is shooting 7-08 out of AR10/SR25's.

This is what everyone needs to remember when they say the 7-08 and 6.5’s are neck and neck. That argument applies mainly to the 162gr Amax/ELD. And you need all the length you can get to make the 162 get some worthwhile speed. Not a good choice for a gas gun.

I say this is a 7-08 shooter that chose it over the 6.5’s ten years ago for my bolt gun. None of my gas guns will ever have that chambering unless some shorter and lighter projectiles hit the market with a worthwhile BC.

Now, if you want a non-6.5 gas gun that can get you close-enough performance, with more energy, reliable feeding, and even better barrel life than the 7mm, then look at the 185 Berger for a 7.62 gas gun.

 

[tuckybill]

Thread hijack! Everyone talks about the 7mm/08 having less recoil than the .308. I looked and found two 150gr factory loads. 7mm/08 had 2611 foot pounds of energy and the 308 had 2648. Won't that mean the recoil is pretty much the same? Does the wider bullet kick harder??? Never shot them side by side with same weight guns to know for sure what the deal is. Same thing with the 6.5 creedmore. Again everyone talks about kicking less but with a 147 bullet vs. a 308 shooting a 150 gr won't it pretty much be the exact same since the energy is very close?

 

[IHFarmer07]

This is what everyone needs to remember when they say the 7-08 and 6.5’s are neck and neck. That argument applies mainly to the 162gr Amax/ELD. And you need all the length you can get to make the 162 get some worthwhile speed. Not a good choice for a gas gun.

I say this is a 7-08 shooter that chose it over the 6.5’s ten years ago for my bolt gun. None of my gas guns will ever have that chambering unless some shorter and lighter projectiles hit the market with a worthwhile BC.

Now, if you want a non-6.5 gas gun that can get you close-enough performance, with more energy, reliable feeding, and even better barrel life than the 7mm, then look at the 185 Berger for a 7.62 gas gun.

Honestly I’ve never nor do I own any 7mm caliber, I have a 6.5prc though. That’s why I’d like a 7mm based cartridge but I’m FLEXIBLE on cartridges though. It was just a consideration.

 

[LRRPF52]

Thread hijack! Everyone talks about the 7mm/08 having less recoil than the .308. I looked and found two 150gr factory loads. 7mm/08 had 2611 foot pounds of energy and the 308 had 2648. Won't that mean the recoil is pretty much the same? Does the wider bullet kick harder??? Never shot them side by side with same weight guns to know for sure what the deal is. Same thing with the 6.5 creedmore. Again everyone talks about kicking less but with a 147 bullet vs. a 308 shooting a 150 gr won't it pretty much be the exact same since the energy is very close?

I honestly don’t feel the difference between .308 Win, 7mm-08, .260 Rem, and 6.5CM when shooting similar bullet weights.

You have to really step up in weight with a .308 or 7mm to make them recoil more, and it still isn’t a huge difference unless you compare it to 107s or 123s in the 6.5mm. If I shoot a 139gr 6.5 next to a 139gr 7mm next to a 147gr .308, I just don’t feel a lot of difference. Put a 107gr 6.5mm next to a .308 185gr, sure.

One thing I’m seeing in big box stores throughout this year’s ammo situation is that there always has been .260 Rem on the shelves, but it’s usually really expensive premium ammo and some kind of hunting loads.

One thing you never see: 7mm-08 target ammo. Not online, not on LGS shelves. As far as I know, every single production 7mm-08 load is a hunting bullet. It’s a great cartridge for sure, and actually does well in the AR-10 since it isn’t a big departure from the 7.62 NATO chamber pressure and bore volume, and it feeds from mags very well without any bullets that slip through the barrel extension teeth like we see with some of the VLDs in 6.5mm and 6mm.

I haven’t seen .308 in months now. When the truck shows up to my local Cabella’s, they offload 9mm, 5.56, sometimes .22LR, occasionally .45 ACP, and 10mm.

 

[IHFarmer07]

I honestly don’t feel the difference between .308 Win, 7mm-08, .260 Rem, and 6.5CM when shooting similar bullet weights.

You have to really step up in weight with a .308 or 7mm to make them recoil more, and it still isn’t a huge difference unless you compare it to 107s or 123s in the 6.5mm. If I shoot a 139gr 6.5 next to a 139gr 7mm next to a 147gr .308, I just don’t feel a lot of difference. Put a 107gr 6.5mm next to a .308 185gr, sure.

One thing I’m seeing in big box stores throughout this year’s ammo situation is that there always has been .260 Rem on the shelves, but it’s usually really expensive premium ammo and some kind of hunting loads.

One thing you never see: 7mm-08 target ammo. Not online, not on LGS shelves. As far as I know, every single production 7mm-08 load is a hunting bullet. It’s a great cartridge for sure, and actually does well in the AR-10 since it isn’t a big departure from the 7.62 NATO chamber pressure and bore volume, and it feeds from mags very well without any bullets that slip through the barrel extension teeth like we see with some of the VLDs in 6.5mm and 6mm.

I haven’t seen .308 in months now. When the truck shows up to my local Cabella’s, they offload 9mm, 5.56, sometimes .22LR, occasionally .45 ACP, and 10mm.

You know, I looked past the .260.....that would be another viable consideration!

 

[_Windrider_]

You know, I looked past the .260.....that would be another viable consideration!

I love my .260 AR10. Shoots Prime 130’s like a mofo

 

[j-dubya]

260 would be an excellent choice. It would be mine under the same premise I went with 7-08: I can make it from 308 brass I have on hand.

 

[IHFarmer07]

260 would be an excellent choice. It would be mine under the same premise I went with 7-08: I can make it from 308 brass I have on hand.

Right! I know there’s a shit ton of creed brass but once that’s sold out or something ignorant happens what would a person have to make creed brass......7mm08 and 260 could be made damn easy, 7mm08 is it’s a good happy medium.

 

[troupe]

7-08 would be a great set up. Satern barrels can make a great 7-08 AR-10. 140's would be great out of a 20"

 

[LRRPF52]

I started out making all my .260 Rem brass from Winchester 7mm-08.

I’m lucky to get 3 loadings out of it.

Once Lapua started making .260 Rem brass, I bought that as well.

 

[LRRPF52]

Any of the high pressure, bottle-necked chamberings based off of .308 Win and .30 TC/6.5CM require constant case trimming and then die an early life, unless you pull back on the pressures and lose the performance edge of the cartridges.

Even pushing towards max loads, you will often not be able to get the gas system to behave properly, so you have to hold back, especially with 140gr in the 6.5mms.

The only bullet weight I have produced and shot as a go-to in the .260 Rem is 130gr Berger VLD. Mine actually feeds and shoots the original 130gr VLD into bug holes, so I shoot it, or at least used to when I shot the .260 more.

Now I just shoot Grendel and almost forget about the .260 Rem...almost.

Haven’t had it together for a while, and raped it for the Geissele trigger for one of my Grendels.

I don’t even trim necks on Grendel brass, and primer pockets last forever it seems. I’ve never lost a pocket on Lapua Grendel brass.

 

[_Windrider_]

Any of the high pressure, bottle-necked chamberings based off of .308 Win and .30 TC/6.5CM require constant case trimming and then die an early life, unless you pull back on the pressures and lose the performance edge of the cartridges.

Even pushing towards max loads, you will often not be able to get the gas system to behave properly, so you have to hold back, especially with 140gr in the 6.5mms.

The only bullet weight I have produced and shot as a go-to in the .260 Rem is 130gr Berger VLD. Mine actually feeds and shoots the original 130gr VLD into bug holes, so I shoot it, or at least used to when I shot the .260 more.

Now I just shoot Grendel and almost forget about the .260 Rem...almost.

Haven’t had it together for a while, and raped it for the Geissele trigger for one of my Grendels.

I don’t even trim necks on Grendel brass, and primer pockets last forever it seems. I’ve never lost a pocket on Lapua Grendel brass.

i can attest to this. I have what is arguably one of the best gas system setups I could produce and it took me a bit to get my 260 to reliably shoot prime 130’s. Ar10’s are finicky. Shooting random calibers just because isn’t advised.

 

[LRRPF52]

The 7mm-08 is a lot more friendly though. The rifle doesn’t really know it’s not a .308 when shooting 120-154gr.

Once you get into 162gr 7mm-08, then you’ll want the small firing pin aperture bolt, and slightly smaller gas port diameter, port location-dependent of course.

 

[IHFarmer07]

i can attest to this. I have what is arguably one of the best gas system setups I could produce and it took me a bit to get my 260 to reliably shoot prime 130’s. Ar10’s are finicky. Shooting random calibers just because isn’t advised.

This is what I’m afraid of with a different/off the wall cartridge.

 

[Michael52]

I just got an AR-10 stripped lower in 6.5 CM delivered today. The rest of the parts for the build on are on the way. I already have a Ruger Precision Rifle in 6.5 CM and I have ammo and components for hand loading, so that made the caliber choice simple.

 

[Slevin182]

I just got an AR-10 stripped lower in 6.5 CM delivered today. The rest of the parts for the build on are on the way. I already have a Ruger Precision Rifle in 6.5 CM and I have ammo and components for hand loading, so that made the caliber choice simple.

If you have an AGB you should be good to go. If I didn't have a 6.5 bolt gun I'd get into another 6.5 built off Aero receivers.

 

[KYAggie]

For all of you who have experienced “finicky” AR10‘s, were you running an adjustable gas block and at least a rifle length gas system? Also, what weight buffer were you running? Was your bolt carrier a standard weight bolt or light weight?

 

[rg1911]

260 would be an excellent choice. It would be mine under the same premise I went with 7-08: I can make it from 308 brass I have on hand.

Another vote for 260 Rem. I load mine with 139-gr Scenar, 140-gr Berger VLD or 140-gr Hornady match. All are running .5 MOA (at 200 yards) and ringing steel at 800.

Another plus for the 260 Rem is that you can run 7.62/308 brass through the sizer and have 260 Rem-equivalent. I have a fairly tight chamber (a mistake I made), so I do have to turn the necks down.

Cheers,
Richard

 

[Stealff]

I love my 260 Rem's as well, used my 16" build to fill my tag this morning.

 

[2aBaC̶a̶]

Would not be venturing into a new caliber right now.

What do you shoot and reload already?

 

[IHFarmer07]

Would not be venturing into a new caliber right now.

What do you shoot and reload already?

Not planning too much right now as most supplies I have are for these calibers specifically and the things needed are hit and miss.
6.5prc, 30-06, .224 Valkyrie and I have the supplies for .223 but haven’t messed with reloading for either my ar15 or my buddies TC encore.
After all this shit is over, I hope it’ll be over, I’ll be doing 1-2 .243’s, probably a few other calibers, depending on the status of the country, what I decide to do with a couple rifles/uppers calibers in mind. I’m not set in stone on what calibers/uppers I’ll build/buy, I’ve got what they call wishful thinking in a seriously bad time for the gun industry.