Atrs modern sporter build .223 vs 6.5 grendel vs 458 socom

[Jamal86]

I ordered my upper and lowerfrom atrs
This will be my first black rifle
Im kind of stuck trying to pick what i want to build, originally i was going to build a 458S, i just sold my 1895 sbl kind of because i developed a flinch with it and my reloads. I was thinking itd be a cool brush gun or hiking gun (bear defense). Then i started thinking, the .223 is so cheap to shoot fmj and i could reload some of the brass with 70g gmx but id mostly shoot 55g fmj and i know thats kinda useless for bear defense also reloading the 70g gmx its about the same cost of reloading 458S. So it was a toss up between which upper i was going to build first.

Then i started looking into the 6.5 grendel, i can look 95g vmax and some 123 or 124g gmx or sst ( cant remember) i know everything ive shot with my creedmoor 143g eldx with hasn't taken a step, so would the 6.5 grendel be the best of both worlds?

What ever i get ill be getting an 18.6 inch barrel, velocity trigger, and probably top it off with a primary arms 1-8 people seemnto like them.

Anyway, anyone that has built ars before if i could get some guidance for my first build that would be sweet

 

[Brianma65]

I just sold my MS in .223 and have another set ordered.
I’ve got all the parts ordered for 6.5 Grendel and I’m going to put it on my AP set.
If I like it , I’ll be ordering a Christensen arms CFW JP barrel.
Also have dies and components on the way.

 

[Jamal86]

I just sold my MS in .223 and have another set ordered.
I’ve got all the parts ordered for 6.5 Grendel and I’m going to put it on my AP set.
If I like it , I’ll be ordering a Christensen arms CFW JP barrel.
Also have dies and components on the way.

So would you say the .223 is fun for plinking but the 6.5 grendel would be a better all around, just a bit more expensive to shoot?

 

[alberta tactical rifle]

From experience the 6.5 Grendel is a great deer cartridge out to around the 400 yard mark with the 123 gr SST bullets. That being said deer die fairly easily and are rather unlikely to attack and try to eat you as a bear can so would be hesitant to go looking for a bear with it. In the perfect circumstance a blackie should fold up with a round or 2. Certainly would be better than 223.
For close range the 458 might have an advantage but without looking closely at the velocities it is hard to say whether many bullets would actually expand. Typically heavy bullets have thicker jackets so require X amount of velocity to perform as designed. The best option I am aware of would be the 300 gr TTSX which was designed specifically for the 458 Socom and so should expand as well as penetrate reasonably well.
For a big bore I would strongly recommend our SLICK SIDE upper due to the larger ejection port and I would not put a port cover on simply to ensure no ejection issues.

The really cool part of modular rifles is how quick you can swap uppers so it is feasible to have a 223 for plinking and playing around with and a big bore for business.

 

[Brian46]

I would also be careful about hot loading the 458 socom to get more velocity and better bullet expansion with the existing bullets on the market. Even buffalo bore factory loads is hot for most bolts available other than those from AR performance or a custom one of stronger alloy.

If going to a custom bolt so you can get a higher performing AR15 for hunting is on the table, have a look at 30rar

 

[Brianma65]

So would you say the .223 is fun for plinking but the 6.5 grendel would be a better all around, just a bit more expensive to shoot?

We have no deer on the island, but if we did .223 would be what I’d use.
So, for me, .223 is for plinking only.
I’m going to take a bear and a moose with my 6.5 Grendel.
I’m sure it’s quite capable.
So my plan is ,two uppers, being .223 and 6.5 Grendel
I’m loading my own, so the 6.5 isn’t that much more expensive.

 

[Jamal86]

I would also be careful about hot loading the 458 socom to get more velocity and better bullet expansion with the existing bullets on the market. Even buffalo bore factory loads is hot for most bolts available other than those from AR performance or a custom one of stronger alloy.

If going to a custom bolt so you can get a higher performing AR15 for hunting is on the table, have a look at 30rar

I was thinking about loading hard cast from jet bullets if I was doing a 458s but I also did like the 325g from hornady. The lead I'd be loading up to 1700fps or so. Again that's if I went that direction. I'll check out the 30rar

 

[Jamal86]

We have no deer on the island, but if we did .223 would be what I’d use.
So, for me, .223 is for plinking only.
I’m going to take a bear and a moose with my 6.5 Grendel.
I’m sure it’s quite capable.
So my plan is ,two uppers, being .223 and 6.5 Grendel
I’m loading my own, so the 6.5 isn’t that much more expensive.

Ya. That's was one option I was thinking, was thinking a .223 and a 458 soccom upper. I'm got my 6.5cm for hunting. But you idea about having a .223 and a 6.5grendel is not a bad idea either, I'm in the okanagan, and hunt here and a bit in revelstoke. Dont think there's much chance of an angry grizzly here even tho I've heard stories about people seeing them. I know the 6.5 dropped black bears, ones I shot with my CM didn't take a step. What bullets are you planning on loading for your 6.5G?

 

[Brianma65]

Ya. That's was one option I was thinking, was thinking a .223 and a 458 soccom upper. I'm got my 6.5cm for hunting. But you idea about having a .223 and a 6.5grendel is not a bad idea either, I'm in the okanagan, and hunt here and a bit in revelstoke. Dont think there's much chance of an angry grizzly here even tho I've heard stories about people seeing them. I know the 6.5 dropped black bears, ones I shot with my CM didn't take a step. What bullets are you planning on loading for your 6.5G?

I’m researching now, thinking of something in the 123g range.
Going to start with Nosler, Hornady and Barnes.

 

[Brian46]

I was thinking about loading hard cast from jet bullets if I was doing a 458s but I also did like the 325g from hornady. The lead I'd be loading up to 1700fps or so. Again that's if I went that direction. I'll check out the 30rar

When my 30rar was built we used my old 450 bolt as a sacrificial lamb (same rim diameter as 458) it could not handle much more pressure than the factory loaded ammo before you could see signs of failure. My new bolt was proof tested with a 20% overcharge from the 55,000psi 30rar produces from its factory loadings. 458 runs at 38,000psi with a smaller rim/bolt face.

Whatever bolt you choose, make sure the manufacturer has done some sort of testing so you know where your limits are

 

[Runt]

I had the same issue & considered exactly what you have written above. It’s a tough decision. From what I have researched my conclusion was the .223 is cheap to shoot, 6.5 Grendal has good ballistics for AR type magazine limitations and it’s an excellent deer round, the .458 Socom likely to drop most medium sized game out to 200 m.

Theoretically could a 6.5 Grendal with the right bullet be used to take down Black Bears if you hit the vitals when hunting? Idunno…. Something that I do have experience with is defense from a Bear, which is different than hunting due to bears behavior (pissed off), distance (close range) and point of impact (generally frontal vs side/vitals) are vastly different when confronted by a angry bruin, compared to hunting which you get to choose the ideal shot (heart/lungs). Some Black bears in BC are not small & can take a significant hit from a shot gun slug to put them down. Therefore, I think the 6.5 Grendal is a poor Bear defense choice compared to the .458 Socom average hard hitting 300 gr. Bullets. If you’re only going to take one and you’re okay with shorter distance shots…. get the .458 Socom upper with an adjustable gas block. Having said that I do not know of a factory 18.5" .458 Socom Barrel manufacturer.