AR15 223 vs 6.5 Grendel - parts interchangeability?

[mrd]

Now and then, I get the urge to build a AR15 in 6.5 Grendel. What AR15 parts are specific to 6.5 and what parts can I use from my 223 parts bin?

 

Barrel, bolt and compensator are of course specific to the 6.5 - what else? Bolt carrier? Upper?

 

Anything else to consider if wanting to build a 6.5 Grendel for up to 1000 yards? School me!

Edited August 24, 2020 by mrd

[TonytheTiger]

Barrel, bolt and mags, thats it. I love 6.5G for what it is but there's no doubt its outclassed beyond 800yds by the 6mm Grendel.

[mrd]

Thanks, Tony! So I could use a 6.5 Grendel bolt with a spare bolt carrier from the bin?

 

I'll check out the 6 mm Grendel. Isn't it a wildcat caliber and I'd need to make my own casings? 

[LeadThrower]

What happens when you toss in the .224 Valkerie into the mix for punching paper and ringing steel at the 1000 yard mark?

 

6.5mm < .224 < 6mm?

 

 

Edited August 24, 2020 by LeadThrower

[belus]

3 hours ago, mrd said:

I'll check out the 6 mm Grendel. Isn't it a wildcat caliber and I'd need to make my own casings? 

Not exactly a 6mm Grendel, but Hornady recently started advertising the 6mm ARC as a commercial cartridge. I haven't read much about it but have a passing interest in building a similar rifle.

[TonytheTiger]

Yup, carriers are interchangeable, but make sure you get the right bolt type for your barrel. 

 

6mmG is a wildcat, but its the easiest one in existence. One step neck down and done, if I can do it anyone can. 

But even easier yet is Hornady's new 6ARC. Its just a very slightly modified 6mmG but standardized with factory support.

[SnipTheDog]

Wouldn't the AR10 be a better platform for the 6.5 vs the AR15?

[TonytheTiger]

8 minutes ago, LeadThrower said:

What happens when you toss in the .224 Valkerie into the mix for punching paper and ringing steel at the 1000 yard mark?

 

6.5mm < .224 < 6mm?

 

 

I don't have a 224V but I've equaled the ballistics with 223 bolt gun loads and I'd easily say 6mm has the edge. Even if the 224V looks slightly better for drop/drift on paper there's no comparison when it comes to effect on target or spotting misses.

[TonytheTiger]

1 minute ago, SnipTheDog said:

Wouldn't the AR10 be a better platform for the 6.5 vs the AR15?

Ballistically yes. But there's a whole list of tradeoffs you get when going large frame.

You gain size and weight, lose modularity, lose lots of barrel life, huge cost increase and most of all AR10's are just plain harder to shoot. The extra reciprocating mass takes a lot more practice to master.

[SnipTheDog]

8 minutes ago, TonytheTiger said:

Ballistically yes. But there's a whole list of tradeoffs you get when going large frame.

You gain size and weight, lose modularity, lose lots of barrel life, huge cost increase and most of all AR10's are just plain harder to shoot. The extra reciprocating mass takes a lot more practice to master.

Great answer.  Thanks.

[mrd]

Great answers, thanks everyone! It seems building a different caliber AR15 upper is not far off, having some bits and pieces in the bin already.

 

I like the 6.5 Grendel for it's capacity to perform where the 223 Remington falls short. Having a AR15 in 6.5 Grendel is like having a baby AR15 6.5 Creedmoor on the cheap - without the bulk, the weight and without having to train for a new platform. There are shortcomings with the 6.5 G too, of course, but it seems pretty great for my needs and budget. Hi-cap magazines appears to be a problem area, though.

[wgj3]

5 hours ago, mrd said:

Great answers, thanks everyone! It seems building a different caliber AR15 upper is not far off, having some bits and pieces in the bin already.

 

I like the 6.5 Grendel for it's capacity to perform where the 223 Remington falls short. Having a AR15 in 6.5 Grendel is like having a baby AR15 6.5 Creedmoor on the cheap - without the bulk, the weight and without having to train for a new platform. There are shortcomings with the 6.5 G too, of course, but it seems pretty great for my needs and budget. Hi-cap magazines appears to be a problem area, though.

I've not had issues with mine and the 25-28rd mags that seem most abundant and available. 

[mrd]

10 hours ago, wgj3 said:

I've not had issues with mine and the 25-28rd mags that seem most abundant and available. 

What type and brand of mags are you running?

[bfilbey]

I built a 6.5 Grendel last year. After a few growing pains and tuning it shoots and functions well.

 

I bought Elander magazines. To make them work smoothly I filed and stoned some rough edges and gently adjusted the feed lips. That said, prior to buying mags I read the reviews on them all. Most brands were praised to some degree as good functioning and equally declared junk by others. I believe the reason for the conflicting reports of performance is caused by two things; lot to lot variations in production magazines and variations in parts selection in individual rifles. Tolerance stacking may require a little tuning with a new gun and new mags to get it to feed and run reliably.

 

Also check out the 6.5 Grendel forum. Lots of good information there interspersed with well meaning but woefully poor analysis. (like most Internet sites)

 

Cheers

Buck

[wgj3]

6 hours ago, bfilbey said:

I built a 6.5 Grendel last year. After a few growing pains and tuning it shoots and functions well.

 

I bought Elander magazines. To make them work smoothly I filed and stoned some rough edges and gently adjusted the feed lips. That said, prior to buying mags I read the reviews on them all. Most brands were praised to some degree as good functioning and equally declared junk by others. I believe the reason for the conflicting reports of performance is caused by two things; lot to lot variations in production magazines and variations in parts selection in individual rifles. Tolerance stacking may require a little tuning with a new gun and new mags to get it to feed and run reliably.

 

Also check out the 6.5 Grendel forum. Lots of good information there interspersed with well meaning but woefully poor analysis. (like most Internet sites)

 

Cheers

Buck

Same on Elander and At least one other as well...c-product or ASC...

[K-Tex]

As much as I like the 26cal AR or not my favorite is the 6.8spc.   6.5g vs 5.56 nato is mags, bolt (carrier stays the same) and barrel.

[twodownzero]

Other things to consider:

The mags aren't the best.  7.62x39 really doesn't fit very well in an AR mag (grendel is the same basic shape, both have the same parent).

 

6mm is a better fit for the powder capacity than 6.5

 

22 with a larger case (ARC or Grendel) and 90s might be better at 1000 than even 6mm.

 

It really depends on what you want to use it for.  I had a 6mm Fat Rat, other than the mags and feeding, it was awesome, but in the end, it wasn't worth the price premium over 223.  It had more ballistic power, but at 600 yards it doesn't matter (maybe if it's crazy windy), and beyond that, I'm usually shooting a bolt gun anyway.  It filled a niche that I thought was important in my head, but in real life, it didn't.  Especially where ranges are known, either from a rangefinder or because you're on a known distance range.

 

I sold my bolt and barrel, installed a similar profile 223 barrel on my rifle, and I am actually surprised how much a 20", scoped, DMR style AR rifle is.  It's useful for almost anything that needs shooting with a rifle.

Edited October 15, 2021 by twodownzero

[K-Tex]

2 hours ago, twodownzero said:

Other things to consider:

The mags aren't the best.  7.62x39 really doesn't fit very well in an AR mag (grendel is the same basic shape, both have the same parent).

 

6mm is a better fit for the powder capacity than 6.5

 

22 with a larger case (ARC or Grendel) and 90s might be better at 1000 than even 6mm.

 

It really depends on what you want to use it for.  I had a 6mm Fat Rat, other than the mags and feeding, it was awesome, but in the end, it wasn't worth the price premium over 223.  It had more ballistic power, but at 600 yards it doesn't matter (maybe if it's crazy windy), and beyond that, I'm usually shooting a bolt gun anyway.  It filled a niche that I thought was important in my head, but in real life, it didn't.  Especially where ranges are known, either from a rangefinder or because you're on a known distance range.

 

I sold my bolt and barrel, installed a similar profile 223 barrel on my rifle, and I am actually surprised how much a 20", scoped, DMR style AR rifle is.  It's useful for almost anything that needs shooting with a rifle.

So true!   I have 11.5, 16, 18, 20, 22 and 24" barrels all in AR, but ammo specific for each.   The 24" has a bull barrel (not much fun too lug around), so nothing wrong with a 556.

[twodownzero]

31 minutes ago, K-Tex said:

So true!   I have 11.5, 16, 18, 20, 22 and 24" barrels all in AR, but ammo specific for each.   The 24" has a bull barrel (not much fun too lug around), so nothing wrong with a 556.

 

I have a 26" bull barrel 20 practical.  It shoots like a laser but it's not a gun you want to carry anywhere.

[TonytheTiger]

8 hours ago, twodownzero said:

 7.62x39 really doesn't fit very well in an AR mag (grendel is the same basic shape, both have the same parent).

They have the same parent and use the same bolt face diameter, but the huge difference in body taper is significant enough to make them two very different cartridges.

[twodownzero]

2 hours ago, TonytheTiger said:

They have the same parent and use the same bolt face diameter, but the huge difference in body taper is significant enough to make them two very different cartridges.

I wouldn't know, as I had a Fat Rat, and the body taper probably had a substantial influence on why it fed like crap and I don't have it any more.

[TonytheTiger]

1 hour ago, twodownzero said:

I wouldn't know, as I had a Fat Rat, and the body taper probably had a substantial influence on why it fed like crap and I don't have it any more.

Yeah I've never tried any of the improved Grendel variants. My 6mm and 6.5 both feed great.