Can one just buy complete uppers and change calibers?

[Zforzachariah14]

I am knew to the whole build your own AR thing so to speak. I built an AR in .556 a couple years back, and was curious if I could just buy a complete upper say a PSA and put in on my AR? I want a 6.5 grendel and it looks like it would be cheaper to buy a completed upper instead of going out and buying a new gun. I like my giselle trigger on my AR and lower a lot so it makes sense to me.

I have 3 options and wonder which one you would choose and why.
1) Buy a diamondback in 6.5
2) Buy a complete upper and swap it out on my AR (if this is possible)
3) build my own with the PSA upper. The PSA complete uppers all have great reviews. My only concern would be if it would be better to buy the 18" or 20" barrel

Help a brother out.

 

[DADI03]

Yes.
Just make sure that you run the right size ammo through the correct upper. Trying to get a bigger bullet through the smaller barrel can end very badly. Clearly mark your magazines.

 

[cmshoot]

I am knew to the whole build your own AR thing so to speak. I built an AR in .556 a couple years back, and was curious if I could just buy a complete upper say a PSA and put in on my AR? I want a 6.5 grendel and it looks like it would be cheaper to buy a completed upper instead of going out and buying a new gun. I like my giselle trigger on my AR and lower a lot so it makes sense to me.

I have 3 options and wonder which one you would choose and why.
1) Buy a diamondback in 6.5
2) Buy a complete upper and swap it out on my AR (if this is possible)
3) build my own with the PSA upper. The PSA complete uppers all have great reviews. My only concern would be if it would be better to buy the 18" or 20" barrel

Help a brother out.

How far out do you plan on shooting your 6.5G?

 

[Zforzachariah14]

How far out do you plan on shooting your 6.5G?

anywhere between 100-300 yards

 

[chrislibby88]

Yes. All you need to swap from 5.56 to 6.5g is upper(barrel), bolt, and mags. The 20inch barrel will probably squeeze a little more performance out of the grendel, but I tend to prefer shorter barrels, if it was me I would go 18in.

You’ll wanna do some research on mags. I think PRI makes a good one.

 

[cmshoot]

anywhere between 100-300 yards

Then go short. I’ve run a 16” 6.5G to 800yds. I wouldn’t have stopped there, but that’s all the range I was on at the time. You don’t need a 18” barrel to make chip shots at 300yds.

 

[Zforzachariah14]

Then go short. I’ve run a 16” 6.5G to 800yds. I wouldn’t have stopped there, but that’s all the range I was on at the time. You don’t need a 18” barrel to make chip shots at 300yds.

If the price is the same, for an 18" upper as the 16" would you still get the 16"?

 

[Hayata]

My only advice is to mark/distinguish your mags somehow.

I do the same thing with my AR in 5.56 and 5.45.

5.45 mags are all metal and 5.56 are polymer.

You REALLY don't want to get them mixed up!

Use a piece of blue painters tape or something to keep them from getting mixed up.

 

[cmshoot]

If the price is the same, for an 18" upper as the 16" would you still get the 16"?

Yep. I have one rifle in 6.5 Grendel and it has a 14.5” with a pinned and welded brake.

 

[cmshoot]

Are the uppers you’re looking at a Type 2? Do they come with a headspaced bolt/BCG?