Switching caliber, AR-15

lnp00

lnp00

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I apologize ahead of time if this is a DOH! type question, but...

I was thinking of converting my AR from .223 to 7.62 and was unsure of how much I would need to replace or whether it would be cheaper just to build one new?

Certainly the barrel, possibly the upper, the lower???

Could someone please he'p with some feedback.

TIA,
Len
 
If by 7.62 you mean 308/7.62x51, you wont be able to. .223 AR15s and .308 AR10s are two completely different upper and lower receivers. You would need a completely new gun.

Now, if you want to be able to shoot 7.62/.308 diameter bullets through an AR15, then you could always look at building a .300 whisper. However this is a whole different ball game and would not match the ballistics of a .308 win or 7.62x51
 
For .300 Blackout you change just the barrel.

For 7.62x39 you change the barrel, bolt and magazine. Same with 6.8 SPC.

For .308/7.62 NATO the AR 15 magwell is too small so you need a whole dedicated .308 AR.
 
VanIsler said:
For .300 Blackout you change just the barrel.

For 7.62x39 you change the barrel, bolt and magazine. Same with 6.8 SPC.

For .308/7.62 NATO the AR 15 magwell is too small so you need a whole dedicated .308 AR.
Click to expand...

As the barrel on an AR is not a quick change affair, this involves changing the entire upper receiver as well, no?

When swapping uppers between calibres that use the same head diameters, can the original bolt and carrier be used, or are there wear pattern issues that require a new bolt and carrier with the new upper?
 
tootall said:
As the barrel on an AR is not a quick change affair, this involves changing the entire upper receiver as well, no?

When swapping uppers between calibres that use the same head diameters, can the original bolt and carrier be used, or are there wear pattern issues that require a new bolt and carrier with the new upper?
Click to expand...

I can change the barrel on either of my AR's in about 5 minutes.

They're not "quick-change", but it's not necessarily a time-consuming venture.
 
tootall said:
As the barrel on an AR is not a quick change affair, this involves changing the entire upper receiver as well, no?

When swapping uppers between calibres that use the same head diameters, can the original bolt and carrier be used, or are there wear pattern issues that require a new bolt and carrier with the new upper?
Click to expand...

Well if you want true quick change a dedicated upper would be best but not necessary.

In the military when shooting C7s we grabbed our BCGs from an ammo box. A used BCG should be able to swap from one used upper to another; if not the upper and/or BCG is ####ed. That level of wear is not common.
 
tootall said:
As the barrel on an AR is not a quick change affair, this involves changing the entire upper receiver as well, no?

When swapping uppers between calibres that use the same head diameters, can the original bolt and carrier be used, or are there wear pattern issues that require a new bolt and carrier with the new upper?
Click to expand...

pretty straight forward, look at this video:

once the barrel nut is off, the barrel isn't held by anything else
[youtube]eryr0wZ71Hg[/youtube]
 
OK, removing the nut then the barrel makes sense.
And that answers my second question!

But for those that dont remove the barrel from the upper, but swap out the upper entirely, is it advisable to keep the same carrier?
 
I have to say that CGN is a brilliant forum. You folks are an amazing wealth of knowledge.

I think I have the answer now...

I was trying to get to the 7.62 NATO that I used to shoot with my old FN when I was in the regiment. So rom what I read, I really need to buy an AR-10.

Cheers,
Len
 
tootall said:
OK, removing the nut then the barrel makes sense.
And that answers my second question!

But for those that dont remove the barrel from the upper, but swap out the upper entirely, is it advisable to keep the same carrier?
Click to expand...

I do not see how it could be a problem, but I could be wrong.

As long as the BCG+bolt is correctly headspaced to all the setups it's good to go. AR barrels and bolts are supposed to be made to be in headspace spec, contrary to bolt actions which should be individually headspaced
 
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