Colt 6720 .308 conversion

AR/M4 AR Technical Discussion
1

Hi all!
I used the search engine to look for “Colt 6720 .308” and got no hits so I hope this is not a repeat thread. I own a 6720 and want to get a .308 upper. All that I read states that a mil spec AR lower should be able to make this change easily. I would be going with a Colt upper (to keep my Colt a Colt). The idea is .223 for range/100yrd zero i. and .308 for the field/300 yrd zero in. I want to confirm with you folks that this is a possibility before I spend money attempting to diversify my rifle and end up with a big paper weight.

Also, any advise on this change would be awesome since I intend on frequently swapping out uppers depending on the job that awaits me. Thank in advance and also sorry in advance if this thread is already out there.

2

Can’t do that with your weapon. You are limited to the size of the magazine well. Lucky for you you can buy a weapon system that does this: http://www.gandrtactical.com/cgi-bin/commerce.cgi?preadd=action&key=LE901

3

What weapon systems are there that would give me this versatility? I can change up my layaway 1 time. Are their M&P’s that can do this? I don’t particularly care for DPMS and that tier of firearm. Since the mag well is an issue do I need to buy one already in .308 and convert downward?

4

You should buy an upper chambered for any of the larger bore rounds that will still work with your lower.

Some of these in no particular order. 6.8 SPC, 300 Blackout, 300 Whisper, and .30AR

5

You might be thinking of Colt rifle discussed in this thread
https://www.m4carbine.net/showthread.php?t=89813

6

Please click the link I provided. It is what you are looking for.

7

Turns out ill need to buy one of each. No worries! I’m getting this one ordered next week. Ill just enjoy 2 rifles and keep in mind it’s less lower wear each. These will be my only 2 AR’s. while the dark side is strong in this Jedi, I still love my wood stock bolt actions! Talked to my LGS and 100 puts me on the list and the say the price is 1500-1700. My LGS only does a 6% max mark up and less for members and frequent customers. Their business model is “sell the guns; make more on range/memberships”. What really like about my LGS is they seem to give better deals on calibers they can’t accommodate. Must be there way of keeping you hooked! Thank you!!

8

You’re limited by the magazine length to the caliber. Since the AR15 was designed around 5.56x45, a much longer cartridge will not fit the magazine well of the AR15. If you want something of larger caliber but do not want to bump up to an AR10 platform, you could research the above mentioned calibers. The most viable convertible platform, maybe the only that has actually delivered, would be the Colt LE901 if you want to go from .308Win to 5.56.

9

Are you talking about $1500-$1700 for two rifles? If so, I want directions to your shop. If for only a Colt 6720, you are getting ripped off by about $400-600.

10

No, that’s the price for AR in .308. It’s the LE-901-16s. My 6720 ran me 1000.00. Sorry for the confusion.

11

1500-1700 is potentially less than what dealers are paying for these rifles so…you might want them to check their numbers.

12

So tell me more about these jobs that await you.

13

Ok, so jobs was a poor use of words. I could feel your sarcasm all the way up in the Pacific Northwest. The idea “was” that the facilities of the closest range to me can only accept up to the .223 caliber. The .223 caliber is the smallest caliber I own. The reloading equiptment I have is for .300Win Mag, and .338 (my bolt action rifles). Whenver I can, I love shooting at 300+ yards (which is out of range for the .223). I have to drive quite a bit further for this; but, there is fun in that too (sometimes). My goal was to have a rifle that is intended for 100-150 yards and also have the ability to switch the upper receiver (get some use out of the rifles versatility) and also be able to shoot at a farther range.

I guess the jobs could be considered as training at 100 yards and also training at 300 yards. I don’t personally see any problem in training at different distances. Im new to the AR world so I was trying to figure out exactly how versatile is my platform. I recieved my answer(s).

I will send pictures of the Armalite 10A4F that I ordered. I was going to go with another Colt; but, the Armalite seems like a great rifle and it was quite a bit less expensive.

14

The .223 can do anything on paper that you can do at 300 yards. I’ve competed with one out to 600 yards and the round has never been the limiting factor.

One of my strongest competitors often used a 16" AR with Federal GM 69 grain ammo. Obviously if you need energy downrange the .223 won’t cut it but for targets it is more than enough.

15

That is understandable. I would say that I got the .308 not for shooting paper only. I’m selling off my .300Win Mag to fund it. I’m not sure about the fine lines WA State has for using this rifle as a hunting rifle; but, if I can I will. If not, I still have my .338 to hunt with and 2 Black Rifles. One with the added energy out a distance of needed.