Colt AR6721 Ten-Step Transformation

AR/M4 AR General Discussion
1

Colt AR6721 Ten-Step Transformation

Start with a stock Colt AR-15 A3 Tactical Carbine (AKA a Colt AR6721) . . .

Step 1. Replace the factory barrel assembly with a Noveske stainless-steel Recon barrel assembly including a set-screwed and taper-pinned low-profile gas block.

Step 2. Replace the factory handguards with a Geissele 13” SMR MK8 M-LOK free-float handguard.

Step 3. Replace the A2 flash-hider with a Smith Enterprise Vortex flash-hider.

Step 4. Install Knight’s Armament front and rear back-up iron sights.

Step 5. Replace the factory fire control group with a Geissele SSA-E fire control group.

Step 6. Replace the A2 grip with a Magpul MIAD grip.

Step 7. Replace the factory trigger-guard with a Magpul aluminum enhanced trigger-guard.

Step 8. Replace the factory buttstock assembly with a Magpul UBR buttstock assembly.

The transformed carbine (without a weapon mounted light or optic mounted) weighs-in at 7 pounds, 12 ounces.

Step 9. Install a Schmidt & Bender Short Dot LE in a LaRue Tactical SPR-E mount.

Step 10. Add a weapon mounted light, sling, bipod or fore-grip as needed.

Arisaka In-Line M-LOK mount.

Magpul cantilever M-LOK mount.

Magpul off-set M-LOK mount.

….

While evaluating the accuracy of various hand-loads from the Recon barrel, shooting from a bench-rest at a distance of 100 yards and using the Short Dot LE set at 4X magnification, the Recon barrel produced the 10-shot group pictured below using Sierra 55 grain BlitzKings. The group has an extreme spread of 0.77".

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2

Sweet blaster!

That rail is on my very short list…

3

That is seriously a sweet set-up.
I am just wondering why you didn’t build on a stripped upper if you were going to swap out so many of the original parts.

4

I think I remember you saying in an old post that you zero the Kac sights at 50 yards using the “2” setting on the rear, is that still the case?

5

I agree with this.

6

Why? You spent more money replacing parts than it would have cost to build it. Nice gun though. :slight_smile:

7

Nice setup Molon!

8

Sometimes it’s not about the money. It’s about the experience. :slight_smile:

9

Maybe he already had the 6721. I’m in the process of refreshing a 6721 too. I went in a different direction, but Molon, that has to be one of the best looking rifles out there. The MK8 is so clean looking.

10

True :slight_smile:

11

dang, sweet. Just purchased a 6721 and will make a few changes, not a rebuild.

12

I zero them at 100 yards on the bottomed out setting. The numbers on the elevation dial don’t match any known load or sight radius anyway… they were designed to split the difference between carbine and rifle length sights with M193/M855. The best thing to do is ignore the numbers on the dial and figure out what the click value is with your own sight radius, then run the numbers with a ballistics calculator and figure out the come-ups for every 100 yard increment for as high as the sight will go.

For example on my 16" middy, these sights give right at 0.6 MOA/click, and my come-ups with M193 are 2 3 4 6 7 8. This gets me from 100 out to 700 yards, which is as high as the rear sight adjusts. I have those numbers written on a card that is taped to the stock.

Very nice rifle Molon. You might call it a state-of-the-art recce.

13

Affirmative.

14

. . . or two.:smiley:

15

Looks great, that MK8/Noveske barrel combo has burning a hole in my pocket for a while!

16

Good parts selection. Now show us the groups!

C4

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While evaluating the accuracy of various hand-loads from the Recon barrel, shooting from a bench-rest at a distance of 100 yards and using the Short Dot LE set at 4X magnification, the Recon barrel produced the 10-shot group pictured below using Sierra 55 grain BlitzKings. The group has an extreme spread of 0.77".

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18

Great. That will work!

C4