Colt AR-15 A4 Front Sight Base

[Flankenstein]

So...I ordered a non F marked AR-15A4 and a BCM 20" upper.

Keep the Colt complete (maybe even with the Magpul furniture) and build another A4 with the BCM Upper

or

Sell off the Colt upper and create a Colt/BCM franken A4.

[Displaced Texan]

Oh crap...I forgot to look for that spare A2 stock...I'll check shortly

[Flankenstein]

My NON M16A4 clone:

July 2014 production, no F mark, ambi-selector, ambi-mag release

[IMG][/IMG]

[ssorg]

Received my Colt AR15A4 from Bud's Gun Shop a few weeks back. NO F-MARKED FSB !

NO BIG DEAL !

Here's a picture of the AR15A4's FSB post zeroed in at 50 yards using the Improved Battle-sight Zero with the elevation drum bottoming out at 4 clicks below the 300m mark.

Guess this proves that the F-marked FSB is not required for a 20" flat top.

[Flankenstein]

Looks like these rifles have dried up. Anybody know whats going on? Even more glad I grabbed one now.

[foxtrotx1]

Looks like these rifles have dried up. Anybody know whats going on? Even more glad I grabbed one now.

http://www.gandrtactical.com/cgi-bin...ion&key=AR15A4

Grant has them in stock

I wish someone with a nice benching set up would test one of these with FGMM or another match ammo. Curious to see the results.

[Flankenstein]

http://www.gandrtactical.com/cgi-bin...ion&key=AR15A4

Grant has them in stock

I wish someone with a nice benching set up would test one of these with FGMM or another match ammo. Curious to see the results.

No he doesn't, try adding to your cart. Been like that for awhile now.

[samuse]

http://www.gandrtactical.com/cgi-bin...ion&key=AR15A4

Grant has them in stock

I wish someone with a nice benching set up would test one of these with FGMM or another match ammo. Curious to see the results.

Probably not too hot.

I think Molon did an accuracy evaluation with an A2 barrel once, I know he did one with a Colt HBAR.

[RMiller]

I will say it DOES matter sometimes.

I helped zero a Bushmaster with a flattop upper. Owner was using a Mapul MBUS. With the rifle as is would not shoot POA/POI, even with the front post almost spun all the way out. I ordered him an extended post and it would zero that way, but the post was alnost even with the ears of the fsb.


My thoughts are yes, you can zero a rifle without an F marked FSB. It MAY require extra parts, it may not. However, it's frustrating to buy a complete rifle, and NOT be able to zero it out of the box.

[Molon]

I will say it DOES matter sometimes.

I helped zero a Bushmaster with a flattop upper. Owner was using a Mapul MBUS. With the rifle as is would not shoot POA/POI, even with the front post almost spun all the way out. I ordered him an extended post and it would zero that way, but the post was alnost even with the ears of the fsb.

Then the front sight post would have still been "almost even with the ears of the front sight base" even with an F-marked front sight base and a standard front sight post because there is no difference in the overall height of an F-marked front sight base compared to a standard front sight base. The only difference between the two front sight bases is the height of the sight “shelf” above the top of the barrel.













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