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AR15.COM
9/22/2004 8:48:18 PM EDT
I will soon be building a SBR AR15 in 5.56.  I see that both 10 1/4" and 11 1/2" uppers are available.  Will the 11.5 upper give me any noticeable velocity increase (or muzzle flash decrease)?

Also, I am aware of the Form 4 and CLEO signoff thing, but how long is the typical wait from the ATF before I can call up and order my upper?  Thanks.
9/22/2004 9:03:31 PM EDT
[#1]
Minor Note:

Building is FORM 1.

Form 4 is Transfering from One party to another.

I'm working on an SBR too.  So if there is anybody in The Know, the two of us would like a Real Wold Answer.
9/22/2004 9:07:08 PM EDT
[#2]

Quoted:
I will soon be building a SBR AR15 in 5.56.  I see that both 10 1/4" and 11 1/2" uppers are available.  Will the 11.5 upper give me any noticeable velocity increase (or muzzle flash decrease)?

Also, I am aware of the Form 4 and CLEO signoff thing, but how long is the typical wait from the ATF before I can call up and order my upper?  Thanks.



AFAIK...you can call and order your upper now...just dont install it till you have completed the red tape
9/22/2004 9:13:02 PM EDT
[#3]
You can order your upper whenever you want . My Form 1 took about 90 days to be approved.

You kill velocity by going with the short barrel, an ammo change might be necessary if you intend on using the weapon for social purposes......
9/22/2004 9:37:42 PM EDT
[#4]
I had a 10" std. 55gr loads chronoed at 2500fps and same ammo from a 20" made 3050fps, I never did my 11.5" cause I just don't care.
9/22/2004 9:41:13 PM EDT
[#5]

Quoted:
Minor Note:

Building is FORM 1.

Form 4 is Transfering from One party to another.

I'm working on an SBR too.  So if there is anybody in The Know, the two of us would like a Real Wold Answer.



Which upper are you going to go with, GiggleSmith?
9/22/2004 11:07:44 PM EDT
[#6]
This one:

11½ Inch Upper

I should have it before the end of the month.
I also made sure it has the one with the M16 Bolt Carrier.
9/23/2004 2:57:51 AM EDT
[#7]
If your set on getting an SBR Ar15 the 11.5 is better only because you'll get better velocity from it. If your potentialy using this for self-defense you should know that the .223 acheives it potential when traveling a minimum of 2,700 fps. Out of the 11.5 using a 55 gr. rd. you'll probably get somewhere around 2,600 fps.

To adjust for the loss in velocity you may try a 50 gr. rd for defensive purposes , either way check out this thread and others in the ammunition section : www.ar15.com/forums/topic.html?b=3&f=16&t=189353