# Best 9mm round to use in a AR-9mm Sporter



## CPAwithaGun (Nov 9, 2013)

I have recently got my hand on an original Colt AR Sporter in 9mm and was wondering what is the best round to use in it? I was just planning on ball ammo but did not know if a heavier bullet like a 147gr would be better than a standard 115gr?
Thanks.


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## rfawcs (Feb 11, 2006)

I built an AR lower myself, with a mag well adaptor w/ Uzi magazines, and used a RRA 9mm upper. It has handled every 9mm round I've tried. I normally shoot 115 grain ball rounds but use 147 grain when I'm shooting suppressed. I would think your experience will be similar.


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## CPAwithaGun (Nov 9, 2013)

Thanks, may be a stupid question but why the 147gr when suppressed?


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## Shipwreck (Jan 26, 2006)

I would assume because they are slower, and then the total overall sound will be lower with the suppressor.


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## denner (Jun 3, 2011)

CPAwithaGun said:


> Thanks, may be a stupid question but why the 147gr when suppressed?


The speed of sound is 1,125 ft/s) per second, generally 147's come in slower than that, i.e. no sonic boom, or if you prefer it's
better to try to suppress a round that shoot's quieter to begin with. I'm sure you've heard the expression of "sub sonic round"


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## rfawcs (Feb 11, 2006)

Sorry I didn't reply sooner. Everyone's right; 147 grain rounds are subsonic in velocity, so there is no sonic "crack" as the bullet leaves the muzzle. If you ever get a chance to shoot a suppressed firearm and can use subsonic and supersonic rounds, it will be very easy to tell which is which. With .22LR rounds, which are quieter to begin with, it's very easy.


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## CPAwithaGun (Nov 9, 2013)

great thanks for the info,


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