What Zero for 9mm SBR AR?

[crossgun]

What is the recommended zero for the 9mm AR? Will be running a Rock River 10.5
9mm with a SWR Trident Suppressor.

Thanks

[LonghunterCO]

Colts 9mm SMG small (long range) apature is labled 50meters. I am in the process of building mine now. Interested in hearing from others on this topic also.

[GaryG]

Yea, I'd be interested in hearing from folks knowledgeable in 9mm ballistics & bullet-drop at various ranges, too.

I understand the 5.56 50/200yd BZO theory, where an AR sighted in so the Point of Aim crosses the Point of Impact at 50 yds, and at 200 yds; and the bullet won't be more than ~2 inches above or below that from muzzle distance out to ~250 or so yards.

I'd love to hear what the equivalent BZO recommedations would be for a 9mm SBR-length barrel.

[Molon]

To start with, you have to seriously evaluate what you expect to accomplish with a pistol round being fired from a carbine. For example, I use my 9mm AR-15 carbine for training at CQB distances at shooting ranges that don't allow rifle calibers. Then understand that the external ballistics of the pistol round will be drastically different from that of a 5.56mm round, therefore you can't use the same sighting schemes as you would on a 5.56mm platform.

That being said, here are two examples of the more practical sighting schemes I've used.

http://www.box.net/shared/static/rpnpqvc7nz.jpg

[rob_s]

Molon, thanks for posting that, as it's something I've been looking for myself for quite some time. Is that for velocities typical of a 10.5" barrel, and do you happen to know what kind of change in velocity we might expect between a 10.5" and 16", and how that might affect the trajectory?

[GaryG]

Molon, perfect, thanks - - just what I was looking for.

[LonghunterCO]

Great post. Would be interested in the barrel lengths as well.

[Paulinski]

I zero'd mine at 25 yards.

Thanks for the graph Molon.

[Molon]

Molon, thanks for posting that, as it's something I've been looking for myself for quite some time. Is that for velocities typical of a 10.5" barrel, and do you happen to know what kind of change in velocity we might expect between a 10.5" and 16", and how that might affect the trajectory?

IIRC, I used the 124 grain HST velocity from a 16" Colt 6450 for that graph. The velocity differences between the 16" Colt 6450 and a 5" pistol barrel is approximately 160 fps, so the 10.5" barrel is going to be somewhere in between that. The trajectories won't be dramatically different from those shown in the graph.


http://www.box.net/shared/static/tprk4uo4o8.jpg

[LonghunterCO]

http://web.archive.org/web/20080124071549/groups.msn.com/TheMarylandAR15ShootersSite/9mmzero.msnw

Here is link to a recomendation for a 25yd zero. Not sure if this is approiate for an SBR.

[crossgun]

ALL Thanks for the info. Seems 25 yards is the answer.