9mm AR 15 build

[cwheel]

Thinking about rounding up the parts to build a flat top M4 style AR in 9mm. Not going to use this for anything serious, mostly plinking with cast bullet reloads. I notice that their are 2 different barrel twist rates available, 1-10" and 1-15". Reason for the build is 22LR is still tough to find and I can reload 9mm with cast much cheaper, just something to target shoot with mostly under 100 yards. I'd like to use cheap ball in the beginning to make fresh cases to reload, but bottom line here is I'd like it to shoot both cast and jacketed well. Anyone have any idea what barrel twist rate would be best ?? I already have a double hole Lyman 9mm mold ( 358242 ) that I'd like to use. Any jacketed would be in the same common 125gr. weight range. On a side note, looks like the 9mm uppers are priced way above the 5.56 price range ?? Anyone else that has done this, I'd appreciate some insight on the barrel twist issue, thanks,
Chris

[lancem]

1-10 would be standard, I would reason then that the 1-15 would be for heavier bullets like the 147 gr.

I've had one for years for pretty much the same reason, cheap to shoot and fun. I bought a rock river arms upper when I built mine.

[SOFMatchstaff]

Where are you located,North or south?? The upper is generic, just find one that usable and cheap. I have some unborn Uzi bbls and Colt style bolts of various manufactures, it doesn't seem to make much difference. Seeing as how you can turn your own stuff, you can get into a 9mm real reasonable. The magazines and adapters are the parts that need your attention. Opt towards the un-modified Uzi mag set up, cheaper, and mags are tough, and the ejector is in the mag adapter so you can use an existing lower and fire control. There are other issues, but mostly dealt with by tuning the recoil parts.

[James6406]

My 9mm AR has a 1 in 10 twist barrel and I use 125gr round nose. From my experiences shooting cast, it left a build up of lead in the slots of the flash hider. Very time consuming to clean. I switched to powder coated boolits to eliminate the problem.

[imashooter2]

1-10 would be standard, I would reason then that the 1-15 would be for heavier bullets like the 147 gr.

I've had one for years for pretty much the same reason, cheap to shoot and fun. I bought a rock river arms upper when I built mine.

You have that backwards. 1:10 is faster than 1:15.

OP, Rock River and Colt use 1:10. I'd have to hear a pretty convincing argument for the 1:15 to choose otherwise.

[Jupiter7]

Palmetto state armory usually has pretty good deals. I recently built a retro 9mm carbine, a1 upper, Colt style mag block, govt profile barrel with FSB, a1 flash hider. I built the rifle with a mix of parts from different vendors with low price being a deciding factor. Got $450 in the gun total, including 5 metal form SMG mags. I used PSA, jse surplus, heavybuffers.com, AeroPrecision as vendors and a RRA LPK I had. With judicious shopping it doesn't have to be a money pit.

[cwheel]

Thanks to all for your input, think I'll go with a 1-10 twist. Although I can turn my own with little trouble, thinking that buying a assembled upper is the way to go. Looking through Shotgun News, ( Firearms News ) seams to be lots of sellers listed doing 9mm upper assemblies. The few of them selling 1-15" barrels made me ask why. Plan on going with Uzi mags as they are cheap, strong, and everyone seams to have them at the gun shows. To answer SOFMatchstaff, I'm about 40 miles south of Carson. Not wanting to build a SBR or anything that would need a tax stamp, no short barrels, keep it lite and simple. Will make my own receiver from a 80%, easy mill job. Flat top upper with a red dot and folding front and rear sights as a backup. Thanks to all again for the input.
Chris