ericskennard

Which mag pouch are you using for Colt SMG style mags? I found the Comp Tech listed. Coda has two, a 3.5 inch or 5 inch. Has anyone tried these?

I was hoping for the best when I got the one with the stainless barrel. I think I can make it shoot pretty well with 147 Zeros. I just have to do some load testing.

So my journey into Pistol Caliber Carbines for steel shoots took me to the Rock River R9 Competition. This is without a doubt one of the highest quality and best built AR15s I have seen in 35 years of using and owning them. But as I have stated in another post it is very ammo sensitive. Bullets with a long bearing surface seem to shoot the best groups at 50 yards. So I am looking at trying the Zero 147 JHP or 147 FMJ bullets. I have several jugs of Vihta Vuori N320 and N340 so I am going to try this powder. I really like both of these powders. So Lapua's load data shows: N320 3.1 grains minimum at 784 FPS to 3.9 grains max at 984FPS. The N340 is listed 3.9 grains minimum at 948FPS and 4.3 grains maximum at 1015 FPS. I am going to speculate that the VVN340 will work a little better with the heavier bullet. Is anyone else using these powders with the 147 bullets? what loads are you using?

That is very curios Led. That is a big difference in velocity between your two barrels. I never considered the buffer might effect velocity. I have seen the buffer greatly effect function and feeding. I am pretty lucky that this R9 has had ZERO MALFUNCTIONS!!! That will jinx me now. I have examined the bore of this barrel with my Hawkeye borescope. It really looks pretty good. I may touch up the muzzle crown on my lathe at some point. It just has been frustrating to have a carbine that doesn't shoot as good at 50 yards as a couple of my 1911's! I expected a lot better. I don't remember the MP5 platform shooting this poorly when I shot them many years ago. I like your # too. I didn't realize the same number would not convert to a life number. When I could finally afford the life membership, the numbers were pretty big so i just keep renewing this one. Also, I am in palm bay and shooting at Port Malabar Rifle and Pistol. Eric

Thank you both for your replies. The barrel on the R9 is a stainless 16" and I believe it is 1 in 10 twist. What type of barrels are you both using? Have either of you tried the Zero 147 JHP?

After a 25 year absence from IPSC while I shot long range rifles, I have become very excited about the steel matches. Forget about power factor. Find a load and pistol that doesn't recoil. Our club doesn't allow rifle caliber carbines on their steel. I needed a 9mm AR. The first consideration was to convert an AR I already had. Ultimately I decided to try the Rock River Arms LAR R9 competition. It has real forged upper and lower receivers, a better 2 stage trigger, a better barrel, and a free float hand guard. It just seemed sensible to get a carbine already fitted up and ready to go. I received it a few days ago. The build quality is above excellent. I have close to 500 rounds through it so far. It has had ZERO MALFUNCTIONS!!!! So Rock River has done something right! My only disappointment is the accuracy. Rock River guarantees a 1.5 inch group at 50 yards. I installed an Aimpoint M3 4MOA sight that I had on another rifle. I got a bunch of Winchester 115 grain white box to test the R9 and break it in. I was shocked when I was only getting about a 7 inch group. Yea I have gotten used to 600 and 1000 yard rifles that shoot 1/4 MOA but 7 inches at 50 yards is pretty extreme the wrong way. I installed my Leupold MK IV 6.5x20 scope on the R9 and gathered up a few different kinds of 9mm ammunition to try a new test. I test fired again at 50 yards using my bench rest rifle rest and rear sand bag. The WW 115 FMJ white box still shot a horrible 7 inch group. WW 124 grain NATO white box didn't do much better. Okay I am getting disappointed. CCI Blazer brass case 115FMJ did a little better. It shot a 3 1/2" group. Next I tried some Federal +P+ 124 grain Hydra Shok I had left over from my uniform law enforcement days {1989~90 vintage}. Much better. The +P+ shot a 2" group. Now the problem is that +P+ Hydra Shok is a little expensive to shoot three times a week. I was thinking that the faster speed made the improvement. So next I tried some Speer Gold Dot 147 grain from the same era. This is very slow ammo. I got a 2 1/4" group from this load. I dug out some IMI UZI +P++ Carine rounds. There were stamped 1986 and had maroon tips. Another good group and 2 1/4". These were fairly high velocity as I recall but they are only 115 grains. I shot some Browning 147 grain TMJ. Wow a 1 3/4" group. I pulled a sample bullet from each batch. Since velocity didn't seem to be a factor in accuracy I wanted to see if there was something else. All the more accurate rounds had a longer bearing surface than the standard 115 and 124 FMJ bullets. So here is my question to all of you, "Are all 9mm Pistol Caliber Carbines so ammo sensitive or is this an anomaly with my R9?" Is the bearing surface difference another common issue? Does anyone else shoot an R9 and do you have the same issues? My hope was to get several thousand Bayou Bullets to load up with VV340 and shoot but I am skeptical whether they will work. Maybe the 145 RN with a long bearing surface? What are your thoughts? Eric USPSA TY2541 NRA Life member I.A.L.E.F.I. member