I am currently trying to determine which ammo will work the best with my new RRA 16" chrome lined barrel (1:9 twist). This is a work rifle so it will see work in CQB as well as some long range shooting (100 - 200 yd). I am curious about which grains will work best as well as brands.

If like my old 1/9 twist RRA rifles you'll be hard pressed to find a more accurate round than the 69grn. SMK sold by Black Hills or Federal Gold Metal.

The RRA rifle also likes and shoots the Q3131A quite well.

Mike

ps - the BH bluebox would be my choice.

As you probably know, every rifle is different.

That said, your best bets are match grade loads with 55 to 69 grain bullets from the major makers.  You might also want to try some of the hunting ammo loaded with premium bullets such as the Nosler Ballistic Tip, Nosler Partition, and Speer Trophy Bonded Bear Claw.

75 grain bullets almost always stabilize in 1/9 barrels that are 20" and longer (higher MV => higher rotational velocity).  Still a box of premium loads in that weight should be tested.  Hornady TAP, Hornady Match, and Black Hills 75 OTM Match (which all use the Hornady 75 HPBTM bullet) get the nod there.

I have been using the Black Hills 75gr OTM in my chrome lined bushmaster 1:9 twist 16in. barrel with excellent results out to 400 yards. I will be testing it out to 600 in the next 2 weeks (weather permitting).  I have also tried some of the new Hornady 75gr TAP out to 300 yards with nice 6-8" groups. I actually took some XM193, BH 60gr, Winchester 64gr Power point, BH68gr, and BH75 grain to the range and tested it all out to 300yards. All shot  under 4 inches at 200 yards and  under 8 inches at 300 yards. The 300 yard testing was starting to be affected by the wind so I expect it will do better next time if I can get a calm day. In spite of the wind, all loads were able to hit man-sized gongs at 400 yards before I had to end the range session. Differences in accuracy between ammo were essentially nil from prone position. YMMV. I would use the heaviest bullet my gun will shoot well. I hope this helps. My advice, try several loads and go with what works best for you.

Quoted: I have been using the Black Hills 75gr OTM in my chrome lined bushmaster 1:9 twist 16in. barrel with excellent results out to 400 yards. I will be testing it out to 600 in the next 2 weeks (weather permitting).  I have also tried some of the new Hornady 75gr TAP out to 300 yards with nice 6-8" groups. I actually took some XM193, BH 60gr, Winchester 64gr Power point, BH68gr, and BH75 grain to the range and tested it all out to 300yards. All shot  under 4 inches at 200 yards and  under 8 inches at 300 yards. The 300 yard testing was starting to be affected by the wind so I expect it will do better next time if I can get a calm day. In spite of the wind, all loads were able to hit man-sized gongs at 400 yards before I had to end the range session. Differences in accuracy between ammo were essentially nil from prone position. YMMV. I would use the heaviest bullet my gun will shoot well. I hope this helps. My advice, try several loads and go with what works best for you.

Most people that use 75 grain bullets with a good quality 16" 1:9 twist barrel experience good results... Its the ones that have poor quality barrels or are misinformed about the actual twist rate of their barrel that have bad results...

Thanks to everyone for your input. I have to qualify with my new rifle, hopefully this weekend, before I can carry it for duty. I plan on trying 3 of the top brands. I will post my test results along with the ammo manufacturer, model, and grain. Thanks for all the input.  Paul

Quoted: I plan on trying 3 of the top brands. I will post my test results along with the ammo manufacturer, model, and grain. Thanks for all the input.  Paul

Looking forward to seeing your results...

Policetacteam:

Did you get to the range to try ammunition yet? I was hoping you would share the results, esp. regarding heavy bullets in your 1/9 barrel.

I have not had a chance to test out different ammo types yet. Our agency has just opened our new, state of the art firearms range (South West Iowa Training Center) so I am hoping to break in the new rifle within a few weeks. My initial thoughts are to go with 3 different types of ammo to keep my costs down. I am planning on using either / or both Black Hills and Hornady TAP in 55 - 70 grains. I will post my results then. Keep checking.