Kimber Mountain Ascent – All Dialed In with Barnes Vortex TTSX

Thought I would write a quick post on the progress I am making on finding the best overall round for the Kimber Mountain Ascent rifle I picked up last fall in .308 Winchester.

I have now tried three different rounds; the Nosler Custom in 165 grain Accubond, the Hornady Superformance in 165 grain Interbond, and the Barnes Vortex in 150 grain TTSX. I plan on using this rifle for an occasional elk hunt, but I bought it primarily as a light gun to carry when I am out helping someone else find their elk or deer, but want to have a rifle “just in case”. Well that all changed when I drew a Montana goat tag fro 2013. I plan on using the little Kimber to harvest a goat if I don’t take one with a bow by mid October.

I wrote about the results with the Nosler loads in a previous article, but to recap, I was getting great accuracy but the rounds averaged only 2680 through my chronograph, a full 140 FPS slower than advertised. Since the Kimber is a 22″ barrel, I expected some loss in velocity but that was excessive.

I next tried the Hornady Superformance and was happy to see them chronograph at an average of 2840 FPS, just below the 2860 advertised. Dispersion in FPS was excellent with all ten shots ranging between 2832 and 2846.

Unfortunately the little Kimber just didn’t like the Superformance ammo.  While I have had excellent results in the past with other rifles with Hornady’s Light Mag and now Superformance lines, this gun just couldn’t digest them. I would get a decent group and then the next would be 2.5″. Very inconsistent.

My first test session with the Hornady ammo had been at 35 degrees. When I shot them again on an 80 degree day, the ten shots averaged 2892 FPS ! 52 FPS higher. And the dispersion became terrible with some rounds clocking 2870 and one at over 3000.  I called Hornady and spoke with Mike, their tech advisor (who was great by the way) and he explained that those kind of velocity spreads were not out of spec with those loads.  Hmmm. They advertise temperature insensitivity. Guess not so much.  But I wasn’t planning on doing too much hunting at 80 degrees, the real reason I decided to set the Hornady load aside was the accuracy.

I have been told, and retold, just how tough goats are. So I decided to try the Barnes Vortex line in their Tipped Triple Shock (TTSX) bullet. The 150 grain leaves the barrel at an advertised 2820 FPS.  I haven’t ran these through my chrono yet but from what I have read, Barnes’  advertised ballistics are usually spot on. I expect these loads to run about 2790 out of the 22″ barrel. I shot three five shot groups. Recoil was very mild. Below is the best at 7/8″ center to center. The worst group was 1 1/4″.  I was shooting prone using a bi-pod and out of fifteen rounds there were no flyers. They just kept punching holes in the same spot.  I believe the gun and the Barnes TTSX is capable of 3/4″ MOA groups or better if shot from a more stable rest  from a bench.

I recovered three of the bullets from the backstop and weighed them. One weighed 148.5 grains, one 148.2, and one at 147.8. Incredible weight retention.  The recovered bullets looked like something out of a Barnes promotional ad with perfect mushrooming. I think I have found my goat round!

Kimber has done a great job with a mass produced rifle weighing 4 lbs 13 ounces that can shoot sub moa groups with factory ammo.

Now to chronograph these rounds and send in the ballistics to Leupold so they can create a custom CDS dial for the VX-3 scope. Can’t wait to try these at 500 yards ! Till then, good shooting !