Mar 28 2012
We put our new 18″ SPR 7.26mm/.308 Winchester rifle through its paces at the range this week. This rifle features our .308 Winchester compatible 7.62mm NATO chambered barrel. The overall performance was flawless. The Chrony was set up 15 feet from the muzzle, and we loaded up with Hornady 155 gr A-Max and Winchester 168 gr Ballistic Silvertip ammo. The A-Max achieved a muzzle velocity of 2685 fps, and the Silvertips hit 2365 fps. Reliability was perfect. At the end of the session we had a nice pile of .308 brass sitting at 3:30 about 10 feet away. Our MA-TEN based BR-X rifles were designed to go bang every time the trigger is pulled, because we know your hunting trip or your life may depend on it.
The first session showed good accuracy with 1.5 MOA 5-shot groups. Took the rifle out for a second range session because we knew it could do better. The first trip out we found that the trigger was terrible. It was a basic GI single stage trigger, but something was obviously wrong with the mating surfaces between the hammer and the sear. This time out we put a Timney single stage trigger in the rifle with a 4.5 lb pull. What a difference. Here’s our setup:
And the view down range:
Targets are 105 yards from the muzzle. No Chrony on the second day as it was raining and miserable. This time we brought several different types of ammo including 150 gr Hornady SST Superformance, and hand loaded 150 gr SMK and 150 gr Barnes TSX
And the results
Starting at top left: the first group was fired with 150 gr Sierra Match King over 46 grains of H4895. The first shot is for sight in, then moved a few clicks left and called it good for testing. As you can see, there are many three shot groups that would be great, but three shot groups are for sissies, so I manned up and shot 5 in each group. This is more a testament to my shooting still than to the rifle. Our professional shooter Dave wasn’t available for this range day so I had to do the dirty work myself. First group came in at 1.36″, measuring the groups as the largest distance between the centers of any two shots in the group. This produced a respectable 1.34 MOA.
The second group at the top right is 150 gr Barnes TSX over 46 grains H4895. Woof! I didn’t even bother measuring that one. From the left at the bottom: 150 SMK over 43 gr Varget, 150 Hornady SST Superformance, 150 Barnes TSX over 43 gr Varget. The rifle obviously likes the SMK’s, and with some time put into load development, should be able to push MOA or better. This will be our focus in the future. I’m also looking forward to the weather warming up and a nice sunny day at the range. Once I get a good load dialed in, it will be time to call Dave to put up some real groups.