I had an accidental lesson shown to me today, in the form of the effects of different brass cases.
I was doing an evaluation of a Legendary Arms Works rifle this weekend, using many different types of ammunition; both factory stuff and some of my handloads. The rifle was LAW’s The Professional, a sweet bolt-action in .308 Winchester, with a good Cerakoted barrel and action, set in a Bansner synthetic stock.
I had four different types of factory loads that I knew had shot well in other .308s. I was recording velocities and group size, and when it came time for the handload portion, I stumbled upon my old supply of .308 hunting ammo.
When I had loaded this ammo, the .308 Winchester was my main hunting rifle, and I used the fantastic Sierra 165-grain Game King hollowpoint boat tail bullet. The load consists of 44.9 grains of IMR4064, ignited by a CCI200 Large Rifle primer. This load has given me MOA accuracy from my old standby Ruger Model 77, with a sporter weight barrel and a terrible factory trigger, topped with an old school Leupold Vari-X IIc 3-9; a decent hunting combination for a young hunter of modest means, and a gift to me from my father.
Back in those days, I scavenged every single piece of .308 brass I could get my hands on, and used them until they cracked. I’m glad times have changed, but I remember how precious the components were to me when I had no money.
Within this plastic box of hunting handloads were about 80 rounds, all carefully handloaded (to the best of my abilities in those days) to the same specifications, except for the fact that they were loaded into different brands of brass. R-P, WW Super, FC (two variations), Super Speed and Win headstamps were all present within my melting pot of ammunition. All the brass was carefully trimmed to the same length, as well as the bullets seated to a uniform dimension.
This LAW rifle is a shooter, showing sub-MOA accuracy with three of the factory rounds. Grabbing the box of handloads and heading to the range, it wasn’t until I had the Oehler Chronograph fail to give me a reading that I realized that this was the hodge-podge collection that I have described.
Looking through the box, I separated them into lots of the same headstamp, and started observing the difference, allowing the barrel to cool properly between groups. The velocities all hung pretty close to 2,650 fps, within 30 fps or so, but the accuracy changed quite radically.
My notes indicated that I developed the load with R-P cases, and they showed the best accuracy from the Legendary rifle, but the accuracy told a different tale. The R-P stuff printed ¾” groups at the 100-yard mark, but the FC headstamp brass opened up to over 2”. I thought it was me; I just wasn’t shooting well today or something.
I gave three of the same FC headstamp cases to another shooter, and the bullets printed the same size group. I grabbed three more R-P cases, and shot a group measuring 7/8”, while the WW Super stuff shot 1 ½”. A pattern was developing here. The Super Speed cases gave exactly one MOA, and a third attempt with the FC cases showed that at least The Professional rifle didn’t like them.
What’s the lesson here? Sometimes the slight variations in case capacity between brands, or even lots of the same brand, can cause a pretty radical change in accuracy.
Don’t get me wrong, any of those loads would have sufficed for the normal deer hunting shots here in the Northeast, but change that scenario to a Pronghorn antelope hunt or other long range affair and the shooter may start to doubt things.
This lot of ammo represents what I had to do in a pinch, when premium brass was unaffordable and I needed to make do with what was on hand. But when hair-splitting accuracy is required, consistency matters.