The 30 BR

In 2023 I traveled to Lewiston Id. To compete in a club level 100/200 yard benchrest score match. I knew almost nothing about score BR shooting but it sounded like a good time. I have always been interested in the pursuit of accuracy, tiny groups and the technology to achieve them. Score benchrest sounded like something more fun than small group work. I had a pretty legit benchrest rifle at the time chambered in 6 BR, it shot the heavy 105 gr. Bergers into tiny little groups and I could use it in matches out to 600 yards with good results. While my results at the match were alright it became clear in short order that the 30 BR round was the ticket. I left that match with some clear ideas about what it would take to be more competitive in score BR matches. The guys at the Lewis Clark Wildlife Club were very helpful with equipment ideas and one person even offered to let me use his Robinett spec reamer when he found out I was an actual rifle builder.

I started my journey into the 30 BR world with a fair amount of web research. Having been a long time 6 BR fan, I went straight to 6BR.com and found out most of what I needed to know. It was clear that there were two primary classes in score benchrest, Hunter Class and Heavy Varmint. The easiest solution for choosing what class to compete in was to simply build two rifles and compete in both classes, right? The quickest way for me to get started was to simply spin up a new barrel for my 6 BR benchrest rifle in 30 BR. While I was offered use of a reamer that would have allowed me to get started right away, I have always like to forge my own path if I have ideas on something. I called JGS Precision and requested the reamer print for the Robinett spec 30 BR reamer. I changed some of the dimensions to better fit with my ideas on chamber design. After talking with Jack Sutton at Hart Barrels, I ordered 2 barrels in .308”, 1-17 twist and profiles appropriate for hunter and heavy varmint classes. I have know those guys for a couple of decades or more, very knowledgeable and very helpful. I ordered some (well OK quite a bit) of Lapua 6 BR brass. I have had a long history using Lapua in other competitive shooting disciplines I knew this was the way to go. Bullets on the other hand I had zero hands on experience with small light weight 30 caliber bullets. On the internet it seems almost everyone was a fan of the BIB bullets in 112 gr. to 118 gr. sizes. There was a small group of shooters that were quite happy with the Berger 115 gr. FB match bullets. The Bergers were available that day so I ordered a 500 round box and back ordered 1000 of the 118 gr. BIB bullets. At the time most powder availability was (and still is) hit or miss. I looked hard for H 4198 and VV N130, unable to locate either, I did run on to some Hogden Benchmark that some people had great success with. Sometimes you don’t get to run what you want but what is available. I ordered a set of 30 BR competition dies from Redding, this was a no brainer for me. Now the only thing left was to wait for all my stuff to show up. Fortunately I was busy teaching long range shooting classes that summer like most and the time flew right by.

As soon as I had a barrel blank and reamer in hand I set about cutting a new barrel for my current heavy varmint BR rifle. My reamer design allowed for use of brass without turning the neck. I have always believed that some processes are truly important to accuracy and some are done simply so that people can say they did them. I spun up the Hart barrel with the 30 BR DE reamer cut it at 24 inches, added a little weight to the back of the stock and came in just under the HV weight limit of 13.5 pounds as intended. Now I have worked and developed my share of wildcat rounds so building brass was not much of an issue, especially with my reamer design. I was certain from the start that I would not have to turn necks or remove donuts from the shoulder/neck junction to get it to shoot like I expected. Building brass for this chamber is simple, lube a case, run it in the 30 BR die with tapered expander, trim to length and bevel the case mouth. That is all I did for case building and prep. Now it was time to get started on serious load development.

I fired a couple of cases to get fully formed brass and test the sizing specs of the reloading dies.

Fired Case Measurements:

Base to Mouth: 1.498”

Web Diameter: .471”

Shoulder Diameter: .461”

Neck Outside Diameter: .332”

Neck Inside Diameter: .310”

Base to Shoulder: 1.112” (using 13/41 comparator)

Sized Case Measurements:

Base to Mouth: 1.501”

Web Diameter: .470”

Shoulder Diameter: .458”

Neck Outside Diameter: .330”

Neck Inside Diameter: .307”

Base to Shoulder: 1.110” (using 13/41 comparator)

               These measurements were exactly as I had expected and was quite satisfied with them. Next, I fired a grid target with 3 shot groups at 35.0 gr, 35.5 gr, 36.0 gr, 36.5 gr. and at each powder charge -.000”, -.003”, -.006”, -.009” and -.012”. The results were interesting and of course very helpful in narrowing down where I needed to be. After looking at groups I narrowed down to -.000” (it showed a preference for -.000” and -.009” with -.000” being consistently a little tighter) and 35.0 gr, 35.5 gr and 36.0 gr. to start real groups of 5 rounds. In the end 36.0 gr looked to be the best and I just needed to see if anything was available on either side of that. I fired 35.8 gr and 36.2 gr. each at +.002” and -.002”. I finally settled on 35.8 gr and -.000”, this seemed to be the most consistent performance of the test, turning in 5 shot groups in the very low 2’s. I was certain that I should be able to get mid to low 1’s, but this was a good place to get started.

After waiting what seemed like forever (patients is a virtue, just not one of mine) I received my BIB bullets and had also rounded up a couple of cans of H4198. There is a reason this is such a popular combo and I’d have started with it had it been available. I ran the same load development grid I had with the Benchmark / Berger combo and easily got into the mid / low 1’s. With this combo in hand I went to my local club benchrest match where they shoot 2, 10 shot group matches and 2, 10 shot score matches. In the 30 BR’s first outing it set new club records in both group and score with .173” and .253” 10 shot groups and a 200 point / 17x score match agg. I couldn’t be happier with my heavy varmint 30 BR.

  My hunter class rifle is of course a different animal, it has to weigh in under 10 pounds ready to roll. The hunter class rifles are restricted to a 2.25” wide forend and a scope with maximum magnification of 6x. I had built the hunter rifle on a McMillan Hunter class stock, one of my Terminator actions (of course) and a Hart barrel. I knew I wanted to run a Leupold 6x Hunter BR scope for this rifle. That scope has been long discontinued and the ones available fetch a pretty good price. So I did what anyone would do and paid for one in really good shape. My son is the manager of the hunting / gun division of Black Sheep sporting goods in Coeur D Alene, Idaho. I showed him the scope since it was unique and not something most people encounter. He pipes right up and says, “I have one of those at the store, it has been there for like 15 years”. So I zipped right down the next day and bought the new in box Leupold for half what I paid for the used scope. It is better to be lucky than good. I had a small hiccup when the stock weighed more than I thought it was going to. To make weight I had to shorten the barrel to 20 inches. I got the hunter class rifle put together and painted the brightest yellow I could find. I started load development with the Berger 115’s and Benchmark since I had a pretty good pile of both and was saving the BIB’s / H4198 for the heavy varmint since it like them so well.

            Load development pretty normal, but the thing that surprised me was how well I could shoot the 10 pound, 6x scope combination. With almost no effort in terms of development I was printing 5 shot groups in the low 1’s using the Berger / Benchmark combo.

I have yet to shoot the Hunter rifle in competition but will soon. Hopefully I can attend a few 2 gun events where they shoot both hunter and heavy varmint classes in aggregate for the event.

I have had such a great experience with the 30 BR so far with its easy development and extreme barrel life that I am having a tough time getting excited about my regular 6 BR group barrels that don’t seem to perform any better than the 30 BR. Stay tuned more to come.