Inside Look at World Record .0077″ Group — The Gun and Ammo

We reported two weeks ago that Texas shooter Mike Stinnett nailed a .0077″ group in competition — the smallest 5-shot group ever shot at 100 yards. This has now been officially recognized as a new NBRSA record, eclipsing the .009″ record group shot 40 years ago by Mac McMillan. Congrats to Mike for breaking the “unbreakable record”. As Glenn C. posted on Benchrest Central: “They said it couldn’t be done. Hats off to Mike for an awesome personal achievement in a Sport/Hobby where getting your name in the record books is a rarity.”

Stinnett Sets .0077″ Record with a .30-Caliber Modified Grendel Cartridge, Pre-Loaded
Many folks have asked about the gun and ammo that produced the .0077″ group. The rifle was chambered as a .30-caliber wildcat, the 30 Stewart, which is based on the 6.5 Grendel case necked up. Mike was using Hodgdon H4198 powder behind BIB 114gr, 10-ogive bullets. Notably, the record-setting ammo was pre-loaded before the match. Unfortunately, we don’t have a photo of the target yet — it is still in the hands of the official NBRSA certification committee. However, Mike has been kind enough to tell us about his rifle and his load.

Mike Stinnett .0077″ Record Group Equipment Report

Mike reports: “Several guys have asked so here is my equipment listing. The hardware build actually started in 2008 with the goal of building two identical Benchrest rifles which could be used for both group and score. The idea was to shoot 6PPC and a 30 Cal without a base rifle change.”

About the Cartridge — 30 Stewart (Based on Lapua 6.5 Grendel Parent Brass)
Mike explains: “Our goal was to shoot H4198 as the optimal powder for stability. There were several versions of the reamer before we settled on the current configuration. I am optimized for the 10 Ogive BIB bullet, powder to the base of the bullet. I found in testing the small 30-cal case did not like compression at all. The bullet is seated only 0.12″ into the case with zero freebore.

Cases were initially created with the .220 Russian (like a PPC) but I later decided it was better to build from the 6.5 Grendel. I size the brass and bump the shoulder back until it will fit into the chamber, fill to shoulder with International Clays, cotton wad packed on top. I have a fire-forming barrel. (I would not recommend this Clays and cotton wad method in a good barrel.) After initial fire-forming, I then mandrel the neck up the rest of the way to .30 caliber, turn the necks and trim.

It takes at least 8 firings to fully form a case! If you fire only three loads I find the brass does not have a sharp shoulder or any pressure on the bolt so any die selection is incorrect. Brass continues to harden well past 25 firings. I have match brass with well over 500 rounds fired, and I have never blown a case or neck yet (using my forming method).

For loading I use a Hornady Custom Shop Sizing Die and a Ralph Stewart Custom Seating Die. For those who are curious, yes the small group was fired with pre-loaded rounds. I do this now and then with local matches or may load 50 in a batch for one match.”

Mike wanted to thank his smiths, Randy Robinett, and all the folks involved in running the matches: “A big THANKS — as these are the guys that make our matches possible and without question maintain the integrity of the targets and record system. I was very fortunate to have all the right people in the right places for this match and my record. As for measurement – I only saw the target for about 10 seconds up close and can say I’m very happy I did not have to measure that group! Thanks again to everyone!” — Mike Stinnett