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.”
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Action: Kelby Panda “Speedy Shorty” with solid bolt and PPC-diameter bolt face. Kelby was asked to build several actions which were identical with the intent to eliminate any variance in head space between the two new rifles. This helped me use a single set-up on sizing dies for both rifles and ammo is interchangeable. Both actions were sent to Thomas ‘Speedy’ Gonzalez to be blue-printed and have Jewell triggers installed. Reamer: 30 STEWART (I just call it a 30 PPC as that is what everyone expects, but it is in fact a custom design and Ralph deserves about 99% of the credit). Barrels: Krieger was selected for the barrels. After discussions with Randy Robinett of BIB Bullets, a 1:17″ twist was identified as the correct, safe solution. Ralph Stewart has cut all my chambers using a custom-designed reamer. [Our goal] was consistent headspace and Ralph has been able to keep my barrels within .0002 variance. The barrel tuner also comes from Ralph Stewart.
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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
Similar Posts:
- Smallest 5-Shot, 100-Yard Group in History — Be Amazed
- Best Group Ever: Michael Stinnett’s .0077″ Five-Shot Group
- Sunday Gunday: The Smallest 100-yard 5-Shot Group in History
- This .009″ 5-Shot Group Set a Record That Stood for 40 Years
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Tags: 30 Stewart, BIB Bullets, Mike Stinnett, NBRSA
Congradulations! What is your barrel length? When I wear out my 6PPC barrel I was thinking of doing switch barrel with 30PPC or 50 Beowulf.
The shorty is the bottom action in the picture, and even though that picture (without captions) was posted by Speedy, and shows the overall action configuration that corresponds to his description, there is one detail that is incorrect. It shows the bolt as fluted, which does not jibe with the description both he and Mike gave. If you look closely at the picture of the rifle, you can see, through the ejection port, that the bolt is not fluted. After the original post about the record, I called Speedy and he was kind enough to tell me about the Shorty.
A brilliant result and a new kind of perfect.
I cannot but wonder now about a rush to the 30 PPC! That will be worth keeping an eye on.
Considering it took this long to break the record unless the 30 PPC happens to do it again soon I don’t see a rush to it anymore than any other latest and greatest. How many latest and greatest have come and gone since the last record was shot?
Oh and is that a typo with the 500 rounds fired on match brass?
Editor: This is exactly what Mike posted on BR Central. I think he may mean he has a set of match brass with over 500 rounds fired on the set, not that a piece of match brass has over 500 rounds.
See: http://benchrest.com/showthread.php?87299-The-quot-Unbreakable-quot-LV-009-WORLD-RECORD-Has-Been-Broken!!!/page2