March 20th, 2012

Wow — Claunch Shoots 0.156 MOA, 0.981" Group at 600 Yards

Tim Claunch 6BRX“Holy Mother of Mercy…” was this Editor’s reaction when I saw the “screamer” group shot by Forum member Tim Claunch this weekend in Memphis, at the inaugural MSSA 600-yard IBS match. Shooting his amazingly accurate 6BRX Light Gun, Tim nailed a 0.981″ group, centered up for an impressive 50-2X score. Conditions were favorable, with a light 3-5 mph wind and 70° temps. Shooting on the first target, first relay, Tim took his final sighter with 10 seconds to go, then drilled five shots “right down the middle” in about 20-25 seconds. The results were spectacular. Tim’s 0.981″ group works out to 0.156 MOA, and three of the shots clustered in about half an inch! This isn’t a new IBS small group record (Sam Hall holds that record with a mind-blowing 0.699″/50 shot in 2010), but it is still one of the best centered-up groups ever shot in IBS 600-yard competition.

Tim was shooting the same 6BRX we featured last month in the Daily Bulletin. It has a 26″ Bartlein 1.250″ straight contour barrel fitted to a Borden action in a Shehane fiberglass Tracker stock. Tim was running Varget powder with CCI 450 primers and pointed Berger 105gr VLD bullets. Tim anneals his Lapua brass after every firing though he does NOT uniform his primer pockets or ream flash-holes.


Just how impressive was Tim’s 0.981″, 50-score-value group?
Well, consider this comment from Forum member JeffG
:

A .981″ group at 600 yards = .981/6.2832 = (H#LY $H*T) = .156 MOA…

Try doing that at 600 yards with wind and mirage and who knows how many little flying insects that might potentially disrupt the bullet… pulling the trigger when the crosshairs are at EXACTLY the same spot (give or take 1/10th the thickness of the crosshairs) EVERY TIME.

CLICK Buttons to HEAR Tim Claunch Talk about Shooting his 0.981″ group.
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With his 0.981″ small group, Tim did take top honors for Light Gun Group. However, he had one shot go wide on another target that raised his Light Gun Group Agg to 2.335″. You’d think that would be good enough to win, but a shooter from Birmingham, Alabama posted a 2.299″ Agg to claim the best Light Gun Agg for the day. Charlie Macke won Heavy Gun group and HG score. The Two-Gun Overall winner was Forum member Stephen Hall. Congrats to all the great shooters at the inaugural MSSA event.

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February 19th, 2012

Forum Member Averages 1.677″ for Six Targets at 600 Yards

Tim Claunch (aka tclaunch) recently put on an amazing display of precision shooting. At an MSSA 600-yard Benchrest Score match in Memphis, TN, Forum member Tim shot six targets in a row, with an average 5-shot group size of 1.677″. Tim’s stellar performance began with a two-target shoot-off for club Shooter of the Year honors (he won). Then Tim shot four more targets as part of the club’s regular 4-target score match. NOTE: this is NOT an official six-target match result. The actual match that day was four (4) targets only, and Tim’s Agg for those four was about 1.8″, still darn impressive. No one is claiming any records here. Still give credit where credit is due — Tim put together six targets in a row, in competition, averaging 0.267 MOA for all six. Tim’s small group (of the six) was 1.351″ and his large group was 2.088″. That shows amazing consistency. This is spectacular shooting by any measure*.

Tim Claunch 6BRX Agg

Tim tells us: “I can check off one of the items on my ‘bucket list’ now — shooting a sub-two-inch Agg. We shot our monthly match here in Memphis at our awesome MSSA range. Though this was a score match, and the first two targets were part of a club shoot-off, I wondered about the average group size of all six. We measured all six targets I shot in sequence on Sunday. I was some kind of happy when I saw it was a 1.677″ 6-target average. That Bartlein and the .140″ FB BRX reamer are a good match. I used Varget with Berger 105gr VLDs and CCI 450 primers. I had never Agged under two inches before in my life (the 4-target Agg was 1.8″). Sure was nice to do it at home the first time.”

Tim Claunch 6BRX Agg

Tim shoots a 6mm BRX Light Gun with Shehane ST1000 Tracker stock, Borden Rimrock BR action, and Bartlein 6mm cut-rifled barrel. He uses a Leupold 45X scope in Burris Signature Zee rings sitting on a +20 MOA rail. Tim jokes: “People might laugh at my cheapo Burris rings. Well I guess those Signatures hold zero just fine.” Tim tried a power-booster lens on his Leupold for a while, but this altered eye relief, producing the occasional smack in the forehead. Not surprisingly, Tim removed the booster.

Borden Action with Dwight Scott Bolt and Firing Pin Upgrade
The action is a Borden Rimrock BR dual-port. “This action is smooth, and it allows me to rip ‘em when the conditions are good. For these six targets I shot fast.” The Borden action has some interesting mods: “The firing pin and bolt body were re-worked by Dwight Scott. He has a weight of pin to power of spring he worked out with Tony Boyer. I could tell a significant difference in performance.”


For better target resolution, click the gear-shaped icon and select 480p playback.

The stock is a Shehane fiberglass ST1000 Tracker bedded by TM Stockworks (Tom Meredith). The metalwork was done by Stephen Hall of Dyersburg, Tennessee. Tim reports: “I can’t say enough about this highly-talented guy. He’s a great smith and a great point-blank benchrest shooter himself. I’ve had four chambers cut by him and couldn’t be happier”. The barrel is a 1.250″ straight contour, finished at 26″. That’s a bit shorter than you’ll find on most 600-yard rigs these days, but Tim wanted some weight off the nose so he could add weight to the butt to balance the gun better (and still make weight). Tim raves about this Bartlein barrel: “Readers should not give up on maybe that next barrel being the one barrel a guy gets in a lifetime. I have tried all the cut-rifling barrel-makers, but I’ve recently gone to Bartlein. Based on my ratio of great-shooting barrels to average barrels I am there to stay.”

Tim’s Accurate Reloading Methods
Tim’s reloading procedures could rightly be described as the “relentless pursuit of perfection”. After two firings, once “the brass has settled down and conformed to the chamber”, Tim anneals his cases. He then re-anneals after EVERY subsequent firing. The brass he shot at the MSSA match had eight firings, so it had been annealed many times. Tim uses current-generation (blue box) Lapua 6mmBR brass, and he lightly turns his necks for an 0.269″-necked chamber. Tim points his bullets, but does not trim them: “These were pointed, no trimming, just point and shoot. I have shot a few of the new Berger hybrids, but I keep going back to the Berger VLDs.”

Superior accuracy, Tim believes, requires ultra-consistent neck tension. Tim uses a K&M arbor press with a force gauge. If the needle shows any notable variance in seating force, Tim will pull the round apart, run a mandrel in the neck, resize the neck, and re-seat the bullet. If the bullet still doesn’t seat smoothly, he won’t shoot the round for record. Tim is also particular about seating depth: “I measure every loaded round base to ogive using a comparator. All my match ammo is held to plus/minus .0005″ (i.e. one thousandth total spread) in base to ogive length. Yes, this is possible if you anneal regularly and monitor bullet-seating force carefully. If you can’t hold .001″ [base-to-ogive] tolerances with good bullets, that’s probably because of inconsistent neck tension.”

Secret of Success — Improved ‘Bench Manners’ and Gun Handling
Tim had a personal break-through not so long ago that improved his accuracy dramatically. Previously he got down on the gun, and would use some cheek pressure. But he noticed some erratic horizontal in his groups. Tim changed his shooting position, getting his head completely off the stock. The change worked: “After cleaning up my ‘bench manners’ and getting my head off the gun, my groups started shrinking. It was a real eye-opener.” Tim shoots with minimal hand contact (“just touching”) on the stock, and he doesn’t pin the gun to the stop. Tim explained: “I run the gun up to touch the stop before each shot, but I don’t use any shoulder pressure. I don’t push on the gun at all.”

Tim Claunch 6BRX Agg

You can learn more about Tim’s amazing six-target display of accuracy in this Forum thread. Registered Forum members can post questions about Tim’s rifle and the shooting conditions, and Tim will answer them when he has the opportunity.

* Just for comparison sake, the NBRSA official Light Gun 600-yard, 6-Target (30-shot) Agg record is 2.092″ (Robert Hoppe, 2006). The IBS official Light Gun 600-yard, 4-Target (20-shot) record is 1.6068″ (Sam Hall, 2011). The IBS does not list a LG 6-target Agg record for 600 yards.

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