September 4th, 2008

Ocock busts NBRSA Rail-Gun Records — 0.1129 200-yard Agg

Arizona gunsmith Gary Ocock ranks fourth overall on the all-time Benchrest Hall of Fame Points list. This Monday he added two potential NBRSA Unlimited (Rail Gun) records to his list of achievements. Shooting in a special Monday Labor Day match at Visalia, California, Ocock demolished the existing Unlimited 200-yard NBRSA record. Gary’s 5-target, 200-yard aggregate was 0.1129. (That’s the measured average of five, 5-shot targets, divided by two). Once certified, this will be a new NBRSA record. The previous 200-yard record was a 0.1396 shot in 2003 by Bart Sauter. Gary’s 100-yard Agg was also in the “teens”, a 0.1534. So, Ocock’s combined 100 + 200 “Grand Agg” was a stunning 0.1331, which would also be a new record, beating Bill Forrester’s 0.1496 Grand Agg shot in 1989.

Record-Setting Railgun with Delrin Barrel Sleeve
Gary Ocock was using a Jay Young Railgun with some custom “enhancements” by Gary. As with most railguns, the barrel is held by a barrel block. But Gary employs something pretty unique. Between the metal halves of the 7″-long barrel block, Gary has fitted a Delrin sleeve around the barrel. This is then clamped in place when the block is bolted together. What’s the advantage of the Delrin sleeve? According to Gary “The Delrin seems to help with accuracy. I had a couple barrels that just didn’t seem to shoot well no matter what load I tried. I first tried a sleeve made from lead and epoxy in an effort to make those barrels competitive. The barrels did shoot better, but the epoxy/lead sleeve was a pain to make. So, I came up with the Delrin sleeve and it works just as well or better. I can’t tell you exactly why it works, but it probably is damping the barrel vibration. With the Delrin sleeve I’ve turned average barrels into winners.”

Jay Young Railgun

At right is a Jay Young Railgun, similar to the Unlimited gun used by Gary Ocock to set two new records. Gary’s gun has a longer barrel (26″) and Gary has devised a special Delrin sleeve that fits between barrel and barrel block. Gary believes the Delrin Sleeve dampens barrel vibration. For more info, email Gary Ocock: onehole149 [at]

Bullets Seated OFF the Lands
For his record-breaking effort on Monday, Gary used a 26″-long, 1.350″-diameter straight-contour 6mm Krieger barrel. Twist is 1:13.5″, and the chambering was a tight-neck 6PPC using Gary’s own 67gr BT match bullets. Gary shot a relatively “mild load” and interestingly his bullets were NOT engaging the barrel rifling. That’s right, he figures his seating depth was about .005-.010″ OFF the lands. The action was a BAT SV with a non-ejector bolt borrowed from another BAT. Scope was a March 50X.

Smart Wind Calls Helped Gary at 200
Watching the wind was key to his amazing 200-yard performance, Gary said: “Mirage was quite heavy, but I noticed things worked best in a light left to right condition. I tried to wait for that condition on most of my shots at 200 yards. On three of the five groups I didn’t hold off at all. On two groups I held off a little. The key was waiting to shoot in that left to right condition.”

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