September 9th, 2011

Sartorius GD503 Analytical Scale Offers Amazing Precision

Sartorius GD503 force restoration magnetic scaleSuccessful long-range shooting demands very uniform ammo. Weighing charges carefully can make shot velocities more uniform within a shot string. Uniformity of velocities is good, because lower ES translates to less vertical dispersion of the shots at long range. Many competitive shooters today try to load charges that are consistent within one-tenth of a grain. Some exacting reloaders, in the relentless pursuit of perfection, go even further — they try to maintain charge weight uniformity down to the equivalent of just one or two kernels of powder.

To weigh charges with this kind of precision, you need a very high-quality scale. Even the $400.00-grade balances (such as the Acculab VIC-123), struggle to maintain single-kernel precision with their conventional strain-gauge load cell technology. But there is a new class of electronic lab scales which employ magnetic force restoration technology. These force restoration balances can reliably (and repeatably) weigh a single grain of powder. In normal use, lab-grade force restoration scales also deliver a stable reading more quickly than strain-gauge type scales. This is a boon for reloaders who like to trickle the final few kernels of a load. But the enhanced speed and precision of force restoration (magnetic) scales come with a stiff price — these technological marvels cost $900.00 and up. That could buy a custom action, or three new barrels.

Trickling Kernel by Kernel with GD503 and Omega Trickler
Do the advanced force restoration scales perform as advertised? Can they reliably recognize a single kernel of powder quickly enough to make trickling practical? Well, thanks to Forum member A.J. (aka AJ), we have a video that answers those questions. Using a Sartorius GD503 Class II force restoration balance with an Omega two-speed powder trickler, A.J. demonstrates how he can weigh charges that are consistent within a single kernel’s weight, i.e. 20-25 thousandths of a grain.

When you watch the video, note how (at 3:45 time mark) the RCBS electronic scale reads 41.7 grains, when in fact the correct charge weight was 41.830 grains, as measured by the GB503. That’s a one-tenth grain (four kernel) error right there. You will also see that the Omega Trickler from Dandy Products really can drop one kernel at a time. It takes some careful adjusting of the drop tube to achieve this sensitivity, but the Omega really is up to the task.

A.J. recently acquired his Sartorius GD503 digital scale from Balances.com. Retail price is $899.99. A.J. reports: “I have to say the [GD503] is one awesome unit. I was loading my 260 with 42 grains of H4350. The GD503 is accurate to .005 (5 thousandths) of a grain. My Acculab was supposed to be accurate to .020 of a grain but couldn’t do that on a good day. This new scale can actually weigh an individual kernel of H4350, it weighs right at .025 per kernel. I weighed a small screw about 20 times throughout one day and every time I got the same exact reading. My load for my 260 now has a SD in the single digits and an ES of 10 fps is not uncommon for 5-shot groups.”

Having seen an actual reduction in his velocity ES and SD, A.J. is sold on his $900.00 GD503: “This thing is amazingly accurate. It repeats every time. The weight does not keep changing or growing like my Acculab VIC 123 or my RCBS Chargemaster. My loads have never been so accurate. Now I don’t have to wait for a Prometheus as I have something better for a fraction of the cost.”

If you’re interested in the Sartorius GD503, below is a video from Balances.com that explains the features of the GD503 and shows how to set up and operate the unit to achieve the best results.

Strain-Gauge Scale vs. Force Restoration Scale — Responsiveness Test
This final video also shows the difference in performance between a strain gauge scale and magnetic force restoration scale (GD503). In the video, both scales are tasked with measuring tiny grains of salt, which are much smaller than extruded powder kernels. You can see that the GD503 responds more quickly when a few grains of salt are added.

Permalink Gear Review, New Product, Reloading 10 Comments »
September 9th, 2011

Results from IBS 1000-Yard Nationals at White Horse Range, WV

IBS NationalsThe 2011 IBS Nationals were held at the White Horse Center Range near Peeltree, West Virginia. This was a 3-target Aggregate match for both Light Gun (LG) and Heavy Gun (HG) with six (6) targets total. The big winner was Shooters’ Forum member Tod Soeby (aka 4Xforfun). Tod, who hails from North Dakota, drove a long way to the match, but his journey was well worth it, as he topped a large, highly-competitive field of 117 shooters. Soeby won BOTH the 2-Gun Overall as well as the Light Gun Group+Score Overall (In Light Gun, Tod was #1 for Group and #6 for Score, shooting a 6mm Dasher). Soeby’s Light Gun Group Agg was a remarkable 3.884″, nearly an inch smaller than the next best Light Gun Group Agg, a 4.724″, turned in by Salley Bauer. Gordy Gritters finished second in 2-Gun Overall, while David Powell secured third place in 2-Gun Overall.

White Horse IBS 2011 1000 yard nationals

Tod’s three, 5-shot Light Gun groups were: 4.489″, 3.760″, and 3.283″. That yielded an average of 3.884″ at 1000 yards. Think about that — Tod’s average is barely over one-third MOA, which is 3.49″ at 1000 yards — seriously small. Yes, those Dashers can shoot!

Wesley Springman was the top Heavy Gun Shooter, placing second in Group and third in Score, to finish first Overall in Heavy Gun class. Don Rabun was second in HG overall, with Eric Springman taking third in HG, edging Don Nagel on a tie-breaker (both Eric and Don racked up 14 Agg Rank Points). As noted above, Tod Sobey won the Light Gun Overall, with Donald Whitlock second in LG, and David Powley third. Notable other performances were Jeffrey Morten’s first place finish in LG Score, and Eric Springman’s outstanding Group shooting in Heavy Gun. Eric finished #1 in HG Group, with an impressively small 5.925″ Agg (that’s for ten-shot groups). And Sharon Ruben nailed the small group for the match, a mind-blowing 2.686″ on her second Light Gun (5-shot) target. For reference, one-quarter MOA at 1000 yards is 2.617″. Amazing.

Winning Rifles: 6mm Dasher Light Gun, 300 WSM Heavy Gun
Tod Soeby provided this equipment rundown for his Nationals-winning rifles.

Light Gun (6mm Dasher): Smithed by Greg Wahlstrom, Straightline Customs, in Ogilvie, MN. Greg also did the stock work and bedding. Action is a BAT “M” multi-flat, 8.5″-long, R-L-R dual port. Stock is a Shehane ST-1000. Barrel is 30″ Krieger 1:8″ twist, chambered as 6mm Dasher with 0.267″ neck. Optics are: Nightforce NSX 12-42X in BAT +20 MOA aluminum ring/bases.

Heavy Gun (300 WSM): Smithed by Clay Spencer. Action is BAT “L”, 10″-long, 2″-round, dual port. Stock is a Bruce Baer 5″-wide thumbhole, with custom rails by Greg Wahlstrom of Straightline Customs. The barrel is a Hart 1:10″ twist chambered in 300 WSM. Optics are: Nightforce 12-42X Benchrest model. Tod is not sure about the source of Picatinny rail and rings.

CLICK HERE for Full 2011 IBS 1K Nationals Results

117 Shooters Competed at 2011 IBS Nationals
Overall, shooters commented that West Virginia’s White Horse facility was a nice range, and many folks hoped that other major events might be hosted there in the future. Despite the predicted hot, humid weather, there was a great turn-out for the event, with 117 registered shooters in Light Gun and 115 Heavy Gun Registrants. The match organizers at White Horse did a good job with such a large field of shooters. The excellent turn-out proves there is a growing interest in long-range benchrest.

Permalink Competition, News No Comments »