German Salazar has posted an informative article about concentricity-checking tools on his Rifleman’s Journal Blog. In that article, German provides a detailed review of the impressive new Bruno Concentricity Checker which features a high-grade dial indicator and an innovative system for holding both loaded cartridges and empty brass in place during the measurement process. German gives the Bruno tool high marks and it is now his favored concentricity gauge, replacing on older Sinclair tool (also reviewed in the article).
German writes: “When measuring a seated bullet, the Bruno [tool] is simple and intuitive in use: adjust the length of the tip holder, set up the indicator to bear on the ogive and get to it. I usually slip a Sinclair hex nut comparator over a bullet to make a faint mark right at the ogive to help me in determining where to set the indicator. I then set the indicator tip about 0.010″ behind the mark so that I am definitely on the bearing surface even if some of the bullets have a bit of variance. It’s a handy way to get set up consistently from one session to another.”
German continues: “Reading an empty case requires a little more effort, but not much…. Once the case mouth is smooth, the readings are in line with those of the Sinclair tool, although easier to read to a fine level of precision due to the finer gradations on the indicator and its horizontal mounting. The Bruno tool has become my principal tool for checking the concentricity resulting from different die setups and for comparing the results of one loading process to another. I simply have more confidence in my ability to get an accurate reading from it. After many years of service, I’ve decided to retire the old Sinclair and make the Bruno tool my primary concentricity tool. It is simply a better made, easier-to-use, more accurate tool and those are the qualities I value in any tool.”
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You’ve probably heard by now, but this is big news, so it bears repeating. Lapua has started production of .260 Remington cartridge brass. Lapua hopes to deliver the first shipments to the USA by late March, 2011. This is a very positive development for hunters, high power shooters, and tactical shooters. With the latest generation of powders (including Reloder 17), the .260 Remington is a potent cartridge with the 140gr-class bullets, and it hammers with the Lapua Scenar 123s or Berger 130s, and H4350-speed powders. In the video below, Kevin Thomas, Lapua’s USA Marketing Manager, provides more specifics about the .260 brass, and Lapua’s other new-for-2011 products.
On the bullet front, Lapua is proudly rolling out its new “L” series of projectiles, starting with the 6mm 105gr Scenar and then expanding to the whole Scenar match bullet line. NOTE: These are NOT new bullet designs — Lapua is not changing the bullet shapes, weights, or internal construction. So you’ll be getting the same bullets, only with tighter tolerances, and improved quality control.
Lapua has tightened its production tolerances for the L series of bullets. Lapua claims that the L series of bullets will be more uniform in weight, with improved concentricity. Length from base of bullet to ogive will be held to very tight tolerances. Apart from the notations on the box, the new Lapua L bullets will be marked with an “L” crest stamped on the bullet heel. Lapua claims this tiny stamp will not affect accuracy nor reduce the bullet’s ballistic coefficient.
Lapua explains: “We have set out to tighten all measures and requirements, including our already famous quality control standards.” Scenar L bullets will exhibit: “closer weight tolerances, tighter jacket wall concentricity standards, and greater uniformity in every dimension, starting from the gilding metal cup, lead wire and jacket forming, ending up to core-jacket assembly, boat tail pressing and tipping.”
Testing the Scenar Ls for Uniformity
Are the new Scenar “L” series bullets actually more uniform than previous Scenars (which were really very, very good)? Based on my quick test of 20 sample bullets pulled at random from a box, I would say the 105gr Scenar Ls are some of the most uniform factory bullets ever. Adam Braverman gave me a box of the new 105gr Scenar “L” bullets. I randomly chose twenty (20) bullets, and measured them base to ogive using a Hornady comparator. With the exception of one bullet, everything was pretty much “dead on”. I listed two at 0.7125″, but they were awfully close to the others. Basically, except for the one bullet measuring 0.711″, they were all the same within the practical resolution of my calipers. Very impressive indeed.
All Bullets within One-Tenth of Grain
Next I checked for weight uniformity. I weighed each of the 20 bullets twice, using a calibrated RCBS ChargeMaster scale. NOTE: This is NOT a lab quality scale. The 0.1 grain total spread among the bullets is within the scale’s range of error. But I did weigh each bullet at least twice, and the ones that were one-tenth of a grain light I weighed four times. Three bullets out of the twenty measured 105.2 grains. All the rest were 105.3 grains. Remarkable.
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Many Forum members are putting together their first custom or semi-custom precision rifle this season. These folks often ask us, “What kind of accuracy can I expect from my first 6mmBR?” Of course there are no guarantees, but a 6BR with a good custom barrel, good chambering job, and a nice bag-riding stock should be able to shoot well under half-MOA (1/2″ at 100 yards), maybe even approach quarter-MOA. Forum member Eric (aka Exercion) provided this interesting report on his new 6BR:
Love at First Groupby Eric
Well, I took my new stick to the range for the first time today. It features a Savage single shot target action in RBLP configuration, 28″ Broughton 5C barrel, Sharp Shooter Supply Dogtracker stock with adjustable buttplate, and Nightforce scope.
Now, I have never owned a 6mmBR before, but from reading here and seeing them in action I decided to build one. Its main purpose in life is mid-range F-Class shooting, mainly at 600 yards, and if the winds are favorable, at 1,000. (I already have a 6.5 for “normal” conditions.) I am most grateful for all the info here, and especially the load data. I picked Reloder 15 under the 107gr SMKs for my first loads, starting at 29.0 grains, and proceeding in half grain increments to 30.0 grains. Jumped the bullets 0.015″. Ran the Lapua brass through the neck-sizer bushing die, and was concerned at the force needed to pull the expander button through the virgin brass necks but figured this was a once per case deal to round them out for initial loading. When I measured the runout on the loaded rounds, I was appalled as they had more wobble than anything I personally loaded before, but I kept reminding myself that this was the fireform/chronograph/scope and gun trial stage.
Three Shots in 0.335″ Edge to Edge
So off to the range this morning. No wind here at the house, so life was good … until I got to the range and the wind started to blow. So I set up everything, leveled the gun in the bags, leveled the scope to the gun, made sure the bore was in the center of the chronograph and bore-sighted. First couple of rounds were off to the right, so I moved the scope over 5 MOA and fired another shot, hit paper with it, so I shot 2 more and stopped because I couldn’t tell what was happening. A walk down to the hundred yard berm revealed a nice hole that measures 0.335″ at its absolute widest edge to edge! That’s the smallest 3-shot group I’ve ever fired with anything. I am so in love!
SDs Improve with Heavier Charge and Run-out Disappears
I kept going ’til I worked my way through my first 100 rounds.Given the conditions, I was more interested in the chrony numbers than group, (though 20-shot strings yielded nice quarter-sized holes) and found that as my charges got heavier the SD was coming down (the 30 grain load gave me an SD of 9). I can’t wait to see what will happen with some load tinkering, as well as bullet trials (have Bergers, Hornady A-Maxs, and Lapua Scenars waiting for the next trip). Also, as I had hoped, fire-forming “cured” the run-out problem. I ran the fired but un-sized cases over my concentricity tool and saw less than 0.001 runout on the necks now.
On the bullet front, Lapua is proudly rolling out its new “L” series of projectiles, starting with the 6mm 105gr Scenar and then expanding to the whole Scenar match bullet line. NOTE: These are NOT new bullet designs — Lapua is not changing the bullet shapes, weights, or internal construction. So you’ll be getting the same bullets, only with tighter tolerances, and improved quality control.
Testing the Scenar Ls for Uniformity
Now, I have never owned a 6mmBR before, but from reading here and seeing them in action I decided to build one. Its main purpose in life is mid-range F-Class shooting, mainly at 600 yards, and if the winds are favorable, at 1,000. (I already have a 6.5 for “normal” conditions.) I am most grateful for all the info here, and especially the load data. I picked Reloder 15 under the 107gr SMKs for my first loads, starting at 29.0 grains, and proceeding in half grain increments to 30.0 grains. Jumped the bullets 0.015″. Ran the Lapua brass through the neck-sizer bushing die, and was concerned at the force needed to pull the expander button through the virgin brass necks but figured this was a once per case deal to round them out for initial loading. When I measured the runout on the loaded rounds, I was appalled as they had more wobble than anything I personally loaded before, but I kept reminding myself that this was the fireform/chronograph/scope and gun trial stage.
