Question on 'extreme' distance shooting

[Fjold]

Consistency is the key.

When I was shooting a lot of competitions my case prep was:

Buy brand new cases in 1,000 count bags
Size all brand new cases
Turn necks to match my chamber
Trim and chamfer
Uniform all the flashholes
Uniform primer pockets
Weigh all brass
Sort cases to within 0.5 grains

From Lapua cases I could usually use about 700 cases and from bulk cases like Winchester sometimes I would wind up with 300 usable cases.

[LynnJr]

On the original question.
Most shooters are measuring powder to the single kernel.Bullets are measured for length bearing surface diameter ogive length boattail length ogive concentricity and boattail concentricity.They are trimmed then re-pointed and spun on a Juenke machine.
The brass is shot twice so it fully fits the chamber then all of the typical brass work is done.Necks turned,trimmed to length.primer pockets uniformed flashholes uniformed.chamferring inside and out case volume is measured and concentricity of the necks and casehead are verified.The cases are then spun on the Juenke machine and neck wall and body uniformity are checked.
The powder charge has a small range to it depending on the cases volume.With a 6BR or 6Dasher the powder window is roughly 0.4-- 0.5 grains wide.On a larger case like the 300 Ackley the powder window is roughly 1.7--2.2 grains wide.
Seating depth is measured with a comparator and all rounds need to be in like groupings.On our 6 Dashers all match loads measure 2.510 in length including the comparator.The ones measuring 2.509 or 2.511 are used for practice and sight in.
At 2300 yards facing due north with your crosshair on the bullseye the bullet will start wide left and make a big corkscrew until it is directly inline with the target.It will then drop what looks like straight down.
With my 50 bmg and a 30 moa rail using a straight 36 power leupold the vertical crosshair at the bottom of the scopes objective bell will be sitting on the bullseye to make the shot.

[Gofasterdammit]

(Please don't get into accuracy vs precision thing - this is a simple question).

Re: the .055 MOA thread, or ANY competition like this...

1. How important is the consistancy of the load? vs. the shooter (i.e. we all have great days and crappy days). I'm assuming the bullets can be matched pretty well, but powder measurements seem to be something everybody battles...

2. Do shooters tailor their loads at the range for the temperature, altitude ect?

3. Or have I missed the big point?

Basically, after getting into reloading, I'm having a hellova time with powder weights, but I might be over thinking and over measuring.. Screwing around with electronic scales and trying to get within .2 grains is really painful.. Are these comp shooters in the .01 grain range??


Just curious. Thanks for your input...

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The consistency of the load is key. As mentioned, for extreme accuracy, brass is purchased in lots, usually 1k pieces. After processing the brass (FL sizing, trimming, neck turning if necessary, and sorted by weight, powder measurement is key. I've seen great accuracy with RCBS Chargemaster's verified with a secondary high end scale such as a Sartoruis. If you want to reach the highest end of high end in powder dispensers/scales the Prometheus is king. http://youtu.be/2sqNcs-uWzYThe Prometheus is leased, not owned. You can lease at Prometheus Gen 2 for $2500 or $3000, I forget which, for 20 years, with a 1 year wait. There might be one person on Calguns that has one. No other powder scale/measure on the market will come close to the Prometheus, hence the lease. After that, bullet choice is paramount. High BC bullets matched to barrel twist rates, number of grooves, depths of grooves, and bore diameter. The shooter in the .055 MOA article was shooting Berger bullets which respond very well to pointing. http://www.bullettipping.com/ After sorting by base to O-Jive measurements, bullets have their meplat's trimmed and pointed, then sometimes trimmed again. Hopefully that helps with #1.

[orangeusa]

Outstanding. This is one of those threads where I think everybody learns from how much you guys have put into what you do.

Kinda like a lot of things - it's easy to get into the top 90%, but the effort and ingenuity to get to the top of the ladder is astounding. Science, gutfeel, experience all come into play.

I'm guessing (wrt the shooting skill part of this equation) that it's perishable and needs constant practice. But again, I'm guessing.

I have a huge respect for the long shooters, it's something I've never had they eyes or patience for...

<if waxing too poetic, call me on it>
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