6.5x47L extreme spreads

[Gman]

Just curious what primers you all are using when handloading Varget & 123 gr Lapua Scenar pills in the 6.5x47 Lapua ?

I am getting too much verticle @ 500 yards, (3") & plan on chronographing this weekend to find out if my ES are too high. I am using CCI 450's.

 

[SG4247]

I just ran that same bullet and powder combo across the magnetospeed today.

My loads today were an average of around a SD of 10. However, the worst 123 scenar 5 shot test was SD=13, and the best 5 shot test was SD=4.2.

These were all tested with #450 primer. If there is a better choice for primers, I am all ears.

 

[FeMan]

I run H4350 with #450's in mine. Nothing else worked as well. The ES wasn't all that great but I am less than 3" of vertical at 1000. It might not be the powder/primer. The wrong neck tension can give you vertical too.

 

[dsculley]

If you have MV data from several range sessions then put it all into a spreadsheet and calculate the SD. This will be closer to your true SD.

 

[FeMan]

If you have MV data from several range sessions then put it all into a spreadsheet and calculate the SD. This will be closer to your true SD.

Keep in mind that if you do this, you are also potentially interjecting powder temperature stability into the mix of other velocity variables. I like the idea of a larger data set but I don't mix results from different range sessions when trying to tune a load for powder/primer. Once the load is tuned, I do compare results from different ambient temperatures to map out the temp stability though.

 

[SG4247]

If you have MV data from several range sessions then put it all into a spreadsheet and calculate the SD. This will be closer to your true SD.

I actually did just this in Excel to determine if there was any velocity swings or change in SD. The averages were within 2 fps from one session to the next, meaning there is very little temp sensitivity using Varget in my loads. Very pleased with Varget.

 

[Clancy]

Did you do an OCW test or anything, or just pick the best load? For all I know you could be a world champ struggling with a new round so please understand I'm just "double checking."

 

[dsculley]

Combining data from different range trips allows you to see how this load will work in the real world. It takes into account your hand loading precision as well as how your rifle performs with this round, your shooting ability and changing environmental conditions. Once I decide on a load, I will try to use my chronograph on the next few range trips and combine all the data. Your SD may go up or down from the group you shot in load development. It will usually go up with more data, but if your loading process is very good then it may stay the same or decrease. Also, 6 * SD is your true ES for this load. The ES from your range trip is just that. It can't be used to predict how well the round will perform over time.

Even though I am using my chronograph, my target(s) are my final arbiter. I will always believe what I see on my target. Chronographs can provide false data from time to time.

Dennis

 

[CharlieNC]

If you want to combine sd from various shootings and not inflate the result due to temperature, lighting on chrono, etc then it is best to "pool" the sd. This is the weighted ( based on number of shots) average of the variances ( sd squared).

 

[Gman]

I just ran that same bullet and powder combo across the magnetospeed today.

My loads today were an average of around a SD of 10. However, the worst 123 scenar 5 shot test was SD=13, and the best 5 shot test was SD=4.2.

These were all tested with #450 primer. If there is a better choice for primers, I am all ears.

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