Primer Selection and Load Validation Test
Following some interesting challenges surround primers and their performance in Raton (USA in August) I decided to validate my primer selection for F-Class shooting (ie up 1000 yards). I decided to shot and measure groups suing different primer brands and loads. I did NOT use a chrono deciding to replicate match environments.
Key questions I wanted answers to were:
1. Is there a meaningful difference between STD vs BENCH vs MAGNUM
2. What worked best in my rifle?
3. Could I confirm my Sweet Spot and what tolerance did I have?
4. Did I have a Primary and Secondary primary that I could readily swop out depending on supply challenges?
How did I test? :
All testing was at 200 yards. Test was conducted in absolute wind still conditions at Bisley in September 2013 suing the same barrel I used in USA.
All tests were for Small Rifle in Lapua cases using Berger Hybrid 155 and H4895. Seating depth was on my "match setting" and kept uniform throughout.
I did a combination of a LADDER test / Primer change. I did loads and shot them up from 47.0 to 47.8.
NOTE this my MY rifle load - do NOT replicate. Developed and validate your own. 
I loaded 3 rounds per Primer per load. The primer options were shot at random - hence why no letter is always the same primer
As an alternate I also did a small batch with Sierra 2156C to see what happens when you swop a bullet out on a known and hopefully accurate load.
PRIMERS : I sourced selected 5 primers :
STD
Remington & CCI Std
MATCH
CCI BR4 & Federal Gold Match
MAGNUM
CCI-Magnum
DETAILED FINDINGS
I will load the photos per group and a summary spreadsheet with my findings.
Round count was 6 x 15 = 90 Rounds
SUMMARY for my rifle / load combination
CCI-BR4 were consistently the best across all loads and displayed the most uniformity.
FEDERAL Gold Match was a far second.
REMINGTON was the poorest.
I did find a sweet spot where the CCI-BR4 clearly performed better here in the sweet spot zone of loads 3, 4 and 5.
It did HOWEVER fall out of the sweet spot dramatically. Past sweet spot - poorest overall groups !!! :roll:
LESSON : I have been shooting the CCI-STD load due to component availability AND poor range discipline!
I.e. I did not double check my loads after I made the changes in powder charge in the search for velocity at the price of accuracy!
The exercise was very worthwhile and validated and changed several assumptions I had. Significant group size difference can de seen with simple primary changes AND across the load range. NOTE : 47.8 + CCI-BR4 is slightly more than USA charge of 47.6 with FED. Besides Batch variations the additional heat factors in USA may have influenced the barrel harmonics in USA.
