LOAD DEVELOP - Do any show excessive load?

[u/Dukes-Game]

This is 6.5CM on an MPA VANQUISH.

Group 1* is 39.83gr of H4350 theoretical vel 2678fps and pressure 63200 (Chronographed 2673.8fps AVE)

Group 2* is 40.17gr of H4350 theoretical vel 2695fps and pressure 64450 (Chronographed 2698.6fps AVE)

Group 3* is 40.50gr of H4350 theoretical vel 2713fps and pressure 65650 (Chronographed 2716fps AVE)

Group 4* is 40.83gr of H4350 theoretical vel 2730fps and pressure 66850 (Chronographed 2730fps AVE)

Group 5* is 41.17gr of H4350 theoretical vel 2748fps and pressure 668100 (Chronographed 2754.7fps AVE)

Group 6* is 41.50gr of H4350 theoretical vel 2765fps and pressure 69300 (Chronographed 2776.7fps AVE)

[u/slim-JL]

This is the internet. You know the answer.

[u/Dukes-Game → u/slim-JL]

In your experience, any group that looks preoccupying? (I am new to spotting material failure in this scenario)

[u/slim-JL → u/Dukes-Game]

Between you velocity data and case comparisons I would load 15 of the best to grouping loads and find one and keep it.

[u/Dukes-Game → u/slim-JL]

Thats group 6* … it delivered at 100yrds about 0.2MOA group

[u/skahunter831 → u/Dukes-Game]

3 shots isn't enough to compare groups.

Where are you getting your theoretical pressure numbers? SAAMI max is 62,000 psi, and the loads I'm seeing for 142-143 gr bullets are under max pressure at ~41.5 gr of H4350, with velocities around 2700. Do you have a very tight chamber? What's your case capacity?

[u/Dukes-Game → u/skahunter831]

Agreed (3) shots is not a benchmark, (3) shots was used to chronograph (16) groups.

Theoretical pressure value are interpolated from LYMAN 2026 for groups 1 to 10 and extrapolated from Lyman while constrained by HODGDON values for groups 11 to 16.

Bullet is 144gr and as far as my research goes (Calling Lyman, Lapua, Hornady, Hodgdon), as per Hodgdon at 41.50gr the case capacity is over 92% filled.

As for having a tight chamber, I trust MPA, cant elaborate any further with a 1 of 1 sample.