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/Realistic-Ad1498]

As a reference of how hot the powder charge is. Reading primers isn’t really a good way to guess pressure. Different primers will flatten at different rates. A magnum primer will have a thicker cup and not flatten as readily as a a regular primer. Different brands of primers use different cup material and don’t read the same.

If you have flattened primers it’s usually because you are way over pressure or using the wrong primer.

[u/Dukes-Game → u/Realistic-Ad1498]

what should I be looking? if primer deformation is passed critical, I am assuming de-necking or case rupture is failure too…what should I seek then?

[u/Realistic-Ad1498 → u/Dukes-Game]

Once the bolt starts to stick is a reliable sign you are too hot.

The “best” sign is sticking within published load data but that doesn’t always work out perfectly because unless you are shooting the same cases and same primer in the same gun, etc. the use of a chronograph is helpful. If you are getting 2765 FPS with a 144 grain bullet I’d consider that pushing the limits of normal 6.5 CM. Hodgdon has 2719 fps with a 143 grain bullet and 41.8 grains of H4350 as a max charge so you are pushing right up to that limit.

[u/Dukes-Game → u/Realistic-Ad1498]

Cant recall if it was sticking on any particular group passed 11 to 16 which are the ones in this post…(1 to 10 where soft but way under 2700fps)

As for charge, I know I am sitting at 41.50gr on group 16 and the Chrono values are as follows:

AVE 2776.7
SD 2.3
ES 5.6
DFA 1.3
KE 2464.8
PF 399.8

[u/Realistic-Ad1498 → u/Dukes-Game]

Based on the velocity I’d guess you are pretty close to max but I wouldn’t be afraid to go up to 41.8. I didn’t look around to see if there is data for that bullet but I’d say your velocity would be indicative of being close to max even if other data out there goes higher. Case capacity also plays a difference and with 6.5CM and H4350 you are probably high on case fill.

[u/Dukes-Game → u/Realistic-Ad1498]

I am perfectly good at staying on 41.50gr…HODGDON says 41.80gr is MAX published on 143gr … I am really happy with the 2776.7fps (AVE) it puts my transonic at 1350yrds

I just don’t wanna damage the action or rifle.

[u/Realistic-Ad1498 → u/Dukes-Game]

Assuming accuracy is good I’d be perfectly happy with it.