Sierra 116 TMK Load Data

[MThuntr]

Doing basic load test and fireforming on 116s and 6mmPRC (NSI) 20" Preferred barrel on Tikka with OG6-S. .180" freebore loaded at 2.98" CCI BR2 primers, Lapua brass, .271 neck bushing, 241 mandrel (yes I'm probably moving more brass than necessary and will adjust things later because these seem to be too snug). Also I hate how Hornady dies smash these bullets so I'll probably get Frankford die set. Weights measured by A&D 120i.
Temp upper 70s and sunny with strong variable winds

RL26
54gr 3088fps
54.5 3088fps
55 3144fps (stiff bolt ejector)
55.5 3170fps (stiff bolt, ejector)
56 3213fps (very stiff bolt and heavy ejector)

H1000
52.5 2830fps
53 2945fps
53.5 2933fps
54 2967fps
54.5 3005fps
55 3013fps
55.5 3061fps
56 3057fps (faint ejector, primer flow)
56.5 3125fps (bolt, ejector, primer flow)
57 3140fps (heavy bolt, ejector, crater)
57.5 3149fps (heavy bolt, major ejector)

These are based off 1 shot so this is tread lightly. Looks like mid 50s is giving me a sign to follow.

54.5gr of RL26 is showing promise. I have 5 rounds loaded but the rain hit so hard I couldn't really see the target so 3 will have to suffice. Velocity hovered around 3100 which I expect will settle down once I get a 10rd session loaded up.

 

[bwill6]

I’m used to seeing rings from the seating die on my eldms, but nothing like this. Far right is my starting load and charge weight increases going left. None felt like they took significant seating force. I’m assuming that it’s related to the load being compressed. But my eldm load is compressed as well and it doesn’t get this mangled. Think a different seating die might fix this?

6mm ARC
Hornady brass
Staball Match from 26.5-31.5 grains
Lee seating die