Sierra Heavy TMK 6MM Testing

[Chris in TN]

I used the 107 TMK projectile that was on the discord. using 53.3 for case capacity (SigSauer brass)


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So, to be clear here, I don't have a 6cm, but I have used GRT a lot with a lot of calibers.

Your case capacity is significantly larger than what I would have expected, but then again I am using Peterson brass (in my 6.5cm) and am used to it and its thicker walls or lower capacity.

If that 53.3 figure is accurate, you're probably ok.

What length barrel and what speed are you getting thus far?

 

[HNTR_NW]

@Formidilosus what is the lower limit of velocity for the TMK from what you and people you are around have seen?

Specifically where the tmk 6mm’s and 6.5’s do not consistently upset and fail to produce larger than “ice picking” size wounds.

Thanks!

 

[philcox]

I used the 107 TMK projectile that was on the discord. using 53.3 for case capacity (SigSauer brass)


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Just measured … 50.5 and 51 … for new brass


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[cq0302]

Got my 116s, put in my rifle build.

Terminus Kratos Lite
PPB 18” 7 twist (hopefully this is right?)
Manners Pro Pack Folder

6um-40?


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[Bluumoon]

Seems like a lot of folks are running around 41 or 41.5 each 4350 for the 107 TMK in the sixth Creed. I’m looking at GRT, and 42.5 isn’t even at pressure. Wondering if I am missing something?

41.5 has no pressure signs. I’m gonna try 42 and 42.5, but wondering why others not pushing similar?


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One of my rifles showed pressure at 41.5gr. Admittedly, I did not check lands.

 

[Formidilosus]

@Formidilosus what is the lower limit of velocity for the TMK from what you and people you are around have seen?

Specifically where the tmk 6mm’s and 6.5’s do not consistently upset and fail to produce larger than “ice picking” size wounds.

Thanks!

No one knows. I haven’t found the lower limit of any TMK. 1,440fps (IIRC) with the 77’s, 1,700fps with the 116gr and 107gr 6mm, 130gr 6.5, and 168 and 175gr 30cal: all have upset correctly.

I still say 1,800fps impact to be safe, but I honestly don’t know.