Sierra Heavy TMK 6MM Testing

[bpitcher]

Finally got my Rokstok back and got to test the 116s.

6 CM 18" PVA .750 Taperless .210 FB 1/7 Twist
Measured the lands at 2.996 COAL
Loaded to the Neck/Shoulder Junction at 2.895 COAL (2.235 CBTO)

I'm going to resist the urge to tinker and load 41 and be done.

 

[KyleR1985]

For anyone wanting 116tmk and dasher fit info:

Here’s 2.40”-2.60” overall length. You’ll probably run out of bearing surface going past 2.60”.

I broke out a 500ct box to supply some smaller quantities, so of course now I’m going to have to load up a handful for my dasher, instead of doing what I need to be doing….

 

[Nine Banger]

I got some 116s.

46gr n565 2.800"
6 creed
18"
2700fps

Quick Drop to 700yards at sea level.

Feels kinda sexual in nature.

 

[Lawnboi]

For anyone wanting 116tmk and dasher fit info:

Here’s 2.40”-2.60” overall length. You’ll probably run out of bearing surface going past 2.60”.

I broke out a 500ct box to supply some smaller quantities, so of course now I’m going to have to load up a handful for my dasher, instead of doing what I need to be doing…

What’s it look like in your .104 freebore?

 

[Tanner]

Got some 107s and 116s to try thanks to @RancherJohn. First thing that caught my eye is how short the BTO is. Very unscientific way of measuring but they have markedly less bearing surface than both 115 DTACs and 109 ELDMs.

I’ll report back with findings.

 

[KyleR1985]

What’s it look like in your .104 freebore?

With no ejector or extractor or firing pin, 2.5” to bolt dropping with no resistance.

Man a .120”-.180” freebore would be about right if you wanted to lob these mortars out of a dasher.

 

[Lawnboi]

With no ejector or extractor or firing pin, 2.5” to bolt dropping with no resistance.

Man a .120”-.180” freebore would be about right if you wanted to lob these mortars out of a dasher.

View attachment 1050410

Looks like I’ll be in good shape.

Iv got a 24” 7 twist is being chambered right now for the 116s. Guessing they will go as fast as the 107s in my 21”. I’d be happy with 2700.

 

[KyleR1985]

Looks like I’ll be in good shape.

Iv got a 24” 7 twist is being chambered right now for the 116s. Guessing they will go as fast as the 107s in my 21”. I’d be happy with 2700.

What freebore?

 

[Lawnboi]

What freebore?

.120

 

[JBahr]

Nice. What's your freebore?

This is a @Unknown Munitions cut 6 PRC originally intended for the 109 ELDM. I don’t think they did anything special, never saw the reamer print. I would guess .180” based on playing the sharpie game to find the lands.