Sierra Heavy TMK 6MM Testing

[huntnful]

The 107s shoot. Theres 10 in there.

Just 31 grains of varget .040 off the rifling loaded up with no work up.


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I had my reservations initially just because the design, which obviously I don’t know shit compared to someone that engineers bullets hahaha. But it’s good to see them wanting to shoot effortlessly is so many different guns. Especially a .292 G7 and being able to push them as fast or possibly faster than a 105 Berger

 

[Lawnboi]

I had my reservations initially just because the design, which obviously I don’t know shit compared to someone that engineers bullets hahaha. But it’s good to see them wanting to shoot effortlessly is so many different guns. Especially a .292 G7 and being able to push them as fast or possibly faster than a 105 Berger

Same, pretty aggressive as far as nose length and bearing surface but so is the 105 hybrid…. And tha bullet shoots in anything 6mm.

I probably won’t even try the 116 in my dasher just because I don’t think the juice will be worth the squeeze in terms of velocity. Plus I’d likely want a 7 twist, even this bullet is marginally stable at negative density altitude in shooting in right now.

I do think the 116 is going to be thee bullet for 6cm though, especially saami 6cm chambers. But like we have seen sometimes jump just dosnt matter

I knew things were going good when my fist three come out like this

 

[Porthunter]

IMO the SAAMI throat is deeper than ideal for the 107’s. Not that they won’t shoot. Hell they shoot great in mine. Just that I prefer to be right near the lands with the bearing surface like 3/4 of the way into the neck. With this bullet and SAAMI chamber, when right near the lands, the bullet is barely inside the case neck.

Obviously you can just jump them a decent ways and everything should probably be fine. Just not my preferred starting point to have a long jump right out the gate.

Good to know… my supplier has a bunch of the 107 and 116s coming. May swap those out to the 116.

Just figured with an 18” barrel the extra velocity would surpass the higher BC of the 116 but based on what you’re saying, may make more sense.

 

[Lawnboi]

Someone cut one in half already

 

[NW_backcountry90]

Well the 107’s in the 6 prc are going to loooong, had the rifle throated for 115 dtacs and 109 eldm, going to be about .100 jump so I can run them at 2.950 mag length we will see how they do. They were dang near hanging out the case by the time I got to the lands haha

 

[Hurley88]

Last year I tested for jump using 6.5CM and 140 ELDM, 30-shot groups. Saw no difference between .030–.120” jump. From all the (admittedly scant) data sources I’ve seen on the subject, short jump isn’t what it has been cracked up to be. I have seen it cause issues down the line twice, those barrels were both 500+ rounds and no cleaning.

I don’t like issues, so these days if I have a jump between .060–.100 and the combo shoots I just roll with it. More time shooting, less time in the reloading room.

That said if I ever have issue I’ll come back here, quote this post, and eat crow.

 

[NW_backcountry90]

Last year I tested for jump using 6.5CM and 140 ELDM, 30-shot groups. Saw no difference between .030–.120” jump. From all the (admittedly scant) data sources I’ve seen on the subject, short jump isn’t what it has been cracked up to be. I have seen it cause issues down the line twice, those barrels were both 500+ rounds and no cleaning.

I don’t like issues, so these days if I have a jump between .060–.100 and the combo shoots I just roll with it. More time shooting, less time in the reloading room.

That said if I ever have issue I’ll come back here, quote this post, and eat crow.

for sure not to concerned gonna shoot em see what they do. I usually just start .030 off and roll with it. If they don’t shoot wait for the 116’s. I have a load with 109’s that shoot lights out already so this is just for fun.

 

[nm.otter]

short jump isn’t what it has been cracked up to be

...at least for modern, tightly-specified chamberings.

 

[Hurley88]

True, but probably also has something to do with bullet design too. Still have about 600-1k rounds to go on a 243, might run a bullet jump test on that to see. Think IIRC the whole freebore is like a cone on that one.