Sierra Heavy TMK 6MM Testing

[SouthPaw]

The 24" Seekins was making 2960 fps without concerning pressure signs, fwiw.

What powder?

 

[TX_Diver]

Was debating what bullet to load for the 6 ARC. Would a 107 tmk likely be the way to go?

Would they gain anything over a 108 ELD-M which are usually a bit cheaper?

Would rather not pay Berger prices for this rifle…

 

[Gstew1930]

Was debating what bullet to load for the 6 ARC. Would a 107 tmk likely be the way to go?

Would they gain anything over a 108 ELD-M which are usually a bit cheaper?

Would rather not pay Berger prices for this rifle…

Dont over look the 95 TMK in the 6 ARC. We've done great with that combo

 

[Carl Ross]

What powder?

H4350

 

[TX_Diver]

Dont over look the 95 TMK in the 6 ARC. We've done great with that combo

I’m interested in those too and I think there’s a 95sst also?

 

[Alpha Echo]

I’m interested in those too and I think there’s a 95sst also?

Not that BC is everything, but the 95 SST's is severely lacking. Flat base. Haven't run the ballistics but was looking at the SST's for my 1:10 243 win barrel.

 

[Gstew1930]

I’m interested in those too and I think there’s a 95sst also?

Yeah i haven't used that one

 

[TX_Diver]

90 ELD-X was the other one o was thinking of. Although I’m sure almost anything will work.

In a 6 ARC it’s not like I gain nearly as much by going with a super high BC bullet I’m betting

 

[mxgsfmdpx]

Not that BC is everything, but the 95 SST's is severely lacking. Flat base. Haven't run the ballistics but was looking at the SST's for my 1:10 243 win barrel.

They are good to 400-500 yards in most hunting guns and are very reliable killers. Normally are very easy to get to shoot well and aren’t picky barrel to barrel.

 

[Alpha Echo]

They are good to 400-500 yards in most hunting guns and are very reliable killers. Normally are very easy to get to shoot well and aren’t picky barrel to barrel.

For that range I've got my 223 with 75 ELD-M's

 

[Terrapin]

I’m interested in those too and I think there’s a 95sst also?

I’ve been having good luck with the 95gr Barnes LRX and the Sierra 90gr TMK in the 6mm ARC. I prefer them to the heavies in ARC, since they give a little better distance before they drop below 1800 fps (probably based more on higher initial velocity & increased case capacity than because of ballistic coefficients).


Sent from my iPhone using Tapatalk

 

[UngulateGuardian797]

290g7 for the 116 isn't great, but it's not disappointing, still adequate. I've shot several K of the 115dtac(non-nosering) over last 3 years in 7.5tw 6cm and 6gt from 2820-2950mv, and BC needed for 1200y truing has been 307-312 depending on the lot being used. These bullets don't upset consistently at all unfortunately.

The 290g7 still hangs with everything we've been using for 6mm heavy hunting bullets, the nose ring cut dtac, 109 eldm, 108 elite hunter and definitely a step above the 108eldm. The only bullet that really stands above them is the 112 Barnes which has trued out to 308g7 in a few rifles I've used them in.

Really looking forward to getting some these next year. Right now I'm spec'ing a 6saw reamer to push this bullet as fast as possible on a 473 bolt face short action while maintaining a long neck length and non-fireforming. It'll hold 54.5ish gr of powder, just trying to figure out freebore needed for these new bullets, preliminary plan is to just put 6cm throat geometry out front but at 0.2445 diameter VS the saami 2435.

Can you start a 6 SAW thread once you get started with it?

I am extremely interested in that and have thought that it would be the perfect case to neck down to 6mm.

 

[khuber84]

Can you start a 6 SAW thread once you get started with it?

I am extremely interested in that and have thought that it would be the perfect case to neck down to 6mm.

I sure will! Sent you a pm with deets.

 

[Carl Ross]

This is in your Seekins 6 CM correct? If so, SAAMI freebore of .183.

Seated at .080 off, where does this put the boat tail to shoulder junction in the case?
Wondering if a longer fb, such as the PVA Standard (.210) might optimize these even more.

Any chance you could take a photo of a loaded round with a bullet lined up next to it?

@khuber84 I think a short 6 CM slinging these 117’s at 2800-2850 would be absolutely phenomenal.

Apologies for the terrible lighting. This is seated at a .085" jump, but this barrel also has over 1400 rounds on it. My typical load is with a Berger 108 EH load, and it's .030" off what the lands started at. Comparing them visually, it's clear the lands have moved pretty significantly.



Going back to this image, I think it has a similar bearing surface to the 115 DTAC, maybe the slightest whisker less boat tail.