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.

 

[huntnful]

116’s with 42.5gr. N555 at 2.900” seems like a good base load in a SAMMI 6 creed.



I’m still not really sold on them precision wise in all honestly. Maybe shooting them 3,000+fps is amplifying the bullet imperfections. But lots of small clusters, with 1/2” type outliers. Not my favorite thing to see, but they’ll kill for sure.

I’d like to see them in a 6 UM at 3,300fps. I bet they’re tough to shoot small.

 

[Q_Sertorius]

I’ve yet to see a Tikka 243 1:8” twist not shoot the 116’s well. The “Mayham” ammo is silly. Send it back, and request normal ammo, or “Forms” load from Blaine. I’ll get them what it should be.

Did you have a preferred load for the 116-grain TMK in a .243? I am currently working with H4350 and Hornady brass.

 

[Tanner]

116’s with 42.5gr. N555 at 2.900” seems like a good base load in a SAMMI 6 creed.

View attachment 1050670

I’m still not really sold on them precision wise in all honestly. Maybe shooting them 3,000+fps is amplifying the bullet imperfections. But lots of small clusters, with 1/2” type outliers. Not my favorite thing to see, but they’ll kill for sure.

I’d like to see them in a 6 UM at 3,300fps. I bet they’re tough to shoot small.

I had seen some of the same behavior in ELDMs, wanting to run a bit slower to shoot well. I would love to know what that is all about. Almost everything I shoot is sub 3,000fps, but it would be nice to pump them faster and still shoot right…

 

[huntnful]

I had seen some of the same behavior in ELDMs, wanting to run a bit slower to shoot well. I would love to know what that is all about. Almost everything I shoot is sub 3,000fps, but it would be nice to pump them faster and still shoot right…

Same here man. I listened to an interview with a guy that was all into ballistics and crazy long range artillery shit.

He said basically it’s an RPM thing that amplifies any imperfections. And he recommended shooting at minimum RPM’s for stability, and no more. Because you’re gaining nothing but inconsistency in bullet flight once your past minimum stability.

Made sense to me. Bullets with minuscule imperfections to amplify probably just shoot better at higher RPM’s in general for that reason.

 

[Tanner]

Has anybody using Hornady Custom Grade Dies, replaced their seating stem with the one they make for the 110 A-Tip? Curious if that would be a better fit for these bullets, as the standard stem in my seating die is leaving a pretty heavy ring on these TMKs and preferably not buy a new seater.

 

[Formidilosus]

116’s with 42.5gr. N555 at 2.900” seems like a good base load in a SAMMI 6 creed.

View attachment 1050670

I’m still not really sold on them precision wise in all honestly. Maybe shooting them 3,000+fps is amplifying the bullet imperfections. But lots of small clusters, with 1/2” type outliers. Not my favorite thing to see, but they’ll kill for sure.

I’d like to see them in a 6 UM at 3,300fps. I bet they’re tough to shoot small.

I had seen some of the same behavior in ELDMs, wanting to run a bit slower to shoot well. I would love to know what that is all about. Almost everything I shoot is sub 3,000fps, but it would be nice to pump them faster and still shoot right…

There are some in this thread- from me, posts 265, 270.

Overall from 2x 6UM’s- the 116’s have averaged almost exactly the same as 115gr DTAC’s from the guns using the same load- .9’ish MOA to 1.2 MOA. That’s at 3,200-3,300fps MV.

 

[huntnful]

There are some in this thread- from me, posts 265, 270.

Overall from 2x 6UM’s- the 116’s have averaged almost exactly the same as 115gr DTAC’s from the guns using the same load- .9’ish MOA to 1.2 MOA. That’s at 3,200-3,300fps MV.

That’s good hear for sure. I think I was unfortunate to get a couple shitty tips on both lots right out the gate, as well as see some sub optimal precision and now I can’t get over it mentally. Now everything weird is just me wanting to solely blame the bullet, and nothing else in the system.

 

[shayes11]

Has anybody using Hornady Custom Grade Dies, replaced their seating stem with the one they make for the 110 A-Tip? Curious if that would be a better fit for these bullets, as the standard stem in my seating die is leaving a pretty heavy ring on these TMKs and preferably not buy a new seater.

I just swapped the stem in my Hornady Customs for the 6arc. Fixed the ring completely for me with the 107s.

 

[Formidilosus]

That’s good hear for sure. I think I was unfortunate to get a couple shitty tips on both lots right out the gate, as well as see some sub optimal precision and now I can’t get over it mentally. Now everything weird is just me wanting to solely blame the bullet, and nothing else in the system.

Haha.


I got a 500ct box of production 116’s and just grabbed a big handful of bullets from it- nothing bad or unusual with the tips.
For sure extreme precision (.5-.7 MOA) is easier with Berger’s in a few flavors (105gr Hybrid) than almost any other bullets. But, the TMK’s have all been 1 MOA for ten or better with little to no effort for dozen guns or so that I have used them in.

 

[Wprinkle]

I got some 116s.

46gr n565 2.800"
6 creed
18"
2700fps

Quick Drop to 700yards at sea level.

Feels kinda sexual in nature.

View attachment 1050338

What barrel twist?