Sierra Heavy TMK 6MM Testing

[Formidilosus]

Form, if i may just clarify. prior to these for 6/243 you recommended 108m over 115 dtac mostly due to neck length and less favorble tumbling at distance in smaller animals which makes sense.

Yes, that was correct. The 95gr TMK was not available, and the 108gr ELD-M and 103gr ELD-X were the best option generally.

These certainly scale up from the the 77s and understand your current affinity. For a 6/243 and choosing between the 116 and 107 - if its 95% deer sized game and one (read hopefully) elk annually are you all in on 116 regardless of game size since neck length is a non issue?

Yep. The 107gr is good too, though not as much use in it yet- but the 116gr is fantastic. In a 243/6cm/6xc size cartridge with a short barrel it’s easy to use straight quick drop or an easy correction factor for it.

secondly, exits are nice but it hasnt been an issue for me yet. but am interested in your exit comparative or thoughts of the 107, 116 and prior experience with the 108m at all distances. I believe you have noted a couple of times about getting exit(s).

J

All the 6mm TMK’s seem to exit more than any other save the DTAC. Haven’t caught a 95gr, 107gr, or 116gr yet- though haven’t used the 107’s and 116’s on elk.

108gr ELD-M’s are variable more than I prefer. Some lots of buckets are devastating, some lots are more controlled wound channel size, and both every once in a while will have a bullet not upsetting, or minimally so.

 

[KyleR1985]

Yes, that was correct. The 95gr TMK was not available, and the 108gr ELD-M and 103gr ELD-X were the best option generally.




Yep. The 107gr is good too, though not as much use in it yet- but the 116gr is fantastic. In a 243/6cm/6xc size cartridge with a short barrel it’s easy to use straight quick drop or an easy correction factor for it.





All the 6mm TMK’s seem to exit more than any other save the DTAC. Haven’t caught a 95gr, 107gr, or 116gr yet- though haven’t used the 107’s and 116’s on elk.

108gr ELD-M’s are variable more than I prefer. Some lots of buckets are devastating, some lots are more controlled wound channel size, and both every once in a while will have a bullet not upsetting, or minimally so.

The two whitetails I recovered last year with the 95tmk’s caught both bullets.

One 20 yards quarter-to high shoulder that seemed to catch most of bullet in cavity and spine. Didn’t open cavity to search it out, but found small fragments in offside hide.

The other 75 yards broadside mid body caught spine. Recovered Bullet in offside hide, probably 40-50% weight retention.

Both in the 24-2600fps impact velocity range.

Only two samples to offer with the 95’s so I can’t pattern it.

 

[Hurley88]

Yep. The 107gr is good too, though not as much use in it yet- but the 116gr is fantastic. In a 243/6cm/6xc size cartridge with a short barrel it’s easy to use straight quick drop or an easy correction factor for it.

This nails it. Personally I’ll run the 107 in my 6ARC but lean toward the 116 for a short barreled 6CM/243, for exactly this reason. MV in the 2600fps range makes quick drops way easier than when it’s up at 2800 or higher.

…can load the 107 down too though.

I don’t think anyone will complain with the wound channels from either.

 

[Carl Ross]

I don’t think anyone will complain with the wound channels from either.

Oh, I bet some will, just not about the wound being to small…

 

[Formidilosus]

Oh, I bet some will, just not about the wound being to small…

Ain’t that the truth.

 

[2Stamp]

Oh, I bet some will, just not about the wound being to small…

"You can't kill them too dead..." Or something like that.

 

[Shraggs]

Yes, that was correct. The 95gr TMK was not available, and the 108gr ELD-M and 103gr ELD-X were the best option generally.




Yep. The 107gr is good too, though not as much use in it yet- but the 116gr is fantastic. In a 243/6cm/6xc size cartridge with a short barrel it’s easy to use straight quick drop or an easy correction factor for it.





All the 6mm TMK’s seem to exit more than any other save the DTAC. Haven’t caught a 95gr, 107gr, or 116gr yet- though haven’t used the 107’s and 116’s on elk.

108gr ELD-M’s are variable more than I prefer. Some lots of buckets are devastating, some lots are more controlled wound channel size, and both every once in a while will have a bullet not upsetting, or minimally so.

thank you so very much!

really taken to the 6 cm, and now considering either a 6 arc or dasher for something legal in all states vs 223/77 - guessing either but speeds may favor the 107, or still 116 in for your use?

 

[Formidilosus]

thank you so very much!

really taken to the 6 cm, and now considering either a 6 arc or dasher for something legal in all states vs 223/77 - guessing either but speeds may favor the 107, or still 116 in for your use?

Both would work. The 107gr probably more the MV that most want in the ARC.

 

[Castle Rock]

This nails it. Personally I’ll run the 107 in my 6ARC but lean toward the 116 for a short barreled 6CM/243, for exactly this reason. MV in the 2600fps range makes quick drops way easier than when it’s up at 2800 or higher.

…can load the 107 down too though.

I don’t think anyone will complain with the wound channels from either.

I would be a bit concerned about complete stability with the 116s with a 1in 8 down here in the mangroves

 

[Hurley88]

I would be a bit concerned about complete stability with the 116s with a 1in 8 down here in the mangroves

Pretty easy to buy a 100ct box and verify. Even easier (less concern over long range issues) if your shot opportunities down there aren’t far.

But to each their own. I grabbed some 107, if they’re good I might not even bother with the 116 just bc their BC numbers are close enough and I don’t want to keep two different bullets in stock for those two rifles. It’s good to have choices, we can be as picky or as lazy as we like.

Either way, exciting times.

 

[Lawnboi]

There’s more to stability than just working at the range on a given day. Density altitude ca vary greatly throughout the year

 

[Jordan Smith]

There’s more to stability than just working at the range on a given day. Density altitude ca vary greatly throughout the year

Yup, and there’s also more to it that just stable or unstable. There are degrees of stability, and that can affect BC. The goal should be an SG of 1.5+ to maximize BC and keep it fairly constant.

 

[bonepoint]

108gr ELD-M’s are variable more than I prefer. Some lots of buckets are devastating, some lots are more controlled wound channel size, and both every once in a while will have a bullet not upsetting, or minimally so.

Why do you think the 108 ELDM is more inconsistent than a TMK, or even has a noticeably different wound channel? I remember someone posting pics of the bullets side cut. I would expect the construction of the ELDM and TMK to be very similar - thin, non-tapered jacket with a relatively soft core, with a front void for the tip. Inconsistency has long been the complaints on cup and core bullets, which drove the bonded and mono bullets 20+ years ago. I guess the one benefit now is that all of these cup and core bullets have very high sectional densities; a byproduct of chasing the high BC.

So, what about the TMK construction do you think makes it work "better"?

 

[Formidilosus]

Why do you think the 108 ELDM is more inconsistent than a TMK, or even has a noticeably different wound channel? I remember someone posting pics of the bullets side cut. I would expect the construction of the ELDM and TMK to be very similar - thin, non-tapered jacket with a relatively soft core, with a front void for the tip. Inconsistency has long been the complaints on cup and core bullets, which drove the bonded and mono bullets 20+ years ago. I guess the one benefit now is that all of these cup and core bullets have very high sectional densities; a byproduct of chasing the high BC.

So, what about the TMK construction do you think makes it work "better"?

I have discussed it for years on various threads here.

Here is one-

Thread 'New TMK announced'

Dec 10, 2025

Looks like sierra is adding new weights for the TMK lineup. I know a lot of people have been hearing rumors of this for the last several months.

Sierra Bullets Announces 2026 New Product Lineup | The Outdoor Wire

Summarized below:
Offerings:

• 22 cal 88gr - 100 pack (SKU 7188), 500 pack (SKU 7188C)
• 6MM 107gr - 100 pack (SKU 7207), 500 pack (SKU 7207C)
• 6MM 115-117gr* - 100 pack (SKU 7216), 500 pack (SKU 7216C)
• 25 cal 133-135gr* - 100 pack (SKU 7334), 500 pack (SKU 7334C)
• 6.5MM 153gr - 100 pack (SKU 7450), 500 pack (SKU 7450C)
• 7MM 185gr - 100 pack...

• 43.6N
• Replies: 466
• Forum: Firearms

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[nm.otter]

Inconsistency has long been the complaints on cup and core bullets, which drove the bonded and mono bullets 20+ years ago.

From what the bullet engineers tell us, holding tight tolerances is far more difficult with bonded bullets than it is for cup and core designs.

 

[43.6N]

Why do you think the 108 ELDM is more inconsistent than a TMK, or even has a noticeably different wound channel? I remember someone posting pics of the bullets side cut. I would expect the construction of the ELDM and TMK to be very similar - thin, non-tapered jacket with a relatively soft core, with a front void for the tip. Inconsistency has long been the complaints on cup and core bullets, which drove the bonded and mono bullets 20+ years ago. I guess the one benefit now is that all of these cup and core bullets have very high sectional densities; a byproduct of chasing the high BC.

So, what about the TMK construction do you think makes it work "better"?

I think @longrangelead cross section pictures that he posted on Christmas in this thread are probably the best visual representation of the construction differences and why they lead to more consistency.

I was given a handful of 117's to mess with and I got curious...
View attachment 991325

View attachment 991326

View attachment 991327

View attachment 991328
Touches the lands in a new 8t factory Tikka 243 @ 2.962" and puts the boat tail right at the shoulder.
Gonna need a M+ mag...

View attachment 991330
2.80" for comparison.

I'll see if I can shoot some this weekend.

The lead core in the TMK leaves a void behind the tip that doesn’t exist in the ELDM. The tip opening is also larger in diameter for the TMK family compared to the eldm. The end result from people whose opinions I trust and who are shooting much lower velocities than I, seems to be much more consistent terminal opening at lower velocities.

Now, an interesting newcomer is the Hornady ELD-VT. I have not seen any low impact testing or discussion yet about how consistent these bullets will be.
But you can see the massive void behind the tip. Using the same logic from the TMK construction, I would imagine this would open very consistently at tremendously low velocities.

 

[Odd1out]

Any have the length of the 116gr tmk?

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