Sierra TMK vs TGK (bullet construction and terminal behavior)

Petey308

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I just wanted to make a separate thread to go along with other one I made about the ELDM vs the ELDX, but regarding the differences between the Sierra TGK and the TMK. The TGK is actually a completely redesigned bullet from Sierra and it's like nothing else they've made before. It has the thickest jackets of any of their other bullets and has one of the hardest lead alloy cores. Most all of their other bullets feature much softer lead cores.

They're really nothing like the original GameKings. The original GameKings are the same as the regular MatchKings and Tipped MatchKings as far as jacket thickness and their core. The only difference between the SMK, TMK, and original GameKing is, depending on the particular GameKing, is it either has a soft point or large hollow point, compared to the polymer tipped TMK and open tipped SMK (OTM).

The GameKings were an original hunting version of the MatchKing. They made them with either a soft point or large hollow point to ensure they expanded reliably versus the small open tip of the SMK.

The TMK was made to be an improved SMK. They gave it a polymer tip to increase consistency from bullet to bullet and also boost BC, plus they improved the aerodynamic profile of them. Ironically, this also made them as reliable as the GameKings concerning expansion, but the TMK has the improved external ballistics. The TMKs are literally just as much of a Tipped original GameKing as they are a Tipped MatchKing.

I personally dislike that Sierra named what is now the actual Tipped GameKing that. I think they should have called it something else, like perhaps a Tipped ProHunter or something since those are a thicker jacketed version of the original GameKing.

In my mind, they could have had a Tipped ProHunter and a Tipped GameKing and used the translucent green tips with both. The opaque tip on the TMK would stay on those. They could then make the exact same bullet and just make one line and product number with the opaque tip and say it's for targets and then another line and product number with a translucent tip and say it's for extended range hunting.

They could then also have the Tipped ProHunter (or whatever different name they prefer) for close to medium range hunting and for medium to large game. It would make for a great lineup and selection and not make things confusing to the hunters without any real knowledge on bullet construction. They'd essentially have three different products and only two actually different bullets.

So anyway, with all that said, here are a bunch of pictures showing a 160gr 7mm TMK and a 165gr 7mm TGK side by side. You can see the differences pretty clearly. The jackets on the TGK are much thicker (.047" vs .026" on the TMK). Obviously there's less core material on the TGK as well. That core, however, is indeed MUCH harder than the core of the TMK. It's a lead alloy and it was very noticeably harder when cutting it and it also took twice as long to melt it versus the pure lead core in the TMK.

The opening/meplat on the TGK is a bit wider, which is beneficial for expansion. That helps ensure it does still expand well having the thicker jacket and harder core. That said, it still won't makeup for it completely. The TGK is definitely a tough constructed bullet and even Sierra recommends it not be used when impact velocity will be below around 2200-2000fps. That's why it's better for closer range work or at least pushed to velocities that keep it above that minimum. The TMK is what you'd want for longer range shots or if impact velocities would be below the 2200-2000fps range. The TMK is still good down to at least 1400fps.

I've loaded both of these bullets in 7mm Rem Mags for customers and they both have done very well. I'll post some pictures as well of some results with them shared to me by the customer. The TGK shots were with the deer on the run and about 200 yards or so away. They definitely still produced plenty of trauma and dropped the deer quick.75815C73-8BD7-4944-BF31-D07BDEDF6B2C.jpeg9B0832E3-2B02-481C-BE12-69B3B7A2C627.jpegF2CDBC38-CC52-414A-868D-D5749FC148D4.jpegDD1382BC-32A2-464E-97D9-4FA6109ED776.jpegC220E9C1-77BD-47BD-A8FA-757DFFD2165E.jpeg6370E68D-2CB3-4405-9B99-242745E45558.jpeg25360305-AE82-40B4-BCD3-B9CE27B64686.jpeg

 

Petey308

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Here’s the jacket measurements:

76471AFD-FC81-4EAC-8C29-65493AF2A8A7.jpeg2562FF75-0495-4FF7-B9FA-32D09CCFE39C.jpeg33F7BE56-DC66-469B-8E3F-A3805784C574.jpegAB8425EA-8516-407E-AA0E-2CB0A9B6944A.jpegD10BB452-20C8-4EF0-8D10-72C136D40127.jpeg07D23AFA-F024-4BE9-8B34-536CC07C6286.jpeg
 

Petey308

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Here’s the deer from the customer’s results I mentioned. Forgot to post those lol.

C235614E-9393-48E9-9019-3AB64B3398D0.jpegA56641D4-E318-4710-867D-AA5FBE057D08.jpeg92D196AC-4F5D-4A5B-85C4-955C223309DD.jpeg165A4396-C3A1-4C64-84C8-3ABB3301E102.jpegF920BE24-83C2-4BEC-9AFF-7BD6F7161401.jpegF6A4D16D-92BB-412E-A34A-F1FA1A8EB68F.jpeg6516C4AA-B447-4CE3-9921-FD6A6C11884F.jpeg6AD859C3-DACA-4373-9FB5-D0D8FEF13BC1.jpeg31B357C0-B12B-4ED0-BB5E-F520ECAB961C.jpegB1B27042-5453-4570-B95D-5377476FCCBE.jpeg
 

AXEFORCE6

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The TGK seems to be a hearty bullet. Wish they were more available. I’d love a 155gr 6.5mm bullet.
 

Petey308

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The TGK seems to be a hearty bullet. Wish they were more available. I’d love a 155gr 6.5mm bullet.
I definitely is. My prefer is the TMK, but there are definitely applications/scenarios where the TGK will perform well.

I think 155gr in 6.5mm would be pretty heavy for such a stout bullet. The BC would likely be pretty good though, so pushed out of a faster cartridge they’d likely retain a good deal of velocity and the distance they hit that 2000-2200fps mark might still be pretty far. At least far enough for a guy’s needs, perhaps.
 

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