New TMK announced

[43.6N]

I hope the numbers for the .264 bullets are better than your calculations. Knowing what I know with personal experience with 147 eld and 153 Berger and what a good friend has seen with the 150 match kings. The new tmks need to be in my opinion .330+ G7. I’m coming at this from a competitive mindset. For shooting animals to me bc isn’t a main concern.

Like I’ve seen the 150 match kings true out at a .350 g7 the new tmk should be on par with a Berger 153. I’ve trued that out at box BC of .356.

Where i hope sierra pulls through is the 147. I’ve seen eld M 147s true out at a .311 and .330 with different barrels with an advertised BC of .351. So if they can make a consistent 147 that kills with a high bc it’ll be a winner over the eld m.


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And yes, I 100% hope that I’m underestimating the BC for these bullets. If the .264 bullets get close to the 150smk bc, that will be an absolute monster

 

[Q_Sertorius]

I did a little math yesterday evening trying to come up with the likely ballistic coefficients for these new TMK.

BC is sectional density multiplied by its form factor.
Sierra has 2 lines of tipped bullets with similar form factors. The TMK line, with a generally better form factor. And the TGK line with a slightly lower form factor. Example: .264 130TMK with g1 bc of 0.518 vs 130 TGK with g1 bc of .510.

If only using the current TMK line, I didn’t have enough data to build a good model. So I also included the TGK line. As a result, these estimated BC values will likely be slightly low compared to what Sierra ultimately reports.

Final caveat, these are simply estimates. I have no first hand experience with these bullets, and no inside info from Sierra. I’m simply a guy with an Idaho public school education and a ti84 calculator. I just wanted to see where these new bullets are likely to end up ballistically, and thought others here might want to know the same!

First is the spreadsheet with the TMK and TGK bullets listed by caliber.View attachment 991922
Next I sorted by sectional density.
You can see a clear trend in BC between bullets with similar sectional density. This trend is the bullets form factor, and can be used to estimate the BC for our new TMK line:
Also you’ll notice outliers in BC for the light for caliber 150gr 7mm and 120gr 6.5mm. This is where these bullets have departed from the form factor model due to their low weight.

The Green highlighted numbers are the new TMK bullets. And my estimated G1 BC is the far right column:

View attachment 991923

Finally, comparing my numbers to the BC numbers in the heavy TMK testing thread, it looks like my estimate is close at least for the 116 bullet. 0.595-0.600 seems to be what those guys have reported so far.

Any idea on the new .257 bullet?

 

[43.6N]

Any idea on the new .257 bullet?

Haha. Sure man. Give me a minute to find some fresh double A for the Ti84

 

[NWBLKTAIL]

Haha. Sure man. Give me a minute to find some fresh double A for the Ti84

You know the less fancy calculators can write”80085” just as well as the ti84….

 

[43.6N]

Any idea on the new .257 bullet?

Probably about 0.610 is a safe assumption.

-The 133 version will have the same SD as the 195 30 cal TMK. And the 140 6.5mm TGK. Between the two, it will almost certainly favor the TMK form factor.
-The 135 version will have the same SD as the 165 7mm TGK (so underestimation of BC)
-Both of those bullets list out their g1 bc at 0.610.

 

[nm.otter]

I still have my HP-25C someplace.

Saved up most of my junior year in HS to pay for it -- RPN for the win!

 

[43.6N]

You know the less fancy calculators can write”80085” just as well as the ti84….

8008135

Fixed it for you pal

 

[NWBLKTAIL]

8008135

Fixed it for you pal

That’s reserved for the pros

 

[ddowning]

My 16” 6 Creed is a 700-800 yard killing gun depending on DA.

I don’t think folks realize not only their capabilities (lack of) or their guns capabilities (way further than their abilities).

There’s probably only a dozen or so folks on this site that should even be trying to kill past 800. Even though everyone thinks they are that guy, I’ve seen nothing but the opposite.

You, my friend, are spot on. We used to have a little regional PResque match series. I managed to stay in the top three for the most part for the last couple years until the finale, which was during youth season. I would stop practicing to hunt with my kids and tank the finale. However, my point is, I could go to the local range and shoot a 1.5 moa steel target at 800 in most conditions. I could also do it all over several states (not mountain), but by that time I had shot nearly all of those ranges at least once if not several times. The number of rounds I was shooting was absurd. I was pretty confident to 800, but there was doubt, especially in tough conditions.

I have not shot matches (a couple to screw around) in 2 or 3 years. I would say 600 is about as likely as 1000 or 1200 was when I was shooting all the time. There are obviously a lot of variables with conditions and positions that have an effect, but shooting past 600 and making a first round hit is not easy. Past 800 is even harder. I agree that you need to shoot a lot in many different, new areas and learn to read the situation extremely well to make first round hits at those distances. Many people think they can do it. At one time, I was able, at this time, I am not. The skill is just too perishable.

I will say, if you put a good shooter next to me to give me the right call, the shot itself is not that difficult from prone as long as you are not rushed. It is making the call, spotting your own shot, and quickly correcting for subsequent shots that diminishes quickly. That, and speed. The amount of practice required is almost to make shooting a lifestyle. People think because they have equipment that can do it, there is very little skill involved. They fool themselves by shooting little tiny groups at distance AFTER they have figured out the conditions.

 

[ddowning]

I get that and am guilty as well.

The thing is, it’s only a “wind advantage” if you can wind call the discrepancy. Relying on a better “wind number gun” doesn’t translate to more hits if you suck at reading and calling wind. Despite everyone seeming to think that it does.

I used to type an example of a 108 berger target at 2800 fps and a 115 dtac at 3100 fps for prs on a 2 moa target at 1000 yards with a 3 o clock wind. It's easy to do the calcs. Most guys are calling wind to 1mph (not guessing 4.5 mph, but 4 or 5 mph). With a 1 mph error, both hit. With a 2 mph error, both miss. One is a 5 mph gun at my DA and the other is a 6.5-7 mph gun at my DA. It takes a lot of ballistics to save your bad wind call.

 

[Speaks]

My 16” 6 Creed is a 700-800 yard killing gun depending on DA.

I don’t think folks realize not only their capabilities (lack of) or their guns capabilities (way further than their abilities).

There’s probably only a dozen or so folks on this site that should even be trying to kill past 800. Even though everyone thinks they are that guy, I’ve seen nothing but the opposite.

Quick question that likely highlights my inexperience with shots much past 400. Im curious about the 800 yards on a 6CM that short though. My 18 incher is getting 2800 fps with 103 eldx and 2700 with 108 eldm.

Assuming 1800 fps is the cut off that puts me at a 600 yard gun here in MN right now but even changing DA to 5000 it looks like it only gets to 700. Looks like you would need 2900+ fps MV or even higher DA to get to 800? - Assuming AB quantum is giving me good info.

Are you getting that high a velocity out of your 16 inch barrel or am I thinking about another one of the variables wrong? Or perhaps I am missing something in AB all together.

 

[Chris in TN]

Are you getting that high a velocity out of your 16 inch barrel or am I thinking about another one of the variables wrong? Or perhaps I am missing something in AB all together.

FWIW a lot of places out west you can start a deer/elk hunt at 8000' and go up from there. I saw elk this year at 11700'. I was standing around 10200' when I saw them.
Bullets that struggle to stay above 2000' at 500 yards here where I live (650') will stretch that out to maybe 650' at 8000' and 750' at 11000', all else being equal. And the guys shooting further are generally using TMKs and trusting them to 1800', which buys you another ~100-150 yards.

 

[Speaks]

FWIW a lot of places out west you can start a deer/elk hunt at 8000' and go up from there. I saw elk this year at 11700'. I was standing around 10200' when I saw them.
Bullets that struggle to stay above 2000' at 500 yards here where I live (650') will stretch that out to maybe 650' at 8000' and 750' at 11000', all else being equal. And the guys shooting further are generally using TMKs and trusting them to 1800', which buys you another ~100-150 yards.

Ok got it, yea I plug in 8500 DA and your at 800 yards, Im sure with hand loads velocity can get a little higher as well.

Where I live its about 950 ft though with the weather this morning DA is right around -95, amazing how big a change that can make.

 

[Chris in TN]

Ok got it, yea I plug in 8500 DA and your at 800 yards, Im sure with hand loads velocity can get a little higher as well.

Where I live its about 950 ft though with the weather this morning DA is right around -95, amazing how big a change that can make.

I'm at 640' IIRC but it's like 70 degrees here and 90%+ humidity right now so our DA is way higher than normal, especially for December.

 

[mxgsfmdpx]

I used to type an example of a 108 berger target at 2800 fps and a 115 dtac at 3100 fps for prs on a 2 moa target at 1000 yards with a 3 o clock wind. It's easy to do the calcs. Most guys are calling wind to 1mph (not guessing 4.5 mph, but 4 or 5 mph). With a 1 mph error, both hit. With a 2 mph error, both miss. One is a 5 mph gun at my DA and the other is a 6.5-7 mph gun at my DA. It takes a lot of ballistics to save your bad wind call.

Indeed. And in the mountains with a first round wind call, the BEST guys I’ve ever shot with, talking guys who shoot in the mountains and in wind weekly, you can bank on closer to 2-3 MPH of error.

 

[mxgsfmdpx]

Quick question that likely highlights my inexperience with shots much past 400. Im curious about the 800 yards on a 6CM that short though. My 18 incher is getting 2800 fps with 103 eldx and 2700 with 108 eldm.

Assuming 1800 fps is the cut off that puts me at a 600 yard gun here in MN right now but even changing DA to 5000 it looks like it only gets to 700. Looks like you would need 2900+ fps MV or even higher DA to get to 800? - Assuming AB quantum is giving me good info.

Are you getting that high a velocity out of your 16 inch barrel or am I thinking about another one of the variables wrong? Or perhaps I am missing something in AB all together.

Most of my mountain hunting and daily shooting in the spring and summer is around 5,000 minimum DA, normally higher.

When I used my 6 creed this fall in Minnesota for rifle season I think it was a 600-650 yard gun most days.

Keeping track of daily DA while hunting (mainly just temp and elevation cause that’s easy) is important while on the mountain as it changes more than most realize.

 

[Chris in TN]

Indeed. And in the mountains with a first round wind call, the BEST guys I’ve ever shot with, talking guys who shoot in the mountains and in wind weekly, you can bank on closer to 2-3 MPH of error.

I'm going to guess, too, that you're talking about mild to moderate total wind speed - like 5-10mph.

Once the wind gets above 10mph, certainly above 15mph, in my experience everything becomes a guess.

ETA: And I am by no means a good wind caller. I know there are worlds of people better than me. I just think there's a point where most of us ought to give up and get closer.

 

[Speaks]

Most of my mountain hunting and daily shooting in the spring and summer is around 5,000 minimum DA, normally higher.

When I used my 6 creed this fall in Minnesota for rifle season I think it was a 600-650 yard gun most days.

Keeping track of daily DA while hunting (mainly just temp and elevation cause that’s easy) is important while on the mountain as it changes more than most realize.

Makes sense, appreciate your help

 

[Karl B]

I wonder what kind of speed you could expect with the 117 out of a 6-284 with an 18-20” barrel. You have me thinking now.

115 bergers and n570 is gonna be about 3125fps in an 18". H1000 and n565 were between 3040-3060fps.

When you run the numbers vs a 105-108gr and the added speed the bigger pills just don't buy you much functional yardage. They can't catch up to the medium sized pills going faster till way way out there.

If starting from scratch on action and components the 6prc makes the most sense for that 50-60gr case capacity but if you've got a standard bolt face the 6-284 is a lot of fun. I had big stock pile of 6.5-284 lapua brass from the covid days, 6.5-284 dies, and a standard bolt faced action so the choice was easy for me.

 

[Jud96]

I’m excited for these and happy to see Sierra stepping up their game. Hopefully they shoot as good and are as consistent as Berger’s in accuracy and flight. I also hope Sierra can keep them on the shelves.