Sierra Tipped MK's seat depth

[Lightload]

Finally.found some Sierra 30cal 175 TMK's. (Widener's has 500's). In the interest of jump-starting my testing, what did you guys find these bullets like.....jump or.jam. I understand they're a lot longer than MK's so magazine length is out of the question. I'd be interested to hear what worked for you.

 

[mjtripper]

I load mine to coal of 2.850 and mag feed them. I called Sierra when I first got them and they said to just use the normal 175 load data and seating info. So far that has worked out for me. I actually just ran my load through that new magneto speed sporter chrono and this is what I got out of my rem 700 24" with 5 rounds of each.

Federall GMM 175
Vel 2624
ES 26
SD 11

Lapua brass, tmk 175, 42.5gr varget, 2.850 coal
Vel 2626
ES 26
SD 11

 

[masterblaster1]

Any other loads out there on this bullet?

 

[mjtripper]

Nobody else yet? I figured people would be eager to try these out.

 

[ZenOhSix]

Here was a great post by JAD762 on ARFCOM:

TMK Review Thread on ARFCOM

I have quoted his posts here for reference:

OK, the bullets arrived in the mail today. I'm going to load them tomorrow in an LC Match case with a CCI Benchrest primer and 42 grains of 4064. Then rain is supposed to move in for the rest of the weekend which means it may be Tuesday before I can get to the range and actually shoot them.

But until then, we can make a basic comparison between the SMK, the Berger VLD, and the TMK.

Earlier the TMK's ogive was mentioned. The SMK has a tangent ogive and the VLD has a secant ogive. Just from eyeballing the three bullets I'd say that the TMK is neither, or a hybrid between the two.

OAL comparison of the three bullets. First the SMK, then the VLD, and finally the TMK.

I randomly grabbed 5 of the TMKs and weighed them. 2 were 168 gr on the nose, 2 were 168.1 gr, and one was 168.2.

Part 2:

Made it to my 600 yard range today. 80 degrees outside, very high humidity, very little wind.

All shots were taken with a custom NM M1A, prone, iron sights, slung.

As a benchmark I shot Federal GM and my SMK hand loads alongside my new TMK hand loads.

Starting with the chronograph,

FGM 2624/2564 - 2585 avg
SMK 2539/2487 - 2517 avg
TMK 2574/2530 - 2544

After chonoing my loads I headed to the 600 yard line.

First up: FGM. Without the flier it was 1moa, with the flier 1.7moa.

Second: SMK. 1.3moa

Now for the TMK's. I started with them .01 off the lands and worked my way out to .08 off the lands.

.01 - 1.3moa

.02 & .03 - I screwed up and cross fired on a target, putting my .02 and .03 groups on the same target. 2moa without the flier, 3.8 with it.

.04 - 1.2moa without the flier, 3.7 with it.

.05 - 2.8moa

.06 - 2.3moa

.07 - 2moa

.08 - 1.1moa

The bullet does seem to be jump sensitive, though the bullets loaded close to the lands seemed to behave similar to the ones loaded the farthest from the lands.

With the rains and flooding, it doesn't look like I'm going to make it out to 1000 yards with it anytime soon.

Like I said, humidity was high and after wearing my shooting coat in it for a couple hours, I was starting to fatigue a bit.

But hey, shooting stuff is fun anyway.

Anyhow, I thought it was some great information. He is a local shooter to me, in which I plan on using his data to help progress my TMK loading as well.

Thanks,
Mike

 

[mjtripper]

That's a good read, thanks.

 

[amlevin]

Any other loads out there on this bullet?

I just finished a load workup using the 175 TMK's in my 24" Benchmark 1:10 5-C barrel.

44.0 gr IMR 4064
Lapua Brass
BR-2 Primers

CBTO 2.150" (just touching lands in my rifle)



Groups at 200 yards were bugholes with zero wind conditions.

I did find that this was a considerably higher charge weight than what I used with the 175 SMK's in my rifle. Best groups with the SMK's came at 42.2 gr. The same load with the TMK's opened the groups up by "half a caliber".

One thing I found is that all the bullets in the box of 500 I purchased were almost exactly the same base-ogive dimension as well as uniform in OAL. What a far cry from the SMK's when a sorting session would yield at least 3 and up to 6 different groups of different dimensions. The only thing that was consistent with the SMK's was the diameter.

So far they tested great "at the lands" so next week I try them closer to magazine length.

 

[Sniper338]

I still cant get em locally... i wanted to try them... i have a buddy that tried them in his 308 and no cigar... his loves the bthp...

 

[stinnett1981]

My seating depth is .017" off firm jam. My load is 44.4g Varget, Lapua brass, CCI large primers and obviously the 175g Sierra TMK bullets. I shot a 148 out of 150 at a FT/R match with this load. I think I shot 6 X's too. This was all at 600 yards. Before I shot the 175 grain regular SMK bullets and I could NEVER shoot this good. These bullets cut the wind and shoot noticeably flatter! Great bullets IMO!

 

[amlevin]

Before I shot the 175 grain regular SMK bullets and I could NEVER shoot this good. These bullets cut the wind and shoot noticeably flatter! Great bullets IMO!

From what I've read the TMK's perform up to their advertised BC and the old SMK's were "overstated" by about 3.5%. Compare the SMK "tested" BC of .488 (G-1) to the new TMK BC of .545 (and that's from 2400 fps and up) and you have a bullet that "flies" 12% better.

 

[masterblaster1]

I ended up at 43.8 Varget in Lapua case, 15 off the lands, Krieger m24 24 inch 10 twist, shoots bugholes, this is 0.7 grains higher than the same rifle than the 175 smk load.

 

[Lightload]

OP here....still working on it. I settled on 42.8grs of Varget (much over 43 and the cases start to stick). Best I've done so far is 5thou off the lands. Tried from 5 in to 25 off. I can get to half minute or just a little under but I sure ain't getting bug holes! Testing at 200, Barlein 10 twist 5R 26 inches.