210 Serria HPBTMK in .308Win

[Rustystud]

I am going to try the Sierra 210 Grain HPBTMK in .308 Winchewster for F-class TR. The OAL will be 2.995. The barrel is a 32 inch Broughton 1:10 5C. Cases are FL sized and trimmed to SAAMI Specs.
Think I will start off with 45. grains of IMR 4350 and work up. Anybody got any experience with this bullet.
Rustystud

 

[SHERMY]

My manual list a max load of 45.1gr of IMR-4350 with a 200gr HPBTMK. This is a Sierra manual,conservative).
I don't know, with the lack of 210 data, I'd start at 43.0gr.
Either way it's going to kick a little bit.
Mike

 

[Travelor]

I really think this bullet is too heavy for the 308. Might look at the 175 SMK or the 190 SMK.

 

[chrisj]

This bullet will work well @ 600 yds or less. It will work Ok for 1000 yards if you can deal with the drop. I think you will be much better off witha 190 or 155 Lapua though.

Good Luck,

Chris

 

[Rustystud]

Have found the 210grain bullet in 308 with previous load goes sub sonic before 1000 yards. I opened up the chamber throat, my round is now 3.125 .002 off the lands. I have a fellow shooter who is shooting a 30 inch barrel with 46.grains of N550 and he is getting 2650fps. He has shot up to 47. grains getting 2700fps with some signs of pressure. He stated he took off 2 inches of barrel 32" to 30" and actually got an increase in velocity. I am shooting the Sierra 210s he is shooting the Berger 210s they advertise a 40 point higher BC. I will try a couple loads with N550 before setting back the barrel if I don't find a load.
Rustystud

 

[DukeDuke]

Is the way to go! Heavy bullets in 308, in my experience perform much better at long ranges. Last week I tried 190MK with RL-19, but was not what I expected. With RL-15 though, different story. Zeroed at 100 yards the drop at 600 was 13moa. Could someone guess approximately the muzzle velocity, I don't have a chronograph.

 

[Rustystud]

DukeDuke:

The NC state Championship F-Class TR was won by a Nick Taylor, he was shooting Berger 210s with 46.5,first day) and 46.,second day) grains on N550 with Ferderal 210GM. I believe he is getting 200-300 fps on my load of IMR4350. Plus his bullet has a 40 point higher BC. He told me he reduced his barrel length from 32" to 30" and picked up a little velocity. I will experiment with the 32" with N550 before I shorten my barrel 2".

The N550 is a high energy powder and may just be the ticket. I have several other shooters that ate interested in doing the same thing with the heavier bullets.

At first when I was getting irratic POI I thought it was the scope. I thought it might be maxxed out. After the first day I ran the scope to the end of elevation and I still had 208 clicks 26 MOA adjustment.

I now am convinced the bullets just became transsonic.
Rustystud

 

[DukeDuke]

Isn't that a lot of powder for that bullet weight? I've to check what Vihtavouri says...well they list for 190gr bullet 47.2gr of N550 as maximum. I'm guessing there are no pressure signs. I'd like to know more about it. Keep me posted, I'd appreciate it!


Duke

 

[Rustystud]

Duke Duke:

My IMR 4350 loads with Sierra 210s were going trans sonic before 1000 yards. Nick won the NC state LT F-Class TR using Berger 210s with N550. He said it was a hot load. He has shot up to 47., grains but has backed down to 46.grains. Remember you should work your loads up, every gun developes pressure differently. This is why the SAAMI specs are the way they are. Most loading books are conservative as much as 10% on their max loads. Except for the powders where volume exceeds capacity. In those cases you run out of case capacity. In most cases better loads have volumes of 98-101% run the best volume, pressue, velocity, extreme velocity spread, and group size. This is controlled by burn rate, primer heat, and barrel length.

Rustystud