Sierra Introduces New 6.5mm 150 gr MatchKing Bullet

[BlueBoy69]

For those who havn't already seen the news on Sierra's blog and other pages.

 

As the title states, Sierra have brought out a new heavier, 150 grain, 6.5 mm Matchking (SMK) bullet.

 

Links below.

 

Sierra blog link

 

Updated load data for the 6.5 Creedmoor that includes the new bullet (PDF)

 

Sierra product page

 

This provides far lower drag (G1 0.713 at 1,760 fps and above) than even their 142 gr (G1 0.626 at 2,850 fps and above) and lower weight SMK bullets, along with all of Berger's and Lapua's 6.5 mm (0.264") offerings.

 

Looks like the gunsmiths will have a field day though, as it needs a 1:7.5" or greater twist to stabilise it

[dannywayoflife]

Would think that would go well out of an X55!

[baldie]

The old Swede shot 160 grain bullets well enough out of an 8" twist, I can't see these needing anything faster.

 

I feel it may be pushing the envelope somewhat from a creedmoor, in much the same way as a 140 out of a 47.

 

There is a tipping point where the case cannot push the bullet fast enough to activate the claimed BC.

 

Would be a good bullet for a swede or 6.5 x .284.

[BlueBoy69]

The old Swede shot 160 grain bullets well enough out of an 8" twist, I can't see these needing anything faster.

 

I feel it may be pushing the envelope somewhat from a creedmoor, in much the same way as a 140 out of a 47.

 

There is a tipping point where the case cannot push the bullet fast enough to activate the claimed BC.

 

Would be a good bullet for a swede or 6.5 x .284.

 

I think it's simply the length Dave. The new bullet is blooming long. I don't have the exact length, but if you look at the Sierra rifle bullet page and compare the lengths of the 6.5 mm bullets, you can see; of course this does depend on them being to scale.

 

Sierra rifle bullet page

 

Ignoring the 6.5 mm 155 grain LR SMK (9570), that doesn't seem to be sold now (was it very popular?), most of the 155-160 gr bullets used in the 6.5x55 are no longer, or even shorter than the 142 gr SMK, as they tend to be hunting bullets. So these are even more stable, as the weigh has increased but the length has not increased and in some cases, decreased. This as (gyroscopic) stability goes up with the mass, if the projectile stays the same length and travels at the same spin rate. So, unless the rifle has a 1:7.5" twist as recommended, there may be stability problems from the common 1:8" twist barrels.

 

Though a bit heavy for the 6.5 mm Creedmoor, their load data gives top speeds in a 24" tube, around 2,700-2,800 fps, so no slouch. Through a longer tube (26-28"), this range should be more easily attainable with the right powder selection, but it's pushing it to it's limit.

 

I agree with you though, it's perfect for the 6.5x284.