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Sierra 6mm 107HPBT Matchking caution

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K31Scout

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Dec 19, 2010
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#1
Bought from Midway, Sierra makes 2 versions of this bullet. I ordered (and returned) a 250 count box and they have 107gr HPBT-CN on the box. Product #1570MP. These are a copper/nickel jacket and seat .020" deeper in my chamber according my Hornady gauge. Midway does not say anything about the copper/nickel. The are a dull copper color and the ogive is obviously different.

My 100 round boxes I've been using are #1570 and have no CN.

I would have tried them but I have a great load worked up with the all copper jacket #1570 tuned up for a set COAL.
 
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#3
It's a different construction and shape. It's Copper-Nickel product number #1570MP.
The bullets I've been using for years are copper jacket only, no nickel product number #1507.
I sent them back, otherwise I'd take a picture but they are obviously different.
 
#4
K31Scout said:
Bought from Midway, Sierra makes 2 versions of this bullet. I ordered (and returned) a 250 count box and they have 107gr HPBT-CN on the box. Product #1570MP. These are a copper/nickel jacket and seat .020" deeper in my chamber according my Hornady gauge. Midway does not say anything about the copper/nickel. The are a dull copper color and the ogive is obviously different.

My 100 round boxes I've been using are #1570 and have no CN.

I would have tried them but I have a great load worked up with the all copper jacket #1570 tuned up for a set COAL.
Click to expand...
CN stands for Closed Nose.
 
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#5
Serria jackets are all the same composition, 95% copper and 5 % zinc.
The lead alloy ...or pure lead adds or detracts from the bullet hardness, depending on use, or recommendation...hunting or target.
The "C" or "CN" suffix is the closed nose design, which brings a higher BC to the bullets.
I like them and prefer them in various calibers...
 
#6
Here's an explanation on the #1570MP. It's not the same bullet as the #1570. The ogive is the biggest difference.

  • 1570 (Standard MatchKing):
    This bullet is a well-established and respected design known for its accuracy and consistency in competitive shooting, especially in high-power and silhouette competitions says OpticsPlanet. It's a boat-tail, hollow-point bullet designed for accuracy and long-range performance.

  • 1570MP (MatchKing with Modified Ogive):
    The "MP" designation likely refers to a modification of the bullet's ogive, or the curved section of the bullet from the tip to the base. Some users have found that a particular pointing system, used on the 1570MP, creates a less uniform ogive, which could lead to reduced performance compared to a different pointing system. This might affect aerodynamic performance, particularly at higher velocities.

  • Possible benefits of the 1570MP:
    While the 1570MP's ogive may be less uniform than the standard 1570, some users may find the 1570MP more suitable for specific competitions or with particular pointing systems, as it might be designed for specific ballistic characteristics.
In essence, the 1570MP is a variant of the 1570, with the primary difference being the modified ogive, which could impact its performance in specific situations.
 
#7
K31Scout said:
Here's an explanation on the #1570MP. It's not the same bullet as the #1570. The ogive is the biggest difference.

  • 1570 (Standard MatchKing):
    This bullet is a well-established and respected design known for its accuracy and consistency in competitive shooting, especially in high-power and silhouette competitions says OpticsPlanet. It's a boat-tail, hollow-point bullet designed for accuracy and long-range performance.

  • 1570MP (MatchKing with Modified Ogive):
    The "MP" designation likely refers to a modification of the bullet's ogive, or the curved section of the bullet from the tip to the base. Some users have found that a particular pointing system, used on the 1570MP, creates a less uniform ogive, which could lead to reduced performance compared to a different pointing system. This might affect aerodynamic performance, particularly at higher velocities.

  • Possible benefits of the 1570MP:
    While the 1570MP's ogive may be less uniform than the standard 1570, some users may find the 1570MP more suitable for specific competitions or with particular pointing systems, as it might be designed for specific ballistic characteristics.
In essence, the 1570MP is a variant of the 1570, with the primary difference being the modified ogive, which could impact its performance in specific situations.
Click to expand...
I spoke to Sierra today and they told me that the 1570 is a closed nose bullet and that the 1570, 1570C and 1570MP are all the same bullet.
 
#8
Last few years I purchased nothing but SMK with closed nose design.
They are better than the old SMK ballistically.
In many cases the old design has been phased out, and I prefer them in other calibers too, like 6.5 and 308.
 

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#10
The top two boxes are not closed nose bullets, regardless of the C on the label, but the bottom one has the 9 twist recommendation, and that is the clue,... and it's a closed nose design.


The next two the 169 gr and 177 gr say CN on the box and they are closed nose design.

A faster twist on the box indicating a closed nose design with a long profile ogive...like these 200 gr and 230 gr 308s requires a fast twist.

Get to know thy bullets, and read descriptions when ordering. Old boxes new boxes, big difference in BC, profile, and twist needed in some cases.
 

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#16
6brshooter said:
Jumped up Jesus, that's got to be hot as shit! Pretty sure 6 dasher is usually in the 2975-3025fps range. How long after firing until you can touch cases?
Click to expand...
Yep, pretty zippy that's Alpha brass....but if ya want to go over 3200 fps with the 107 SMK ya need some hybrid cases with LR primers.

Here are some 6 Dasher hybrid LR primed cases being fireforned with Varget. Probably the first ever successful 6 Dasher hybrid cases in existence...for going really fast.
 

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#18
I'm not trying to be a dick, and I've got a 140eldm 6.5creed load that's running 2890 in a 26" barrel with lapua brass. Just gotta remember there is some people on here that don't test, they just go to mach Jesus cause they saw someone else get that speed. Not knowing what freebore/action/bore dia is used, can cause some body to eat a bolt.
 
#19
TO be clear on the "C", when the C is part of the part number as in 2200C it is a 250 or 500 round packaging. When it shows up as "Hollow Point Boat Tail - Closed Nose (HPBT-CN)" in the description the part numbers will be different if the size was the same as a different design.

The first bullets to use this closed nose were the 177 and 169 SMK. The bullets at that time did not contain a different description. Sierra has since revised the description to included the CN designation and the newer Matchking bullets are of this type. I believe the 107 has always been of the CN design.
 
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#21
The older 107smk were an open tip design and had a g1 of .529. About 5 or 6yrs ago they made them closed nose and bc bumped up to .547. That number and the older number, with open tip, were spot on in several rifles.
 
#22
6brshooter said:
I'm not trying to be a dick, and I've got a 140eldm 6.5creed load that's running 2890 in a 26" barrel with lapua brass. Just gotta remember there is some people on here that don't test, they just go to mach Jesus cause they saw someone else get that speed. Not knowing what freebore/action/bore dia is used, can cause some body to eat a bolt.
Click to expand...
With hybrid cases I've ran 140 gr bullets to 3152 fps in 6.5 CM with a 24" barrel. I have a new 26" ready to replace the factory 24".
I usually run the heavier bullets around 3000 fps the 147 eldm, 150 gr SMK a favorite, and the 153 Atips, is where the accuracy is at.
Case necks are fully machined including the shoulder angle with a tight radius in the neck shoulder junction, to eliminate any tight spots in that area.
The 308 with hybrid cases totally smokes the 6.5 CM in standard form. There is no way to achieve the energy delivered to the target with the 6.5 with the 308 running over 3800 ft/ lbs of energy and hitting 4000 ft-lbs. In long barrels. And bullets with .8 plus g1 BCs available in 308, like the 230 and 250 Atips.
So that's why the hybrid cases are used in every caliber including 6.5 CM to bring it up to speed.
 
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