Sierra .270 175gn Tipped Game King

Lou270

Member
Joined
Jan 1, 2006
Messages
21
Have some for my 270 wsm 1-8. Not tried them yet. Midway has or at least had them in stock. They are long - about 1.63

Lou
 

Calvin45

Well-Known Member
Joined
Apr 13, 2019
Messages
832
Location
Nipawin, Saskatchewan, Canada
I was excited by these...at first. But if you look at the picture on sierras site you’ll find it’s just the 140 TGK with the bearing surface area stretched longer, the boat tail and ogive are exactly the same. Time and again it has been shown that simply making the cylindrical portion/bearing surface/whatever it’s called :) longer while leaving all other dimensions/proportions the same gains little bc in comparison to the velocity reduction caused by the extra weight. The 140 tgk has a bc of .500 and the 175 only manages .560. That’s a 25 percent increase in weight for a 12 percent increase in bc. It’d take a long long distance and require very fast initial launch speeds to catch up....
 

Lou270

Member
Joined
Jan 1, 2006
Messages
21
They are advertising the bc at .616. However, I agree the BC could be higher. If the nose is more aggressive like a berger it would require a longer OAL and not fit in short action/be finicky to reload. Winchester/Browning said wanted the heaviest/highest BC (min .6) could fit in a short action and get good velocity and not be finicky. There are already plenty of super long heavy 7mm bullets can do custom loading for in a long action. I am not advocating just stating what they said as their design parameters. As an example I have a 270 WSM 1-8 twist on Kimber action. With Berger 170 EOL to the lands with the berger is 3.06 (going from memory but it is at least 3.06). With the 175 Matrix it is 2.96 and incidentally the 165 ABLR is also 2.96. If optimize for BC, the ogive could be made longer but would be even longer jump to lands / finicky staying at 2.95" for cartridge.
 

Calvin45

Well-Known Member
Joined
Apr 13, 2019
Messages
832
Location
Nipawin, Saskatchewan, Canada
I’m not sure where the .616 bc number you mention comes from but this is straight from Sierra’s website regarding the projectile. To be honest if it was running at .61 that’d be a good bit more appreciable benefit but it would seem they’ve revised their figures or someone other than Sierra is advertising it differently. Not trying to be nit picky just citing where I’m getting my numbers from
 

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Lou270

Member
Joined
Jan 1, 2006
Messages
21
I think the lower number on sierras site is due to low velocity. If look at other offerings they are higher as velocity goes up. Here is one ex of 616 number
 

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