number crunchers what did i miss

[ar10ar15man]

i currently shoot a 300 win mag at 3.6xx with a berger 230 at 2900 fps at 2000 yards. it stays super sonic past 2k. it is super sonic starting at 2800 fps past 2k
if i substitute a hornady 220 even at 2900 it is SUB sonic before2k
with a 220 cutting edge (NOT OUT YET) i get the same answer..SUB sonic before 2000.

10 grains of weight, even with a bit more velocity the 220s go sun sonic before 2k.
the cutting edge is 1.8 long solid copper

what am i missing

 

[codyadams]

The issue is not weight but bc. The 230 Berger has a higher bc than the 220 eld-x. And at the same starting velocity, the higher bc bullet (in all cases) will maintain better velocity and less wind drift at range. The weight will only affect energy.

 

[ar10ar15man]

your chart has me confused.
i have his books not his software,
so please explain the 2 sets of lines
and thanks

 

[codyadams]

The dotted line references velocity, represented on the right axis. The solid line references drop, represented (in inches) on the left axis. The numbers on the bottom axis is distance in yards. The blue is the 220 eld-x @2900 fps, the yellow is the 230 Berger @2900 fps

 

[ar10ar15man]

cody, thanks
can you do a" what if" ?
what bc does a 220 need to hit 2000 use both 2800/2900fps
thanks

 

[adam32]

It's all about BC...remember, BC will outrun velocity all day every day.

 

[ShtrRdy]

What I understand is from Brian Litz's books. From those it says Ballistic Coefficient is dependent on the bullets weight. Basically BC is the bullets Density divided by its Form Factor.

Density is the bullets weight divided by its diameter squared

Form Factor is the drag coefficient of the bullet divided by the drag coefficient of the reference bullet ( such as G1 or G7 )

 

[Canhunter35]

The 212 will get farther before going subsonic than the 220. The 225 does even better.

 

[ar10ar15man]

thanks. i was only using them for weight. i think the 230 berger works well. was hoping to jump to solid copper. the 220 ce is not out yet( i have ONE) WAS HOPING TO SHOOT IT AT 2K BUT the bc may not work out...it has not been tested yet and my rifle is nearly complete. got to make some decisions.

The 212 will get farther before going subsonic than the 220. The 225 does even better.

 

[Canhunter35]

thanks. i was only using them for weight. i think the 230 berger works well. was hoping to jump to solid copper. the 220 ce is not out yet( i have ONE) WAS HOPING TO SHOOT IT AT 2K BUT the bc may not work out...it has not been tested yet and my rifle is nearly complete. got to make some decisions.

throated for 225eldm, 230berger, 230smk, and 230 atip would be my choice. Good luck, at least there's many options

 

[Rhovee]

Not sure how your not going transonic before 2k yards. According to my app, shooting a 230 Berger at 3030 goes tipsy at 1850.

 

[ar10ar15man]

my app has it super past 2k
i have shot the rifle a fair bit.
this is my second build as a match chamber, long load and the old build does 2910.
you do not have my parameters so do not see how you did the math. let me know.
and there is no spec that all bullets the go transonic go "tipsy", more like some do
not all

Not sure how your not going transonic before 2k yards. According to my app, shooting a 230 Berger at 3030 goes tipsy at 1850.

 

[ar10ar15man]

navy seal mk13 is throated for the smk220 at 3.5, the berger fits at 3.6

throated for 225eldm, 230berger, 230smk, and 230 atip would be my choice. Good luck, at least there's many options

 

[Rhovee]

I'm just assuming 2900 FPS with a 230 Berger. I have my app at 29 Baro Pressure. You must be higher/lighter than me by quite a bit. I'm at sea level.