number crunchers what did i miss

[codyadams]

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

If you look at my chart I posted, it shows it staying supersonic past 2000 yards with the 230@2900 fps. That is set at my current atmosphere here at 6600 ft in Wyoming. Altitude makes a massive difference in long range performance!!! Ha ha.

 

[Silly_Ghillie]

That is set at my current atmosphere here at 6600 ft in Wyoming. Altitude makes a massive difference in long range performance!!

I'm living at about the same altitude in CO- That extended super sonic range is fantastic at these altitudes. I sometimes go up to 9000+ and do some mountain plinking and it amazes me how much more I can squeeze out. wind has a substantially lesser influence at high altitude as well, which is good for you considering the dang wind up there never drops below 100mph.

 

[codyadams]

I'm living at about the same altitude in CO- That extended super sonic range is fantastic at these altitudes. I sometimes go up to 9000+ and do some mountain plinking and it amazes me how much more I can squeeze out. wind has a substantially lesser influence at high altitude as well, which is good for you considering the dang wind up there never drops below 100mph.

Know how that goes, our camp for high mountain mulies and elk is similar, our camp is at a mountain top at 10,050 ft, and we glass stuff from about 8,750 up to the top of a big peak that is about 11,000. Running the numbers up their for wind is entertaining, our area was nice last year, I had a no wind call shot at my mulie at a little over 500, was a done deal before I pulled the trigger!! I love it up there.

 

[Bro Dave]

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. View attachment 134695

nice graph

 

[Bro Dave]

I am curious. How do you keep pressures within specs with a 230gr bullet at 2900fps?

 

[Stgraves260]

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

Yeah mine is 1775 Yard at 1200ft above sea level. I'm even giving the bullet 3000 FPS. He must be really high in altitude.

 

[ar10ar15man]

the gun in question is a NAVY SEAL MK13 sniper rifle/loose clone. the basic ammo is a 220 smk at 3.5 oal, fed brass, h1000 powder, nickle mag primer(mk248 nod1). the pressure limit for this cartridge 681xx psi in a stiller action and a lilja bbl at 26-26.5" with a suppressor added.
they use a shorter newer rifle now and do 2800 from a 24". while i did work up a load with the 220, i am not limited to USA powders as the mil is, and i went with the berger 230 and rl26. getting .6 at 200 yards and 2910 for velocity. that was in colorado, matches at raton and montana.
the new rifle was an opportunity to try a natch chamber with a solid. may not work out if the bc is too low.

I am curious. How do you keep pressures within specs with a 230gr bullet at 2900fps?

 

[Bro Dave]

the gun in question is a NAVY SEAL MK13 sniper rifle/loose clone. the basic ammo is a 220 smk at 3.5 oal, fed brass, h1000 powder, nickle mag primer(mk248 nod1). the pressure limit for this cartridge 681xx psi in a stiller action and a lilja bbl at 26-26.5" with a suppressor added.
they use a shorter newer rifle now and do 2800 from a 24". while i did work up a load with the 220, i am not limited to USA powders as the mil is, and i went with the berger 230 and rl26. getting .6 at 200 yards and 2910 for velocity. that was in colorado, matches at raton and montana.
the new rifle was an opportunity to try a natch chamber with a solid. may not work out if the bc is too low.

Thanks. Good answer. taking it to 68+++ with a 26" barrel is key.

 

[fiftybmg]

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

That statement on it's own is misguided, and serves to muddy the minds of the young. It requires distance for context.

Heavier bullets at higher BC intersect with lighter bullets with lower BC somewhere far downrange. Do the math, and be surprised.

 

[HobieH3]

I'm living at about the same altitude in CO- That extended super sonic range is fantastic at these altitudes. I sometimes go up to 9000+ and do some mountain plinking and it amazes me how much more I can squeeze out. wind has a substantially lesser influence at high altitude as well, which is good for you considering the dang wind up there never drops below 100mph.

Been there. Amazing how something that seems not exist when you're trying to breathe can blow right through you...

 

[codyadams]

That statement on it's own is misguided, and serves to muddy the minds of the young. It requires distance for context.

Heavier bullets at higher BC intersect with lighter bullets with lower BC somewhere far downrange. Do the math, and be surprised.

The only aspect that they intersect in (for hunting purposes) is velocity, and when they intersect the heavier higher bc bullet begins to have more velocity. This happens around 200-700 yards depending on many different things. The lighter bullet going faster will have less drop for essentially all hunting purposes, but this is only usefull if you want the farthest point blank range. So outside of roughly 400 yards or so, where pretty much any cartridge/bullet combo is going to begin to need correction, the lighter bullet looses all benefits it may have at one point had. Also for elr, the heavier bullet does again intersect with the lighter, because the heavier bullet begins to have less drop. This can be 1500 yards or farther however.

The heavier high bc bullet always has more energy and less wind deflection than lighter faster lower bc.

There is of course a bell curve to this. Too heavy for a certain cartridge looses the benifits because it cannot be propelled fast enough. If you try to shoot the new 250 grain a-tip in a .308 win at approximately 2000 fps (estimation) , your results will likely not be as beneficial for long range as shooting a 215 at 2550 fps.

This all must be looked at objectively. If it were possible to shoot a 125 grain bullet with the same bc as the 215 berger in a 300 wm, the long range performance would be outstanding, with the only lacking factor possibly being energy. This is likely beyond the ability of physics however. All data points must be quantified and added up to see what performs the best.

 

[fiftybmg]

The heavier high bc bullet always has more energy and less wind deflection than lighter faster lower bc.

No. Only if the velocity says so.

And energy in itself is just a number, it is not an indicator. The graph presented early in the thread shows two lines that differ mathematically, and that difference may or may not reflect the reality of what's happening downrange.

 

[codyadams]

No. Only if the velocity says so.

And energy in itself is just a number, it is not an indicator. The graph presented early in the thread shows two lines that differ mathematically, and that difference may or may not reflect the reality of what's happening downrange.

Can you show me a practical instance where a lighter faster lower bc bullet has more energy and less wind drift than a heavier higher bc bullet in the same cartridge?

 

[codyadams]

Here is a very dramatic comparison for you. A 110 v-max at 3800 fps vs a 215 Berger at 2950 fps. As I stated, the heavier higher bc bullet has less wind drift and more energy from the start. And catches up in velocity in less than 500 yards. The only thing the lighter bullet gains is less drop, which is relatively neglegable for long range. However very useful for sub 400 yards varmints.