Can someone help expand my knowledge of BC?

[LRS_Ranger]

If you have 2 bullets with the same BC, and you launch them at the same speed, they should have the same drop and retained velocity regardless of weight right?

For instance, a 155 Scenar and 175 SMK have just about the same BC, so why do people feel the need to get the 155's up to 2900+, where as 2700 is acceptable for the 175. I know that we all want the best possible performance, but a 155 and SMK at the same speed should hold just about the same dope, elevation wise right? I know the 175's should buck the wind better though.

Also, can anyone point me to a good read on the difference between G1, G2, G5 etc?

If this has already been hashed up or discussed, please point me to that thread, but I couldn't find what I was looking for with the search. Thanks for the help!

 

[thekubiaks]

Re: Can someone help expand my knowledge of BC?

Here you go

http://www.eabco.com/store/products/Appl...tz-1943-58.html

 

[LRS_Ranger]

Re: Can someone help expand my knowledge of BC?

I think I'll order one of those.. Thanks.

 

[Powder_Burns]

Re: Can someone help expand my knowledge of BC?

Theres a 2nd edition coming out sooner or later, keep your eyes out for it.

 

[TiroFijo]

Re: Can someone help expand my knowledge of BC?

Same BC and velocity = same trayectory and wind drift

the trick is using an <span style="font-style: italic">accurate</span> BC for the bullet

 

[HillbillyfromAL]

Re: Can someone help expand my knowledge of BC?

The heavier bullets are pushed slower, but retain their velocity longer. The reason you'd try to push a bullet as fast as possible is simply to minimize the affects that environmental conditions have on the bullet. If you could push a 175 at 2900 then you'd probably want to.

 

[9H_Cracka]

Re: Can someone help expand my knowledge of BC?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LRS_Ranger</div><div class="ubbcode-body">

For instance, a 155 Scenar and 175 SMK have just about the same BC</div></div>

Right there is the start of your problem Sir - they have the same ADVERTISED BC, not the same ACTUAL BC. The 175 is good, the 155 Scenar is overstated. It is down in the .480s with the rest of the good 155s - Berger 155.5 Fullbore, Sierra 2156.

Re-calibrate your expectations and understanding around the fact that this is rampant in the industry and it'll make more sense to you.

Oh that and buy Brian Litz's book

http://www.appliedballisticsllc.com/

 

[LRS_Ranger]

Re: Can someone help expand my knowledge of BC?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: _9H</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: LRS_Ranger</div><div class="ubbcode-body">

For instance, a 155 Scenar and 175 SMK have just about the same BC</div></div>

Right there is the start of your problem Sir - they have the same ADVERTISED BC, not the same ACTUAL BC. The 175 is good, the 155 Scenar is overstated. It is down in the .480s with the rest of the good 155s - Berger 155.5 Fullbore, Sierra 2156.

Re-calibrate your expectations and understanding around the fact that this is rampant in the industry and it'll make more sense to you.

Oh that and buy Brian Litz's book

http://www.appliedballisticsllc.com/ </div></div> Thanks, I'll be sure to pick a copy up; looks interesting. Actually, Lapua has the 155 Scenar at .460, people on the 'Hide were saying to use .500 for both the 155 and 175, and JBM uses .508.
If the 155 is under .5 I can see using the 175s for longer ranges. Next range trip I'm trying the 175's at roughly the same velocity.. then I can compare some real world come-ups..

 

[9H_Cracka]

Re: Can someone help expand my knowledge of BC?

Interesting. The last time I looked at the Scenar it was .505. That is what I was basing my statements on.

If you are finding .460 for it and .505 for the 175 SMK, why did you state in your OP "For instance, a 155 Scenar and 175 SMK have just about the same BC"?

 

[LRS_Ranger]

Re: Can someone help expand my knowledge of BC?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: _9H</div><div class="ubbcode-body">Interesting. The last time I looked at the Scenar it was .505. That is what I was basing my statements on.

If you are finding .460 for it and .505 for the 175 SMK, why did you state in your OP "For instance, a 155 Scenar and 175 SMK have just about the same BC"? </div></div> I'll look for the thread, but there was few people on here that agreed .500 is an accurate number for both. I know that advertising is not always spot on, so I was assuming that the guys on here who are actually shooting both of them and analyzing their comeups have the most accurate number. I'll run the numbers against the data I get in the field and see what number I come up with. I guess that's the answer, I just need to shoot more!

 

[EXTREMEPREJUDICE]

Re: Can someone help expand my knowledge of BC?

You can go to the SOURCE!

http://www.appliedballisticsllc.com/ You can not only read it but you'll actually understand it.

He's here, from time to time.

 

[CPRifle]

Re: Can someone help expand my knowledge of BC?

A big +1 to Bryan Litz's book. There is an entire chapter on this topic alone. I can't say enough good things about the book.

After reading the book, you'll never use the G1 standard again... at least I didn't.