bullet comparisons

[mitchellchandler_au]

Hi all,

I was wondering if there is a bullet that will match the 175SMK for drop and wind drift out of a 308 win. The 175 SMK have reached the $60-$75 mark in aus and iam looking for an alternative bullet to use.

Thank you

 

[sewwhat89]

What about 155 Scenar? Or the Berger 168 and 175 VLDs?

 

[ThunderDownUnder]

Matching drop and wind drift is all about BC. I looked up the G7 BCs of a few projectiles that should be available to you and have listed them below. The 155gr bullets can be run at higher velocities and match the ballistics of the heavier bullets.

I recommend buying Bryan Litz's new book,Applied Ballistics For Long Range Shooting) and evaluate for yourself a better replacement for the SMK. All the G7 BCs I have quoted have come from Bryan's book!

Current bullet Sierra MK 175gr BC = 0.243

1. Berger VLD 175gr BC = 0.255,probably the most expensive)
2. Hornady Amax 175gr BC = 0.240
3. Lapua Scenar 185gr BC = 0.247
4. Lapua Scenar 155gr BC = 0.236
5. HBC 155gr BC = 0.236,local manufacture, best price)

Lapua and HBC would be easiest to locate and buy in Oz then Hornady and Sierra are pretty good with Berger having the least presence and highest cost.

 

[Asscott4]

Matching drop and wind drift is all about BC. I looked up the G7 BCs of a few projectiles that should be available to you and have listed them below. The 155gr bullets can be run at higher velocities and match the ballistics of the heavier bullets.

I recommend buying Bryan Litz's new book,Applied Ballistics For Long Range Shooting) and evaluate for yourself a better replacement for the SMK. All the G7 BCs I have quoted have come from Bryan's book!

Current bullet Sierra MK 175gr BC = 0.243

1. Berger VLD 175gr BC = 0.255,probably the most expensive)
2. Hornady Amax 175gr BC = 0.240
3. Lapua Scenar 185gr BC = 0.247
4. Lapua Scenar 155gr BC = 0.236
5. HBC 155gr BC = 0.236,local manufacture, best price)

Lapua and HBC would be easiest to locate and buy in Oz then Hornady and Sierra are pretty good with Berger having the least presence and highest cost.

I have a question. are you talking about Ballistic Coefficients because if so, the number you have down doesn't match the BC of the bullet on Sierra's website. Sorry to butt in but I would like to know. The sectional density of the bullet is .264 and the BC of the bullet is .505 @ or above 2800fps and .496 between 2800 and 1800fps. I;m not trying to call you out I would just like to know why the numbers are way different than the numbers posted on Sierra's site. If im wrong please set me straight! Thanks!

 

[ThunderDownUnder]

Asscott4, I have quoted G7 BCs not G1 like Sierra have listed. Its easy to get confused if you think the numbers quoted are G1. G7 BCs more realistically match long range projectiles and offer more accurate analysis for ballistic curves. I recommend you buy the book I mentioned above and have a read.

Have a quick read about G1 vs G7 here: http://02b0516.netsolhost.com/blog1/?p=62

Get used to G7 BCs being given as this is the direction the industry will take for long range projectiles!

The G7 BCs I have quoted, more accurately compare the bullets than G1, BC numbers. The comparisons I have given above of projectiles is correct and available in Oz.

 

[Bryan Litz Ballistics]

Thunder,

Thanks for the references.

One important thing to keep in mind about G1 vs G7 BC's when running ballistics programs is that if you input a G7 BC, you need to indicate that. Not all programs accept G7 BC's but some do. One great program is the free, online ballistics software by JBM:
http://www.jbmballistics.com/~jbm/cgi-bin/jbmtraj-5.0.cgi

You can select G7, then input a G7 BC. If you try to use a G7 BC in a program that cannot accept them, it will just interpret the G7 BC as a G1 BC, and the output will be garbage.

Hope this helps,
Bryan

 

[Asscott4]

Asscott4, I have quoted G7 BCs not G1 like Sierra have listed. Its easy to get confused if you think the numbers quoted are G1. G7 BCs more realistically match long range projectiles and offer more accurate analysis for ballistic curves. I recommend you buy the book I mentioned above and have a read.

Have a quick read about G1 vs G7 here: http://02b0516.netsolhost.com/blog1/?p=62

Get used to G7 BCs being given as this is the direction the industry will take for long range projectiles!

The G7 BCs I have quoted, more accurately compare the bullets than G1, BC numbers. The comparison I have given above of projectiles stands as being factual and available in Oz.

Oh right on i appreciate the information. I was unaware of that. thank you for setting me straight lol!

 

[mitchellchandler_au]

Hi all,

I have been trying the 167 scenar and was wondering what the G7 for them are. and if anyone is or has used them in the 308win what is your opinion and some loads for them.

Thanks,

 

[TonyR]

Bryan Litz lists the average G1 BC at .423 versus the published Lapua value of .470. Bryan lists the average G7 BC as .216. Page 503 of Bryan's new book. Lots of useful stuff like this in there.