#10MinuteTalk

G1 and G7 BC’s - what the heck are they and which number should I plug into my ballistics calculator to get the best drop and wind drift solutions? Mark Boardman grabs Reuben Aleckson and Ryan Muckenhirn to get the 411 on G1 and G7 BC’s.
As always, we want to hear your feedback! Let us know if there are any topics you'd like covered on the Vortex Nation™ podcast by asking us on any one of our social media platforms and using #VortexNationPodcast.
00:00 - Intro
1:33 - G1 vs G7
6:05 - Is a higher BC Better?
8:36 - Wind Deflection
11:01 - Using the G1 vs G7
14:13 - Multi BC
15:31 - Ballistic Solvers
20:45 - G1, G7 Drag Models and Truing
25:26 - Closing Thoughts
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[@connerchatelain6383]

This podcast helped me figure out why my data was so messed up at a DMR match a few months ago. I was shooting 2-3 moa flatter than what my calculator said at distance, and just couldn’t figure it out. Just used the G7 BC in my ballistic app, and it shows exactly what I was observing at the match!

[@jaredfuller1729]

Ruben is a great podcaster, wish he could be on every episode.

[@cloojure]

Don't forget that weight/mass of the projectile is an important component of BC. The two bullets shown have near-identical outside shape, but the lead-core bullet is approx 20% heavier. *THAT* is why the lead-core bullet has a higher BC than the all-copper bullet.

[@nathanhumphrey354]

This was a good one. As soon as it dropped I knew I had to watch it ASAP.

[@TMar129]

Always love these podcasts. Well done fellas

[@natebennett6840]

This definitely helped clear up a lot for me. Biggest take away as a hunter - ground truth your equipment and verify everything based on bullet construction and its intensions - G7 sounds like its more dependent on standard shape when shooting WAY too far to ethically harvest animals, but is there in case you want to hit a target with the right calls after it goes transonic. Good stuff for the layman. % × ÷ 🧠

[@DLN-ix6vf]

I use to watch these videos when they were truly 10 mins. one I looked at earlier was 1.5hrs.

[@Dmounts]

I was happy when I found out the difference!

[@Joeatsaco69]

Multiple points here from different references. 1. In the Berger manual the way I read it was that the G1 is for more traditional bullets and the G7 is for (like y’all said) the higher performing bullets. But also that the G1 is based on the bullet at the muzzle. Many different MV will change the BC. If you run a G7 its at envy velocity. So someone please correct me if I understood that wrong. 2. A heavier bullet will have a higher BC because it can buck=k the air better but it will also be at a slower MV because of the weight. This is all dependent on if you run the load at a lower node vs a mid load vs a higher node. The Node selections should also be in the same realm. 3. Then we get to a lighter faster bullet or a heavier slower bullet with different BC… the more time it spends in the air (MV) the more time effects have vs the faster bullet spends less time so less time to be effected. I guess the real conversation and choice would be at what range to you expect to have a max range and then decide on the bullet. It gets deep. But great conversation. I love to get opinions on the science of it. I am the bullet geek that reads the front of he manuals and not just the data within.

[@carlpreston1680]

Manufactures also use G1 numbers on non G1 bullets because the numbers are higher and it looks better for sales also I think Barnes rates there BC numbers at 300 yards versus other companies rate them at 200 or 100 yd

[@jfess1911]

The G1 BC of a sleek bullet varies with the bullet velocity because the bullet is not shaped the same as the model (the model has a flat base, fairly short ogive). What matters is that the BC you are given is in the velocity range you are using. If they give the BC of a bullet from a 300 Win mag, it won't be accurate for the slower 300 Savage, for example.

[@Joeatsaco69]

There ya go. It’s all about at what rage and speed at the muzzle or distance was it measured. I thing it should be standardized on the box at the muzzle or 100, 200 etc. so we can get apples to apples. I know that I always work off my BC calculator and then true it with what my MOA is in actual findings as rifles as well as the data given fluctuates.

[@tmager2545]

Mark and those print outs lol

[@travissmith-wz5nc]

Boys are putting out great content

[@jfess1911]

BC is defined as a form factor multiplied by the sectional density. Two bullets can have the exact same shape (form factor), but different BC's if one is heavier Copper is less dense than lead, so a thin-walled cup and core bullet that is mostly lead will will weigh more and have a higher BC than an an all copper bullet of the exact same shape. Things get a little fuzzier with bullet designs that have a lot of copper and relatively smaller fraction of lead, like the Terminal Ascent bullets. They end up somewhere in between.

[@bobbysusenbach9687]

Is the GA category for airgun projectiles (diablo shaped pellets)?

[@amn1308]

Can't get away from discussing drag models even watching gun videos. But June is almost over.

[@colinw2104]

Always use G7. Bryan Litz from Applied Ballistics would agree with me.

[@jamses23]

We need an episode where Ryan talks about the 16” 50 Caliber MK 7 rounds.

[@coryk6839]

OOOOH, bringin in the heavy hitters

[@justahologram2230]

Now I'm wondering if a faster than standard/recommended barrel twist or at least a gain twist that ends up there would help the older lever gun rounds. A .45-70 will be lethal as long as you connect with the target so if more aggressive twist would help stabilize it through the trans sonic barrier, why not?

[@jaydunbar7538]

Faster twist requires the bullet to be harder to handle the forces, which is not ideal for a slow moving projectile in most hunting scenarios. While it certainly could help the long range accuracy, the question then becomes if your trying to use a hammer to tighten a screw instead of just grabbing the proper tool.

[@justahologram2230]

@@jaydunbar7538 I've seen 400gr solid copper hollow points claiming to be designed for subsonic use, I would hope that a similar philosophy to the twist of the 8.6blk could be applied to older slow rounds using copper bullets

[@thestrawberrypatch5644]

You can do all the math in the world and maybe it's right but you need to verify your temperature sensitivity for your powder with a chronograph and verify your scope before you go with your calculated values. You should also verify your calculated values to determine error and apply to your table.

[@z987k]

Ryan, you can have that Barnes performance with really high BC's. Badlands bullets.

[@johnl5974]

My 308 - 168 match is close to G7, the 175 is close to G1 - very confusing. Good episode, thanks.

[@charlesludwig9173]

Yeah, G7 gives impression that the 175 is like a laser in wind. With G7 I get an MOA wind constant of about 20 at 1000 yards when the truth is an MOA wind constant of 10 as proven in NRA Long Range Competition where I shoot in High Master Classification.

[@jfess1911]

The basic equations assume that your bullet is shaped like the model. If you ever cover this again, just show pictures of the bullets used for G1and G7 models. If the bullet looks more like the G1, use that model, if it looks more like the G7, use that model.

[@joshuadavis5923]

I don’t quite understand the reluctance to use a g7. It seems if I were looking at a bullet that seems it would benefit from a g7 I wouldn’t be asking why I can’t use a g1. Any reason Ryan tends toward a g1?

[@chadillac95]

I wish you guys would've talked about how the posted BC on a box of factory ammo is only accurate at the posted velocity

[@dethmgnt4257]

That doesn't make any sense, you can buy projectiles separate from the rest of the catridge components and they still have the same B.C. on the box.

[@chadillac95]

@dethmgnt4257 that's correct. I'll give you an example since I was just looking at this bullet vs. this cartridge. Barnes LRX 190 gr. 30 cal projectile has a BC of .541. That's just the bullet for reloading. A box of barnes vor-tx 300 win mag 190 gr LRX has a BC of .499. That's for a box of ammunition. Why? If I had the answer, I wouldn't want them to go into depth about it

[@jamesjams5085]

Just how cold is it in that studio?

[@justme294]

👍🏼

[@matthewgroseclose4973]

25 Creedmoor

[@charlesludwig9173]

So far G7 does not sync with good MOA wind constant for .223 77 grain and .308 175 grain match bullets. It is double the reality and thus only half of needed adjustment for wind and a miss for sure at long range from any wind.

[@ronaldsloan5235]

Wow. I should have taken Physics

[@JVR-gd7zw]

Drag coefficient

[@jaypee389]

136gr .375 Raptor @ 3300fps is better then a 147gr 6.5 Creedmoor inside 400m. SR25. 16 inch. Comped.

[@rman713]

For some reason Reuben makes me think of a South Park character

[@JacobTerherst]

Hornady 4DOF or nothing.

[@colefahey9032]

This isn't Hornady

[@jaydunbar7538]

Do you not think precision scope makers have just as much interest in such topics as a precision bullet manufacturer? They go hand in hand

[@vincentc3286]

Don’t use either. You should be using the custom curve for your projectile.

[@amym828]

G1 for flat base projectiles, G7 for boattail projectiles, it couldn't be easier folks

[@charlesludwig9173]

But it is wrong, delivers exaggerated MOA wind constants for many VLD’s shot at LR. G7 tells me M118LR at 2610 fps has a constant of about 20 at 1000 yards when G1 says 10, which is correct. I get similar distortions from G7 shooting 77’s from 223 at LR.

[@gushughes3689]

First