Bullet weight, how big can you go?

[Punisher]

Maybe I don't understand your post or charts but are you using about 2950 FPS and identical conditions for each bullet? If you are, the math isn't correct on the results.

No, I can't push a 180 gr VLD at 2950 without flattening primers. I backed it off to about 2840.

Both loads are just under max pressure for the cartridge, and both shoot very well in my gun. But the 168 is outperforming the 180 in both wind and drop.

 

[Edd]

What does that 2946 in your first chart represent?

 

[KYpatriot]

Nobody cares about drop. There should be little to no uncertainty about the drop on a long range shot if you care about precision. It's all about wind, there is always uncertainty there. The heavier bullet will have similar wind performance, and will eventually at long enough range best the wind drift of the lighter bullet, and have more energy while doing so.

If you are taking point blank shots or shooting within the crossover range where the time if flight isn't long enough to show the difference then yes it doesn't really matter.

But today we are blessed with long range bullets with superb ballistic characteristics (form factor) and the higher bc will win out given enough range. As noted, the only disadvantage us that it will drop more, but no credible long range hunter or target shooter is guessing on drop anyway so that becomes a moot point.

I think the op is saying that in his rifle he cannot get the 180s to a speed high enough to overcome the velocity advantage the 168s start with. While that may be true for him, many are shooting the 180s at a speed high enough that they show an advantage sooner, though they still start out slower than the 168. The 168 is a superb bullet, and the difference in BC isn't that great anyway.

 

[Punisher]

What does that 2946 in your first chart represent?

Corrected average bullet speed for ambient temperature that day. I got 2953 when I calibrated my velocity, but atmospheric conditions were automatically compensated for.

 

[Punisher]

Nobody cares about drop. There should be little to no uncertainty about the drop on a long range shot if you care about precision. It's all about wind, there is always uncertainty there. The heavier bullet will have similar wind performance, and will eventually at long enough range best the wind drift of the lighter bullet, and have more energy while doing so.

If you are taking point blank shots or shooting within the crossover range where the time if flight isn't long enough to show the difference then yes it doesn't really matter.

But today we are blessed with long range bullets with superb ballistic characteristics (form factor) and the higher bc will win out given enough range. As noted, the only disadvantage us that it will drop more, but no credible long range hunter or target shooter is guessing on drop anyway so that becomes a moot point.

I think the op is saying that in his rifle he cannot get the 180s to a speed high enough to overcome the velocity advantage the 168s start with. While that may be true for him, many are shooting the 180s at a speed high enough that they show an advantage sooner, though they still start out slower than the 168. The 168 is a superb bullet, and the difference in BC isn't that great anyway.

I am highly concerned with drop! The less drop my load gives the more forgiving that load will be if my range wasn't that good on the target. Or the target is moving slowly.

I am suggesting that a 180 gr bullet is not just too heavy for me to ge to perform as well as then168, but it is too heavy for the cartridge, being 7mm Rem Mag. The further out I go, the worse the performance is getting. Maybe a 7mm STW would be better for that bullet.

 

[elkaholic]

I haven't read thru all the posts carefully, so I may have missed this being covered? Obviously, b.c. is important when talking long range, and energy is to a point. Here is what I think is often overlooked. When I started making my own bullets several years ago, I began to pay a lot more attention to the velocity needed to open a particular design of bullet on game. This is why I am such an avid proponent of bullet testing! You may find that a certain heavy bullet will have more energy, and a higher b.c. than one which is 10 grains lighter , but lacks the velocity needed to expand the bullet at a given distance. Energy is not the primary contributor to killing power. Tissue damage is! A bullet which expands with 200 ft/lbs. less energy that one which pencils through, I will take EVERY time! There is never a pat answer to what is better. You have to answer several questions before that can be determined. In summary, heavier, even with a higher b.c., is not always better, particularly at long range..........Rich

 

[blksno]

I don't deal in theoretical velocities. I deal in actual velocity at the most accurate load for each bullet.
For instance.

In my 7mm Match with RL33.
My most accurate load with 180 VLDs was 3105 with no pressure signs.
My most accurate load with 180 Hybrids was 3066 with no pressure signs.
My most accurate load with 168 VLDs was 3030 and ran out of case capacity.

At 1000 yds with a 10mph full value wind (at my location)
180 Hybrids delivers 1352lbs of energy and takes 6.4 mil of elevation and 1.4 mil of wind
180 VLD delivers 1381 of energy and takes 6.3 mil of elevation and 1.4 mil of wind
168 VLD delivers 1117 of energy and takes 6.9 mil of elevation and 1.6 mil of wind

Now those VLD numbers are almost the same as the Hybrid numbers...but the Hybrids are just easier to fine tune the seating depth.

The amazing thing is...the exact same charge weight, and die setting is used for all three of those loads. Seating depth is different obviously...but I don't adjust my dies at all.

So if I run short on bullets, which shouldn't be an issue, I can just load up some 180 or 168 VLD loads and run with it.

 

[KYpatriot]

I am highly concerned with drop! The less drop my load gives the more forgiving that load will be if my range wasn't that good on the target. Or the target is moving slowly.

I am suggesting that a 180 gr bullet is not just too heavy for me to ge to perform as well as then168, but it is too heavy for the cartridge, being 7mm Rem Mag. The further out I go, the worse the performance is getting. Maybe a 7mm STW would be better for that bullet.

Maybe so, but I shoot them at 3015 from a 7 rm. Anyway, I seriously doubt you will see a difference unless you can call the wind to 1 mph.