204- 40 grain looks much flatter than 50 grain bullets?

[hemiallen]

Doing the math on the 204, I believe a 40 grain NBT can be run to 3800 fps, and from searching the 50 gn Bergers top out around 3300 fps. Using JBM calculator, drop for the 50 grainer is 10" more drop at 600 yds, but 5" less wind drift.

Seems from this math the 50 grain 204 isn't an improvement over the 40 grain bullet ?

Am I missing something, or is the 50 grain bullet too much for the case capacity? My data points are: Zero at 200 yds, and plot to 600 yds every 50 yds.


Thanks for any input


Allen

[Rick in Oregon]

Allen - You'll get alot of input on 204 case capacity using the 50 grainer, but for the record, I'm getting over 3,900 fps in my PN 11-twist 204 Match chamber using both the 39gr SBK and both Nosler and Hornady 40's.

Personally, I consider the case capacity of the 204R lacking for the 50's. A much better choice would be a 20BR, 20PPC, or 20 Dasher. JMO

[hemiallen]

Thanks Rick


Looks like that extra 100 fps gains 3.5" at 600, but truth be told I probably need to stop at 500 yds when I compare them.


Interesting , never thought of the 20 Br but that would fit my SA well...


Thanks

Allen

[moorepower]

The .20-250 would be another.

[Rick in Oregon]

The .20-250 would be another.

Yep, I thought of that after I posted. It may be the better choice because of bolt face issues.

[ClaimJumper]

hemiAllen,

the 50 Berger has a BC of 281

the 39 Sierra BK has a BC of 287

39 = faster bullet with a higher BC

[hemiallen]

Thanks

I never looked at the BC, using JBM allows one to put it on cruise control...


Thanks, makes a lot of sense.

Allen

[Steven]

ClaimJumper,

Think about it for a while...how can a 39g projectile have a BC higher then a 50g projectile of the same calibre....same with the 40g Hornady...a much longer projectile then the Sierra...i think you'll find Sierra's BC is based on theory not fact.

Steve

[ClaimJumper]

Steve,

How do you explain the .224 53 Grain Hornady V-Max and it's 290 BC? it has a higher BC than all the bullets in .224 from 50-65?

Must be a conspiracy? lying bullet makers? Marketing ploy? Missprint? Theoretical guess? This one bullet is a "Game Changer" for the .224 crowd.

My statement said that, "A higher BC results in a flatter trajectory"

Bullet performance explained,

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

The formula for calculating the ballistic coefficient for bullets only is as follows:[1][2]

BC_{Bullets} = \frac{SD}{i} = \frac{M}{i \cdot d^2}

where:

BCBullets = ballistic coefficient
SD = sectional density, SD = mass of bullet in pounds or kilograms divided by its caliber squared in inches or meters; units are lb/in2 or kg/m2.
i = form factor, i = \frac{C_{B}}{C_{G}}; (CG ~ 0.5191)
CB = Drag coefficient of the bullet
CG = Drag coefficient of the G1 model bullet
M = Mass of object, lb or kg
d = diameter of the object, in or m

This BC formula gives the ratio of ballistic efficiency compared to the standard G1 model projectile. The standard G1 projectile originates from the "C" standard reference projectile (a 1 pound (454 g), 1 inch (25.4 mm) diameter projectile with a flat base, a length of 3 inches (76.2 mm), and a 2 inch (50.8 mm) radius tangential curve for the point) defined by the German steel, ammunition and armaments manufacturer Krupp in 1881. The G1 model standard projectile has a BC of 1.[3] The French Gavre Commission decided to use this projectile as their first reference projectile, giving the G1 name.[4][5]

A bullet with a high BC will travel farther than one with a low BC since it will retain its velocity better as it flies downrange from the muzzle, will resist the wind better, and will “shoot flatter” (see external ballistics).[6]

When hunting with a rifle, a higher BC is desirable for several reasons. A higher BC results in a flatter trajectory which in turn reduces the effect of errors in estimating the distance to the target. This is particularly important when attempting a clean hit on the vitals of a game animal. If the target animal is closer than estimated, then the bullet will hit higher than expected. Conversely, if the animal is further than estimated the bullet will hit lower than expected. Such a difference in bullet drop can often make the difference between a clean kill and a wounded animal.

[Steven]

ClaimJumper,

i agree a higher BC will shoot flatter....since you are the mathematician here work it out with your formula and show me us your results...I'm not the sharpest tack in the box but when I put a 39g Sierra, 40g Hornady and a 50g Berger side by side i cant believe what Sierra says their BC is....It might also be a rumour but somewhere on here or another forum someone mentioned Sierra making that BC to correspond with their ballistic program...I will be doing real world tests on these 3 projectiles myself just to satisfy my own curiosity...wont be with a 204 Ruger but a 20ppc as my Bat has a 1 in 10 twist and I can use the one rifle.

Steve

[ClaimJumper]

Seems from this math the 50 grain 204 isn't an improvement over the 40 grain bullet ?

Berger 50 grain "Match" 281 BC
The 39 Sierra Blitz King has a higher BC
The 40's from Nosler and others don't

Steve.

.I will be doing real world tests on these 3 projectiles myself just to satisfy my own curiosity.

Please update us with your data, and your methods for collecting it.

[Steven]

My main tests will be the Sierra against the Hornady...loaded to the same velocity and zeroed at 100y then shoot at 550y to see what the trajectory difference will be...JBM ballistics shows the difference to be less then 1/2" in favor of the Hornady at 500y...haven't finished load development with the 50g Bergers yet but they aren't my main concern...the Sierra BC is what I can't get my head around...i have a 204 Ruger I can use with the Sierra's and Hornady's so if you have any suggestions on a fairer way to test let me know how you think I should to it....both my rifles have Pacnor supermatch barrels on them and both have shot sub .2" groups at 100y...you will also see the BC for Sierra is only 0.287 at speeds between 3600 and 5000 fps, anything under and its lower then the Hornady.

Steve

[boomer84]

OK so i'm scratching my head a little. I'm sure there is a reason but my undeveloped brain keeps seizing on this!

SBK 39gn = .287
Vmax 40gn = .275
Nosler 40gn = .239

I expect them to be different to an extent but why is the Noslers so much lower compared to the others?

If there is a reasonable explaination can it be kept simple so us laymen can understand!

Boomer

[Wrangler John]

Okay, first off don't hold me to this because I read too much and have a lot of trivia rattling around in my brain. Somewhere I read that B.C. is not an absolute, it varies with changes in conditions for each shot, and even during the time of flight of each shot. Velocity, temperature, atmospheric pressure, humidity, rotational speed, and a bunch of obscure factors all effect the B.C. for each shot. The B.C. number we see in manuals and bullet data tables is a "best guess" number that is an approximation, an average, an - "oh heck we had to put something in the box" number. So what to do? Well, one thing would be to actually shoot a given bullet design at the various ranges in question and log the impact points. Or, like I did for years in competitive matches, select the most accurate bullet, the load that is consistent and accurate, and then have my spotter tell me where they were hitting and adjust accordingly, logging sight adjustments for the next time. Now I have been told, by a rather sober dweeb type with more degrees than a thermometer, that some bullets don't stabilize until they have flown a bit farther than 100 yards - when the nose drops a bit and the yaw smooths out around their center of gravity. Whatever!

So that the heavier, more aerodynamically streamlined (less drag) bullet with its physical and dynamic centers of gravity closest together should be more accurate at longer ranges.

Now I'm sitting here looking at a 40 grain Hornady V-Max (B.C. .275), a 50 grain Berger HPBT (B.C. .281), and a 55 Grain Berger HPBT (B.C. .381), are they pretty. I'm banking that the 50 and 55 grain Bergers will outperform the 40 grain Hornady at longer ranges, 250 + yards, when fired in barrels of the proper twist at 3,000+ fps muzzle velocity. My fastest twist barrel is 1:8.5" and the 55 grain requires 8" or faster. Remember that the 6XC cartridge as fired by David Tubb uses a 6mm DTAC 115 grain VLD bullet (B.C. estimated @ .585) at 3,020 fps in a 1:7.5" twist 29" barrel at 1000 yards (he shot a perfect score with the combo). So, we may assume that high B.C. bullets require specific barrel properties to realize their potential.

I managed to get the 50 grain Berger up to 3,287 fps and the 55 grain up to 3,064 fps with the .204 Ruger and Varget powder in some testing I did last year. Both shot around .5" at 100 yards in the 1:8.5" twist 24" barrel. So what to do if the idea is to shoot high B.C. heavyweights at longer ranges? Obtain a 27" or longer, 1:8" twist or faster barrel and go for it, I know those velocities can be bested. I would do more testing if I didn't have varmint hunter attention deficit disorder - I'm already on to something new and more interesting (or frustrating).

[stevienicknacks]

The .20-250 would be another.

Now that soudns like a fun round to shoot