Flattest Shooting Rifle Round

[valnar]

Pretty much anything that is a barrel burner cartridge since it'll go farther without dropping. As with everything, there are trade-offs.

 

[Jim Watson]

Velocity and ballistic coefficient buy you windage, not "flat shooting" when the ranges are long.

Wrong - it "buys" you both..

I ran the ballistics on two .308 F-T/R loads I have used.
The 175 gr SMK at 2654 fps actual from my rifle has about two FEET more "drop" at 1000 yards than the 155 gr Palma at 2850. So the lighter faster bullet shoots "flatter" all right.
But it has about one INCH less wind deflection. So the "flatter" trajectory shoots a tiny bit closer to the wind, too. Hard to spot at 1000.
And the 175 groups a little better in my rifle.

 

[EdLaver]

6.5 Creedmor is pretty flat shooting to me...I wish it was a more popular cartridge...

 

[Potatohead]

I see what the OP is getting at even though it's a bit of an open ender. I would love to learn more about all the different rifle calibers and what they do well, and not so well, and at what ranges-also from least to most powerful, generally speaking. I wonder where I could find a list like this, preferably all in one place? Im sure there's a book out there, can anyone suggest a title?

PM me if this constitutes a hijack.

 

[Jim Watson]

I was using JBM which applies the staggered G1 BC that Sierra likes, and a 600 yard zero.

That got me the 175@2654 with 239 inches of drop at 1000 from a 600 zero and 103 inches in a 10mph full value wind.

The 155@2850 came out 214 inches down and 102 inches of wind.

Berger is more optimistic on the windage.

But then what I have most recently loaded was the 155 Scenar at 2900 fps, which beats both the Sierras on ballistics. I don't know if it is quite as accurate, though. I am not a good enough shot to tell at Long Range, the conditions eat me up.

I have had good shooting with JLK VLD heavy .22s, I will likely try some of them in .308 should I get back into F class.

 

[RPRNY]

I see what the OP is getting at even though it's a bit of an open ender. I would love to learn more about all the different rifle calibers and what they do well, and not so well, and at what ranges-also from least to most powerful, generally speaking. I wonder where I could find a list like this, preferably all in one place? Im sure there's a book out there, can anyone suggest a title?

PM me if this constitutes a hijack.

See post #25. I provided a link to a non-exhaustive list of cartridges providing their Maximum Point Blank Range and mid trajectory stats. It's a good place to start. For something more encompassing, Cartridges of the World, available online.

 

[TRX]

You'd probably be looking at something in the .25-6mm-6.5mm range. 6mm bullets are very highly developed due to their popularity for benchrest competition.

I've always been a "more is better" big bore fan, but I've been looking at the 6mm-06 a lot lately...

 

[Skylerbone]

I'd add .408 CheyTac to the list, supersonic to 2,200 yds. with a 419gr. solid and nearly 8,400 lbf. using .505 Gibbs as a parent case.

 

[iShoot17]

Pretty much anything that is a barrel burner cartridge since it'll go farther without dropping. As with everything, there are trade-offs.

Although it is the case with many rounds, with one example being the 6.5x284, I don't think it to always be the case.

Someone suggested I look into a 6.5 SAUM for a build...the more and more I read it, the more and more appealing it looks. Shooting 140gr pills flying at 3100FPS+ and barrels lasting out past 3,000 rounds. That is one heck of a fast, flat, lasting cartridge!

But otherwise, I agree with your statement!

 

[Potatohead]

See post #25. I provided a link to a non-exhaustive list of cartridges providing their Maximum Point Blank Range and mid trajectory stats. It's a good place to start. For something more encompassing, Cartridges of the World, available online.

Thanks

 

[Caliper_Mi]

I ran the ballistics on two .308 F-T/R loads I have used.
The 175 gr SMK at 2654 fps actual from my rifle has about two FEET more "drop" at 1000 yards than the 155 gr Palma at 2850. So the lighter faster bullet shoots "flatter" all right.
But it has about one INCH less wind deflection. So the "flatter" trajectory shoots a tiny bit closer to the wind, too. Hard to spot at 1000.
And the 175 groups a little better in my rifle.

Jim, your example is not entirely aplicable to other calibers. The 155gr Palma bullet is an oddball and has a significantly better BC than other .308 bullets of the same weight. Actually, since it has nearly the same BC as the 175gr SMK all you're showing is that the same BC with a higher MV will shoot flatter/less windage. For example you won't find the same situation comparing 120 vs 140gr match bullets for a 6.5mm because you'll need to trade MV for BC.

Bottom line is, two things play into a flat shooting cartridge: MV and BC, that's it. Increasing either or both is the right direction.

 

[LeonCarr]

Another vote for the .408 Cheytac.

Just my .02,
LeonCarr

 

[gamestalker]

My gun smith is telling me the 7mm LRM is one of the flattest shooter's now days.

GS

 

[Jim Watson]

I understand that, Caliper, but that was the only comparison I could provide from personal experience. In that case a lighter faster bullet shoots "flatter" but without an advantage in the wind.

I have a 6.5 twist .223 set up for 90 grain VLDs. It is not hard to find a lighter faster bullet that will shoot "flatter" at varmint hunting ranges, but they are more subject to wind. That combination computes to shoot the same as a 175 gr .308, but I have not been able to make it do so at 1000 yards. It is a jewel at 600 though.

 

[B!ngo]

The whole 'flat shooting' term is always perplexing.
Flat shooting implies that there is little bullet drop over a given distance. In the case of the OP and the term in general, less drop over more and more distance is a flatter shooter.
The two things that affect flat shooting is muzzle velocity and drag. Drag is affected by the ballistic coefficient.
As an analog to an old physics experiment, all bullets drop at the same rate. Whether they are 'flat shooting' or not is just a function of how much ground they cover while they drop (i.e. their speed and rate of deceleration). Whether it's a .22lr or a .50 bmg, once they leave the barrel they (more or less) will hit the ground in the same amount of time. But the .50 BMG travels a longer distance so is considered a flatter shooting round.
There are other factors here as well. The drag of a bullet can change (when compared to another bullet) when traveling at super, trans and sub sonic speeds. So the best is to state over what distance the OP wants to find the flattest shooter and the calculations can be run.
My guess is that something like the 338 Lapua can get out to 1000 yards quickly enough to chart a pretty 'flat' course. But some of the smaller/fast rounds notedin the thread will remain quite flat, albeit for less distance than the Lapua. But that's just a guess.
B

 

[B!ngo]

deleted

 

[jmorris]

Maddigriffin used to have 50 BMG loads that used 180g bullets in sabots at over 5200 fps., an up scale of the old Remington accelerators.

The 22-243 middlestead can shoot 5203 fps.

http://www.reloadersnest.com/query_bw.asp?CaliberID=100&BulletWeight=30

 

[USAF_Vet]

My 6.5 Arisaka is a very flat shooting round, at least up to 300 yards. Haven't shot it at longer distances yet.

 

[jmorris]

A BB gun on a frozen lake is pretty flat shooting, in a bowling alley way.

 

[jmorris]

If someone knows of something "flatter", please post the MV and bullet BC here, so we can calculate and see what we come up with.

My calculator won't allow velocities over 4500 fps.

The example above is using a 30g .224 bullet @ 5203 fps with a .193 BC.

 

[Skylerbone]

On .338 SnipeTac, from its creator:

"I ran velocities up into the 3500fps range using the 300 SMK bullet, this proved to be too hot for normal shooting but showed what was capable with this case. Best loads are kept in the 3300fps area for good case life and ultimate acuracy. Sub 1/2 MOA was achieved with the test rifle in excess of 1000yds."

So let's keep it real. For .408 CheyTac, the stated GI is .940 with an MV of 3,000. Haven't run a calculator, either way they both (as do others listed) qualify in my book as flat shooters (though the CheyTac does it with a 419 gr. bullet vs. a 300 gr. for SnipeTac).

 

[B!ngo]

The only two things you need to know if you want to compute "flatness" of trajectory and wind drift is, 1) velocity and, 2) projectile BC (ballistic coefficient). Two projectiles leaving the muzzle at the same speed with identical BCs will have the exact same trajectory and same amount of wind drift. And, yes, I am not taking atmospheric conditions into account - this is if the 2 bullets are fired at the same time, at the same temperature and same atmospheric pressure.

That is why earlier in this thread I brought up the .338 Snipe-Tac; very high MV (3450) and very high BC bullet (.818 G1, Berger 300 OTM). I'm sure there is something flatter shooting than that, but I have not seen it yet. And, no, none of the Weatherby's, the 50BMG, 408 Chey-Tac or the flattest shooting factory 6.5mm (26 Nosler) will beat that.

If someone knows of something "flatter", please post the MV and bullet BC here, so we can calculate and see what we come up with.

You said it much more effectively than I did DZ. Thanks.
And very impressive work on your site. Brilliant.
B

 

[Jim Watson]

Yes, and we can always assume that somebody looking for the flattest or the fastest or the bestest or the mostest or the newest or the uniquest of whatever has plenty of money (or time and knowhow) to sink into it.

 

[Skylerbone]

DZ, what MV is needed on the .408 to equal the .338, if you would be so kind? Just curious what it would take, I realize the pressure would likely top 65,000 but curiosity has me wondering. Could you run the numbers?

To the OP, you can now see why the issue gets muddied, flat is a single plane but at distance wind drift is also a factor. Much like golf, the right club will get you distance but introducing a slice or hook may not get you on the green.

 

[Potatohead]

Howabout the 6.5 Grendel? Where does it stand in the pecking order?