Question about flat base vs boat tail bullets

[tpcollins]

On another forum someone said a flat base bullet is more accurate out to 200 yards than a boat tail bullet, but the BT becomes more accurate at longer ranges.

Is this actually true? I would think the BT would be superior at any range unless the longer contact surface of the FB improves spin and therefore accuracy - but how does the BT have a supposedly better long accuracy - the gyro effect of the rear end? Thanks.

[Wyosmith]

My experience is that flat base bullet are more accurate a lot farther out then 200. Depending on the bullet and the cartridge that's firing it, those distances can be out to 600-800 yards.

The boat tails give less drag, but not more accuracy, and the boat tail is better at extreme ranges because with less drag it goes trans-sonic farther away, but those ranges are far more distant than most folks think. As an example a standard 270 Winchester with a 150 grain flat base bullet is just about to go trans-sonic at 965 to 1000 yards. A 150 grain ROUND NOSE flat base 270 is still going about 1700 FPS at 600 yards. It doesn't go trans-sonic until it gets out to about 850. That's nearly a half mile.

A 30-06 with a 150 grain ROUND NOSE flat base is still super sonic at 700 yards.

Such advantages for long range target shooting can be important, but I would not worry too much about shooting flat base bullets for hunting.

For myself, I almost never shoot BT bullets except in my 223s. The only ones I will generally use on big game are either bonded core bullets of expanding solids. The bonded ones will not slip the cores and the solid ones have no core to slip. But about 80% of all my hunting rifles are zeroed for flat base bullets.

[Don Fischer]

Heard this before. I don't think anyone really know's, all theory! What can happen to the boat tail to make it more accurate at any range? I'd read several years ago that competition shooter's found the flat base more accurate. Don't know if that's true or not but most the match bullet's I've ever seen are boat tails! I've had good luck with both kind of bullet's.

[Mobuck]

I won several $20 bills shooting flat base match bullets @400 yards and killed several coyotes with the same bullet @ 450-525 yards.
Barrel preference is a bigger issue than flatbase vs boattail.

[jmr40]

Flat base bullets will theoretically be more accurate at any reasonable range. But that is theoretical, and the difference is miniscule. But BT bullets retain speed much better at long ranges. You reach a point where flat base bullets slow to the point where they are no longer stable. A BT bullet will remain stable at greater distances and at extreme ranges be more accurate.

And even at moderate ranges flat base bullets will have more bullet drop and impact with less speed on game animals, even though they may well be slightly more accurate.

[Jim Watson]

Transonic? Stability? Sure.
But I think the dividing line is where the boattail shooting closer to the wind than the more accurate flatbase takes over.
A friend has a good example, a .223 that groups closer in calm air with 55 gr FB but the 75 gr BT with higher BC takes over in much of a breeze beyond 100-200 yards.

[RC20]

And it annoys me that they make those fancy boatails that go out to 1 million yards and you can't get a flat base match round.

Cut the cost, get me a nice match round that goes 300 yards, about as far as most of use ever get to shoot!

[NHSHOOTER]

Depending on the rifles I own, I shoot both and use whichever groups best. You never know till you shoot both FB and BT of the same weight and powder weight at the same distance..

[JJ45]

I'm with NHSHOOTER, Too many other variables at work for accuracy than to worry about JUST bullet shape like powder, charge weight, primer, seating depth, etc. Rifles are fickle

A boattail in the same weight usually offers better ballistic coefficient. This usually means it will shoot flatter over distance than a flat base, all other factors being equal.

FWIW...the military sniper bullets are almost always of boat tail configuration...The Sierra .308 HPBT Match is a goof example in either 168 or 175 grain weight.

[Sure Shot Mc Gee]

I'm not a long distance stationary target shooter. I hunt game animals. That's all I do and I do it well.
All my game hunting bullets are Flat based soft points.
For the hunting distance's I shoot. I never received a knowingly benefit when using BT over Flat Based. In fact I found Flat Based a bit more accurate than BT's.
Being a frugal individual. Cheaper in cost Flat based bullets vs BT? Why not save a few bucks when you can.

[Rimfire5]

I have some data shooting off a bench with a F-Class bipod and a rear bag with my CZ 527 Varmint .223 at 100 yards with 52 grain Sierra Match King HPBT # 1410 bullets versus 52 grain Berger #22408 Flat Base bullets and 53 grain Sierra Match King #1400 Flat Base bullets.
-------------------------Average --- # grps -- difference
52 SMK #1410 HPBT -- 0.397 ---- 374 -- 0.039
52 Berger #22408 FB -- 0.383 --- 347 -- 0.025
53 SMK #1400 FB ------ 0.358 --- 218

I also have data with my Remington 700 .22-250 with the same bullets under the same conditions:
-------------------------Average --- # grps -- difference
52 SMK #1410 HPBT -- 0.363 ---- 96 --- 0.057
52 Berger #22408 FB -- 0.348 --- 265 -- 0.042
53 SMK #1400 FB ------ 0.306 --- 280

The overall averages seem to confirm the theory at least at 100 yards.

[DukeConnor]

Boat tails are easier to seat when loading. Differenc in acuracy ? Meh

[wild cat mccane]

It's not all the theoritical.

Federal has a 223 load in 55gr that is boat tail. Federal has a 223 load in 55gr that is not boat tail.

[bamaranger]

It's been well explained that boat tails slip the wind better and carry better at distance. Simply shooting a boat tail slug in itself will not automatically improve accuracy.

I've read where the rear of the bullet is what steers it. I've read that a B-tail can be more consistently formed than a flat base. I know for certain that FMJ -military typed boat tails with an exposed lead base and enclosed, solid point, are not as accurate in any of my .223 or .30 rifles as a good flat base, or a boat tail with an exposed or hollow point.

[RC20]

Boat tails are easier to seat when loading. Difference in acuracy ? Meh

Yep.

I don't agree flat base are harder to make than boat tails. Any form adds complexity to a machine operation.

I would like to see the listed references that say a boat tail is easier?

[Sodbuster]

All I know is I took a liking to the 140-gr Winchester FailSafe in .270. A flat base.

[Bimus]

308 win heavy barrel Speer 165 gr spitzer flat base 600 yards .

[JohnKSa]

I seem to recall something to the effect that serious benchrest competitors use flat base bullets.

[603Country]

Some years ago I read that flat base bullets tend to be potentially more accurate because they can be made with a more consistent base than boattail bullets. When the bullets exit the muzzle, the escaping gas will be more evenly distributed with a flat base bullet and not influence or unbalance the bullet. The whole thing (theory or fact) seemed to be based on accuracy going to bullets with a more perfect base.

The article did a much better job explaining it than i can, and it made sense to me at the time. Today, however, maybe the boattails can be made to a more perfect standard than flatbased bullets, though i tend to doubt it.

It was a long time ago when i bought a lot of match grade .224 bullets, and they all had flat bases back then. I don’t know about today’s match grade bullets for short range, which is what i was doing back then. Seems like these days the focus is on long range, and the long range guys want high BC, which means boattails.

[FiveInADime]

Originally Posted by JohnKSa

I seem to recall something to the effect that serious benchrest competitors use flat base bullets.

The one I knew did. He gave me a few boxes of his preferred match bullets which were 6mm Berger FB match bullets. I'm pretty sure he did whatever Walt Berger was doing, for the most part.

That's 200 yard benches though. Not long range.

Sent from my SM-G965U using Tapatalk

[disseminator]

If you do a search on this title: "Flat-Base And Boattail Rifle Bullets" you will find a few good articles that explain it quite well.

I tend to shoot boattails myself, but mostly because the bullets I like happen to be boattail designs. I think there is a flat base called a "Partition" a few people like...

[Buzzcook]

I mostly shoot Hornady spft they and the rifle I shoot them out of are more accurate then I am.

However when I've shot similar spbt bullets, they are also more accurate than I am.

From my limited experience out to 600yds they act the same.

[Red Devil]

Flat Base vs Boat Tail bullets.

Flat Base - are more accurate when supersonic.

Boat Tail - are more accurate and efficient subsonic.

The Supersonic pressure wave negates any drag effect from the tail of a standard bullet. Boat tails are generally used to aid in production bullet seating.

What affects accuracy is how the bullet leaves the muzzle, and how the gasses (muzzle blast) affect it.

When a Flat Base bullet leaves the muzzle, it leaves immediately and cleanly. Gasses are directed out from the flat base perpendicular and away.

With a Boat Tail, the tail is still in the bore when the gasses are unsealed. The barrel is also vibrating, so the bore/bullet gap is also variable. These variable gasses are directed parallel, and then deflected off the tapered tail, imparting uneven perpendicular forces on the tail of the bullet while the tail is still in the bore, and as it exits.

Not an inherently good condition for precision.

When the bullets go transonic, the boat tail becomes much more efficient.

VLD bullet design may have improved supersonic ballistic coefficients, but they have not resolved the issue of bullet egress.




Red.

[HankC1]

Is there any difference on preferred velocity? Seems like flat base bullets are more used in light weight varmint rounds that run at higher velocity, but I also use flat base in 300BLK and 7.62x39 which run at mid velocity and shoot great. I don't shoot long range!

[pete2]

Boat tail bullets are easier to seat in the case. My experience. Hold velocity a little better when you get out to about 9000 yards. Very important to most of us, especially in a 30-30.