Flat back more stable then boat tail

DevinL

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Jul 3, 2020
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I was doing some load comparing and the boat tauils i used seem to be unstable compared to flat back maybe its just what my rifle liked
 

OLD308

Gunny Sergeant
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Jun 8, 2018
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The smallest, easily repeatable, supersonic loads, for paper punching only, have always been flat based bullets for me. The .308 150 Berger flat based match bullets for inside 500 yards are astounding. Supposedly, there is a better/uniform seal at the rear of the bullet. Think rebated boat tails, drive bands, ect.
I'm certainly not implying this to be a foundational truth. Just my experience taken from my extremely limited time in bench-rest shooting decades ago.
 

DevinL

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Jul 3, 2020
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factory savage 110 26 in 1:10 tried berger elite hunter 180s hornady interlock boat tail fails flat back interlocks seen best group this was in my 300win mag working on hunting load
 

FarmBoy87

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Sep 4, 2020
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The smallest, easily repeatable, supersonic loads, for paper punching only, have always been flat based bullets for me. The .308 150 Berger flat based match bullets for inside 500 yards are astounding. Supposedly, there is a better/uniform seal at the rear of the bullet. Think rebated boat tails, drive bands, ect.
I'm certainly not implying this to be a foundational truth. Just my experience taken from my extremely limited time in bench-rest shooting decades ago.
There is a reason flat base bullets are used in short distance competition...I have a theory that its because the gas seals more consistently...my 1-12 twist 22 250 is almost always more accurate at 100 yards than my 1.9 and 1.8 twist 22 250s with 75 and 88 gun boattails.
 

theLBC

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Jun 21, 2019
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i read something about boat tail bullets allowing more gas deflection as the bullet leaves the barrel.
can't recall the article, but they suggested when a barrel wears, this gets worse and using a flat bottom bullet can help.
 
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DevinL

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Jul 3, 2020
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i read something about boat tail bullets allowing more gas deflection as the bullet leaves the barrel.
can't recall the article, but they suggested when a barrel wears, this gets worse and using a flat bottom bullet can help.
Brand new rifle may have 10o- 150 through it but at the range the other day and a guy mentioned that about boat tails i always thought they flew better as a rule of thumb im kinda locked in for now but later on may do my tests
 

Supersubes

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Brand new rifle may have 10o- 150 through it but at the range the other day and a guy mentioned that about boat tails i always thought they flew better as a rule of thumb im kinda locked in for now but later on may do my tests
They have higher BC’s, so they retain energy and drift less than flat based bullets. When you say unstable, do you mean the bullets were going through the paper sideways or off axis to some degree? That would be lack of stability. Or were they just shooting shit groups? Lack of accuracy does not equal lack of stability. Those are entirely different things. Try another bullet.
 

DevinL

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Jul 3, 2020
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They have higher BC’s, so they retain energy and drift less than flat based bullets. When you say unstable, do you mean the bullets were going through the paper sideways or off axis to some degree? That would be lack of stability. Or were they just shooting shit groups? Lack of accuracy does not equal lack of stability. Those are entirely different things. Try another bullet.
bad groups and strange holes / tears in the rarget
 

gigamortis

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Oct 23, 2013
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Flat base bullets have more rear drag than boat tail ones, so they have good manners at closer distances. Once out past 300 yards, boat tail bullets tend to have their pitching and yawing from launching out of their system and start spinning more uniformly on their true center axis. I have found that if your barrel twist rate is too fast for your chosen boat tail bullet, groups at 100 and 200 yards can be rather unimpressive to the point of you giving up on them. Try some 300-500 yard groups with them and you will likely see better results.

For instance, one of my .223 rifles with a 1:7 twist has suck ass groups at 100 and 200 yards with 55gr bullets. At 300 yards, the groups with the same bullets are half the size of the 200 yard groups.