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boat tails
coloman1954
Member Posts: 19 ✭✭
im a reloader in colorado the results are in my freezer right now
but
i talk to some reloaders and they say boat tails are bad for your barrel
any advice or new discussion about whether boattails are not good for your barrel
coloman1954@yahoo.com
but
i talk to some reloaders and they say boat tails are bad for your barrel
any advice or new discussion about whether boattails are not good for your barrel
coloman1954@yahoo.com
Comments
I shoot a lot but not enough of one rifle to burn barrels out in it. Let alone really put a lot of wear on it. I have 1500 rds through my 7x57 shooting mostly boattails. I don't load them super hot and I don't shoot when the barrel is hot. I don't compete so the extreme wear isn't felt by my barrels.
However, the only thing I really find is that it is easier to push out a flatbase at max than a boattail. This would account for the difference in energy expended to get the bullet to go the speed you wish. Some references say the difference can be as much as 15%. I have found it more in the range of 3-5%. That isn't enough to worry about unless you are in high level competition and you are worrying about if your barrel will only stay accurate to 1900 rds instead of 2000 rds. But that is only my case.
What I've read on the subject is that the gasses pushing the bullet will push at a 90 degree angle to the shape of the bullet. This is the most obvious loss of energy. That the force is not being applied to a face which can absorb the most energy. The base, which is perpendicular to the force of the expanding gases. It is being applied to a face that cannot absorb the full pressure. Thus the seal at the edge of the bullet must absorb it. Still it is efficient enough to stay right up with flat base bullets. Of course, you get the better BC downrange.
find out for yourself.
But the answer is no, its not bad for your barrel
Here are some things for you to 'kick around'.
Everything we put into our gun barrels is bad for the life and quality of those barrels. It's that plain and simple.
If you want or expect a barrel to maintain it's quality, don't shoot it. Ever. Put it in the safe or up on a shelf or rack and just look at it.
The so-called gun writers around the world ran out of topics to write about, 50 years ago. Everything since then, outside of new products, has been recycled way too many times. That is until one of them runs into a tiny tidbit of plasma physics and aerodynamic shapes that could be manipulated into a controversial article. Controversy for a gun writer is a good thing, it boosts readership and his numbers go up in eyes of the publisher.
The shape of the base of a bullet will have an effect on how the pressure is distributed in the bore behind the bullet as its fired. The pressure (and plasma) is deflected or reflected off of the shape of the base.
In order for the bullet to travel down the bore efficiently, it has to obturate or obstruct the bore completely. It has to seal those gases (plasma) in order to use as much of the energy as possible.
Boattail bullets do not obturate as readily as flat base bullets do.
Flat base bullets have a pressure ring, wiper ring or drive band at the intersection of the shank and the base of the bullet. This pressure ring can run 0.0003" and 0.0006" larger than the functional diameter of the bullet. Nominal .308 bullets will have a pressure ring that measures .3083" to .3086" in diameter. This serves to seal the inside of the rifle barrel faster than the boattail bullets do.
All-in-all, it's a matter of minutia. When everyone has a grasp of the big points, we start examining the smaller details. And when we get done with those smaller details we look for even smaller details.
If you want to shoot, go shoot. If your barrel wears out, replace it. If you don't want to replace a barrel, don't shoot it.
Best.
I shoot nothing but BTs, even VLDs which are super BTs by Berger. My barrels are just fine afters thousands of rounds.
+++++1 on the Berger's![;)]