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Chokes and BR?

Since many shooters, that are focused on precision accuracy visit this subforum, I thought it best to pose these questions here. I've wondered for quite some time what is the specific role of a choke in a barrel and how does it play a role in BR shooting? First of all what is the main purpose of a choke? I know the choke makes the internal ID of the bore smaller towards the end of the barrel but why? Does it re-size the pellet? Is the main bore diameter larger than the pellet from the breech to the choke? Does that mean there is air blowing by a pellet and causing turbulence prior to the choke? If there is blow by does the air in front of the pellet cause accuracy issues as the pellet exits the muzzle? So if the choke does resize the pellet then why the concern about the specific size of the pellet going in?

I've read that choked barrels are preferred for pellets and non choked straight barrels are preferred for slugs. Why is this?

Sorry for so many questions but I am just trying to understand and learn more about chokes and what role they play in creating the most accurate potential in airgun barrels.

If someone can point me to other resources on the subject feel free to instead of re-hashing what's already been written.
 
Pope was well known for his barrels... which I believe were taper lapped.
The thing about accurate barrels is that no matter how it gets there, the tightest spot in the barrel MUST be the exit. Any other combo is not as good as it could be because the projectile is sized as it follows the bore and if the exit isn't the tightest spot, it can induce yaw. Choking is a way to insure that but a perfectly straight bore can be as good as anything. The taper lapping can be considered insurance for the wear on the projectile as it travels the bore.
Part of the issue for airguns is that fitting processes can create irregularities AFTER the barrel is manufactured . I wouldn't consider myself to be in the same league as a good number people on here, but I have fitted and "touched up" a fair number. My largest number have been LW's and though maybe not perfect , are typically pretty consistent . When I buy a blank and check it carefully , the bore is usually pretty consistent in size and finish. When checking a fitted barrel, this is rarely the case. A lot of stresses are induced into the barrel by the sizing/rifling process and when machined to a smaller diameter to fit a breech or for threads for something on the muzzle, the bore usually grows in diameter. To me, THIS is the main reason to choke... insurance that the exit is the smallest part of the bore.
Have you ever pushed a pellet through pretty much ANY HW barrel and felt the constricted bore through the breech block, opening up most of the way down the bore, then choking the last .25 to .5" at the muzzle ? If it wasn't pressed into the breech block, it really wouldn't need to be choked.
I've been told in the past that it was to gain more velocity but I call bs on that. It's just a cheaper manufacturing method that can work well enough. BTW, I'm not picking on HW... most are done that way... just most of us have experience with HW's

My $0.02.
Bob
 
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