What are the diameters of the 12 gauge bore and the advantages of over boring or can a gun be too much overboard?
Chicken630
There is no conclusive evidence that over-boring improves patterns. Indeed, a lot of evidence that it makes no difference whatsoever.
It will lighten the weight of the barrel, if that is your goal.
I shoot a Kolar TS with a .750 bore and the recoil feels softer than others I have shot with .740, it is also lighter in the barrel and swings like a dream.
If you get an Italian gun, there're certain restrictions from the Italian proof house, 12 ga bore can't exceed 18.8 mm. But considering possible gas/pressure leaks, they typically stay under 18.7 mm.
Italian factory big bore barrels have the same thickness as their standard 18.4 mm bore, so it's not lighter.
Here, you can over bore to whatever you desire, but mind you when you shoot in cold weather, your standard size plastic wad may not seal the bore, and creating gas leak.
In some case under not so cold weather, that'll make you feel less recoil too.
Italian factory big bore barrels have the same thickness as their standard 18.4 mm bore, so it's not lighter.
Here, you can over bore to whatever you desire, but mind you when you shoot in cold weather, your standard size plastic wad may not seal the bore, and creating gas leak.
In some case under not so cold weather, that'll make you feel less recoil too.
Yes .729 is the standard 12 g bore. I had a Mossberg 835 unimag pump gun .775. 10 g bore. My first 100 in singles with the mossberg. Then went to a TM1 p gun.
How does a over bored barrel affect the choke patter out the other end? The reason I ask -- We have a fun day when we bring out our front loader black powder shotguns -- Since every thing has to be pushed down from the barrel you can't choke them--- Couple people went to screw in chokes that you have to remove fore every shot - My shotgun is a old timer that I had jug choked -- Witch is nothing more than a over bored section at the end to expand the shot then restricts the shot back down for a tighter pattern-- Does a over bored barrel have the same affect When it hits the choke?
"Maybe if we say a Over Bored barrel shoots a Shorter Shot String than a standard bore , it would explain a lot ?"
No. It wouldn't "explain" anything. Two reasons:
1. Saying it doesn't make it true, and
2. In the American Rifleman article which has been posted here many times, Ed Lowry provided the mathematical route by which any trapshooter could easily prove to himself or herself that shot string plays no role whatever in trap..
The way to document the relationship between the performance of the old standard diameter bores and the currently popular oversized ones is to test both using real variables like pattern percentage, pattern spread, and pattern evenness. Such tests have not found any superiority in oversized bores. Making up variables like shotstring-length and deciding that there is a difference and one is better is nonsense. There's no reason to explain anything anyway since there nothing to explain. Except, perhaps, you could explain the popularity of over-bores as a result of the gullibility of shooters and their preference for trying to buy success rather than working for it.
Neil
No. It wouldn't "explain" anything. Two reasons:
1. Saying it doesn't make it true, and
2. In the American Rifleman article which has been posted here many times, Ed Lowry provided the mathematical route by which any trapshooter could easily prove to himself or herself that shot string plays no role whatever in trap..
The way to document the relationship between the performance of the old standard diameter bores and the currently popular oversized ones is to test both using real variables like pattern percentage, pattern spread, and pattern evenness. Such tests have not found any superiority in oversized bores. Making up variables like shotstring-length and deciding that there is a difference and one is better is nonsense. There's no reason to explain anything anyway since there nothing to explain. Except, perhaps, you could explain the popularity of over-bores as a result of the gullibility of shooters and their preference for trying to buy success rather than working for it.
Neil
Everything has it's place. Even backboring I agree with what Neil has said. I will add however some impressions that were of a few industry professionals in the area of barrel tuning and chokes. Optimum bore diameter is dependent on shot charge volume. The way it has been described the ideal bore diameter is one that has the shot charge square. What they mean is that the shot charge is no taller than it is wide. I believe that makes a trap load probably work best in a bore around .730. Now if we were shooting 1 1/2 oz loads of 2's then their may be an advantage to the bigger bore. Lets get one thing straight a big bore barrel is not the same as backboring an existing barrel. If you back bore an existing barrel you will do two things I'm certain. First you will make it lighter which should make it kick more. Second you will increase the choke constriction so it may shoot tighter. Going from .030 to .o35 constriction will make a barrel shoot tighter but that says nothing about pattern efficiency no more than changing a choke tube for .oo5 more constriction in any barrel. The terms get so messed up by many trying to repeat what they have heard.
It would be interesting to read the last 2 posters thoughts on the difference of Over Boring , Back Boring and the effects of Swaging the barrel to make the barrel sound bigger ?
There really is something to this , wouldn't you think , as even the pricier Smoke Poles are offering it ! OR , just a sales pitch with no substance ?
There really is something to this , wouldn't you think , as even the pricier Smoke Poles are offering it ! OR , just a sales pitch with no substance ?
Lol......the old 682 X Trap is 18.4 (about .725) with fixed chokes.....yesterday we had a Champion of Champions event, which is 25 target double barrel (2 shots permitted, either barrel hit = 1) 25 single barrel (one shot only) and 25 point score (first barrel hit = 3, second barrel hit = 2, miss = 0).
I hit 25 in the DB, 24 in the SB and 24 in the points with 2 second barrel hits with that old 18.4 gun. The guy who won it hit 73/75, same as me, but he didn't miss in the points, so he beat me by a couple. And I'm pretty sure that extra .2 or .3mm had nothing to do with me missing.
Take the money you were going to spend having the barrels overbored, or backbored, or whatever you want to call it, and spend it on ammo and practice tickets.
Just my 2c.
I hit 25 in the DB, 24 in the SB and 24 in the points with 2 second barrel hits with that old 18.4 gun. The guy who won it hit 73/75, same as me, but he didn't miss in the points, so he beat me by a couple. And I'm pretty sure that extra .2 or .3mm had nothing to do with me missing.
Take the money you were going to spend having the barrels overbored, or backbored, or whatever you want to call it, and spend it on ammo and practice tickets.
Just my 2c.
No, there isn't anything to it.
Yes, it's just marketing with no conclusive evidence of superiority.
Here's a test I did with fellow trapshooters.com member Dukefan. Make your own conclusions.
In my mind, this tells me that within the range of normal barrel bore diameters for 12 gauge shotguns, the only thing that matters much is choke constriction. That, and if you have a barrel that already shoots good patterns, sending it out to be "tuned" may be a waste of money.
http://www.trapshooters.com/threads...m/threads/pattern-testing-results-four-guns-one-with-a-wilkinson-barrel.302858/
In my mind, this tells me that within the range of normal barrel bore diameters for 12 gauge shotguns, the only thing that matters much is choke constriction. That, and if you have a barrel that already shoots good patterns, sending it out to be "tuned" may be a waste of money.
http://www.trapshooters.com/threads...m/threads/pattern-testing-results-four-guns-one-with-a-wilkinson-barrel.302858/
Many have seen the Perazzi promotional video about this, AA. The part that most interested me was that the maker had been able, with the new bore diameter, to achieve both reduced recoil and increased pellet -penetration.
This is indeed an impressive claim, since it infers both greater speed and reduced recoil. People have been trying to do this since Newton and the only fuss made about it is a short video? I would have thought that a rewriting of Newton would have made more of an impression...
Of course, this is small potatos compared to Federal's claim of 14% recoil reduction with the Gold Medal Grand shells accomplished by adding about a quarter-inch of air space in the new 12C5 wad, so we should expect Stellium III+ barrels from Beretta to have negative recoil if they have any at all.
I suppose that a whole different ballistic technology must be required for your counter-clockwise spinning birds, or do your clocks go the other way too which I guess would make changes unnecessary?
Neil
This is indeed an impressive claim, since it infers both greater speed and reduced recoil. People have been trying to do this since Newton and the only fuss made about it is a short video? I would have thought that a rewriting of Newton would have made more of an impression...
Of course, this is small potatos compared to Federal's claim of 14% recoil reduction with the Gold Medal Grand shells accomplished by adding about a quarter-inch of air space in the new 12C5 wad, so we should expect Stellium III+ barrels from Beretta to have negative recoil if they have any at all.
I suppose that a whole different ballistic technology must be required for your counter-clockwise spinning birds, or do your clocks go the other way too which I guess would make changes unnecessary?
Neil
No mate, we're Aussies. Recoil doesn't bother us. In fact we bash people who have a recoil pad of any sort on their gun.
I hope I say everything right ,,, I have a Baker Big Bore 84 which I am told is 840 in the bore, on a TMX frame ,It seems to do the job ,smokes targets with FGM red dot and a 12so claybuster wad..
I don't have it too long ,like got it at the end of summer and been breaking 46 and up to
50 x 50 . When I shoot AA with CB AA clone I get some weird sounding ones ,but still break the bird .
Any one have any insight or have ever had a Baker BB 84 Thanks CC
I don't have it too long ,like got it at the end of summer and been breaking 46 and up to
50 x 50 . When I shoot AA with CB AA clone I get some weird sounding ones ,but still break the bird .
Any one have any insight or have ever had a Baker BB 84 Thanks CC
The Baker BB84 (Baker Big Bore 1984) has a diameter of 0.8". The one I have shoots fine in testing but does not do any of the amazing things that were claimed of it in the multitude of articles that were written about it on its introduction. Don Zutz, for example, required two issues of Shooting Trap to say enough good things about it. An odd thing is that I couldn't make a consumer chronograph work in confirming the greater shot-speed that all the other reviewers reported, which went along with the reduced recoil they all lauded. My speed readings were all over the place and I couldn't get any of the paired chronographs I use to test every shot to match one-to-the-other.
I'll have to get around to writing up my test, but since the gun has never totally taken over the sport as so many writers predicted it would, I think the pressure is off and I can wait until I can figure out how to measure its shot-speed before getting down to work.
Neil
As a side note, the gun required a wording change in ATA rules from "12 gauge" to "12 gauge chamber" because in bore size it's a 10 gauge or something.
I'll have to get around to writing up my test, but since the gun has never totally taken over the sport as so many writers predicted it would, I think the pressure is off and I can wait until I can figure out how to measure its shot-speed before getting down to work.
Neil
As a side note, the gun required a wording change in ATA rules from "12 gauge" to "12 gauge chamber" because in bore size it's a 10 gauge or something.
The Baker Big Bore was nothing more than a re-emergence of the "chamberless" guns of the early 20th Century. And not surprisingly the same hype! Stan was a good guy and did some beautiful work tho.
Any bunker or pigeon shooter can tell you that 18.4 bores hit harder and are the most desirable for those games. Common sense tells you that the 18.4 bore compresses the shot charge more and as a result hits harder. I'm pretty sure that's how it works. Which of course makes bigger bores something for sissies.
IIRC one of the Russians when asked about the monster loads they shot said We are not children. They prolly had 18.2 bores.
Any bunker or pigeon shooter can tell you that 18.4 bores hit harder and are the most desirable for those games. Common sense tells you that the 18.4 bore compresses the shot charge more and as a result hits harder. I'm pretty sure that's how it works. Which of course makes bigger bores something for sissies.
IIRC one of the Russians when asked about the monster loads they shot said We are not children. They prolly had 18.2 bores.
.729" is the world standard for a 12-bore.
The guys with overbored guns .735" and above, will tell you that is the way to go.
The guys with non overbored guns .734" and below, will tell you that is the way to go.
In other words, no one will ever agree.
This is why women should be the rulers of the world...........
The guys with overbored guns .735" and above, will tell you that is the way to go.
The guys with non overbored guns .734" and below, will tell you that is the way to go.
In other words, no one will ever agree.
This is why women should be the rulers of the world...........
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