overboring

wudjalike2no · December 31, 2004, 08:51 PM

does overboring help with accuracy and recoil and velocity?
i am planning on getting the mossberg 835

(.775)"Overbored" 12 gauge 835 Ulti-Mag barrel (left) -vs- our standard (.731) 12 gauge barrel

HunterTRW · December 31, 2004, 10:07 PM

According to Bob Brister in his book, Shotgunning, The Art and Science, "Pushing a heavy load of shot through a small hole is simply inefficient; it creates more recoil, deforms pellets, and elongates the shot string." He also states, "The less traumatic and jolting ride the shot charge is given through barrel and choke, the less damage to pellets and to the shooter's face!"

Thus, some degree of overboring does make sense in terms of reducing recoil, pellet deformation, and shot-string length. However, he notes that 10-gauge boring (0.775) is too large to get suitable sealing with 12-gauge plastic wads.

Mr. Brister recommends having a gunsmith enlarge the inside diameter of the 12-gauge barrel (typically 0.729) by approximately 0.010, and states that this can work wonders in reducing felt recoil and improving patterns. He also recommends having the forcing cone evaluated at the same time and, if necessary, reducing its angle (in essence lengthening it). This also helps to make the ride of the shot charge, "...less traumatic and jolting..."

After having one of his own guns with a tight barrel diameter and a steep forcing cone worked on by a Seattle gunsmith, Stan Baker, (who slightly overbored the barrel and reduced the forcing cone angle) the effect was a slight increase in velocity as measured by chronograph. The net result was a gun that was much more pleasant to shoot.

Good luck, and good shooting!

Danindetroit · January 1, 2005, 03:55 AM

I have an 835, what type of negative consequences are likely to be encountered with the sealing issue. Has a load been checked to see if there is a difference btw, the 835, and a standard gun. I was hitting trap very far out, I patterened it at 75', as measured by a 100' tape with AA #7 1/2 at 1300 fps, it was at a large steel plate with white paint, and it was a decent pattern. Some people do not like a 2 bead set-up, but I like it.

HunterTRW · January 2, 2005, 06:53 PM

The negative consequence alluded to by Mr. Brister is the possibility of gasses from the powder charge moving past the shot cup and spoiling the desired pattern.

I am not aware of any pattern comparisons, using identical loads, between the Mossberg model 835 and their standard-bore 12-gauge gun. (If anyone is aware of such, please respond).

Concerning your model 835, now that you know how it patterns at 25 yards, try patterning it at 40 yards using the identical load and choke. At this distance any problems with patterning should become readily apparent.

Good luck, and good shooting!

Danindetroit · January 2, 2005, 10:27 PM

I am not sure how far a commercial trap machine, throws a clay, but I got one on the way down, had to lead it a whole lot. 17 yds, + that distance, with the factory full choke, and it broke into about 3 pieces. I am wondering if this is a scientific thing, or just a theory. I e-mailed some ammo companies, and asked them, it usually takes them a long time to reply.

HunterTRW · January 3, 2005, 06:41 PM

In answer to your question about how far a commercial trap machine throws a target, according to the rules of the Amateur Trapshooting Association, "Targets, whether singles or doubles, shall be thrown not less than 48 yards (44m) nor more than 52 yards (47m) measured on level ground in still air."

I don't understand what you are asking in the second part of your post.

As for chokes for trap guns, The Gun Digest Book of Trap & Skeet Shooting by Chris Christian states:

"Trap shooters also favor tighter chokes than those pursuing Skeet and Sporting Clays. A fast trap shooter, shooting from the 16-yard line, might get onto a target when the bird is at a range of 25 yards. More likely, it'll be 30. If he is a little slower, the bird could be 35 to 40 yards away from him. A Modified choke is considered to be a relatively open choke for trap, although I feel it is about the best choice for the 16 Yard game if the shooter is using quality, hard-shot loads. The Handicap and Doubles games are best played with Improved Modified or Full choke.

"A shooter engaging targets from the 27-yard handicap line is looking at shots of 40 to 50 yards, and many will opt for Extra-Full choking."

Hope this helps.

Good luck, and good shooting!

P.S. The aforementioned book is good, and includes the offical rules for Trap, Skeet, and Sporting Clays. The ISBN number is 0-87349-163-7.

Danindetroit · January 3, 2005, 11:50 PM

I e-mailed some ammo companies about shooting various loads through the bore of my 835, and if there is velocity loss, or pattern degredation. I have noticed nothing bad about the gun, it shoots well, I am willing to get a 500 series, of it is proven that it is really not a good gun. I think this person, might have a good on paper observation, but it doesn't pan out. Depending on the wad, I think it might expand enough to get a good seal.

HunterTRW · January 4, 2005, 09:40 AM

There are few absolutes in life, and this applies to shotgunning, too. If your preferred loads perform well in your preferred gun, then I would not let Mr. Brister's observations about this issue trouble you. As the late Gene Hill observed in his Shotgunner's Notebook, "Such is the world of the shotgunner and I, for one, hope the arguments, the debates, and the hairsplitting never, ever cease." To which I say, Amen!

Good luck, and good shooting!

December 31, 2004, 08:51 PM	#1
wudjalike2no Senior Member Join Date: November 29, 2004 Posts: 109	overboring does overboring help with accuracy and recoil and velocity? i am planning on getting the mossberg 835 (.775)"Overbored" 12 gauge 835 Ulti-Mag barrel (left) -vs- our standard (.731) 12 gauge barrel

December 31, 2004, 10:07 PM	#2
HunterTRW Senior Member Join Date: December 3, 2004 Location: The Lower Forty of Hill Country Posts: 177	According to Bob Brister in his book, Shotgunning, The Art and Science, "Pushing a heavy load of shot through a small hole is simply inefficient; it creates more recoil, deforms pellets, and elongates the shot string." He also states, "The less traumatic and jolting ride the shot charge is given through barrel and choke, the less damage to pellets and to the shooter's face!" Thus, some degree of overboring does make sense in terms of reducing recoil, pellet deformation, and shot-string length. However, he notes that 10-gauge boring (0.775) is too large to get suitable sealing with 12-gauge plastic wads. Mr. Brister recommends having a gunsmith enlarge the inside diameter of the 12-gauge barrel (typically 0.729) by approximately 0.010, and states that this can work wonders in reducing felt recoil and improving patterns. He also recommends having the forcing cone evaluated at the same time and, if necessary, reducing its angle (in essence lengthening it). This also helps to make the ride of the shot charge, "...less traumatic and jolting..." After having one of his own guns with a tight barrel diameter and a steep forcing cone worked on by a Seattle gunsmith, Stan Baker, (who slightly overbored the barrel and reduced the forcing cone angle) the effect was a slight increase in velocity as measured by chronograph. The net result was a gun that was much more pleasant to shoot. Good luck, and good shooting! Last edited by HunterTRW; January 2, 2005 at 08:22 PM.

January 1, 2005, 03:55 AM	#3
Danindetroit Senior Member Join Date: October 1, 2004 Location: Detroit Posts: 757	I have an 835, what type of negative consequences are likely to be encountered with the sealing issue. Has a load been checked to see if there is a difference btw, the 835, and a standard gun. I was hitting trap very far out, I patterened it at 75', as measured by a 100' tape with AA #7 1/2 at 1300 fps, it was at a large steel plate with white paint, and it was a decent pattern. Some people do not like a 2 bead set-up, but I like it.

January 2, 2005, 06:53 PM	#4
HunterTRW Senior Member Join Date: December 3, 2004 Location: The Lower Forty of Hill Country Posts: 177	The negative consequence alluded to by Mr. Brister is the possibility of gasses from the powder charge moving past the shot cup and spoiling the desired pattern. I am not aware of any pattern comparisons, using identical loads, between the Mossberg model 835 and their standard-bore 12-gauge gun. (If anyone is aware of such, please respond). Concerning your model 835, now that you know how it patterns at 25 yards, try patterning it at 40 yards using the identical load and choke. At this distance any problems with patterning should become readily apparent. Good luck, and good shooting!

January 2, 2005, 10:27 PM	#5
Danindetroit Senior Member Join Date: October 1, 2004 Location: Detroit Posts: 757	I am not sure how far a commercial trap machine, throws a clay, but I got one on the way down, had to lead it a whole lot. 17 yds, + that distance, with the factory full choke, and it broke into about 3 pieces. I am wondering if this is a scientific thing, or just a theory. I e-mailed some ammo companies, and asked them, it usually takes them a long time to reply.

January 3, 2005, 06:41 PM	#6
HunterTRW Senior Member Join Date: December 3, 2004 Location: The Lower Forty of Hill Country Posts: 177	In answer to your question about how far a commercial trap machine throws a target, according to the rules of the Amateur Trapshooting Association, "Targets, whether singles or doubles, shall be thrown not less than 48 yards (44m) nor more than 52 yards (47m) measured on level ground in still air." I don't understand what you are asking in the second part of your post. As for chokes for trap guns, The Gun Digest Book of Trap & Skeet Shooting by Chris Christian states: "Trap shooters also favor tighter chokes than those pursuing Skeet and Sporting Clays. A fast trap shooter, shooting from the 16-yard line, might get onto a target when the bird is at a range of 25 yards. More likely, it'll be 30. If he is a little slower, the bird could be 35 to 40 yards away from him. A Modified choke is considered to be a relatively open choke for trap, although I feel it is about the best choice for the 16 Yard game if the shooter is using quality, hard-shot loads. The Handicap and Doubles games are best played with Improved Modified or Full choke. "A shooter engaging targets from the 27-yard handicap line is looking at shots of 40 to 50 yards, and many will opt for Extra-Full choking." Hope this helps. Good luck, and good shooting! P.S. The aforementioned book is good, and includes the offical rules for Trap, Skeet, and Sporting Clays. The ISBN number is 0-87349-163-7.

January 3, 2005, 11:50 PM	#7
Danindetroit Senior Member Join Date: October 1, 2004 Location: Detroit Posts: 757	I e-mailed some ammo companies about shooting various loads through the bore of my 835, and if there is velocity loss, or pattern degredation. I have noticed nothing bad about the gun, it shoots well, I am willing to get a 500 series, of it is proven that it is really not a good gun. I think this person, might have a good on paper observation, but it doesn't pan out. Depending on the wad, I think it might expand enough to get a good seal.

January 4, 2005, 09:40 AM	#8
HunterTRW Senior Member Join Date: December 3, 2004 Location: The Lower Forty of Hill Country Posts: 177	There are few absolutes in life, and this applies to shotgunning, too. If your preferred loads perform well in your preferred gun, then I would not let Mr. Brister's observations about this issue trouble you. As the late Gene Hill observed in his Shotgunner's Notebook, "Such is the world of the shotgunner and I, for one, hope the arguments, the debates, and the hairsplitting never, ever cease." To which I say, Amen! Good luck, and good shooting!