835 Ulti Mag Questions

[unworthy]

Whats all this about my 835 being "back bored"  I am looking to pattern my gun this weekend.  It has a factory choke tube in it, but everything I read on here tells me to get a .670 or .675 constriction.

[Skeeterbait]

Backboring means the inside of your barrel is larger diameter than a standard 12 gauge.  The internal diameter of the 835 is .775.  The nominal bore of a 12 gauge is .729.  Many manufacturers deviate from the nominal bore diameter but the 835 is the largest.  .775 is actually 10 gauge size.  This does several things for you.  It nearly eliminates the forcing cone, It reduces friction on the wad, it reduces recoil a bit, it makes patterning easier.  The .670 to .675 constriction recommendation comes from the experience of many on this forum and others that most turkey loads pattern tightest in the 835's with these constrictions.  Tighter the pattern is blown, more open and the pattern opens up.  Some prefer a more open pattern and shoot .680 and .690 in their 835's  Just depends on what you want out of the gun.

[unworthy]

Very insightful, Thanks!

[knightrider]

Backboring means the inside of your barrel is larger diameter than a standard 12 gauge.  The internal diameter of the 835 is .775.  The nominal bore of a 12 gauge is .729.  Many manufacturers deviate from the nominal bore diameter but the 835 is the largest.  .775 is actually 10 gauge size.  This does several things for you.  It nearly eliminates the forcing cone, It reduces friction on the wad, it reduces recoil a bit, it makes patterning easier.  The .670 to .675 constriction recommendation comes from the experience of many on this forum and others that most turkey loads pattern tightest in the 835's with these constrictions.  Tighter the pattern is blown, more open and the pattern opens up.  Some prefer a more open pattern and shoot .680 and .690 in their 835's  Just depends on what you want out of the gun.

good explination

[hookedspur]

 

[paturkeyhntr]

Thanks Skeeterbait for the explaination.  I have 2 835's and didn't know what backboring was.

[Gobble!]

Backboring means the inside of your barrel is larger diameter than a standard 12 gauge.  The internal diameter of the 835 is .775.  The nominal bore of a 12 gauge is .729.  Many manufacturers deviate from the nominal bore diameter but the 835 is the largest.  .775 is actually 10 gauge size.  This does several things for you.  It nearly eliminates the forcing cone, It reduces friction on the wad, it reduces recoil a bit, it makes patterning easier.  The .670 to .675 constriction recommendation comes from the experience of many on this forum and others that most turkey loads pattern tightest in the 835's with these constrictions.  Tighter the pattern is blown, more open and the pattern opens up.  Some prefer a more open pattern and shoot .680 and .690 in their 835's  Just depends on what you want out of the gun.

well said. I have a friend that used a .690 jelleyhead with the 3.5" 2.25oz #6s and got 240+ at 40 yards inside a 10" circle.

[Nick_The_Tinkerer]

 

[mightyjoeyoung]

Actually back boring is taking a shotgun barrel with an certain inside diameter and phsically enlarging it with reamers/cutters to larger than the nominal, standard bore for that gun. OVERBORING is when the barrel is already over the nominal bore diameter for a given gauge right from the factory...like the 835.  It has a .775 bore or a 10 gauge barrel diameter. The reason for almost no forcing cone is simple in that the chamber is a 12 gauge but the barrel is a 10.  Don't need a forcing cone if the barrel is already that much larger than the chamber.

[Spit n Drum]

The 835 is a good gun for turkey hunting. The choke has to match the load, size of shot, and type of shot. I get good results from 2 1/4 oz. nitro loads M510c, H510c, and H51013a through a .695 Rhino choke. I got even better results from the old H51013m loads. Those 835's also improve alot from the deep cleaning and polishing. I got about a 20% improvement in the 10" after polishing. Good luck this spring.

[MossbergMike]

This is the first I have heard of this. Glad I just found that out. This will definitely change my patterning technique this up coming week. thanks.