Thread: choke boring

gidday team im looking at buying a 12ga o/u shottie, top barrel is full choke is it possible to ream it out to 3/4 size so i can shoot steel?

Easy peasy.ues the cylindrical stone that fits in power drill ..measure lots and go slow.

I have not done it but understand you must also extend the forcing cone as well

Nope...it's good to have long cones for perfect pattern for clays but yeah nah for real life...heck some of us still using shotguns made fifty or more years ago.before long cones were a thing.

I had though of setting it up in the four jaw, Dailing the taper (cone) and machining the 0.05 out then polishing with some 800 grit

Here is a full explanation from Dean, (he knows his stuff), if the forcing cones are no modified it can lead to increased chamber pressure and damage to the gun !

https://gunsmith.co.nz/blog/shotgun-...or-steel-shot/

Originally Posted by Micky Duck

Nope...it's good to have long cones for perfect pattern for clays but yeah nah for real life...heck some of us still using shotguns made fifty or more years ago.before long cones were a thing.

See my reply, are you confusing the choke with the "forcing cone" just past the chamber ?

I'm thinking forcing cone just past chamber yes. But the choke is in reality just a slight taper/restricting of barrel diameter. When steel first hit our shores.panic panic.many good guns got butchered.many got reamed,the lucky ones got threaded and aftermarket chokes screwed in. I'm a cheap Hua so we opened our chokes ourselves using crude methods but they have worked fine for twenty years. If you open up a choke you are reducing the construction... ANY reduction from full makes them now no different to a new steel comparable choke.and some new steel chokes that extend PAST muzzle are just as tight as old full was.

Originally Posted by Fssprecision

Here is a full explanation from Dean, (he knows his stuff), if the forcing cones are no modified it can lead to increased chamber pressure and damage to the gun !

https://gunsmith.co.nz/blog/shotgun-...or-steel-shot/

look at the date....that article and many like it caused most folks to "drink the cooliad' and ship guns off for work to be done...WE HAVE LEARNED.... with modern steel loads the wads themselves are 100 times better than wads were back then...the days of barrels being scored by steel shot are thing of the past.
to put it in perspective I have an under n over bakail...arguable one of the tightest choked guns out there (top barrel) IF you simply measure the size of the hole in end of barrel...the bottom barrel measures half choke the top over full. we have used steel loads through it for ten years with two conditions...and these are I believe critical...loads of LESS then 35grms for top barrel and #3 or smaller only...I have used some #2 steel but in lighter 32grm loadings..by dropping payload and shot size it allows shot to squeaze inwards easier and prevent the "bridging" sometimes seen in early loads...
having cut open a kent load that had been sitting in maimai for 3 or more years I was shocked to see steel shot had rusted into a solid lump...that would have hurt to fire it...
also read in tht article what chokes he recommends..... absolute bollocks depending on load used. EG the federal blackcloud with flightstopper wad through an open choke will patttern tighter than a remington hypersonic through half choke or quarter choke...and there are spreader loads out there with cube shaped shot...the n winchester Xpert with its welding slag and different shot sizes (its one of the very best loads and I would happily use it all the time..it just kills) we now have huge selection of loads..back when article was written that wasnt the case.... and 1100fps loads sucked1200fps loads sucked 1300fps loads sucked less..1400fps HELLO now we getting somewhere,1550fps loads and ducks died just as good as we could point them....the 16-1700fps boot like fook and I cant kill ducks any deader with them and dont believe they patterned worth a damn.possibly ok in over bored gass powered semi with expensive aftermarket chokes....
Ive never altered forcing cone..just past chamber..but sure as shit have opened up chokes to open up pattern..Ive even sawn barrel off below choke and heated barrel and put jug choke back in...and you dont want to bet against me if Im using that particular gun LOL.... also reading it..2" loads??? 2 3/4" maybe..... no mention of 3 1/2" as they werent even invented then....
read article carefully and what is being said is if the gun is old,rattly,loose action elcheapho...it probably wont last long using steel...yip can agree with that.