shot gun forcing cone question

[fox fire]

How can a man check a forcing cone lenght when lookin at a shot gun in the store

 The reason I'm asking is I'm thinkin of buy'n/tradin for a turkey gun, and if I remember the longer the forcing cone is the better it should shoot some of the heavier than lead shot, so I'm try'n to find out which manufacturer makes the better focing cones, but by lookin thru the barrel I dont know if I can see that much of a difference.
 
                                                                                             Thanx in advance

[gunnut69]

Bore mechanics is not my cup of tea but you likely won't be able to tell very much from a naked eye inspection. The biggest advantage of the long forcing cone seems to be less damage to the plastic wad column resulting in better, read denser patterns. Checking websites of the various makers is probably the most effective way to get this info. Of course this won't let you know if custom changes have been made to the gun in question. Backboring also has a serious effect on patterns and is said to reduce recoil, but I expect this is more because of the larger bore creating less pressure which will lower velocities and recoil... Patterns also tend to get better(tighter) as velocities lower at least that's been my obervation.. Screw in chokes really have made a big difference here and turkey gun patterns can be really improved by simply changing tubes.. My Browing BPS 10Ga. with the second tightest choke made produces very dense killing patterns with it's favored load all the way to 70 yards.. Of course my good friend Bob's Browning requires the tube .005 inch tighter to get the same effect.. Good luck and it won't be long 'til gobble time!!!!!

[fox fire]

From what I've dug around and found out is the longer forcing cones dont deform shot or disturb the shot load as bad which supposedly helps it throw a better pattern, but dont seem to make as much of a difference when using lead shot but helps the heavier than lead shot(tungsten and the like ) quite a bit.

 The lead shot deforms during it's trip thru the forcing cone because it's softer and the shot load stays together better,  the heavier than lead shot (since it's a harder material) dont deform and during the trip thru the forcing cone, and (supposedly) since it cant deform when the shot load makes contact with the forcing cone somethings gotta give, so the shot load gets bounced around (so to speak) and it starts to separate.

 I aint a gun smith and really cant say, but to me ther may be some thing to it because ther are a lot of turkey hunters and match shooters that have custom barrels made with a lengthened forcing cone or have a smith lengthen the cone in a factory barrel.

 I found some info on the backbored barrel but need to read it again before I make a say, I think browning barrels are backbored and (also Mossberg 835 and 935 but have a short forcing cone and a ruff bore) they have a longer forcing cone on some of ther barrels also, they call it the vector pro barrel (*** I THINK, I MITE BE WRONG ABOUT THIS *** ) and the Ithica turkey slayer has a longer forcing cone, a piece I read said Ithica manufactured this barrel with "exsessively long forcing cones on both ends of the barrel". ( I found this on GUN TEST.COM)

[gunnut69]

Actually the shot load can't really be jostled as it's being accelrated by the expanding gases from the powder charge. The lead shot is damaged by setback(acceleration of the shot by powder) and passage thru the forcing cones(front of chamber and in front of the choke section. Lead is often plated with copper to harden it a bit to better resist deformation as deformed pellets tend to leace the pattern as fliers thus degrading the pattern density. Heavy shot(other than bismuth) are so much harder than lead that in some instances they will 'bridge' in the forcing cones and if the steel is thin actually ring the barrel. Steel was especially bad and is the reason it was not reccommended for some guns(thin barrels). Back boring is simply giving a gun a larger bore than would be normal for that particular guage. It produces lowered pressures and velocities and recoil..

[fox fire]

 Thank ya sir, interesting how it all works.