Lengthening the forcing cone......

[kotengu]

I've been reading up in the "back issues" of THR and TFL and lengthening the forcing cone seems to be a popular thing to do, and it seems like it's mostly done to improve the patterns of buckshot.

Is there any down side to having this done? Will it hurt my bird shot patterns, or slug accuracy? Could it increase pressures or wear out my barrel faster (can a shotgun barrel EVER wear out?)?

Is there a set "length" to increase it, or does it differ for which shotgun you're using, and what you want it to do? How much should I expect to pay a 'smith to do this for me, and what kind of questions should I ask to make sure he knows what he's doing?

Last but not least - if this is so great, why do the guns not come this way?

Sorry for all the questions - I've been searching and reading, and while some of these are partially answered, it seems like the more I read the more questions I had.......

Thanks in advance!

 

[9mmMike]

I have had the forcing cone done on several barrels.
It does not hurt anything and seems to be one of the few honest to goodness, no downside modifications that you can have done.
It is supposed to improve pattern as well as reduce felt-recoil.
My 870's are all soft-shooters and I suspect that the forcing cone has some part in that.
The guys who did mine are top notch shotgun smiths called .
Allem's Guncraft and I highly recommend them. I think it cost me about 40.00.
For my 870's the standard length seems to be 2.5 inches.
I have read that some of the newer SG's are now coming with barrels that already have lengthened forcing cones.
Mike

 

[kotengu]

Thanks for the quick reply, but I guess you've brought up another question - how do I tell if mine has been cut or not?

 

[9mmMike]

Pull the barrel off and look through from the chamber end. If you can see a step just passed the chamber, yours is not lengthened. When they alter the forcing cone, they will basically lengthen the "step" so that it will be a gradual transition from the chamber to the bore.
In mine, I can see the tapered cone as a shiny section just after the chamber.
Mike

 

[Dave McCracken]

The forcing cone is a funnel just in front of the chamber where the transition from the hull to the bore is accomplished.

In days of yore they were cut short for the most part to enable the fiber wads and slow powders of the time to build up enough pressure to produce good velocity.

Plastic wads driven by modern powders and higher brisance primers play by different rules. A longer cone shortens the pressure spike and felt recoil is a bit less. The important thing though is that pellet deformation is less,thus producing patterns with fewer pellets leaving due to not being round. The pattern is denser, but not tighter.With most target loads, this can amount to another 50-75 pellets in that pattern, definitely an improvement.

Proper length on a long cone is a much debated subject. Two good smiths I know say that about 1 1/2" is optimum.

A cone job costs about $50. This includes a good polish on the new surface metal.

There seems to be no downside.

As to why they don't come this way, some do. All do not because the average shotgunner really doesn't care.

 

[PJR]

In a couple of very limited circumstances, there are potentially a couple of downsides to lengthening the cones.

In certain countries, the UK for example, a barrel modification of this nature would take the gun out of proof and it could not be resold.

Secondly, on a gun with thinly struck barrels such as a light European side by side, lengthening the cones could remove metal ahead of the chambers and take the barrels below safety minimums.

In the vast majority of situations however, lengthening the cones doesn't have a downside, it's not an expensive modification and it seems to improve patterns and reduce recoil.