[McKie]

The common wisdom seems to be that a lengthened forcing cone reduces recoil. Just yesterday a guy out at the range fired a few rounds from my 870 20 gauge, and said it kicked too hard, (!) and that I should get the forcing cone lengthened. Mostly, this guy knows what he's talking about, but can anyone explain to me why the hell a longer forcing cone should reduce recoil?

 

[javven]

I have a hard time believing a 20ga needs a forcing cone job. Does it recoil too much for you?

 

[McKie]

Hey, javven. No, I can shoot it all day with no problem. It's just that his comment rekindled my curiosity about the main question of whether longer cones actually affect kick.

 

[pigeonhunter]

Thats really for competition guns, where you'll want anything that can give you an edge.

 

[javven]

Yes, it can reduce recoil. This isn't always desirable, however - even in competition guns. Example, a 12ga might have the 12-bores opened and the cones lengthened, but the smaller bores will not (assuming a skeet gun with a sub-bore tube set). Reason?

Reliable setup for the other bbl. Of course, a mechanical conversion (subject for another article) negates the need for this.

 

[Bill M.]

I was told that lengthening the forcing cone on a 20 gauge with a 3" chamber really has little effect when shooting 2 3/4 inch shells anyway. In a sense it is already lengenthen some.

 

[Salmoneye]

The way I understand it is that lengthening the 'forcing cone' allows for a slightly more gradual rise in the spike of the pressure when the shell is fired...Basically makes it a more gradual 'push' instead of 'kick'...Same working pressures are reached, but the spike is reached over a split second longer time...

I agree that if you have a 3 inch chamber, just fire 2 3/4 inch shells...Same effect as lengthening the cone...

 

[winders]

I agree that if you have a 3 inch chamber, just fire 2 3/4 inch shells...Same effect as lengthening the cone...

Having a 3" chamber versus a 2 3/4" chamber when firing 2 3/4" shells does not have the same effect as lengthening the forcing cone. Chamber depth and forcing cone length are independent of each other.

The forcing cone length is measured from the point where the barrel starts constricting from shell diameter to actual bore diameter to the point where the actual bore diameter is reached.

To lengthen the forcing cone you have to lengthen the cone shape. In otherwords, you have to make the constriction more gradual which results in less severe angles. This leads to less deformed shot which leads to better patterns.

Scott

 

[uglydog]

At best, lengthening forcing cones flattens the recoil impulse as stated by Salmoneye but does not reduce the foot pounds of recoil. It is rather minor but may be noticed by some people and likely would have no affect on the setting of the triggers of an inertia gun. Lengthening the cones merely makes the transition from chamber diameter to bore diameter more gradual which lessens the deformation of lead shot. This phenomena is most noticeable in standard bore sizes with shot larger than #4 but does have a positive affect on smaller sizes. Using a short shell in a long chamber is nothing like lengthening the cones, the distance the shot has to travel to go from chamber diameter to bore diameter is still the same. Standard forcing cones of the past were in the 5/8"-3/4" range but many guns are now coming from the factory with cones of 1 1/2" of more. More than this length rapidly reaches the point of diminishing returns and increases the possibility of reaming the cones crooked. As for forcing cone length in sub-***** tube sets, Briley and Kolar have been using longer forcing cones for at least a decade that I'm aware of. My 28 ga Briley set for my 16 ga gun has 2 1/2" forcing cones as does the 20 ga set for an old damascus gun.

 

[McKie]

Thanks to all for the responses - seems to confirm my suspicions that the procedure might have a good effect on patterns, but minimal on recoil.

 

[Claydust]

seems to confirm my suspicions that the procedure might have a good effect on patterns, but minimal on recoil.

My wife had a BT99 done by a well known professional shop.

Neither she, nor I could detect any recoil reduction. She was dissapointed, this was a few years ago and the general thought at the time was that this would make the BT(( much easier for her to shoot.

Good thing she liked her 1100TA really well, anyway.