cutting a forcing cone to 11°

[Wally]

Have been told that on revolvers that shoot CBs that one should have a FC cut to a 11° taper for the best accuracy. Brownells sells the tool cutter for $50 that works for calibers from .38 to .45--has anyone tried this? It is a bit daring to me to try it and I'd like to read about the experiences of others that have already tried it.

Wally

[S.R.Custom]

This only works on a new barrel, or if you set the old barrel back... Factory forcing cones are typically cut at 18°, which is wider than the 11° of the Brownells tool. (In other words, you can't put back what already has been cut away.)

As for the efficacy of the 11° cone itself... well... it varies. In and of itself, I've not found it to enhance accuracy at all. What it does do is leave more meat at the barrel throat-- which is a good thing in the magnums. But that's about it.

In revolvers with mis-aligned chambers/bores, the 11° cone actually has to be cut deeper into the barrel than an 18° cone to yield the same throat diameter sufficient to 'capture' all of the bullet diameter as it transitions from the chamber to the bore. This deeper cone creates more freebore in the barrel throat, which in turn diminishes accuracy.

I've found the most accurate forcing cones are the 18° ones, cut no deeper/wider into the throat than is absolutely necessary to capture the bullet as it leaves the chamber. Of course, this assumes that any bore/chamber alignment maladies have been corrected first.

[Wally]

Thanks for the feedback...I guess I'll use them "as is"... If I may ask how often do you clean the forcing cones in your pistols...what method do you use?

[S.R.Custom]

Whenever I clean the bore... A dry, bronze brush pushed through the bore is usually sufficient. In particularly ornery situations, I'll chuck up a piece of cleaning rod in a drill and spin a dry brush in the cone.

[Wally]

A great idea....doesn't the brush fall apart after a short time?

[S.R.Custom]

It does... but it's still cheaper (and much more effective) than a collection of potions and solvents.

And I use the "downhill" method of brush use... when a 45 caliber brush is no longer effective in a .45, I use it in a .40 caliber, etc...

[Wally]

Sounds like me, as I do the same...however bristles start to break off and soon the "core" looks like an old Christmas tree--with no needles...

I have a lot of trouble with gunk buildup in my .357/.44 Magnum revolver cylinders when I shoot Specials through them--the only effective method that cleans them out is a old brush coated with 0000 steel wool that is spun in on a drill. Any ideas of a better method?

[S.R.Custom]

Not really... but I try to keep steel out of the cleaning process. Unnecessary wear & tear, you know...

I save all the brass trimmings from my case trimming operations in a coffee can. It makes a handy brass wool for the same application you use the steel wool for...

[missionary5155]

Another solution to the "ornry forcing cone cleanup" is the standard Green scrub pad my wife uses to scrub out the pots and pans. So far I have not seen any evidence of metal deterioration... I do not use it weekly either... just when that clot is there and does not want to budge.

[S.R.Custom]

Gawd, those are worse than steel wool! Those pads are chock full of aluminum oxide, and will abrade steel very quickly. If you have any doubt as to that, try scrubbing the outside of your gun with it. (I'm kidding-- don't do that.)

[dwtim]

Wally,

Have you considered the copper variant of these?

http://www.choreboyscrubbers.com/metal.htm


I love SuperMag's choice of the word "potion". As in magic potion. Magic is certainly a requirement to make some of those noxious chemicals work as advertised. I use new bulk brushes with sharp ends on the bristles. For anything thicker, I have a Lewis lead remover.

[Wally]

I have tried..the copper material doesn't seem to hold up well when spun in a drill. You need to pack it tightly to make it effective and it breaks apart very quickly--the steel wool is so much easier. Have also tried the brush w/steel wool and attached a "patch" of aluminum mesh or bronze...that works quite well and is my latest method.

[S.R.Custom]

Again, be warned about the use of aluminum products-- aluminum oxide is prevalent on such tools. That's why the stool shooter crowd uses brass cleaning rods. ;)

[Wally]

Yes, Alumimum will be coated with the abrasive Aluminum Oxide, but it is a very thin and very fragile layer, also very, very fine...it will do no damage whatsoever as I have used it for years and have carefully checked.

[felix]

Certainly no worse than the grit flying around the river where I shoot. Using high antimony lead with little compensating tin is prolly even more abrasive than the aluminum oxide covering. In other words, those fine abrasives act as a premium polisher for the most part. The downside of this logic appears at the throat where wear and tear will not be uniform unless all is perfectly concentric. This is why rounds should not be indexed at all. Indexing will force a non-concentric wear pattern. ... felix

[Firebird]

You can get bronze wool (http://www.brownells.com/aspx/NS/store/productdetail.aspx?p=7391&st=&s=) from Brownells. Should work just the same as fine steel wool but can't scratch steel.

[Wally]

Yes, that would be better---I have to admit that I am too cheap to bother with it---0000 steel wool is so fine and fragile that I have yet to find that it has damaged my cyliders as I have used it for over 20 years. I do admit that using bronze wool would be preferable.

[S.R.Custom]

Certainly no worse than the grit flying around the river where I shoot. Using high antimony lead with little compensating tin is prolly even more abrasive than the aluminum oxide covering. In other words, those fine abrasives act as a premium polisher for the most part.

Which is a fancy way of saying "wear"... I'm not trying to be argumentative, but I've found it to be good policy to eliminate sources of unnecessary wear wherever possible. A good revolver is pricey and generally hard to find, and once found and invested in, I try to make it last as long as possible. :D

[44man]

Supermag is right on the money. No steel wool or Scotch Brite. Only use bronze brushes or wool. I do use both bad things in shotgun barrels when they get bad with some rust or pitting. Guys bring some real crud here for me to take care of.
I find M-Pro 7 with a bronze brush will remove almost all crud from cylinders. It will take almost all of the carbon out of the pores of steel.
One thing you can use Scoth Brite on is the outside of stainless revolvers. It will remove a scratch fast. When you see how it works you will think twice about putting it inside your gun. You might as well use valve grinding compound.

[Wally]

What is a M-Pro 7....I never heard of it before...thanks...

[felix]

http://www.pantheonchemical.com/mpro7.htm

... felix