M29-2 44 Mag. forcing cone specifications

[243winxb]

44 Magnum. Forcing cone diameter- SAAMI doesnt seem to have a specification on it. Online a guy said groove diameter X 1.05" = diameter.
My S&W 44 mag would have a forcing cone mouth diameter of .450" using this math.

The photo shows .451" diameter bullet in the barrel. Not even close to a tight fit.

The flat base bullet has stopped in the barrel where it measures .451" Seems like a lot of slop?

The factory set the barrel back last year. & cleaned up the forcing cone.

Does anyone have specifications of what it should measure?

Thank you.

 

[BLUEDOT37]

The number I've seem is .020" larger than nominal bullet diameter, so that'd be .429+ .020= .449"

Another way to gage it is to take a fired (unsized) cartridge & see how much goes into the forcing cone to get an idea.

If it's a little larger & you aren't having any related issues don't worry about it.

Most of my revolvers that I've checked are larger but don't cause a problem.

.

 

[armorer951]

Brownells sells barrel plug gauges to verify proper throat diameter.....

BROWNELLS BARREL CHAMFERING PLUG GAUGES | Brownells

 

[garbler]

As armorer951 advises the forcing cone depth plug is available at Brownells and my advice is never attempt to re-cut a cone without this plug gauge. It’s not expensive really and like ‘ go-no- go ‘ chamber gauges it’s just good insurance. It literally takes just a turn too much or too much pull to ruin your barrel with these tools.

 

[243winxb]

A .430" flat base bullet goes in about .258" deep with a factory forcing cone.
A .451" flat base bullet goes in about .100"

A 11 degree may go .265" from barrel face to the .430" barrel diameter?

Would seem my forcing cone is ok.

Using very crude measurements & eyeballing it.

Not going to change anything. Just snowed in & bored.

Thank you.

 

[WR Moore]

OK, the 0.020 in over groove diameter is not carved in stone and handed down from a mountain top. The OD of the barrel shank has to be taken into consideration. Take a J frame as an example.

Once upon a time I ran across a listing of the maximum forcing cone diameters (as published in the American Rifleman?) and recorded it*. Per that list a .44 Spl/Magnum forcing cone should be 0.445 inches nominal. Measuring that accurately would require either pin gauges or the gauge Armorer951 suggests.

Your forcing cone seems a bit generous. But, there are various other designs of forcing cones than the straight taper from the barrel end. If it shoots OK, don't obsess over it.

*FWIW, the following was the listed spec for maximum forcing cone OD +/- 0.005 inch.

.38/.357- 0.370 in (have seen a lot of factory J/K frames at ~0.365 in).

.41- 0.425 in

.44- 0.445 in

.45- 0.470 in.

 

[243winxb]

photo- 45 acp revolver 11 degree.

Revolvers/ barrels/forcing cones

Takes the whole bullet? Seems odd? A 45 acp revolver with a new 11 degree throat. 200gr 45 swc bullet
a 625 S&W.

I had some heavy leading when testing a new bullet & load. The old loading did ok when first tested, when gun was returned from S&W.

 

[WR Moore]

There was a thread on here awhile back about a forcing cone design that-at least at one time-supposedly had some popularity with the bullseye/PPC set. Like a number of other similar innovations-like cylinders shortened to just barely over the length of a wad cutter cartridge-the benefit may be entirely theoretical.

That particular thread had to do with lengthening the forcing cone until the point where the bullet engaged the rifling was either within the frame or possibly the entire bullet was within the barrel. As noted above, i'm not sure there's a measurable accuracy difference and/or which way it may go.

Your link shows someone who's either a believer in that system or someone who makes $$$ off those who do. OK, we're all bored, just don't take everything you see on the internet seriously.

 

[Protocall_Design]

Taylor throating is a system where there is a straight counterbore (cylinder) in the back of the barrel that is bullet diameter, then tapered into the rifling. There is a small forcing cone funnel at the very back of the barrel. Some seem to like it.

I have never tried it because I have always been able to get tight groups with conventional means. To me, it seems redundant because you already have a throat in the front of the chamber to serve that purpose.

That is also the reason that case length is normally not a big deal (to me). For a shorter case in a longer chamber, you still have the chamber throats to line up the bullet before it goes into the barrel.

 

[243winxb]

Taylor Throat

Ok. Ty. Taylor throat. I get it now. The Taylor Throat

 

[trulyapostolic]

What Jerry was trying to show with that thread on Bullseye-L was the Taylor Throat allows the bullet to fully leave the cylinder before engaging with the rifling. The dimensional design of the Taylor Throat will center the bullet in the barrel as it eases it into the rifling at 1.5 degrees. It's safe to say that very few revolvers have PERFECT cylinder chamber/throat to barrel and forcing cone alignment. Taylor Throating helps to alleviate issues caused by this misalignment that can't be improved by an 11 or 5 degree forcing cone recut.

 

[BLUEDOT37]

I like the 5° cutter that Brownell's has in their Chamfering Tool Kit.

I've used it on several of my revolvers to smooth out the factory forcing cone (FC) jobs.

I was lucky enough to get one of the early M66-8s when they came out. A batch of them had FCs way to small & people were reporting unusual amounts of debris (lead & copper jacket pieces) being ejected from the barrel-cylinder gap.

I found mine was bad too before I ever fired it & got to use my Brownell cutter one more time & get my $$ worth out of it.

Too bad the 5° cutter only comes for 38/357s.

I didn't invest in Brownells Forcing Cone Gages. They didn't seem like a good value & I don't think, for the average over the counter revolver, it has to be an exact measurement, witness what I previously observed.
.

PS: I bought an extra set of the brass pilots with my kit so I'd have two of each. I like to have one pilot on each of the extreme ends of the rod, within the barrel, to keep things aligned rather than rely on the externally used tapered center guide staying in place at the other end.

.



.
.



.
.



.
.



.
.



.

 

[6string]

Another objective in using the Taylor throat or other "long" forcing cones is that it can help eliminate thread choke issues caused by "crush fit" barrel-to-frame threading.