S&W 686 357MAG with .354" bore? - Page 2

LeadIsBest · 11-06-2009, 04:08 PM

Shoestring,
I thought you wanted your cylinder throats bigger than your boolit so they don't size it down?

For example; if you bore was .357" and you sized your boolits .358" then it would be best if the throats were at least .3585"

Do I have this backwards?

jameslovesjammie · 11-06-2009, 05:30 PM

Boolit should be bigger than the throat.

Thoat should be bigger than barrel.

When you fire the cartridge, the throat should align the boolit with the forcing cone by swaging it down, and the the forcing cone should finish the job and swage it down to barrel diameter.

Ed K · 11-07-2009, 05:42 AM

When it is said throat should be smaller than boolit, how will loaded rounds fit? I can understand it there were a leade or taper of some sort but if the throats are a straight cylinder, how can you chamber those rounds without force?

I thought ideal boolits were supposed to be about 0.0005" under throat diameter.

shooting on a shoestring · 11-07-2009, 06:19 AM

Jameslovesjammie has it right. Boolit should be bigger than throat, throat should be bigger than bore.

Ed K the answer is slight force. Grossly oversize and of course it can't load if your leading band has to swage way down into the throat. However, a thousandth over has not been a problem for me. Most of my loads don't have the entire leading band in the throat, just the leading edge of it.

anachronism · 11-07-2009, 08:42 AM

I too, think you have thread choke at the frame juncture. I've had a couple of 686s come from the factory this way. One wasn't too bad & it came out with fire lapping. S&W rebarreled the other one at no charge. The new barrel also had choke in it, but was lappable. My range rod wouldn't pass through either bore.

LeadIsBest · 11-07-2009, 11:05 AM

I was trying to get an idea if there was just a tight spot in the barrel if the whole thing was tight. I don't know if this is a good way to measure this but I started a slug down the muzzle about .250" but left enough out that I could pull it back out with pliers. The portion that was just inside the muzzle was .354" also. What do you think?

Ed K · 11-07-2009, 07:03 PM

Quote:

Originally Posted by shooting on a shoestring

Most of my loads don't have the entire leading band in the throat, just the leading edge of it.

In a revolver everything forward of the crimp groove is in the throat.

11-06-2009, 05:30 PM	#22
jameslovesjammie Boolit Master Join Date: Aug 2007 Location: Minot and Plentywood Posts: 409	Boolit should be bigger than the throat. Thoat should be bigger than barrel. When you fire the cartridge, the throat should align the boolit with the forcing cone by swaging it down, and the the forcing cone should finish the job and swage it down to barrel diameter. __________________ Looking for a Lyman 280642.

11-07-2009, 06:19 AM	#24
shooting on a shoestring Boolit Master Join Date: Dec 2006 Location: Near Austin Posts: 378	Jameslovesjammie has it right. Boolit should be bigger than throat, throat should be bigger than bore. Ed K the answer is slight force. Grossly oversize and of course it can't load if your leading band has to swage way down into the throat. However, a thousandth over has not been a problem for me. Most of my loads don't have the entire leading band in the throat, just the leading edge of it. __________________ "Time and money don't do you a bit of good until you spend them." - My Dad

11-06-2009, 04:08 PM	#21
LeadIsBest Boolit Mold Join Date: Nov 2009 Location: Roseburg, Oregon Posts: 10	Shoestring, I thought you wanted your cylinder throats bigger than your boolit so they don't size it down? For example; if you bore was .357" and you sized your boolits .358" then it would be best if the throats were at least .3585" Do I have this backwards?

11-07-2009, 05:42 AM	#23
Ed K Boolit Man Join Date: Apr 2006 Location: Central NH Posts: 138	When it is said throat should be smaller than boolit, how will loaded rounds fit? I can understand it there were a leade or taper of some sort but if the throats are a straight cylinder, how can you chamber those rounds without force? I thought ideal boolits were supposed to be about 0.0005" under throat diameter.

11-07-2009, 08:42 AM	#25
anachronism Boolit Master Join Date: Mar 2005 Posts: 574	I too, think you have thread choke at the frame juncture. I've had a couple of 686s come from the factory this way. One wasn't too bad & it came out with fire lapping. S&W rebarreled the other one at no charge. The new barrel also had choke in it, but was lappable. My range rod wouldn't pass through either bore.

11-07-2009, 11:05 AM	#26
LeadIsBest Boolit Mold Join Date: Nov 2009 Location: Roseburg, Oregon Posts: 10	I was trying to get an idea if there was just a tight spot in the barrel if the whole thing was tight. I don't know if this is a good way to measure this but I started a slug down the muzzle about .250" but left enough out that I could pull it back out with pliers. The portion that was just inside the muzzle was .354" also. What do you think?