reducing .357" bullets to .355" ?

SL1 · February 5, 2011, 09:39 PM

Has anybody tried using the Lee cast bullet push-through sizing devise to reduce the diameter of plated or jacketed bullets? If so, how does it work? I am particularly interested in any experience doing that with Gold Dots.

SL1

Ideal Tool · February 5, 2011, 09:55 PM

Hello, SL1. With plated bullets, would work ok, but you had better have one big sturdy press for jacketed. The principle of bullet swaging is in expansion..taking a slightly undersize jacket & filling it with lead & putting it under pressure to bring bullet to die I.D. The jacket material, being springy, tries to resume it's original size, therby gripping the lead tightly. the lead core for the most part remains at swaged size due to it's softness. When you size down that jacket..you are compressing that lead core..remember it tends to remain at sized dimensions..while that springy jacket wants to return to .357" dia. result is a loose core..not too good for accuracy.

Jim Watson · February 5, 2011, 10:05 PM

The barrel will size it down in less than a millisecond with a few pounds pull on the trigger. And do it safely as long as the loaded round will chamber freely.

If it is tight in the chamber so that the case neck cannot expand to release the bullet, THAT will generate excessive pressure. That is what Extreme Experimenter Clark calls "bullet pinch" and is dangerous.

Adamantium · February 5, 2011, 10:47 PM

You may consider slugging your barrel as well. My 9mm slugs at .357 anyway and while every caliber can have barrels slightly out of spec it just seems much more common in 9mm listening to other people.

vladan · February 5, 2011, 11:42 PM

IMO it is not needed, I have loaded .357 bullets in 9mm and .357sig in both diameters - .357 and the same bullets sized trough LEE sizing die to .355 with identical results. So yes, you can size them down ( jacketed as well as plated or lead) to .355 or leave them in .357.

Another thing to consider is the real bore of your pistol, I have noticed that when I slugged my barrels, the dimensions between 7 barrels I have ( 9mm Luger and .357sig ) vary from .3545 to .358

SL1 · February 6, 2011, 11:17 AM

My barrels slug at 0.3549" to 0.3553".

And, the .357" bullets don't slide into my fired 357 Sig case mouths (like the .355" bullets do).

I guess I could make a casting of my chamber throats to see how much clearance I have. But, that means I would REALLY need to pay attention to brass thickness at my various case mouths for any reloads using .357" bullets.

I am really just thinking about swaging-down Gold Dots to get a bullet with a cannelure for my 357 Sig. I don't THINK I would get "jacket" rebound with those because they are really plated, so the "jacket" is less springy and is bonded to the lead. The way those bullets are manufactured involves multiple swaging steps after the plating process. I would just be adding one more.

I really don't like lead in high-pressure auto-loaders.

I do have a cannelure tool. But, my past experience with it is that it can bulge the bullet on either side of the cannelure, potentially leaving me with the need to swage that bulge back down again to avoid chambering problems and perhaps "bullet pinch." Hence, the question about swaging is still pertinent, even with the tool.

SL1

February 5, 2011, 09:39 PM	#1
SL1 Senior Member Join Date: November 8, 2007 Posts: 2,001	reducing .357" bullets to .355" ? Has anybody tried using the Lee cast bullet push-through sizing devise to reduce the diameter of plated or jacketed bullets? If so, how does it work? I am particularly interested in any experience doing that with Gold Dots. SL1

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February 5, 2011, 09:55 PM	#2
Ideal Tool Junior member Join Date: October 6, 2010 Location: Michigan Posts: 1,080	Hello, SL1. With plated bullets, would work ok, but you had better have one big sturdy press for jacketed. The principle of bullet swaging is in expansion..taking a slightly undersize jacket & filling it with lead & putting it under pressure to bring bullet to die I.D. The jacket material, being springy, tries to resume it's original size, therby gripping the lead tightly. the lead core for the most part remains at swaged size due to it's softness. When you size down that jacket..you are compressing that lead core..remember it tends to remain at sized dimensions..while that springy jacket wants to return to .357" dia. result is a loose core..not too good for accuracy.

February 5, 2011, 10:05 PM	#3
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,528	The barrel will size it down in less than a millisecond with a few pounds pull on the trigger. And do it safely as long as the loaded round will chamber freely. If it is tight in the chamber so that the case neck cannot expand to release the bullet, THAT will generate excessive pressure. That is what Extreme Experimenter Clark calls "bullet pinch" and is dangerous.

February 5, 2011, 10:47 PM	#4
Adamantium Senior Member Join Date: June 6, 1999 Location: El Paso, TX Posts: 1,021	You may consider slugging your barrel as well. My 9mm slugs at .357 anyway and while every caliber can have barrels slightly out of spec it just seems much more common in 9mm listening to other people.

February 5, 2011, 11:42 PM	#5
vladan Senior Member Join Date: March 14, 2010 Location: Central Florida Posts: 813	IMO it is not needed, I have loaded .357 bullets in 9mm and .357sig in both diameters - .357 and the same bullets sized trough LEE sizing die to .355 with identical results. So yes, you can size them down ( jacketed as well as plated or lead) to .355 or leave them in .357. Another thing to consider is the real bore of your pistol, I have noticed that when I slugged my barrels, the dimensions between 7 barrels I have ( 9mm Luger and .357sig ) vary from .3545 to .358

February 6, 2011, 11:17 AM	#6
SL1 Senior Member Join Date: November 8, 2007 Posts: 2,001	My barrels slug at 0.3549" to 0.3553". And, the .357" bullets don't slide into my fired 357 Sig case mouths (like the .355" bullets do). I guess I could make a casting of my chamber throats to see how much clearance I have. But, that means I would REALLY need to pay attention to brass thickness at my various case mouths for any reloads using .357" bullets. I am really just thinking about swaging-down Gold Dots to get a bullet with a cannelure for my 357 Sig. I don't THINK I would get "jacket" rebound with those because they are really plated, so the "jacket" is less springy and is bonded to the lead. The way those bullets are manufactured involves multiple swaging steps after the plating process. I would just be adding one more. I really don't like lead in high-pressure auto-loaders. I do have a cannelure tool. But, my past experience with it is that it can bulge the bullet on either side of the cannelure, potentially leaving me with the need to swage that bulge back down again to avoid chambering problems and perhaps "bullet pinch." Hence, the question about swaging is still pertinent, even with the tool. SL1