Primer Pocket Uniformers -- Question

mkl · February 25, 2018, 01:48 PM

I seem to recall that on several threads in here some replies to questions regarding uniformers state that the tool reams only the sides of the primer pocket and not the bottom.

My confusion lies in that I just looked at my Sinclair carbide uniformers and they definitely have a cutting edge at the bottom which will deepen the pocket if necessary.

Either I'm confusing a reamer with a uniformer or am making another mistake in the definition of the tool that cuts an undersized (diameter) or a shallow(depth) primer pocket back to standard dimensions. My Sinclair uniformers seem to do both.

Clarification of correct definitions appreciated.

condor bravo · February 25, 2018, 02:22 PM

The uniformer only reams the primer pocket to the optimum depth. If they would ream on the sides, that would result in a loose pocket. The better uniformers like the Redding are non-adjustable for depth and accordingly are set to the proper reaming depth, usually considered to be around .003 below flush.

std7mag · February 25, 2018, 04:32 PM

Absolutely correct.

There is a crimp remover if your shooting military brass. Otherwise you'll likely never get the primer in the hole.

**Unclenick** · February 25, 2018, 06:28 PM

A primer pocket uniformer, like the Sinclair, has smooth sides and cutting edges on the end (tip) for cutting the depth of the primer pocket to a specific value. A primer pocket reamer has cutting edges along the sides and a smooth flat on the tip so it can only cut the pocket profile but not its depth.

There exist square ended chucking reamers that can cut in both directions at once, and I'm not sure why that design profile has never shown up in a reloading tool. It is possible that it has been tried, but that it was found too difficult to cut all the way to full pocket depth by hand without wobbling enough that the side teeth opens the primer pocket diameters too much.

mkl · February 25, 2018, 06:59 PM

Thanks all. That clears it up quit well.

rottdogsparky · February 26, 2018, 10:16 AM

So this begs a question at least for me what does a swager do? Depth and concentricty?

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condor bravo · February 26, 2018, 10:38 AM

The swager is for compressing outward, or swages, the upper portion of the primer pocket with military cases having crimped in primers, thereby removing the crimp. It does not affect the depth at all.

**Unclenick** · February 26, 2018, 11:40 AM

Rottdogsparky,

The swagers only affect pocket width, so they are analogous to the primer pocket reamer, but work by forcing a ram with the SAAMI pocket dimension profile into the pocket rather than cutting away the excess brass. Either will clear military crimps or will loosen the overly tight primer pockets found on some foreign brass. The swagers with an anvil inside the case also flatten out flash hole burrs and can bend them over the flash hole, so be prepared to run a drill bit through the flash holes afterward or to use a deburring tool before swaging them to avoid the problem.

rottdogsparky · February 26, 2018, 12:39 PM

Great recommendations! I learn something new everyday and I guess the next question begs what is the best process to use 1 for plinking Rounds and 2 if you want to make more accurate rounds what is the best procedure?

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T. O'Heir · February 26, 2018, 01:33 PM

"...what does a swager do..." Same thing as the reamer but without cutting.

condor bravo · February 26, 2018, 01:52 PM

It's not really a question of which process is best since in many cases neither process is needed. But instead if one process is called for. Use the swager or reamer if using military brass that has crimped in primer pockets. That is a necessity.

Use a uniformer if you can tell that new primers are not seating below the case head slightly. Primers seating above the case head are probably not seated all the way however so make sure the primers are bottoming out before using a uniformer. High primers can result in a premature detonation prior to using the trigger, referred to as a slam fire. This is a consideration with semi-auto rifles with free floating firing pins. If using a semi-auto rifle, it can be a good idea to use a uniformer just to make sure primers will seat properly below flush.

**Unclenick** · February 26, 2018, 02:35 PM

I once bought some bulk 45 Auto Match brass made by IMI that had primer pockets so tight I actually crushed a few primer trying to seat them, and many others wouldn't seat fully with my Square Deal's normal seating stroke. Those cases all went through my Dillon 600 to get them working, but I didn't need to alter the depth.

As to process, if you are shooting a light plinking load in a pistol, you can probably ignore flash hole burrs or just use a drill bit (5/64" is close enough for large flash holes) and push it through to get the burrs out of the way after swaging. Cutting them off matters mainly to precision rifle loads with harder to ignite or very slow powders.

Gary Wells · February 26, 2018, 02:44 PM

Do not use on nickel plated cases. Will definitely shorten the lifespan of the cutting tool surface.

February 25, 2018, 01:48 PM	#1
mkl Senior Member Join Date: April 25, 2008 Location: DFW area, Texas Posts: 494	Primer Pocket Uniformers -- Question I seem to recall that on several threads in here some replies to questions regarding uniformers state that the tool reams only the sides of the primer pocket and not the bottom. My confusion lies in that I just looked at my Sinclair carbide uniformers and they definitely have a cutting edge at the bottom which will deepen the pocket if necessary. Either I'm confusing a reamer with a uniformer or am making another mistake in the definition of the tool that cuts an undersized (diameter) or a shallow(depth) primer pocket back to standard dimensions. My Sinclair uniformers seem to do both. Clarification of correct definitions appreciated.

February 25, 2018, 02:22 PM	#2
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	The uniformer only reams the primer pocket to the optimum depth. If they would ream on the sides, that would result in a loose pocket. The better uniformers like the Redding are non-adjustable for depth and accordingly are set to the proper reaming depth, usually considered to be around .003 below flush. __________________ Ouch, the dreaded "M-1 thumb", you just know it will happen eventually, so why not do it now and get it over with??

February 25, 2018, 06:28 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	A primer pocket uniformer, like the Sinclair, has smooth sides and cutting edges on the end (tip) for cutting the depth of the primer pocket to a specific value. A primer pocket reamer has cutting edges along the sides and a smooth flat on the tip so it can only cut the pocket profile but not its depth. There exist square ended chucking reamers that can cut in both directions at once, and I'm not sure why that design profile has never shown up in a reloading tool. It is possible that it has been tried, but that it was found too difficult to cut all the way to full pocket depth by hand without wobbling enough that the side teeth opens the primer pocket diameters too much. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 26, 2018, 10:38 AM	#7
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	The swager is for compressing outward, or swages, the upper portion of the primer pocket with military cases having crimped in primers, thereby removing the crimp. It does not affect the depth at all. __________________ Ouch, the dreaded "M-1 thumb", you just know it will happen eventually, so why not do it now and get it over with?? Last edited by condor bravo; February 26, 2018 at 11:32 AM.

February 26, 2018, 11:40 AM	#8
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	Rottdogsparky, The swagers only affect pocket width, so they are analogous to the primer pocket reamer, but work by forcing a ram with the SAAMI pocket dimension profile into the pocket rather than cutting away the excess brass. Either will clear military crimps or will loosen the overly tight primer pockets found on some foreign brass. The swagers with an anvil inside the case also flatten out flash hole burrs and can bend them over the flash hole, so be prepared to run a drill bit through the flash holes afterward or to use a deburring tool before swaging them to avoid the problem. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 25, 2018, 04:32 PM	#3
std7mag Senior Member Join Date: June 23, 2013 Location: Central Taxylvania.. Posts: 3,609	Absolutely correct. There is a crimp remover if your shooting military brass. Otherwise you'll likely never get the primer in the hole.

February 25, 2018, 06:59 PM	#5
mkl Senior Member Join Date: April 25, 2008 Location: DFW area, Texas Posts: 494	Thanks all. That clears it up quit well.

February 26, 2018, 10:16 AM	#6
rottdogsparky Junior Member Join Date: December 13, 2017 Posts: 10	So this begs a question at least for me what does a swager do? Depth and concentricty? Sent from my SM-G950U using Tapatalk

February 26, 2018, 12:39 PM	#9
rottdogsparky Junior Member Join Date: December 13, 2017 Posts: 10	Great recommendations! I learn something new everyday and I guess the next question begs what is the best process to use 1 for plinking Rounds and 2 if you want to make more accurate rounds what is the best procedure? Sent from my SM-G950U using Tapatalk

February 26, 2018, 01:33 PM	#10
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	"...what does a swager do..." Same thing as the reamer but without cutting. __________________ Spelling and grammar count!

February 26, 2018, 01:52 PM	#11
condor bravo Senior Member Join Date: August 23, 2014 Location: Nevada/Ariz/CA Posts: 1,753	It's not really a question of which process is best since in many cases neither process is needed. But instead if one process is called for. Use the swager or reamer if using military brass that has crimped in primer pockets. That is a necessity. Use a uniformer if you can tell that new primers are not seating below the case head slightly. Primers seating above the case head are probably not seated all the way however so make sure the primers are bottoming out before using a uniformer. High primers can result in a premature detonation prior to using the trigger, referred to as a slam fire. This is a consideration with semi-auto rifles with free floating firing pins. If using a semi-auto rifle, it can be a good idea to use a uniformer just to make sure primers will seat properly below flush. __________________ Ouch, the dreaded "M-1 thumb", you just know it will happen eventually, so why not do it now and get it over with??

February 26, 2018, 02:35 PM	#12
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	I once bought some bulk 45 Auto Match brass made by IMI that had primer pockets so tight I actually crushed a few primer trying to seat them, and many others wouldn't seat fully with my Square Deal's normal seating stroke. Those cases all went through my Dillon 600 to get them working, but I didn't need to alter the depth. As to process, if you are shooting a light plinking load in a pistol, you can probably ignore flash hole burrs or just use a drill bit (5/64" is close enough for large flash holes) and push it through to get the burrs out of the way after swaging. Cutting them off matters mainly to precision rifle loads with harder to ignite or very slow powders. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 26, 2018, 02:44 PM	#13
Gary Wells Senior Member Join Date: August 22, 2009 Posts: 180	Do not use on nickel plated cases. Will definitely shorten the lifespan of the cutting tool surface.