Primer Pocket Uniformers -- Question

M

mkl

New member
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.
 
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.
 
Absolutely correct.

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