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Old April 1, 2013, 11:57 AM   #1
Bill Daniel
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K&M vs Sinclair Primer hand press

Any one have any thoughts on comparing K&M's primer vs Sinclair's as to quality, durability ect. Is Sinclairs worth twice the cost of K&M's.
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Old April 2, 2013, 10:05 AM   #2
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Twice the cost?

The K & M retails for $110.00

The Sinclair retails for $114.99 from Brownells

Are you asking about the primer seating tool instead perchance?

If so, I have both, both are excellant and are of good quality. If you wish to impress your friends get the Sinclair, if you wish to impress your savings acct. buy the K & M.

BTW I purchased both of my Sinclair tooling from their Disc. table when they were still headquarted in Fort Wayne, IN.

Don't remember about the priming tool but the arbor press was discounted to $35.00, it was short the locking handle, made one when I got home for free.

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Old April 2, 2013, 01:14 PM   #3
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There are two K&M tools. The K&M Primer Deluxe ($52 at K&M, $45.36 AT Bruno Shooters Supply), which competes with the Sinclair on functionality, and the K&M Primer/Gage tool ($125 at K&M, $105.84 at Bruno) version that has a dial indicator gage.

These designs are all based on trying to meet Creighton Audette's parameters that were the subject of the last articles he wrote (Precision Shooting circa 1994, IIRC). He suggested primers should be thought of as analog rather that digital, as their sensitivity and speed of ignition varied with how firmly you seated them which controls setting the bridge (the thickness of priming mix between the anvil and the inside cup bottom. He went on to suggest a basic design that allows you to feel the primer anvil feet touch bottom in a primer pocket, and then you would seat deeper to set the bridge, also by feel.

All three work with one primer at a time. All three hold the case square to the primer seating punch. All three constrain the primer so it enters perpendicular to the pocket. All three use Lee Auto Prime type shell holders to adjust for the case size. All three have separate large and small primer rams and ram housings that have to be changed when switching out primer size.

Here are the differences:

The Sinclair is mostly stainless steel, and at 12 ounces has the most heft and the longer and thicker body to get your fingers around. The feel is the smoothest of the three by a small margin.

To use it, you insert a Lee shell holder into its shell holder head, and retain it with a a couple of set screws. As you screw and unscrew the head, the Lee holder is moved up and down over a thick-walled tubular nose on the primer punch housing that just goes through it. With the holder head loose, you place a primer in the hole in that nose and a case in the shell holder and tighten the holder head back down until the case is firmly against that nose. This is what keep it square to the primer. When you operate the handle, it presses a ram up through the hole in the nose that pushes the primer up into the primer socket in the case. The leverage is such that it lets you feel the anvil feet touch. You then use trial and error to learn the feel of how much harder you want to push the primer in after that.

On the minus side, it takes set screws to change the shell holder and you have to screw and unscrew a lot to change cases, so speed is not a feature. You have to be good enough at feel to gage how far you are setting the bridge.

On the plus side, you can adjust the ram position on its threads to obtain 0.005" or any other fixed protrusion of the ram from the end of the tubular nose of the punch housing, then just seat all the way to get that fixed primer set depth. This mimics the Forster Co-ax press primer seating system, which limits the ram to a fixed 0.005" deep, and this is a good general purpose number. It's a good way to ensure your self-loading service rifle type action with floating firing pin isn't finding the primer too soon. You can adjust it for uniformed depth primer pockets to get exactly the bridge set you want in this way.

K&M Deluxe
The K&M Deluxe is mainly carbon steel. Instead of set screws, it depends on the fit of its ram housing nose inside the Lee shell holder to retain it (I've got a couple it didn't quite fit through and that had to be slightly lapped open). The housing nose is spring loaded and rises as you press the handle to use a spring's force to square the case to it, so you don't have to screw down the shell holder housing to slip a case in and out. Adjusting the shell holder housing on this tool adjusts the leverage at the point the primer touches down, so you can alter its feel some. I like to leave it half a turn unscrewed, preferring the feel at that point. Like the Sinclair, you feel for primer anvil touch down in the primer pocket and learn the feel of uniform bridge setting beyond that point.

On the minus side, while you can theoretically fix primer depth by unscrewing the head far enough, you'd have to add a set screw to keep the adjustment, so I don't consider that the adjustment is real. The spring of the squaring nose had to be compressed, robbing you of a portion of the feel sensitivity you have with the Sinclair, but it's not bad. A bit less heft and finger feel.

On the plus side, the spring loaded sleeve makes the K&M faster to use since you don't have to tight the shell holder housing for each case. It's also a little faster to change shell holders in, since no set screws are involved. It's less than half the price of the Sinclair and still very high quality. It's not like you'd be sorry you bought it.

K&M Primer/Gage tool
This is the only tool made that lets you compress a bridge to an exact measured number of thousandths without uniforming primer pockets or selecting primers by height of their feet protruding from the pocket. It does everything Audette envisioned, but with better control than Audette's own proposed design could do.

To use the tool, you put a case into it the same as you do the K&M Deluxe tool, but you first put the primer open end down on a platform on the outside that moves with the seating ram. The platform turns to slip the primer under the tip of a dial indicator. You press the seater handle until the primer ram bottoms out in the flash hole, then rotate the gauge dial so zero coincides with the dial hand. You now have a gauge zeroed for the depth of the individual primer pocket and the height of the individual primer. You let the handle open and remove the case. You rotate the platform to release the primer. You put the primer into the ram housing recess, anvil-up this time. Return the case to the shell holder and proceed to seat the primer. The platform moves with the ram and when it presses the indicator to read zero, the anvil feet are just touching the bottom of the primer pocket. You can then press it in further by any additional number of thousandths you prefer to work with.

On the minus side, this is very slow going. I can only bring myself to use this for load development where I want every single variable minimized until I find the best load. I loosen my grip on variables afterward to learn which ones matter to that load in a particular gun. The spring loading of the dial indicator is added to those of the sleeve and ram, so this has the least sensitive feel of the three. Dick Wright at one point commented that he’d lost the patience to do it for his benchrest loads, but that Mrs. Wright had not and that Mrs. Wright was beating him at the matches at the time.

On the plus side, this is the only tool that gives fully measured control of primer seating depth. If you feel for primer anvil touch down, you can skip the zeroing and just look at where the indicator happens to be when you bottom out and advance it some additional number of thousandths. That speeds things greatly, but is less precise and it’s easy to pick up a thousandth or two in tolerance.

One last thing you need with this tool is some idea how much to set the bridge. Wright said Federal told him 0.002” beyond anvil contact for small rifle, and 0.003” beyond anvil contact for large rifle. I have a 1979 declassified document showing Olin (Winchester) and Remington recommending 0.002”-0.006” for both large and small primers. I recommend, if you get this tool, you check each lot of primers you buy by trying 0.002” through 0.006”, perhaps 20 rounds of each all with the same load, to see if you get a difference in muzzle velocity standard deviation. The lowest SD would tend to indicate the best ignition consistency, and that’s what you want.
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Old April 2, 2013, 08:57 PM   #4
Bill Daniel
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Join Date: February 10, 2000
Location: Bowling Green, KY.
Posts: 428
K&M vs Sinclair Primer hand press

jcwit- Thanks and indeed I meant "primer seating tool" Thanks for sharing your experience.
Unclenick- Thanks for the detailed explanation. The K&M Deluxe looks like the best option for me.
Thanks again to you both!
Prosecute criminals to the fullest extent of the law and their weapons will become harmless.

"Let us speak courteously, deal fairly, and keep ourselves armed and ready." Theodore Roosevelt 1903
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