Size of primers

alan self

Where can find the sizes of primers? A list of measurements.Like to make some gauges to check used cases.

nononsense

alan self,

Here are the dimensions:

http://www.jamescalhoon.com/primers_and_pressure.php

Best.

amamnn

Since that info is 14 years old, you might want to contact the manufacturersor verify it for yourself, which is ALWAYS the best way. Specs change, and at least one of those published on that URL is incorrect by my micrometer.

nononsense

amamnn,

The age of this data shouldn't have anything to do with the accuracy of the data. Data of this type doesn't change with any kind of frequency unless it's an insignificant change. Otherwise all of the brass manufacturers would need to adjust their specifications to match the dimensional change on that primer. This will hold true so long as the batch measured for this chart wasn't defective. Contacting the manufacturers, while possible, is not feasible simply because they won't have the data on hand nor are they likely give it out to John Q. Public.

The possibilities are that the dimension you state as being wrong, is the result of typographic error. This is certainly quite possible, in my opinion, after having read a number of articles on the internet.

Another possibility is that your micrometer and measuring environment are not the same as those used to create the dimension chart. I can give 5 different shops the same part to be measured and get 5 sets of dimensions that vary with significance.

Micrometers and other measuring instruments need to be calibrated periodically. If your micrometer hasn't been calibrated by a reputable lab, the potential exists that it might be in error.

Please post which particular dimension is wrong, I'm curious.

Best.

iceracerx

I'd love to see a primer manufacturing facility to see how they hold the dimensions without any +/- tolerance.

here's another site with dimensions, however, the author got rid of all those pesky tenth of a thousandth dims.

http://www.dave-cushman.net/shot/boxerprimers.html

Tailgunner1954

And in all this discussio, the fact that the primers are a press fit into the cases has been overlooked.
IOW the pin gauges the OP is after will need to start a couple thou SMALLER than the primers (and increase in increments of about 2-tenths) inorder to "measure" the pockets with any degree of accuracy.

shoff14

When using pin gages though, you are just comparing. In order to truly measure the hole, you would have to use a CMM.

The fact that the primers are going to be punched out on a die makes the variance in them pretty small. You should see them be able to hold .002 " with ease. Do to the fact that they are a thin metal piece, that flexes and is pressed into the whole that is being used. I would guess the tolerance range on primers is rather large. Maybe even as large as .010" for the diameter to the larger side. The wall thickness is whats important to them.

amamnn

Nonom: I do have my micrometers calibrated and a lot more often than most people including "expert" gun rag authors, as I use it most every day. I don't recall which of the Federal primers mentioned was out of current tolerances in the article you sited, but since you must have the same accurate micrometer you'll have undoubtedly checked it for yourself. In addition, what you overlook, and what was not even mentioned in the article you quote was the manufacturer's voluntary guideline for tolerances which did change in past years being in 1993 .115 to .125" for cup depth in a Federal (or any) small rifle primer, for example. The written-in-stone "fact" presented in your cited article gyves .111" as an absolute measure no tolerances given. Makers will periodically change their own tolerances within the industry guidelines as economic conditions permit. The difference is small, to be sure and not of great significance to many outside BR circles. Had this been a post asking for info for idle curiosity, I would not have posted a reply, but the man wants to build tools. I would expect he is more interested in what the makers are doing today than 14 years ago, or 16 years ago as according to one author, beit yours or mine.

For those interested, this information can be found in the pages of Precision Shooting Magazine Oct. 1993 in an article titled, "Prime Nonsense" Written by Dick Wright. This is more like the information the poster requires if he is going to be designing tools.The Manufacturers are, in my experience, willing, if not eager to help out those who engage in such projects. I have never had any serious inquiry made to an American manufacturer ignored, and even Norma and Lapua will answer my e-mails. They can't tell who I am by my E-mail address, so I assume they will do the same for him. Or you, unless they have some reason not to?

nononsense

amamnn,

Amen Brother! What ever you say.

"Or you, unless they have some reason not to?"

All I can tell you is that I'm on their Christmas card list...

Best.