Reference ammunition


#1

This subject was discussed before viewtopic.php?f=8&t=9323&p=66958&hilit=reference#p66958 but reading this got me more confused than I was before reading. Since now I actually have a box myself (see below), may someone explain its usage in the plainest English possible? I am acustomed to minimum 2 standards (high and low) and frequently 3 standards (high, low and normal). How does this single box serve that function?


#2

Hi Vlad
As I understand it these were made to a certain standard, which would be considered highly acceptable, then set aside to be used as a standard for other production, or to test other factors that might need a point of reference or a standard to see if acceptable or not.

So when production was needing to be checked, current production was compared / tested against the reference samples. Reference items can be found just as cases, or just bullets, or just primers, or just powder or as you now have completed cartridges.

So if the test against this ammunition was not satisfactory, SCRAP it or fix it, & if satisfactory SHIP it.


#3

Vlad–The primary use of Reference Ammunition is to test and set up the Pressure-Velocity barrel at the factory. Reference Ammunition is made under very rigid conditions and then test fired at an accurately measured air pressure and temperature.
Based on this test for a given lot of Reference Ammunition, a chart is produced that shows what pressure or velocity you should get for any other air pressure and temperature combination on the day you are doing test firing of a batch of ammunition. This chart is sent along with the Reference Ammunition when it is ordered. This gives the tester a baseline (or Reference) against which to compare the results from firing the lot of ammunition being tested. Normally 10 shots are made with the ammunition being tested and the average pressure and velocity for those 10 shots is compared to the data obtained from firing Reference Ammunition. If the results do not fall within a +/- amount set by SAAMI for that type of ammunition, the lot is rejected.


#4

Ron

I think you are mostly correct except for the SAAMI part.

Ray


#5

I don’t know about Lake City’s ballistics lab practices, but the commercial loaders use reference ammunition for instrument calibration. For example, if the reference ammunition is supposed to produce an average peak chamber pressure of 38,500 at stated conditions in a test barrel (assuming use of a piezo gauge), but the actual average peak pressure readout at the same conditions is 38,900 psi, then they would use a correction factor of -400 psi. Same would be true for velocity and port pressure (if determined). Every so often, the piezo gauges are sent back to the manufacturer for calibration, as they have precise ways for doing this, while the ballistics labs do not.


#6

Ray–Why do you say “except for the SAAMI part”. The procedure I outlined was a consolidation of the method as shown in the following manual.

You are correct as far as the SAAMI standards do not apply to Military ammunition, but only for commercial manufactures. However, I think that the military uses the same procedures.

If you mean SAAMI does not recommend pressure limits, here is a page from the above manual designating the SAAMI pressures and velocities for some pistol and revolver loads. They are voluntary standards, but recommend. And, before anyone says that CUP is no longer used, I realize that most (if not all) companies have changed over to Piezo type pressure guns, but that does not substantially change the method of use.


#7

Ron

What I meant was that SAAMI standards or procedures do not apply to military ammunition.

Ray


#8

Ray–I thought you might be referring to the military not using SAAMI standards. In my original post above, I was just trying to explain, in general, how Reference Ammunition was used, not necessarily referring to the Military Reference box as posted by Vlad.


#9

Ron

We’re good. :)

Ray