Reloading

norma usa background - two hunters in hilly landscape

301. How should I store my ammunition/powder?

We recommend in a cool place at a constant temperature (12-15°C) and approx. 50 percent relative humidity. The chemicals in the powder slowly start to decompose after about 20 years. If you store the powder at a high or fluctuating temperature, this process starts earlier.


302. What is gunpowder?

Gunpowder is made of cellulose, which is obtained from the seed fibres of the cotton plant. Nitration (treatment with a mixture of nitric and sulphuric acid) adds oxygen to the cellulose. To ensure that the powder burns at the right rate, the powder grains that are of different sizes are treated with various chemicals (see the Norma manual, p. 88-121).


303. Are magnum primers required for large cartridges?

Fast ignition with an adequate amount of powder is important. The more powder used and the more surface treated (sluggish), the more difficult it is to ignite. A magnum primer is required for loads containing more than about 5 g powder, but can also be used for smaller loads.


304. Where can I obtain information on reloading?

Our reloading manual contains simple instructions and loading data. If you wish to find out more about the technology and equipment, various reference books (usually in English) are available on the internet. In addition, shooting magazines run articles on the subject from time to time.


305. Why can't you use all bullet sizes in a particular gun?

Short (light) projectiles require less rifling in the barrel than long ones to achieve gyroscopic stability. Every bullet has a specified twist rate that is designed for certain projectile weights. Problems occur when you use extremely long (heavy) bullets and the twist rate is not high enough to stabilise the projectile. Example: the .308 Win has a twist rate of 12 inches. All bullets up to around 12 g are suitable. Heavier projectiles may result in an oval bullet path and reduce accuracy. Lighter projectiles receive more spin than they actually need, which is however practically without significance.

306. Where can I buy equipment for reloading?

Larger shooting suppliers usually carry a good range of equipment. The choice is greater on the internet, but you have to know exactly what you need. It is better to familiarise yourself with the procedure for reloading and the equipment required first. If possible, get a friend to show you the individual steps.


307. How much energy is required to ignite a primer?

This question is not very easy to answer, as it depends very much on how fast the firing pin strikes it. According to military specifications, dropping a steel ball from a given height must ignite virtually all of the primers. There are also rules where the drop height is low and none of the primers should ignite.


308. Does Norma have instructions for reloading?

Only in the form of the reloading manual.


309. Can I use different primers without any problems?

All primers are suitable for the intended purpose, but you should not use different types of primers. If you use another primer, the firing point may change. The difference can be 10 m/s, depending on the primer, with the pressure also changing accordingly. The primers are likely to have some effect on the barrel vibrations and with that on the precision and target location.


310. Why does the bullet flight path not correspond to the table data?

Before a true comparison can be made, the test conditions have to be exactly the same. The stand, the gun's firing position and the shooting angle all have to be same, for example, to ensure that the reason for different target locations is not something other than the projectile's flight path.

One reason may be that the velocity is not the same. All manufacturers measure the pressure and velocity of barrels that correspond virtually to the minimum dimensions both for chambers and barrels. This is done for safety reasons. Gunsmiths also try to prevent problems with excessive pressure and take certain plus tolerances into account in their dimensions. If these dimensions are greater than the ammunition manufacturers', there will be reductions in pressure and velocity.

Short or worn barrels naturally also result in lower velocity. In all probability there are bullet manufacturers who determine their ballistic coefficients with calculations and not with measurements after firing shots. If the BC used for calculations is too good (e.g. 0.45 instead 0.38), the projectile flight path obtained will be straighter than it actually is.


311. What substances does a primer contain?

The recipe frequently has the following constituents: barium nitrate, lead styphnate, calcium silicide, lead dioxide, antimony sulphide and tetrazene.

A primer normally contains a priming compound of approx. 30 milligrammes.

 

 

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