Should I warm up my shotgun cartridges?

Should I warm up my shotgun cartridges?

It’s a ‘hot topic’ (excuse the pun!) frequently discussed on social media shooting forums, alongside images of cartridge boxes neatly lined up on top of a radiator. Indeed we’ve even seen one keen countryman’s photo of a full cartridge bag ‘cooking’ on top of an Aga in readiness for a day on peg! 

The response is always mixed, with some devout cartridge warmers advocating the practice, whilst others brand it a silly waste of time.

But what is the official advice from cartridge manufacturers? It’s a ‘no’ from us here at Gamebore. 

Whilst in the excitement of preparing for a day in the field, it might be tempting to heat your cartridges to give them that extra ‘oomph’, however this is something we advise against. Not only is it completely unnecessary with the new technology and modern propellants, applying extreme heat to cartridges could cause pressure spikes which are potentially dangerous. 

Most shooters know that keeping cartridges in cold or damp conditions is a big no-no. We’ve all noticed an unusual amount of unburnt powder down the barrels after a day’s shooting in freezing temperatures when compared with a warm day in Summer. Particularly if the cartridges have been left in the boot of a car overnight during the winter months. 

If there’s unburnt powder, we can assume that the cartridge didn’t perform quite as well as it should, although the average shooter probably won’t notice a difference. 

It’s common knowledge that cold temperatures can adversely affect the performance of a cartridge, but what affect do hot temperatures have on your ammunition? 

Extreme heat can also dry out the powder, thus affecting the way it burns. Powders are blended to exact specifications, to generate specific pressures which make the cartridge perform a certain way in ‘normal’ conditions. Expose the powder to any extreme temperature, and you can expect a difference in performance, even if you might not notice it.

Heat can affect the powder just as much as colder temperatures can. That’s why all of our cartridges are boxed in packaging which states ‘Store at room temperature. Adverse temperatures may affect performance.’

The Move to Steel Shot

Another important reason why shooters should be wary about how their cartridges are stored is the recent emergence and growing popularity of the non-plastic, bio-degradable wad cups used with steel shot, particularly with the ongoing phasing out of lead shot. 

These newly developed, environmentally friendly wad materials are very different from the fibre and plastics that shooters are familiar with. Although some of you have warmed your fibre wad cartridges time and again with no noticeable ill effects, you must remember that manufacturers are currently developing and introducing new materials, so extra attention should be paid to the guidelines on the boxes they come in. 

Shooters who have got in to the habit of warming up their ‘traditional’ cartridges should certainly avoid doing this when making the move over to steel shot and biodegradable wads. These different materials have different characteristics compared with fibre and plastic, and should not be exposed to extreme heat. 

So where should cartridges be stored?

We recommend avoiding warm airing cupboards or cold garages. The optimum storage conditions for shotgun cartridges is indoors, at ‘room temperature’ of 18-20 degrees.