Airgun ammunition – Phil Hooper on the use of lead

Phil Hooper offers a balanced view on a weighty topic – the continued use of a poisonous metal to manufacture airgun ammunition 

In terms of lead content by mass, one 28g 12-bore cartridge equates to 11 .22 LR rounds or 50 .177 airgun pellets

What is the most suitable material for airgun ammunition? The short answer is simple: lead. Amongst affordable metals, it is the most dense, and wins on the basis of fundamental physics. Also, it is soft enough to conform to the lands and grooves of the bore of a barrel and to seal acceptably well to maximise propulsion from a blast of air or CO2.

But the full answer requires further consideration. Lead is a toxin, its poisoning is cumulative and there is no “safe” level for humans or animals. It is capable of causing neurological damage, leading to learning and behavioural difficulties, particularly in children. At high levels it has the potential to damage most of the major organs.

Tetraethyl lead in petrol was a very effective way of improving the octane rating, but led to a serious pollutant, with lead compounds ingested by breathing in exhaust fumes. Taking the lead out of petrol 20 or more years ago was undeniably the right thing to do, and with the best scientific minds engaged, equally effective alternatives were possible in this instance.

Many airgun shooters will also own and use shotguns, so they may have kept pace with developments affecting them in the UK. For some time, shooting over wetlands has required non-lead shot, having identified lead poisoning in swans and other birds which scoop up gravel to aid digestion. 

Last year, multiple organisations, including BASC and the Countryside Alliance, issued a joint and somewhat controversial statement that in the UK the industry should adopt a five-year target for the complete removal of single-use plastics and lead from shotgun cartridges. 

The trend away from plastic wads to fibre wads, to avoid strewing the countryside with non-biodegradable plastic waste, has long been evident and the use of recycled plastic for shells is progressing.

The options available

Bismuth and tungsten are possible alternatives to lead for shot production, but are much more expensive. Steel shot cannot be used in some guns and reproofing can be necessary for others. Chokes tighter than ½ choke cannot be used, and for a propellant charge, ballistic performance is inferior for longer range shots – high birds, although going up two shot sizes such as 6 to 4 can help, but not resolve this.

Regarding lead for other firearms, here is a Q&A from the Countryside Alliance:

“What about ammunition for: rifle target shooting, including with muzzle loading and historic arms, clay shooting and live quarry rifle shooting (including pest control and large game shooting)?

Viable alternatives are being researched. Where lead ammunition is used in a contained environment, such as a range, or there is an absence of reasonable alternatives, we feel lead should continue to be used.”

By 1 December 2022, all Forestry and Land Scotland (FLS) contractors will use lead-free ammunition for shooting deer and feral pigs. 

Clearly, steel is not a viable alternative for rifled airgun pellets, although it’s fine for low-powered BB gun ammo.  

Various non-ferrous alloys have been considered as alternatives to lead, bearing in mind the density and softness requirements noted above. H&N Sport, for example, have been offering non-lead pellets since 2009.  

Achieving sufficient softness isn’t the main problem, it is the lower density that is. Lower density leads to an inferior Ballistic Coefficient (the BC identifies the drag deceleration of a bullet or pellet and depends on its shape, mass and cross-sectional area) and poorer performance, particularly at  longer ranges.  

One way of offsetting this to some extent would be to launch the pellet with a higher muzzle energy. This is one approach adopted with shotgun and firearm non-lead ammo, but we’re restricted to 12 ft-lb in non-FAC air rifles and UK legislators would be unprepared to raise this limit.

To illustrate the limitations of lead-free pellets we need to consider implications to both accuracy and kinetic energy. 

In Airgun Shooter issue 142, Mike Morton examined the accuracy of H&N’s Baracuda Green in .22 and identified good accuracy at 30 yards, but poor grouping at 40 yards. 

OK, this was just one review, but a not unexpected result, suggesting unsuitability for FT/HFT. My regular ammo is H&N Field Target Trophy in .177 and I’ve looked at H&N Sport’s own data to compare the ballistic performance with that of H&N Baracuda Green, a pellet 

I thought I might try as possibly the nearest non-lead alternative (I didn’t choose the FTT Green as it is almost one grain lighter than even the Baracuda Green).

Interestingly, at 50 metres, the lead FTT retains 53% of its muzzle energy whereas the tin alloy Baracuda Green retains just 35%. This difference is largely down to the lower mass of the Baracuda Green at 6.64 grains compared with the 8.64 grains of the FTT, leading to an inferior Ballistic Coefficient (already very low for airgun pellets compared to firearm bullets), a more curved trajectory/greater drop and lower residual energy at longer ranges. 

Again, this is only a limited exercise, but it is still pointing to the fact that with only something under 12 ft-lb to play with, airgunners need the most efficient available ammo for performance over all but short to moderate ranges.

These are some of Phil’s pellets of choice following accuracy and chrono testing – each is optimal for a particular rifle, pistol and purpose

Common sense?

With reducing velocity at distance comes greater susceptibility to crosswinds, too. Green pellets cost twice that of lead pellet equivalents, but that isn’t the overriding point. More than 10 years of development have shown that technology still can’t overcome basic principles of physics.

Interestingly, the USA Shooting and Civilian Marksmanship Program produced a publication in 2013 entitled ‘Guide to Lead Management for Airgun Shooting’.  This is an excellent paper containing very sound safety advice and is well worth reading. It is predominantly concerned with 10 metre target shooting.  

Having mentioned the USA, let’s take a look at California. It was California that led the way in automotive emissions control, starting in the late 1960s. In terms of firearm ammunition, it is illegal to hunt with anything other than non-lead ammo. 

The predominant argument being the lead contamination within the animal, due to bullet fragmentation, which could be ingested by the person eating the meat. The only exception to this is airgun ammunition. So, even a really strict approach there recognises the needs of the airgun. We need a similar stance from shooting bodies and legislators in the UK.

In terms of airgun hunting for the pot, mostly head shots are used so that lead traces aren’t likely to be present in the meat eaten subsequently.

Carcasses resulting from pest control should be disposed of such that they cannot be eaten by foxes or birds. In target shooting, pellets should be caught in a trap and disposed of correctly, with care again taken over lead dust.  If plinking in the garden, avoid littering the lawn with spent pellets if there’s a toddler or pet that might find one and put it in their mouth, whatever the material (but lead adds a toxicity hazard). 

In comparison to the use of a 12-bore shotgun using lead shot, not much remains. Twelve bore loads typically vary between 21 grams to 36 grams of lead shot. Taking 28 grams as an example, then one discharge equates, by mass, to 50 pellets in .177 or 30 pellets in .22 (H&N FTT used for this calculation in both cases). I’d prefer to leave none behind, but this does help put the environmental impact into perspective.

If we all protect our health and demonstrate safe practices to those we interact with, then hopefully, with appropriate support from BASC and others, we won’t sleepwalk into stringent legislation to the detriment of our sport. For some shooters lead-free ammo may prove to be fine, but for a significant number of others, extracting the best performance from low-powered air rifles and pistols will require lead pellets.

In my opinion, the choice should continue to be ours.

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