Ask the experts: Prescription inserts or lenses and more…

Let us know if you have any questions to ask – we have the experts to answer them!

Send your questions for our panel to fieldsports@futurenet.com or to the Bromsgrove address on our contents page.

Your experts

Richard Atkins

Clay Shooting’s resident technical expert, Richard has decades of experience reviewing guns, cartridges and accessories.

He’s well equipped to solve problems on everything from shot sizes to stock dimensions.

Ed Lyons

Director of Flint & Partners, Ed’s optometry work has helped top-level athletes reach their goals on domestic and international level. Countless shooters rely on him to keep their vision in top shape.

Stuart Farr

A lawyer specialising in the shooting sports, Stuart has extensive experience in all things legal – from solving civil disputes relating to firearms ownership, to helping a governing body draft its code of ethics.

Prescription inserts or lenses?

Q: I read James Marchington’s recent article about shooting glasses and it struck a chord with me, because I too have tried prescription inserts and been less than delighted with the results. Do you suggest I go to a shooting vision expert like yourself for inserts better suited to the sport, or would I do better to bite the bullet and go for shooting glasses with full prescription lenses?

A: James was quite right that the prescription as measured by a high street optician is meant for glasses where the lenses are in a relatively flat plane. When this ‘flat’ prescription is put into a curved insert, “fishbowl-type” distortion can be experienced. There are limitations to what strength of prescription inserts can handle, too. It all depends on the level of curvature the design uses.

Prescription lenses require a dual lens frame

There are ways that even higher order prescriptions can be optimised – this involves recalculating the values taking the base curve, wrap, forward tilt and other measurements into account. These are termed ‘individualised digitally surfaced lenses’ and whilst more costly than generic plastic resin can be a lot better quality-wise.

That being said, inserts are always a compromise as they can sometimes steam up in adverse conditions and limit one’s field of vision, and so many people are moving towards fully glazed prescription lenses.

At present, we cannot make a prescription lens in a single wraparound shield so a dual lens frame needs to be used. There are plenty of good designs to choose from – you can see some examples on our website www.flintandpartners.co.uk.
Ed Lyons

Do fibre wad cartridges recoil more?

Q: With the ongoing moves against plastic wads I have started using the fibre wad version of my favourite cartridges and I’m getting on well with them. However I’m convinced I feel more recoil with the fibre loads, despite using the same 28g shot load as before. A friend I shoot with tried a few and said he couldn’t tell for sure. Is it possible that fibre wad cartridges can recoil more?

A: In a word, yes! Fibre loads can feel sharper than an equivalent plastic wad load. However there is no simple answer because several factors influence recoil. The key factors in the actual recoil produced are the weight of the ‘ejecta’ (everything that exits the barrel upon firing) and the velocity at which it is ejected. 

There are always differences between plastic and fibre wad

The most obvious component of this is the shot load. This is nominally the same in cartridges marked as being 28 grams, but if you look back through past cartridge reviews in this magazine, you’ll see it’s not unusual for there to be a few pellets’ weight difference between any two cartridge types. 

Then there are the wads used – plastic wads typically weigh less than the fibre type wad and the thick ‘nitro’ card used with them. Propellant powder charges are often larger in fibre wad loads too, to make up for some gas leakage past the fibre wad. This requires more energy initially to achieve a similar velocity – fibre wads are less efficient than plastic wads.

So the combination of more powder, heavier wads and the possibility of a slightly greater payload will mean an actual increase in recoil due to the increased momentum produced.

Then there’s the factor no-one can precisely quantify: felt recoil. Our bodies feel the effects of recoil differently; your shooting pal may be less sensitive to recoil than you are. 

On top of all this, the way the ballistics are achieved affects felt recoil. This is too complex to fully detail here but one factor is the compressibility of the wad. Plastic wads in lead shot loads have a long, collapsible, centre section. This compresses substantially upon firing. Some say this alone allows them to ‘feel the difference’ between fibre and plastic wad loads. 

It’s difficult to quantify, but it is certainly a factor. Baschieri & Pellagri invented their Gordon cartridge case, where the base wad in the cartridge case compresses slightly, especially to reduce felt recoil.

It therefore seems a reasonable assumption that plastic wads, which compress much more, can achieve something similar.
Richard Atkins

Will my medicine get me banned?

Q: I am an experienced clay pigeon shooter and have shot many domestic competitions. I’d like to spread my wings and try something with a more international flavour – but I have a concern. I have recently been diagnosed with high blood pressure and prescribed a number of medications as a consequence. I am not sure whether this would effectively disqualify me or cause problems for me if I wish to compete. What should I do and where can I go for advice? I am naturally reluctant to follow this new path if my new medication is unlikely to be permitted.

Some drugs are banned in competition, even when used for legitimate medical reasons

A: The first thing I would say is that shooters are human and can succumb to medical issues or conditions just like anyone else. The question is how those conditions are dealt with and whether they are long term. The important point for you is whether your medication is prohibited in an international competitive environment.

Blood pressure is one of those long term conditions which can be controlled in a variety of different ways, and sometimes with drugs which work in different ways on the body. Often, several drugs are used in combination, because this can keep the relative dosages smaller, and help the patient to manage any potential side-effects.

Some drugs are expressly prohibited, while others are not. Beta-blockers, for example, are prohibited in shooting disciplines because they have a direct impact on the heart rate. Diuretics are another class of drugs which are banned from competition.

Organisations such as the CPSA subscribe to the policies of the World Anti-Doping Agency, which in turn publishes up-to-date information on all the prohibited classes of drugs and specifically lists the most common types.

This is available to download on their website – see www.wada-ama.org.

You would be advised to check this initially, as well as the ISSF rules – which include exemptions for ‘therapeutic use’ of certain drugs – at www.issf-sports.org/theissf/antidoping.ashx.

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