I'm going to share the knowledge I accumulated on the subject through experience, experimentation and by observing. My methods and observations might by no means be the best way of doing things but will put you on your way to bench shooting.
I'll post this in sections since it is such a vast amount of information.
PCP bench shooting is a relative newcomer on the block of competitive bench shooting. There’s black powder bench shooting, centerfire bench and rimfire bench shooting that preceded it.
PCP bench shooting is becoming more popular by the day, in South Africa more so because of legislation making it very cumbersome to obtain a .22 rimfire licence if you not already had one before new legislation. Quality rim fire ammo is both costly and hard to come by compared to air rifle pellets.
PCP technology has grown in leaps and bounds and I envisage that PCP bench might soon overtake rim fire bench locally number of competitor-wise. Rim fire ammo cannot be custom reloaded like centerfire ammo so it ranks with PCP ready bought pellets as for shooters skill involved in creating ammo.
It’s about CONSISTENT accuracy
The two most encountered areas of interest within any shooting sport are arguably power and accuracy. Power is simply measured by metering devices and leaves little room for controversy. Accuracy on the other hand can be divided into two areas of immense controversy:
1) Equipment accuracy potential.
2) Shooter’s accuracy potential.
Bench shooting rules allow for minimum shooter interference with the accuracy potential of the rifle by allowing for the rifle to be ‘rested’ while aiming and shooting. These include a separate front and rear rest on a stable platform or ‘bench’.
Since minimal physical effort is expected from the shooter, bench does not warrant gender classification, men and women compete in the same classes and physically handicapped folk can participate on equal grounds.
Just before we see this discipline as easily mastered using the right equipment, let me mention that one variable is added that’s not controlled by the shooter or equipment; Wind interference. Bench competition is an outdoor event.
I have always maintained that accuracy is a relative concept. It varies from shooter to shooter. John Doe is happy with making Coke tins jump at 50 meters, Adam Acme boasts about his very accurate rifle and pellet combo on U-Tube by popping balloons at a 100m, or even 200m, video material can be edited so we perhaps don’t see the amount of misses for every popped balloon.
The dedicated bench rest shooter looks at obliterating a 2mm circle at a measured 25m under windy conditions, 25 times in a row. The target is an A3 sheet with 35 circles of 38.8mm diameter each. 10 of these are for sighting and 25 for scoring. The bull or ‘x’ is 2mm in diameter.
Looking from this perspective, a .5mm of movement at the rifle butt pad, (that’s less than the thickness of a credit card), can take the pellet 30mm off the 2mm bull at 25m resulting in a complete miss of the target with a 17.4mm radius, given there’s no wind interference and the rifle is 100% accurate!
There are 3 power classes being shot currently, 12fpe, 20fpe and 30fpe. It’s not unlikely to see 12fpe rifles competing in 20fpe class, but 20fpe allows for the larger calibre of 5.0mm so 12fpe 4.5mm rifles (standard .177 air rifle) compete against heavier pellets and more energy. Same goes for 30fpe, using a 20fpe 5.0 rifle you’ll be competing against 5.5mm 30fpe rifles. So, if you are serious about bench and plan on competing in all classes you will ideally need 3 rifles.
The Daystate MVT rifles with precision adjustable regulators would have seen one rifle competing in all three power classes but were unfortunately recently ruled out of bench competition in South Africa, it’s a single shot manual action with an electronic regulator where the official rule specify; ‘any regulator may be used, as long as it’s integral to the rifle.’ They have since been allowed back in the 30fpe and 50m grouping classes, unfortunately not Protea or international classes so hardly worth the expenditure and limitation of such advanced technology.
Technological advance will prevail in the end like it did in Field Target shooting and one might then be able to tackle PCP bench shooting with the affordable option of using one rifle for all classes which will strip PCP bench from its stigma of being an ‘elitist rich man’s sport’.
There’s no compromise here. A quality competition grade barrel with a good crown (the exit hole of the pellet) is a must, battling accuracy issues caused by wind is enough, a bad barrel complicates things. A pellet launched with a barrel with bad crown for instance might perform more or less satisfactory under windless conditions. When wind effect is added to instability the problem is amplified and a 4mm flier might become a 40mm flier.
If you are planning on using a standard production barrel, be sure to get a rifle on which barrel changing is an easy procedure. I have seen bench shooters changing barrels to a ratio of as many as 5 barrels per every rifle before they achieve accuracy.
Before deciding on the accuracy of a given barrel multiple tests must be conducted under as near windless as possible conditions.
Use best quality undamaged pellets, JSB’s or AA’s, eliminate as many variables as possible. If your rifle offers magazine fed and single shot options, use the single shot option.
Make sure you start with a clean barrel, especially if the rifle was purchased used. In case of a virgin barrel I prefer to do at least a thousand shots with regular cleaning in between before I test for accuracy.
If it’s a competition grade barrel chances are it was lapped (precision polished inside) before leaving the factory so the 1000 shots might not be needed. Do not attempt lapping unless you have studied the techniques involved. You might wear down the bore at the crown end and at the breech end or worse, ream the choke.
Lapping is best done with a precision fitting plug impregnated with polishing grit. The plug is cast in the barrel to fit the individual barrel’s grooves, a job best left to a specialist. If simply ‘polished’ by pulling grit through the grit will have more eroding effect while it is fresh at the start of the barrel where it’s inserted and less in the center part of the barrel where it’s dulled already. The idea of precision lapping is to remove irregular tool marks in the barrel, not using a cast plug to do so will also reshape the edges of the grooves and lands which is detrimental to accuracy and typical symptoms of a very old worn or badly neglected barrel.
If an indoor 25m range is not available, shoot under windless conditions. My favourite is late night sessions at 50m. I use a portable neon light at the target and one at the bench. This way mirage is not present and convection currents are minimal, the colder the better. Be sure to use a windicator, if you are a smoker the slightest draft can be detected by watching a lit cigarette in a torch beam.
Accuracy cannot be decided in 5 shots, after shooting multiple 5 shot groups at 50m you’ll begin to get a gut feel about the barrel’s accuracy. Finally, shoot for score, one shot per target and keep the results for later reference. Needless to say, before deciding a barrel is not accurate you must be convinced you did your best as far as shooter’s technique is concerned.
Accurising a rifle is such a vast field that it would take up a book to cover it all.
Free floating barrels seem to be the most popular amongst bench shooters. Since the rifle stock is in contact with the rests this makes total sense, slight stock to rest movement to adjust aim for the next target in the row will have no influence on the barrel’s harmonics. (The barrel ‘swings’ when a pellet is accelerated through it while biting into the grooves to force it to spin, this is known as harmonics. The pellet needs to exit the barrel every time at the same point of swing or oscillation of the barrel to ensure consistent accuracy.) The phenomenon of different weight pellets having sideways POI shift, not only vertical shift as would be expected, even in accurate barrels, is a confirmation of harmonics.
Varying stress on a barrel caused by a barrel band could influence optimal accuracy and consistency. Shrouding a barrel can serve two purposes of importance to a bench shooter, it will aid to minimise harmonics if floated and can contain an integral air stripper. (Air strippers are designed to strip the pocket of compressed air that envelopes a pellet away from it upon exiting the barrel, again to improve consistency, especially in cross wind situations, that is if the stripper sits in a shroud where cross wind cannot interfere with its function.) Sound moderation will be an added benefit but not crucial to bench shooting.
Since the shooter’s contact with the rifle is kept to an absolute minimum in bench shooting, the typical bench stock can be rather simplistic. Attention is rather given to the stock to rest contact surfaces than ergonomics.
A wide flat fore end is preferable. It can be as wide as 7.62 cm at the fore end and 2.5 cm at the butt end. Since there are few dedicated bench PCP’s available shooters adapt their sporter stocks like fastening a metal block 7.62 cm wide to the fore end bottom to utilise maximum permissible fore end width in contact with the front rest.
Bench shooting is all about rifle stability and consistency in the rests, most importantly sideways or canting stability. Believe it or not but there is sideways or torsion recoil present in a PCP, even more so at higher power levels using heavier pellets. A stationary pellet is accelerated forward and forced to roll in a twisting motion and for every action there’s a reaction, the rifle will exhibit sideways roll in the opposite direction the pellet gets spun in and rearward recoil as the pellet goes forward. Since we cannot do anything about this, the secret lies in letting it happen with exact consistency shot after shot. The wider the fore end the more the rolling recoil is minimised. Remember this when we have a look at the advantages of using a ‘machine rest’ over using a sandbag front rest.
The intricate shoulder pads and butt hooks we see in FT shooting is superfluous in bench shooting. The rifle is not ‘shouldered’, even in the center fire classes the 6PPC rifles are allowed to free recoil in the rests. (Some shooters use talcum powder to even assist in free recoil) Also absent on most 6PPC stocks is a cheek piece. Once parallax is mastered with a scope a cheek piece becomes redundant, one less thing on the rifle to touch that could influence the rifle’s movement. We’ll have a look at parallax when we get to shooting technique.
The most accurate rifles I’ve had and have are free floating in their stocks, save one contact point where a single bolt holds a small square flat but sturdy action surface to the stock. Torsion, however minimal, applied to the stock by the rests is not transferred to the action, cylinder or barrel.
Stock weight is governed by bench rules and classes. Enquire at your club about the latest rules. To counter recoil one should aim to get the total weight as close to the permissible weight as possible without exceeding it, remember, you won’t be holding the rifle, the rests do that.
We need 25 very consistent shots in a row, and on a windy day add at least 10 more shots for sighters. We thus need at least 35 shots with minimal fps spread. You will be allowed to refill during competition if you have a really bad shot count and speak to the range officer but picking the rifle up from the rest or leaving your seating position during competition goes against all good sense as far as consistency is concerned. A shot count of 35 very stable shots should be regarded as minimum.
Audrius after market regulator
Great results were obtained earlier with non regulated rifles shooting in the ‘sweet spot’ but unfortunately these are rapidly fading into rear ranks as regulator technology advance and the non regulated rifles get out gunned. Even shooters of the ‘classic’ rifles had to turn to after market regulators to stay competitive while preaching ‘it’s only about reading the wind’.
Best regulation could be achieved shooting with a large reservoir like a scuba cylinder attached to the rifle connected through an external regulator. Rules prohibit this; the regulator and air reservoir must be integral to the rifle.
The only way to test a regulator is shooting over a chrony and calculating ES (extreme spread). If the ES is abnormal for the specific rifle the regulator might need a service, the firing valve might be sticky, hammer travel irregular or hammer bounce might be present. The smaller the ES the more consistent your results will be, another variable that can be eliminated.
By now we have seen that shooter interference with the rifle must be kept to a minimum. The trigger is in fact the only contact point the shooter should have with the rifle if he prefers. This calls for a competition trigger, set to single or double stage as the shooter prefers. Release should be as light as possible. Safety should be the only limiting factor. Trigger pull should be exactly rearward; angled trigger shoes are defeating the object and will result in angled rearward force applied to the rifle. The target is exactly in front of the rifle; recoil will be in the opposite direction the pellet is accelerated in and a wide fore end should limit canting recoil, so angled sideways interference from the shooter will be detrimental to rifle recoil behavior, especially during follow through or lock time.
Scope spec is much less vigorous as in Field Target shooting where the scope is used for range finding (distance measurement) and aiming. In bench the known target distance remains the same during the class shot and as many sighters as needed can be shot with time being the only constraint.
We need to clearly see the 5mm bull at 25m and the crosshairsmust be thin enough as not to obscure the target. We also need to be able to see where every shot lands in order to compensate for wind. The crisper the image the better, the good news being that fixed focal length scopes, scopes that cannot zoom can be built of better optical quality for cheaper than zooming scopes. Since we are dealing with a target at a fixed distance zooming is superfluous.
Scope magnification will be a shooters own preference; I use a 24x scope with thin crosshairsfor 25m score and 50m grouping. The higher the magnification the more prevalent mirage becomes. Mirage is the optical shift and movement of a fixed point viewed through a volume of unstable air varying greatly in density. This is most noticeable on hot days and the effect is enhanced by looking through an optical device with high magnification, be it a camera lens, binoculars or rifle scope. 25m sounds immune to the effects of mirage, looking through a 24x scope on a hot day it is not, worse at 40x magnification and hardly manageable at 50m with a 50x scope. Scope quality cannot resolve the mirage problem, only the magnification ratio can.
A crisper scope puts less strain on the eye and gets appreciated after a full day’s shooting. You might ask; what’s the definition of a ‘crisp’ scope? Same as in photographic terms, its ability of optical resolution of fine detail. How well can you see closely spaced fine lines on a piece of paper at 25m before they appear through the scope as a single grey line? What makes a scope crappy? The optical quality of the glass used, quality of lens anti reflective coating and lastly, it’s overall design in terms of element spacing and precision of alignment on the optical axis.
Inferior glass with impurities will display internal light scatter, less noticeable under low light conditions and glaringly obvious under high contrast bright light conditions. If you can see colored fringes around dark objects against a bright background then you are looking through budget glass at a phenomenon called chromatic aberration, the inability of the glass to focus all colors that makes up white light on the same plane..
Much the same for lens coating which is supposed to eliminate unwanted light entering and reflecting from internal lens elements from angles not included in the viewing area. This also leads to light scatter and ‘milkyness’. A lens hood or shade can help by excluding frontal light from angles when shooting with the sun in front of you.
To compensate for poor resolution the zoom or magnification can be cranked up but although the bull will become bigger it will not become crisper and on a hot day it will swerve and float around in your view because of mirage. In very low light it will bleed into its white background in a grey non definable blur lacking the contrast of a good scope.
If you plan on shooting in extremities of light and dark, or to shoot long sessions, invest in good glass. The ‘crisper’ the image the less magnification is needed to align your crosshairson a target, that’s basically the bottom line.
If cost is a restraint, rather settle for a fixed magnification scope with not more than 25x magnification and not less than 10x magnification for 25m work. 40x and more fixed at 25m on a hot day will have you cursing at the mirage. Since zooming scopes have very complex designs to cover a wider range of magnification, much better quality glass is needed, the higher the max magnification the more so. They are thus either cheap and dirty or very expensive.
AO (front focusing) scopes work fine for bench since you only focus once, the target stays at the same distance. These are usually also cheaper than side or saddle focus scopes of the same optical quality because of simpler design.
Scopes can be mounted as low as the loading system allow, the lower the less the effect of canting.
Canting moves the pellet path in an arc. The crosshairscan be on the bull but the pellet will strike to the left or right high. To eliminate this, an inexpensive bubble level purchased from a hardware store can be used to check leveling. Other than with FT shooting where the shooter must be able to constantly have the level in eye view while aiming, the bench level can be fixed on any practical level surface on the rifle. Once set the rifle is not supposed to be moved or bumped other than when cocking and changing target aim.
Last but not least, the adjustment turrets of a bench scope should be readily accessible. Constant adjustment might be needed on a windy day. This will depend on your shooting style. Some prefer to zero once and compensate for wind by holdover while some will tweak the scope for every row of targets during competition by watching the windicators closely.
As for reticles, once more it will depend on your individual shooting style. I have used both normal crosshairsand intricate LRX reticles, I liked the LRX since it gave me plenty reference for holdover on days when the wind changed both direction and intensity constantly during a single discipline. Trying to zero under such conditions will be totally frustrating and confusing. On a windless day the multiple lines in a LRX scope might become annoying and distracting. Whichever reticle you decide on, stick to it on all rifles you use for bench since it will dictate your shooting style.
Soon next: Rests etc.