Mark Camoc­cio tells us why plot­ting our tra­jec­tory is so im­por­tant

Air Gunner - - Contents -

Know the tra­jec­tory of your gun! Mark Camoc­cio ex­plains this ba­sic re­quire­ment for ac­cu­racy

I’ve been shoot­ing air­guns for nearly four decades now – which looks pretty fright­en­ing in print! – and from quite an early age, I was hooked into com­pe­ti­tion shoot­ing. This can be in­cred­i­bly de­mand­ing, and ev­ery as­pect of our ap­proach ends up be­ing eval­u­ated in a bid for suc­cess. How­ever, which­ever branch of our great sport you choose to fol­low, be that hunt­ing, tar­get shoot­ing or fun/ca­sual ‘plink­ing’ ses­sions, sev­eral prin­ci­ples and meth­ods re­main valid through­out.

It’s all about hit­ting the tar­get, after all, and that means know­ing and learn­ing the tra­jec­tory of our ri­fle. It’s a ba­sic re­quire­ment that re­ally is fun­da­men­tal to what fol­lows, yet it still amazes me how many new­com­ers to the sport have lit­tle grasp of what’s re­quired – un­der­stand­able, I sup­pose be­cause we just take it for granted.


As with any shoot­ing sport, grav­ity plays a big part be­cause it pulls down on our pro­jec­tile. The best air­gun pel­lets are sur­pris­ingly ef­fi­cient in terms of bal­lis­tics, and are highly ac­cu­rate, yet all suc­cumb to ex­ter­nal forces. For ex­am­ple, spe­cial­ist heavy pel­lets can have an in­cred­i­bly bowed tra­jec­tory, and un­der­stand­ing the ef­fects, and track­ing and chart­ing the re­sults that oc­cur down­range has to be the way for­ward. Sev­eral fac­tors in­flu­ence the tra­jec­tory, in­clud­ing the height of the scope mounts; high mounts will in­crease the height of the sight line above the bar­rel; low mounts will ob­vi­ously re­duce this, and the pros and cons of such are in­deed a com­plex sub­ject in them­selves, per­haps a topic for an­other day.

Plot­ting the tra­jec­tory needs to be done with a ze­roed scope/ri­fle com­bi­na­tion. For the record, I zero at 35 yards with .177 cal­i­bre, and 25

yards would be a good start­ing point in .22, but I’ll deal with choos­ing a zero dis­tance an­other time. So, for the pur­pose of this ar­ti­cle, I’m as­sum­ing that we have a ri­fle/scope com­bi­na­tion set up and ze­roed al­ready, and we just want to plot the tra­jec­tory ef­fec­tively, to know ex­actly where the pel­let’s point of im­pact is at each dis­tance.

I shoot hunter field tar­get, and I need to know ex­actly where my pel­let lands at tar­gets set from 8 yards right out to 45 yards. Of course, I still need to es­ti­mate that dis­tance, but the key piece of prepa­ra­tion is to know how your gun per­forms, and have it all down on pa­per. It goes with­out say­ing that when tak­ing on live quarry, ex­actly the same data knowl­edge is a pre­req­ui­site, so it re­ally is a vi­tal early stage.


Any pre­ci­sion work needs still air, and for this rea­son, in­door ranges are spring­ing up all over the coun­try, where shoot­ers can eval­u­ate their kit un­hin­dered by the el­e­ments, but if you have per­mis­sion to shoot on a piece of land, or more com­monly, a club ground, then wait for a su­per- calm, still day – and then strike!

If the ses­sion has to be at the club, then ideally, pick a day when you are likely to be undis­turbed be­cause the process does re­quire walk­ing up and down the range to check re­sults. The aim is to shoot a few shots at each dis­tance to see the im­pact points. Place tar­get boards out at 8 yards – the min­i­mum dis­tance in hunter field tar­get – then at 10 yards, and then 5- yard in­ter­vals there­after, right up to 55 yards. This cov­ers dis­tances used in field tar­get cour­ses, and com­fort­ably any other range at which a 12 ft.lbs. air­gun would be ef­fec­tively shot. Of course, in be­tween dis­tances can be checked too, as re­quired.

It’s eas­ier to run this tra­jec­tory check when you are on your own, undis­turbed, and you can just set­tle down and re­lax. In this in­stance, you can ei­ther put tar­get boards at each dis­tance, or just have one board and keep mov­ing back in five- yard in­ter­vals, fir­ing a few shots at each range. For­get about elab­o­rate tar­get de­signs here be­cause we want to be able to see the shots eas­ily. Just get some white card – ce­real pack­ets are ideal – and draw round a coin with a light- coloured marker. Red seems ideal be­cause it’s nice and vis­i­ble, yet the shots still shows up from a dis­tance. An­other sim­ple method is to use a straight line with a side scale. Just shoot at the line at each dis­tance, and keep mov­ing back to each de­sired dis­tance that needs to be checked. I mark the side scale in inches, but this is more of a guide from the fir­ing line be­cause it ob­vi­ously makes sense to mea­sure and log the re­sults af­ter­wards.

Next month, we’ll com­plete this vi­tal ex­er­cise, and see what we can do with the data gath­ered.

“we want to plot the tra­jec­tory ef­fec­tively, to know ex­actly where the pel­let’s point of im­pact is at each dis­tance”

Pick a calm day with no wind and set­tle down, undis­turbed, for proper eval­u­a­tion

BOT­TOM LEFT: A straight- line tar­get such as this can be used, mov­ing out to each range

TOP LEFT: Use white card for ul­tra­un­clut­tered, clear re­sults

BE­LOW: Use club boards if nec­es­sary, and place them out at 8 yards, then 10, and then 5-yard in­ter­vals

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