Which is Best?

Gary Wain in­ves­ti­gates the peren­nial .177 ver­sus .22 de­bate

Airgun World - - Contents -

Gary Wain re­vis­its an old chest­nut - which cal­i­bre for ac­cu­racy, .177 or .22?

Hav­ing fin­ished writ­ing Fe­bru­ary’s ar­ti­cle, I felt al­most as if my mind had been read when our es­teemed editor, Terry Doe, pointed me in the di­rec­tion of a let­ter that had been sent in by one of our read­ers, a Mr Robin Lam­bert. In his let­ter, Mr Lam­bert said he would be in­ter­ested in see­ing a real-world test be­tween .177 and .22 that would set­tle the ar­gu­ment be­tween those who in­sist that .22 holds its en­ergy bet­ter and those who are adamant that .177 re­tains more power – either that, or solve the Mid­dle East cri­sis.

Well, Mr Lam­bert, and I guess many oth­ers out there who might be won­der­ing the same thing, let’s see if we can at least shed some like on this per­pet­u­ally thorny sub­ject, but be warned, I sus­pect this par­tic­u­lar rab­bit hole is quite deep.

In or­der to un­der­stand the an­swer, you must first de­ter­mine ex­actly what the ques­tion is. To do this, the first thing we need to do is de­fine what ex­actly we mean by ‘en­ergy’ and ‘power’. Now, I should per­haps point out that I am nei­ther a prac­tis­ing nor arm­chair physi­cist, and so my def­i­ni­tions and prin­ci­ples should be ap­pre­ci­ated as such. What I will do, though, is at­tempt to link an un­der­stand­ing of the prin­ci­ples with what we shoot­ers need to know, and with luck, re­late that to the ques­tion in hand.

KI­NETIC EN­ERGY

So, with the above caveat in mind, the laws of physics in­form us that en­ergy is as­so­ci­ated with either mo­tion (ki­netic en­ergy), or the abil­ity to cre­ate mo­tion (po­ten­tial en­ergy). We’re fur­ther en­light­ened that en­ergy can nei­ther be cre­ated nor de­stroyed, but only changed from one form to an­other. This con­cept is known as the prin­ci­ple of con­ser­va­tion of en­ergy and is ac­claimed as the first law of ther­mo­dy­nam­ics. For the physi­cists amongst you, I ap­pre­ci­ate that this is not true,

“this is sim­ply too much to ad­dress within the scope of a sin­gle ar­ti­cle”

strictly speak­ing, but can be broadly ac­cepted within a closed sys­tem. In shoot­ing terms we think of en­ergy as the amount of ki­netic en­ergy im­parted to a pro­jec­tile at the muz­zle, and it is typ­i­cally mea­sured in foot-pounds, ab­bre­vi­ated here to ft.lbs. It is widely ap­pre­ci­ated that the heav­ier the pel­let and the faster it is mov­ing, the higher its muz­zle en­ergy and the more dam­age it is ca­pa­ble of do­ing. Do please note that ve­loc­ity plays an im­por­tant part in this equa­tion. The equa­tion for cal­cu­lat­ing ki­netic en­ergy is Ek=1/2mv squared, where E=En­ergy, V=the ve­loc­ity of the bul­let, and m=mass. Riv­et­ing though this for­mula is, we’re lucky in that when pro­grammed with the mass of a pel­let in grains, chrono­graphs are able to cal­cu­late the en­ergy in ft.lbs. au­to­mat­i­cally.

BAL­LIS­TIC EFFECT

Power is a lit­tle harder to de­fine. I sus­pect that nei­ther you, I, or in­deed, Mr Lam­bert, are think­ing of power in re­gard to clas­si­cal physics, wherein it is de­fined as ‘the rate of do­ing work’. More sim­ply un­der­stood as the amount of en­ergy trans­ferred in a given unit of time, and al­though this def­i­ni­tion might tip its cap vaguely in the di­rec­tion of ter­mi­nal bal­lis­tics, more likely we’re think­ing of that much de­bated term ‘stop­ping power’. Stop­ping power de­fines the abil­ity of a pro­jec­tile to in­flict suf­fi­cient trauma to the tar­get to in­ca­pac­i­tate it im­me­di­ately. What we’re talk­ing about here is the ter­mi­nal bal­lis­tic effect and the bal­lis­tic wound chan­nel.

From the tests I’ve al­ready done, we know that a pel­let pro­duces a cav­ity within the sub­ject tar­get mat­ter. There are two types of cav­ity; the first re­lates to the ac­tual di­am­e­ter of the pel­let, and the lat­ter to the tem­po­rary dis­place­ment of the tar­get ma­te­rial as the pel­let passes through. In the ex­per­i­ments we’ve done with bal­lis­tic clay, to some ex­tent we have been able to ob­serve and mea­sure th­ese tem­po­rary bal­lis­tic ef­fects in the form of the plas­ter of Paris core sam­ples.

This leaves us with two dis­tinct sets of units to mea­sure. The first is the en­ergy that a pel­let pos­sesses, not only at the muz­zle, but also at ever-in­creas­ing dis­tances, and the sec­ond is the en­ergy that pel­let is able to im­part to the sub­ject mat­ter. As you may have al­ready guessed, this is sim­ply too much to ad­dress within the scope of a sin­gle ar­ti­cle, so I will first look at the con­cept of en­ergy as ques­tioned by Mr Lam­bert, and in par­tic­u­lar the man­ner in which this is af­fected by dis­tance. As we will be gath­er­ing data on ve­loc­ity, we will also look at how this is af­fected by dis­tance.

OLYMPIC EVENT

So, we come to test­ing. Armed with my trusty R2A chrono­graphs, cour­tesy of Black­pool Air Ri­fles, I set up a range to mea­sure the ve­loc­ity and en­ergy of pel­lets from both .177 and .22 at

“Ini­tially ,I thought it would be a great idea to mea­sure every me­tre”

dis­tances be­tween one and 40 me­tres. As with all test­ing, it’s im­por­tant to elim­i­nate, or at least mit­i­gate as many vari­ables as pos­si­ble, and thanks to Ter­ence Lo­gan, and the team at Daystate, I was able to get loan of a .22 Pul­sar to com­ple­ment my cov­eted .177 Pul­sar. True to his word, Ter­ence had ac­tu­ally pro­vided me with a .22 Pul­sar with a muz­zle en­ergy that was to within .02 ft.lbs. of my .177. Not only that, but Ter­ence had also sup­plied it with a match­ing MTC Viper Pro Tac­ti­cal 5-30 x 50, and an iden­ti­cal, hard-wear­ing, black lam­i­nate stock. When it came to pel­lets, I was aware from pre­vi­ous test­ing that the Pul­sar per­forms well with a range of pel­lets, but like many ri­fles, seems to love the AA Di­abolo Field, so I would use the 8.4gr in .177 and the 16gr in the .22.

Ini­tially, I thought it would be a great idea to mea­sure every me­tre, from zero to 40 me­tres, but as each shot re­quired me to get up, walk to the chrono’, record the value, lift the heavy work bench one me­tre fur­ther away, walk back, sit down, re-aim and then re­peat, to be hon­est, by the time I got to the 25 me­tre mark I was to­tally knack­ered, For­get biathlon, they ought to have this as an Olympic event. I quickly worked out that by the end of test­ing both ri­fles I’d have walked 3280m, so I de­cided to agree with Mr Lam­bert and just mea­sured every five me­tres.

OB­SER­VA­TIONS

At the end of a full day’s test­ing, and an aw­ful lot of walk­ing back and forth, what had I learned? Well, al­though not a di­rect part of the ques­tion, let’s look at ve­loc­ity first. From the real-world data ob­tained, it’s clear to see that the heav­ier 16gr .22 pel­let is much slower than the lighter 8.4gr .177 pel­let. That said, in the first 20m, the .22 pel­let loses less ve­loc­ity than the .177. How­ever, .22 then loses much more ve­loc­ity than the .177 be­tween 20m and 40m. When we look at en­ergy, mea­sured in ft.lbs., we see that both pel­lets have roughly the same amount of en­ergy up to the 20m mark, at which point .22 starts to lose en­ergy at a faster rate than the .177 pel­let. In prac­ti­cal terms, this was ob­served in the test­ing process be­cause up to the 20m mark it was pretty easy to shoot both cal­i­bres through the small opening in the steel guard. Above 20m, I no­ticed that it was much harder to get the .22 pel­lets through than the .177 ones, as the dam­age to the guards will at­test.

From the data ob­tained we can there­fore con­firm that that the lighter .177 pel­let re­tains en­ergy more read­ily than the heav­ier .22 pel­let, a great deal of this be­ing re­lated to the higher ve­loc­ity. Of course, the ques­tion is, what hap­pens to this en­ergy when the pel­let im­pacts the tar­get? I al­ready strongly sus­pect that the .177 will sur­ren­der more of its en­ergy more read­ily, as seen in the plas­ter-cast core sam­ples, but in fu­ture ar­ti­cles I hope to put some fig­ures to­gether to al­low us to see just how much of dif­fer­ence there is in the power de­liv­ered to the tar­get on impact. As ever, if you’ve got any as­pects of pel­let test­ing or bal­lis­tics you’ve al­ways won­dered about, do please mes­sage us and we’ll do our best to look into it.

What could be bet­ter than one Pul­sar?

The steel baf­fles did their job and pre­vented an em­bar­rass­ing call to Black­pool Air Ri­fles.

For­get biathlon – they ought to make shift­ing this lot 1m at a time for 40m an Olympic event!

How hard can it be at 1m?

It might look sunny, but it was cold enough to snap a mous­tache off!

A Daystate Pul­sar, MTC scope and rangefinder and I’m good to go.

Where are you putting your money – .177 or .22?

Which cal­i­bre proved the most trou­ble­some?

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