Achieving correct Gun and scope Fit.

[pianoman 3,587]

Ladies and Gentlemen.

Further to my thread about spring rifle shooting accuracy. I thought we'd take a closer look at an area some shooters may not be aware or certain of. Gun Fit. How well does his rifle and scope combination truly fit him/her in the field. Because how well your rifle and scope fits you, is a measure of how consistently well you will shoot with it.

 

The shotgun fraternity have long since known that a comfortable, correctly fitting gun is crucial to accuracy. Which is why gunmakers like Purdey & Son and Holland & Holland exist to provide the shooting man and woman with a gun that is made perfectly to their individual measures. Such guns are also works of hand-crafted art and the price tags are seriously, serious money. Thankfully our sport is well served by a whole raft of air rifles, irrespective of cocking/action/power type, that will basically SUIT very much all of us. The trick is now to make it FIT!

 

When you get your chosen rifle home, make it fit you as perfectly and comfortably as possible, with fullest regard to correct hold, as I described before, and as little compromise on your part as possible. To achieve it, the goal is always to achieve PERFECT scope eye-relief and weight ballance in the CORRECT hold of the rifle at your shoulder. When you have accomplished these three factors, you will shoot with more consistent accuracy than you ever shot with before.

 

1. SCOPE FIT. EYE-RELIEF AND PARALAX ERROR.

IT IS ESSENTIAL that you understand correct scope fit and set up to begin with. Eye Relief is just the term to simply describe the measured distance needed between your eye and the eye-bell lens of the scope, to enable you to see clearly through the reticle optics to the target. Most scopes have an eye relief of around 3 to 3.5 inches; some a little shorter or even longer. So, that's how far or near your head and aiming eye needs be from the rear lens of your scope to be able to see a clear, unblurred but, sharp-focused picture of the target. If your eye is up too close the image will blurr and darken around the edges creating a "tunnel" effect. Too far back and the same effect happens. Both are useless to your accuracy. A perfectly set eye relief creates a sightpicture that is sharply focused, bright and clear right to the edge of the circumference. The reticle, regardless of whether you choose mildot, 30-30, duplex whatever, needs to be seen ONLY as a sharply focused super-imposure on the magnified target. You should be able to see your target in pinsharp focus by focusing your eye soley on it, NOT ON the reticle or crosshair! When you can view your target clearly, with out having to concentrate your vision on the reticle, but see it clearly as part of the whole target image together... You have perfect sightpicture.

 

2. WHAT IS PARALAX?

In simple terms paralax is the angle at which you view something from your position relative to it. If you and I stood 30 feet apart and viewed a rabbit in a field 50 metres away from each of us, we would be seeing the same target, at the same range but at a different angle to one another.

In shooting with a scope, it is the error of angle at which you are viewing the reticle on to the target. If you placed the crosshair perfectly onto the target but you are viewing from a left side, high or low bias you will miss the target to the left, high or low of it. It sometimes occurs that you are happily shooting dead on centre to centre zero, then your shots begin grouping off-target. That's a bit of paralax error; not your scope losing zero. Adjustable front lens focus scopes correct a lot of this error by allowing you to get a clear sight-picture focus at differing ranges and so keep any neccesary adjustment in the vertical plane to hold-over/hold-under. (Shooting accurately in gusty side and crosswinds is a matter for practicing in gusty conditions to see exactly how your choice/weight and calibre of pellet is affected over range distances.)

 

You are shooting free of paralax error when you are sighting perfectly in-line, through the scope and reticle, along the rifle and on to the target, with a rifle perfectly held in position from your shoulder to your hands. That's when you have perfect gun/scope fit.

 

3.BEGIN WITH A ROUGH-FIT OF YOUR SCOPE MOUNTS AND SCOPE.

It is a fact that the most common position you will use in the shooting field is to lie down flat in the prone. This position is concealing, very comfortable and supportive but, it also pushes your head a little further forward down the buttstock than standing and kneeling positions do. I start with taking my rifle into my garden, wearing my shooting jacket and set up my prone shooting position with my riflescope focused to ten metres or so and roughly mounted to my rifle. My first consideration is my scope's eye relief in this position and weight ballance. The goal is to achieve perfectly correct and comfortable eye-relief in the prone position. Because that will also serve standing, sitting and kneeling shots equally well. If you shoot with a PCP, the amount of adjustment on the scope rails is usually very limited to just two fixing rails over the regulaltor and magazine area. It is ESSENTIAL your scope's eye relief length does NOT REQUIRE you to mount the scope beyond the range afforded by the amount of clearance between the mounts on the scoperail or you are going to have to compromise and that's really a no no unless you buy a scoperail adaptor to give you a bit more play.

 

Equally, if you shoot a break-barrel spring rifle, you are going to be limited by the length of scope you can mount onto the cylinder rails. I've found that certain Hawke scopes have a longish eye-relief that makes them unsuitable for my Weihrauch rifles but fine for my Air Arms TX200s.

 

With my rifle comfortable in my shoulder and hands., I now just need to get the perfect eye relief distance,. Once this is found, I next find the best point of ballance between scope and rifle. This is why I never use single piece mounts but 2-piece Sportsmatch ones. With an adjustable length of play between them the weight of the scope can be better distributed more efficiently than a single-piece mount can. I get both perfect fit and ballance regardless of my shooting position. And that really pays me back well when it's a long day out in the fields with a rifle that doesn't feel at all heavy, and it's perfect on aim quick!

 

All the very best for your shooting. No matter what you shoot with!

 

Simon

[rossi_j 99]

Another informative post there simon, its clear some thaught and heaps of expirience have gone into these

.atb. .ste.

[Treganin 2]

Nice One Simon, Thanks Very Much Again!

[Buster321c 1,010]

Simon ,

 

Very informative post and well put across . I too have recently looked into `Stock Fit ` and its benefits . Basically i have been shooting a few years with `standard ` stocks , and although they afford you some degree of `Fit` they are taylored to the masses . A rule of thumb is that the butt to grip should be the same as distance from inside elbow to grip... ie instead of sticking butt in your shoulder, stick it in elbow cleft and see if hand is stretching to reach grip or has too much slack . This can be helped if you have a butt extension or adjustable butt pad . If you have an adjustable , then your next step would be set cheekpeice to the height that is comfortable . Then try and set the scope to that in terms of height and eye relief, but if you're doing HFT then most prefer the scope as close to the barrel as poss for trajectory reasons... but still check the eye relief and head position. Then check the butt is allowing a neutral muzzle, ie it's not pushing it up or down when all feels natural... if it's pushing muzzle down, raise, and the opposite follows if it's pointing high. This is the reason why FT shooters have fully adjustable stocks . Every possible margin of error is eliminated , before the shot is taken . Anyway , im waffling a bit now

 

Buster

Edited December 27, 2010 by Buster321c

[pianoman 3,587]

Thanks so much for your kind remarks to my posts gentlemen.

 

No Buster mate, good points are never waffle . Thanks for the kind compliment too. With regard to the correct fit of the buttstock being from your elbow cleft, along the inside of your arm to your hand holding the grip, you are correct to raise that detail of point. It's an old rule of thumb but a good one still. This is one of the reasons why I love Weihrauch air rifles so much, apart from their brilliant accuracy. The HW80, HW95 and HW77 fits me like a bespoke, hand tailored rifle. Same goes for the Air Arms TX200.

 

Getting the reticle of the scope as close to the bore centre as possible is also a good point. As a youngster I was very keenly impressed on having a big scope with an impressively large objective lens mounted high on my rifle. Now, older and wiser, my preference is for more compact, low-mounted 40mm scopes, to a max 50mm front objective for light-gathering quality. 4-14x and 6-18x mag range is perfect for hunting.

 

The main point is getting the rifle you have, with your chosen scope mounted, combined together so it all comes lightly to the shoulder and correct sightpicture straight to your eye in one fluent moment without having to jiggle your head about the buttstock to get a properly set-up aim.

 

I hope what I have written will be understood by, and help the less experienced shooters get a better idea of what they should set out to do to get more from their shooting, without stumbling along in the dark.

 

ATB

 

Simon

[Buster321c 1,010]

Great Post , well explained

[davyt63 1,845]

hi simon

great post buddy

SPA

 

regards

 

davy

[pianoman 3,587]

Hi Davy mate.

Thanks for being so kind in your compliments mate. By the way, that comment of mine on Si's YouTube vid. Your comments came up 'COMMENT REMOVED' Just checked back there and lo and behold, you are there for all to read!

 

Ah well, heyho!

 

Cheers davy

 

Simon

[fazerman 3]

hi simon thanks for another very infomative thread to help us rookies,keep up the good work.

atb

tony.

[pianoman 3,587]

You're more than welcome Tony mate I'm still trying to figure out the perfect method to achieve the perfect shot. But, after 40 odd years of air rifle shooting, I have managed to learn a few enough tricks and tips I'm willing to pass on because I know that they work.

 

There are still more questions than answers with this sport Tony. I still set up some days to target-practice shoot and my shots are flying all over the place and I cannot figure why before I've exhausted a few avenues that get me back into smooth accuracy again.

 

Hope you find what I've written a big help for your own shooting mate

 

ATB

 

Simon

[fazerman 3]

thats half the fun simon i think we are all chasing the perfect shot what ever that is, one day maybe.