ACCURACY...ITS THE LITTLE THINGS
By SingleShotLover
\Part of the enjoyment of firearms is trying to get that last tiny bit of accuracy out of them. Most of us go to great extremes to achieve what we perceive as the "perfect" group only to find that our efforts have been wasted. Many times it is the old adage of not being able to see the forest for the trees. We focus on new guns, bedding, barrel length or weight and etc. and forget the basics that need to be addressed. Since I have made just about every error imaginable in the 40 plus years I have been shooting, maybe these little things will help someone else avoid my mistakes.
Define Your Accuracy Goals
The first thing to do is define a reasonable degree of accuracy for the firearm in question. Expecting .25" groups from a shot out barrel or a poorly bedded rifle is a waste of effort.
If working with varmint calibers, reasonable accuracy is usually considered to be sub-minute of angle (under 1 inch groups at 100 yards) with most shooters expecting groups half that size or less. Remember that Remington's excellent 40X target series have factory standards of just under .5" in most of the common varmint calibers.
When working with larger game cartridges, 1- 1 1/2 MOA is considered excellent though many cartridge/rifle combinations can still beat that. Do remember that many cartridges have a known tendency to stabilize once past the 100 yard mark, resulting in groups smaller at extended range than logic indicates from their 100 yard groups.
Handguns fall under their owns set of rules, but on the average, 2-3" groups from a bench at 50 yards are not necessarily out of the question.
Making a Case For Case Preparation
In the interest of uniformity I usually buy brass in lots of 1000, look them over for obvious flaws and resize all of them in one operation. Next step is to de-burr the flash holes and trim to minimum case length for the cartridge. This is followed by outside neck turning with the cutter set to only shave any irregularities from the outside of the neck to help uniform neck diameter and bullet tension. Final case prep is chamfering the inside of the case mouth since the outside has already been taken care of by the neck turning operation. (Pistol brass gets outside chamfering only. This leaves a square inside mouth edge for better crimp grip) Priming is done by hand for that perfect seating "feel" and powder and bullet seating follow.
Is it necessary to neck turn brass and de-burr flash holes? It can't hurt. Since de-burring only needs to be done once in the life of a case and neck-turning only needs to be done when the case needs to be trimmed again, I find the extra efforts to be reassuring since they eliminate possible variations that might affect accuracy.
To Neck-Size Or Not To Neck-Size
I have long since given up on neck sizing cartridges. Neck sizing in itself is not a bad thing, but sooner or later your case shoulders will need to be set back by full length sizing to allow for ease of chambering. Cases full length resized lose the coveted snug fit in the chamber of your rifle required for accurate alignment.Instead, I adjust my sizing dies to size the entire neck and just "bump" the case shoulder, keeping it from being moved forward during the sizing process. The additional benefit of this method is that the die only lightly touches the body of the case which assists in cartridge/bore alignment. Cartridges sized in this manner easily chamber in the original rifle and maintain minimal headspace.
Since I often have several rifles in the same caliber, I also have die sets adjusted and dedicated to each one. Brass is also dedicated for each.
Powder Selection
Having fallen prey in the past to the idea of one powder for most of my rifles, I understand the reasoning but have long since surrendered to the facts. It is seldom that a single powder will be the best choice for every caliber in your cabinet. It is not at all uncommon for two identical rifles of the same caliber to perform best with different powders.The best rule of thumb for accuracy is to try the powder that best meets your targeted velocity with the bullet weight you wish to use while occupying as much space within the case as possible. Charges that lie unevenly along the case in firing positions do not burn uniformly from shot to shot and seldom shoot accurately. Charges that more nearly fill the case usually provide better shot-to-shot uniformity.
Be prepared to try several powder and bullet combinations until you find the "perfect" combination for your particular firearm.
Choose Your Bullet
Select the bullet weight and style most likely to result in success. Be sure that the bullet is designed for the velocity and purpose to which you wish to subject it. Hornady SX bullets have proved to be very accurate in a wide selection of my rifles and expand explosively on small game but do have velocity restrictions. I once attempted to (stupidly) use 50 grain SX bullets at close to 4,000 fps in a .220 Swift. The end result was a visible "vapor trail" enroute to the target and no holes. That little bullet with its fragile jacket works great up to about 3,500 fps but self-destructs under a combination of high velocity and twist rate.
Don't get bogged down with a loyalty to a specific style or brand. Some barrel's rifling require a harder jacket for stabilization while others like a softer jacket. A game bullet may (and usually does) differ from a purely match bullet. (As an aside, match bullets commonly come equipped with a hollow-point. Do not be fooled. The hollow-point on match bullets is designed to increase the weight-to-length ratio for stability. Match bullets generally have jackets much to hard for expansion.)
Bullets for big game require different characteristics. They are usually required to penetrate deeply, expand a reasonable amount, and shoot straight. There are many good bullets on the market that do all of the above. The only bullet style that I would avoid is the ballistic tipped variety for big game. Their performance has not been notable and have resulted in a long list of wounded and/or lost game. Better choices would be bullets of the controlled expansion variety such as Nosler's excellent Partition bullets or Combined Technology's FailSafes. Both have earned reputations for accuracy and dependability.
Bullet Seating Depth
Another huge variable in the equation is bullet seating depth. Though I have usually had good luck seating the bullets to a depth not quite touching the rifling, I have also had rifles that required a generous "running start" down the chamber throat for accuracy. Correct seating depth for your particular rifle will be a matter of trial and error.
Sight Issues
Sights fall into two basic categories: Open and Scopes.
Open sights should be of a style that allows you the sharpest sight image while allowing you a generous view of the target. Special attention should be taken to eliminate any signs of sight leaning, or "cant" when firing.
Scopes are a rule unto themselves. Choose your scope with care and consideration. There are many "bargain" scopes on the market that are anything but a bargain. Crisp clear optics, substantial eye-relief, positive adjustments, parallax and mounting height above the receiver are all important considerations.
Parallax (overly simplified) is the positioning of the cross hairs on the target in relation to magnification and eye position. This can be checked by placing the rifle on sand bags with the cross hairs aligned with the bull's-eye. Without touching the rifle, move your eye to various positions behind the scope. If the cross hairs seem to wander over the target, excessive parallax is present.
Scope adjustments can ruin your day too. Though I am a big believer in turret-type target scopes which allow me to adjust for each distance, many of even the most prestigious scopes can have adjustment "lag". Adjustment lag occurs, as an example, when an adjustment of 5 clicks is required but the cross hairs only move 3. This is not unusual and many shooters have developed the habit of doubling the distance and backing it off. This means that for an adjustment of 5 clicks right, you would rotate your turret 10 clicks right followed by 5 clicks left. This double adjustment will usually cancel out the "lag". It also sometimes helps to rap the scope mounts after adjustments. This has the effect of jolting the adjustment into place.
Be sure that your adjustments stay in place. Recently I tested a scope from a moderately priced line that moved the point of impact 1/8" left for each shot up to 5. After the 5th shot, the group stopped moving and stayed firm. Adjusting the point of aim back to the original position just started the sequence all over again. The adjustments were sharp, accurate and repeatable, but the tension spring for windage was too weak to hold position under recoil; and this was on a .223! The manufacturer was commendably apologetic and the scope was replaced with no further problems.
Shooting Bags
All shooting for accuracy should, of course, be conducted from a solid bench using bags. Care must be taken when choosing shooting bags and filler. The bags should be of a shape to provide consistent support for the weapon. Sand is not necessarily the best bag filler. It can compact causing the surface to be too hard. Firing a rifle or handgun from a firm or hard surface will cause it to shoot to a different point of impact from shot to shot.
Better fillers would be rice, dry beans, kitty litter, dry corn etc. This type of filler allows the weapon to be cushioned from vibration and lets it "snuggle" into the bag for a better support. Of course, such bags need to be kept dry to prevent clumping or even spoilage of the material used.
The Clean Scene
Copper and/or lead fouling is guaranteed to make the quest for accuracy a lost cause. The bore of our firearm should be clear of any fouling. Proper cleaning techniques take care of the average bore but rough bores may need some help. Lapping with J-B Bore Compound can solve a lot of problems. A thin strip of cleaning material spiraled around a snug (not tight) brush and coated with J-B can be run through a bore 10-20 passes with remarkable results.
I do not recommend "fire lapping" since this method also lengthens and enlarges the chamber throats if not careful. This method should be used only by persons completely qualified to make a multitude of critical measurements.
Keep Good Records
Most reloaders keep records of their loads. The true accuracy nut looking for that perfect group goes much further. Shooting records that include temperature, humidity, wind direction and speed, lighting conditions and group sizes are valuable. Once you have gathered several pages of this type record, careful analysis can reveal important patterns that may point to accuracy problems or indicate an area for improvement.
Be Honest With Yourself
Time and again I run into shooters proudly showing off a tiny group. That this group was a fluke and couldn't be duplicated in another week's worth of steady shooting seems to be immaterial.
Before you get mad at me.....I used to delude myself with exceptional groups too. Years ago, reality set in and I realized that I was only fooling myself. That tiny group that generated so much pride was of no use in my calculations. What mattered was the size group that a given rifle could be guaranteed to duplicate every day of the year.
Tiny groups are irresistible but can lead you down the wrong path. I once had a Ruger M77 V/T in .243 Winchester that produced a 200 yard 5 shot group measuring .390". Pretty darned good, and should have been a bragging group. The fly in the ointment was that I knew from previous shooting session records (and a bit of soul searching) that this particular rifle/load combination could be relied on to produce 5 shot groups hovering around .75 - .90" at that distance on a good day. The .390" group was a pleasant surprise, but was not the norm.
It makes no ethical sense to attempt a shot on game requiring accuracy on the order of 1/4" MOA when the average ability of your rifle is in excess of 1" at 100 yards just because the rifle shot a .25" group once upon a time, on the range and under perfect conditions.
Determine what your particular rifle or handgun is truly capable of and don't fool yourself into thinking that those rare groups are the rule. Your next trip to the range will soon show you the error of your ways and leave you dis-satisfied with your progress.
Know Your Ballistics
Be fully aware of the trajectory of your chosen load. Don't take the published velocity tables as gospel. With the availability of inexpensive chronographs such as the Shooting Chrony, guessing at your velocities is no longer acceptable. Actual and published velocities can be in variance by up to 200 feet per second depending on barrel length, chamber quality, bullets, elevation and temperature. The only way of knowing what a particular load produces in your firearm is by chronographing it.
Ballistic tables are useful only if you can determine your true velocity. The best combination is a chronograph and an interactive ballistic program to determine the trajectory characteristics of your weapon. Printed "cheat sheet" notes can be taped to your scope to remind you of the correct bullet path above or below the "zero" for your particular rifle and load and shooting distance.
I have had excellent luck with both the Shooting Chrony and a free ballistic software program called PointBlank. The program is flexible and accurate. When coupled with information from my Chrony, it provides an in-depth look at the bullet path and the influences of outside forces. It is free to download at http://www.huntingnut.com/pointblank.html.
Remember, the information generated by any software is only as good as the information you input. Garbage in......garbage out.
Colonel Townsend Whelen is said to have stated that "Only accurate rifles are interesting." I would respectfully have to disagree. Making a rifle accurate is the truly interesting part.
Good shooting.
SSL
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