Frequently asked questions

Is there an obvious need for measuring?

Is the Bersin tester really worth its price of approximately US$ 250.--?

What is the meaning of “Measuring”?
“Measuring” with respect to the BERSIN device is defined as turning a rifle cartridge around its longitudinal axis inside a replica of a cartridge chamber, the tip of the dial indicator touching the cartridge in the area of the projectile’s tip. During a full turn of the cartridge (360 ^o), flaws in the longitudinal axis of the cartridge (projectile with respect to the cartridge case) can easily be detected by reading the indicator deviation.

Is there an obvious need for “Measuring”?
Ideally the longitudinal axis of the cartridge case and the projectile are precisely equal and aligned. In such case, the deviation of the indicator’s needle is 0. In fact, it is not uncommon that with industrially manufactured ammunition one observes deviations between 4/1,000” and 25/1,000”. Reloaded ammunition has decisively lesser flaws, provided they are produced by an experienced person with the utmost care, using high precision reloading tools. However, even under such circumstances, one can very often observe deviations between 2/1,000” and 8/1,000”.

What is the meaning of “Adjustment”?
By turning the alignment knob, detected mistakes in the longitudinal axis of the projectile with respect to the cartridge case will be corrected. The alignment tip, rounded off or equipped with a ball joint and touching the projectile in the area close to its tip, thereby moves the projectile sideways, until both axes are perfectly aligned. The entire process is controlled and dosed by a high precision dial indicator, displayed into subdivided 1/100 mm (4/10,000”) units (or for particular tools in bench rest and varmint hunting, into 5/1,000 mm (2/10’000”) units). The contact of the adjustment tip with that of the projectile tip is carefully chosen to guarantee an equal distribution of the aligning forces on the projectile.

Is there a risk of loosening the neck tension on the projectile?
In principle: no.

For better understanding here are some technical details with respect to the manufacture of cartridge cases: The cases are shaped out of a thin brass sheet, which consists of an alloy containing 69– 72 % pure copper and approximately 30 % zinc. Several stages of production lead to the final shape of the case (stamping, forming and deep drawing together with several stages of annealing). This results in a case wall that is half hard but elastic and the molecular structure of the case body being aligned along the longitudinal axis of the case.
After the initial stages  of production, the structure of the material is hard, this is what is required for the bottom of the case. In a final production step, controlled annealing of the top of the case results in a soft, elastic but strong case neck for holding the projectile.
The process of drawing the brass causes the metal to work harden which is just what is required for the cartridge base. The wall of the case however is required to be more elastic and thus the need for annealing, annealing of brass is a controlled heating process. The final annealing of the neck, on bottle neck cartridges, usually occurs following the forming of the bottle neck. A significant reason for this is to prevent age cracking; this is caused by leaving brass in a heavily work hardened state over a very long time. The annealing leaves the neck in a half hard but compliant state. 
Alignment of the cartridge in accordance with the BERSIN instructions does no harm to the stability of the projectile inserted into the case neck. Due to the molecular structure of the case and its particular properties, the re-alignment forces initially affect the brass in the longitudinal axis of the case. The elastic molecular structure of the brass in the neck section, resulting from the annealing, will not permanently deform to the adjustment forces, as long as pressure is applied in accordance with the included instructions and not significantly exceeded. The projectile will not be loosened.
However, with incorrect adjustment (ignoring the instructions), in particular by repeated pushing  of the projectile from one end to the other - applying excessive pressure, then pushing back the projectile), loosening of the projectile cannot be excluded.
Further more some cartridges can be encountered that are poorly manufactured and of inferior brass (impure copper and zinc alloy, no or poor annealing of the neck). With such low quality cartridges there might in certain circumstances be a slight loosening of the projectile. As a rule, the resulting minor reduction of the neck tension does not really harm accuracy.

What is happening while adjusting the cartridge for concentricity?
There is lateral pressure applied on the projectile with the help of the adjustment knob. The contact area is chosen in a way to ensure that there is an even pressure concentration on the projectile in its entire length and positioning. Projectiles with a thin coating may require a more sophisticated alignment - specially manufactured alignment tips protect against any kind of deformation or damage on the projectile’s surface.
A slightly poor insertion angle of the projectile may partially be corrected by a minor improvement of the projectile's position in the neck only. But usually a missed insertion angle will have a negative impact on the case neck, i.e. its alignment with the axis of the case body.
The initially perfectly aligned brass will be brought out of axis while seating the bullet, by deformation in the weakest section of the brass, the transition zone between the neck and the case shoulder. This area of the cartridge case is the major reason for most concentricity problems.
The executed aligning pressure moves the projectile with the case neck, i.e. the leverage concentrates re-aligning forces as a whole at that weakest area of the case; the pressure applied brings the projectile together with the case neck back on axis, which brings the desired improvement in concentricity to the whole cartridge.

How about damaging the projectile by alignment pressure?
This question addresses a serious problem. Each damage or torsion on the coating of the projectile causes similar out of round problems in the same manner as eccentricity of the cartridge.
As a matter of fact, there are a number of relatively thin or soft-coated cartridges. The concentration of alignment pressure executed, by a rounded off alignment tip, damaging of the projectile cannot always be excluded. The manufacturing of certain models, such as Bench Rest, Varmint Hunting, as well as Large Rifle and Ultra Magnum, carefully consider these circumstances. A highly sophisticated alignment tip equipped with a ball joint and a relatively large touching zone to the projectile makes any damage to the coating virtually impossible.

What does it mean when the seat of the cartridge in the bore of the tool seems to be relatively loose?
The cartridge is not supposed to be in contact with the entire inside surface of the tool bore. Otherwise possible irregularities on the surface of the case outside (unevenness in diameter, irregularities with pre-fired cases) might disturb the exactitude of the measuring process. Also it would not be possible to accommodate both factory cartridges and reloaded rounds in one and the same bore. Finally unwanted friction caused by irregularities would have a negative impact on the precision of the measuring process.

The issue is resolved by positioning the cartridge in the receptacle (which is a precise replica of the individual cartridge chamber) as shown:

The inserted cartridge will be pressed sideways by a spring-loaded diameter compensator on to the opposite wall of the bore. Carefully chosen over dimensioning of the bore (clearance zones with respect to the manufacturing specification of the cartridge) provide a cartridge seat fixed only by four contact points on the case: these contact points are in the area of the center of the case body (diameter compensator’s tip, which compensates for surface irregularities of the case body), further in the top and bottom section of the case body (where deformations are rare) on the bore wall opposite to the diameter compensator, and finally in the shoulder segment for horizontal lift. The minor sideways movement of the whole cartridge once inserted in the bore is executed in axis, by the help of a moveable shoulder ring.

The BERSIN Tester is a high precision measuring tool, which should to be handled with the same care as when using a micrometer. Applying physical force on the bottom segment of the case and pushing the cartridge in a direction opposite to the diameter compensator will naturally result in an unwanted deflection of the dial indicator by a few thousandths of an inch (a few tenths of a millimetre). On the other hand, slight pressure in the opposite direction (same direction as the pressure executed by the diameter compensator), will not show any deflection since the cartridge is touching the wall of the bore.

Turning the cartridge around its longitudinal axis should be possible without any major resistance, neither is the seating of the cartridge to be shaky or loose. If turning the cartridge requires physical force then reduce inner tension of the cartridge seat by loosening the brass screw of the diameter compensator (for better handling use a rubber piece). By that method you will be able to loosen the spring tension on the inside of the means. Conversely to tighten the seating, tighten the brass screw.

Bottom line, relating to the technical of the device, a somewhat loose but not shaky seat of the cartridge is intended and functional. As long as the device is handled with the skill needed to work with a precision measuring tool, the relative stability of the cartridge in the system is guaranteed, even for cartridge cases being on both ends of C.I.P. or SAAMI tolerances. A too tightly constrained cartridge on the other hand is contradictory to the intention of the designer.

Measuring and alignment of cartridges with uneven case surfaces

With the help of diameter compensators opposite the dial indicator, it is very possible to measure, as well as align, cartridges with uneven cartridge cases. What is important to note is that out of round cases with uneven exterior surfaces will be identified by an irregular deviation of the indicator needle. Sudden movements in opposite directions indicate an out of round or damaged case (another important function of the Bersin device).

How can flaws in the seating depth (total length) be identified?

In particular, after the adjustment process, an uneven seating depth of the projectile can be identified by a differing deviation of the needle compared to other cartridges of the same type and/or calibre - when comparing different cartridges, the deviation of the indicator should be somewhat even within a few 1/100 mm (4/10,000”). Once you experience a particular move of the indicator in a positive or negative direction with a certain cartridge (compared to other cartridges), this will imply a flaw in the seating depth of the projectile (total length of the cartridge).

At this point and time it must be emphasized that this verification in practice is often done with a couple of specific devices without initial control of the axis (i.e. a verification of the alignment of the projectile with the cartridge case). Such results are unreliable, in particular when measuring is executed in a lateral manner on the projectile. Under such circumstances, the Bersin device is of great assistance.

What are the technical consequences of eccentricity of a cartridge?

A few technical details are necessary in order to understand the following explanations with respect to concentricity/eccentricity: After igniting the load of the cartridge, the projectile is subjected to huge forces and tremendously accelerated. It then leaves the neck of the case and passes the relatively short transition zone to be pressed into the base of the barrel. This passage of the projectile from the acceleration to the entrance into the actual barrel is called “rotationless” (there is no grip by the lands and grooves of the barrel at this stage), the stage between leaving the case mouth and being pressed into the barrel is called “free movement”.

In ideal circumstances, i.e. with a perfect alignment of the cartridge and thereby a fully round movement of the projectile, the projectile is pressed into the barrel throat and into the barrel in a precisely centric way. This means, any deformation and/or rotational imbalance of the projectile can be excluded. 

On the other hand, if there is an eccentricity between the projectile and the cartridge case, you will note a relevant deformation of the projectile before it is even pressed into the barrel, which will inevitably lead to a rotational imbalance of the projectile. This imbalance is not, as one might assume, dampened or neutralized by the fields and grooves of the barrel, but may even be accentuated during the stage of passing through the barrel. At the very end, the projectile will, once it leaves the end of the barrel, continue and enhance itself during the entire trajectory.

By the mere fact that there is an uneven deformation of the projectile during the firing process, before its actual entrance into the barrel, the exactitude and precision of targeting is seriously hampered - the technical diameter of group size (target diameter) of a fixed barrel widens to astonishing dimensions.

To which degree can an improvement of the shooting results realistically be expected?
A frequently asked question, which must be answered individually for each type of ammunition and for each marksman.

Serially (commercially) manufactured ammunition is with respect to concentricity of a very wide spread. Match ammunition of best quality may be anywhere from 1/100mm to 15/100mm (0.5/1,000“ to 6/1,000“) out of round, regular factory rounds anywhere from 5/100mm to 75/100mm (2/1,000“ to 30/1,000“). Reloaded rounds, even when using high precision tools, are rarely under 5/100mm (2/1,000“) on a regular basis. Even experienced reloaders will often have up to 5/1,000“ out of round or more. Only by measuring and sorting allows one to locate the real good cartridges. Rounds of lesser quality will be shot anyway, but only after being corrected by alignment with the tester.

Seating depth of the projectile is another topic. The only reliable way to compare seating depth (which has nothing to do with overall length basically, but with which it is often confused with) is to measure the distance from one defined area on the case shoulder to a specific area close to the projectile’s tip. Most seating depth measuring tools do not permit this measuring procedure and hence are not accurate. In addition measurements that are taken without regard to out of round errors, thus providing for further inaccuracy of measurements. The Bersin tester gives a highly reliable comparison of seating depth within the same group of cartridges measured.

The best one third of cartridges shot will usually give a relatively good group, in particular when keeping a check on seating depth while measuring concentricity and sorting out. Many tests prove that by only selection by measurement a major improvement (10% to 30% better group) will be achieved, depending on the quality of the worse two thirds, shot for comparison.

After sorting out cartridges with no more than 2/100mm (1/1,000“) run out and immediately using these for competition, the question is what to do with all other cartridges? Aligning these cartridges to a concentricity level as good as possible and using them first of all for training purposes is a first step. After realizing groups as good as with the best cartridges sorted out, one might easily decide to align all cartridges in future, even if they are as concentric as les than 5/100 mm (2/1,000“) run out. The most significant test with comparison between excellent and to an utmost concentricity level adjusted cartridges (under 1/1,000“) and relatively bad cartridges of the same ammunition gave differences of 20% - 50% group reduction.

Please take into consideration that all our tests are executed in a tunnel, free from the effects of wind and variable light and from a machine rest. Other elements like distance (exponential effects of out of round with increasing range) as well as firing interval (heating effects on the barrel) must be respected, too.

Every marksman must know that besides concentricity and seating depth, there are other qualities of ammunition with possible negative impacts on precision. Primer quality, powder quality and quantity, brass qualities all have the potential to detract. Further reasons for not hitting as accurately as intended might be quality of the rifle (barrel and bolt), atmospheric conditions and human error. As far as the latter is concerned, it of course is of psychological importance that test series established from the shoulder and shot outside are executed blind (no knowledge of the test person, which kind of ammunition is shot in the individual test).

The BERSIN tester is not the „secret weapon“ which allows its user to step up from being average and to become a world champion within days, due solely to the use of measured and aligned ammunition. However, the BERSIN tester allows you within a very short time to eliminate cartridges that are bluntly „unable“to hit with precision. Flyers will be minimized and average rounds will be improved dramatically. Eliminates absolutely unnecessary losses of points in a competition, a bad shot while hunting or dramatic events in security forces’ operations will be avoided, as far as they relate to poor concentricity or irregularities in seating depth.

Utility of the device for the reloader

Although the device most visibly (physical reduction of group size) yields to the consumer of industrially manufactured ammunition, the use for reloaders is (percentage wise) none the less efficient and highly recommended.

Nowadays a couple of high precision reloading tools promise, particularly with respect to seating depth accuracy, precision dimensions of up to 1/1,000 of an inch (0.025 mm). Whether or not these manufacturers can keep their promise is a question we will not discuss - this question can only be answered by conducting an inspection with a similar precision measuring device. Regardless, it does not make sense to address high precision seating depth without keeping a close eye on the concentricity of your cartridge at the same time - doing so, will undoubtedly falsify the accuracy of your results as they pertain to seating depth of your projectile.

As mentioned above the real problem in this context lies in the fact that there are no reliable measuring devices available. In particular repeat-functions are often very unsatisfying, and hazardous dial indicators have scale units which are never at a level of 1/10’000”. The Bersin device makes up for all hazards in this regard. In addition, the device allows you to align your cartridge to the utmost possible concentricity dimension.

Even the most experienced reloaders admit that, on a regular basis, mistakes such as a slightly bad angle occurs while inserting the projectile. These mistakes are so minor that they hardly are noticeable and therefore very difficult to avoid. Nevertheless, in practice it is exactly these flaws which make the difference between the championship and a bad day. Even the best high precision reloading tools are not a reliable weapon against these annoying flaws.

In addition it is well known that a major percentage of flaws in concentricity are not even caused by reloading inaccuracy, but by lacks of concentricity in the brass. Unevenness in the brass reacts on pressure and other physical influence during the reloading process with in turn either provoke eccentricity or out of round problems of the cartridge case - both of which are taken along into the loaded cartridge. These mistakes can only to be identified in a reliable way once the reloading process is finalized. Condition for a precise establishment is a highly precise measuring device with an absolute accuracy of repeat functions.

To date, only the Bersin device offers you the capacity to measure, control and align all at once - thus it is highly recommended.

What am I supposed to do with a damaged and/or unsuitable device
(i.e., size of the cartridge doesn’t match the size of the device bore)?
If the device is flawed with defects in material and/or workmanship, the manufacturer of the device offers a three-month operating warranty from the original purchase date and you may return it to the manufacturer. The manufacturer will honour said warranty provided that the guidelines for operating and care mentioned in the Owner’s Manual have been followed.
It is important to note that each device, including the dial indicators, are tested several times before leaving the manufacturer’s facilities. Therefore, as a result of such rigorous testing, and given that each device is wrapped in shock proof packaging, a lack in operating ability is highly improbable provided the plastic foil welding is untouched.
This being said, if for any reason, you are unhappy with your device, because it does not fulfill its intended usage, please contact the manufacturer (imachine@localnet.com).
The bores for the cartridges (replicas of cartridge chambers) are specified by different calibre groupings of different dimensions. All bores (whatever size the device) are based on international SAAMI-specifications for weapon (cartridge chambers) and ammunition (cartridge case) manufacturing. Therefore, a reloaded cartridge (which is slightly widened) will still fit within the bore of the Bersin device, provided the cartridge chamber of the used weapon was manufactured in keeping with the international SAAMI-specifications as they relate to tolerances. Accordingly, the slightly widened reloaded cartridge (i.e. the case) can still be inserted into the appropriate bore with no problem.
It is important to note that during the manufacturing process, the bore’s tolerances cannot be overstretched to address this potential imperfection in the cartridge chamber of the weapon: addressing such rare and explicit imperfections (i.e., unsuitable rifle manufacturing or oversized cartridge chambers) by excessive widening of tolerances would impede the exactitude/precision of the bore’s device for the vast majority of users.
This being said, if your reloaded cartridge does not fit into the appropriate bore, despite the fact that the size of the cartridge is intended for this specified bore size, you most likely are faced with an oversized cartridge chamber of your rifle - . Under such circumstances, the applicable warranty would not apply. However, you are most welcome to contact the manufacturer at imachine@localnet.com who will attempt to assist you in resolving this issue by widening the bore of your device. Such adjustments do not carry any warranty, and all ensuing costs are to be paid in full by the customer. 

Is the Bersin tester really worth its price of approximately US$ 250.--?
Bad shots often cause a lot of distress and confusion, particularly if you are an experienced and skilful marksman. Questions are raised, answers sought, precision rifles are even taken apart or changed in order to find the underlying causes/reasons for a bad shot. In certain cases, opticians have been consulted with the ensuing result of a costly investment for shooting glasses. In the end, atmospherical adversities or a simple bad day are blamed as the culprit for a bad shot - the entire explanation may have rested in the simple task of measuring the ammunition, which would have shown the underlying reasons and/or causes of the problem. Possibly a careful adjustment of the ammunition before shooting it would have avoided a lot of trouble and frustration, or at the very least provided some conviction that the problem was and/or is not ammunition related.
Frustrations experienced by sports shooters is one thing. As a hunter loosing a prey is another, however, causing unnecessary suffering to an animal is unacceptable.
Moreover, where ammunition is used by precision shooters or in police services - even reloaded cartridges must always be tested for irregularities with respect to concentricity, seating depth, and out of round cases - the lack and/or omission of such testing could have devastating effects. Testing has clearly demonstrated that even high quality brass cartridges, which are reloaded with high precision tools, can be improved.