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North Fork Technologies

Frequently Asked Questions

    What is the purpose of the grooves?
    The purpose of the grooves is twofold. First, whenever a bullet passes down the barrel, the lands of the rifling must engrave the bullet. The material that is displaced by those lands must have a place to go. In a conventional bullet, with a thin jacket and a full-length lead core, the jacket and core can easily yield to the lands. In a monolithic bullet or one with a monolithic rear section, the only route of escape for the displaced material is to make the bullet longer. Considering the material in this area will not yield, as easily as if there was lead underneath it, the stresses, between the bullet and the barrel, will exceed the sheer strength of the jacket material. This increased stress sets up a galling action, which is one of the major causes of jacket fouling. What the grooves do is to allow the material that is displaced by the rifling lands, an easy escape route. This allows the stresses between the bullet and the barrel to stay below the point at which galling (fouling) occurs.

    The second advantage of the grooves on the rear section is that they allow the bullet to be more forgiving to variations in bore dimensions. The dimensions of different barrels commonly vary by, plus or minus, .0003”, and it is not unheard of that they can vary by more than .0010”. If you put a solid sectioned bullet down a barrel that is over standard size, you probably won’t have too much of a problem; accuracy may suffer but, generally, it won’t be dangerous. Unfortunately, the reverse is not so benign. A solid sectioned bullet fired down an undersized barrel can cause, dangerously high, pressure spikes as well as increasing the probability of severe fouling. The grooves lessen this problem, as they are designed to receive more than the standard amount of displaced material.
    What media do you test the bullets in?
    We utilize 3 different media/media combinations to optimize terminal performance. One media alone, such as ballistic gelatin, is not enough to simulate all of the possible conditions our bullets may experience. We use gelatinous material that is often called flexible glue or bookbinder’s glue. I’m not positive, but I think it is similar (if not the same) to what Rick Jamison, of Shooting Times, calls animal glue. From bullets returned from actual field use, the glue appears to be a very good simulator of muscle tissue. Is it the perfect simulator of flesh? No, and neither is anything else. It is excellent for comparing the pros and cons of different brands of bullets fired into it. It is also, repeatable, reliable, and reusable.We utilize Perma Gel to visually monitor a bullets path and wound channel. Lastly, we utilize a combination of organic materials, including hide, bones and an "artificial rumen" to simulate an animal. This test is as close as we can get to field conditions yet in a controlled manner.
    What are the ballistic coefficients of the bullets?

    (Short answer) At this time, we do not have the facilities or equipment to obtain accurate BC's.
    (Long answer) The determination of accurate BC's is far more complex than most people assume. Any BC's acquired by measuring bullet drop or by measuring the velocity of a string of bullets at the muzzle and then moving the chronograph out to some distance and firing another string, are absolutely useless and equivalent to generating nonsense; the old, “garbage in, garbage out”.

    The only useful method is to have two chronographs that are calibrated to each other and are set apart at an accurately measured distance, plus or minus no more than one inch. (Is the range that you use measured to that accuracy? I can tell you for certain that mine isn’t). Add to this, altitude, barometric pressure, temperature, and humidity and things get very complex. I will tell you outright that we do not have the facilities or equipment to measure the BC's to the accuracy that I would demand. A few of the larger companies have the resources and are very diligent in measuring and publishing accurate BC's. Some others are a little optimistic and others are down right laughable. Published BC's are one of those things that should be taken with a large grain of salt. When the equipment is acquired and the time becomes available, we will publish real world BC's and post them here. Until then, if you would like calculated BC values, please contact us and we will provide them to you.
    Might as well take this time to cover the “why don’t you” questions that pertain to the ballistic coefficient. Why don’t you put a plastic tip on the bullet? Why don’t you put a boattail on it? Why don’t you reduce the size of the meplat so the bullet has a sharper point on it?

    Let’s start with the plastic tip. The bullets that we manufacture have a high content of copper (see cutaway) and as such are already long for their weight when compared to conventional lead cored bullets. A plastic tip would only make the situation worse. Not only will the length of the plastic tip be added to the total length, but also the jacket would have to be extended in order to provide a space for the base of the tip to be locked into. The total of the two would add more than a quarter of an inch to the OAL of the bullet, necessitating deeper seating of the bullet by the same amount. That is a price that I am not willing to pay for a little increase in BC.

    Why don’t you put a boattail on it? In the first place, a boattail would also make the bullet longer. (Are you picking up on the fact that I don’t like long bullets without a very good reason?). And second, the installation of the boattail brings another manufacturing variable into the equation. The more variables there are, the more likely that one of those variables will be detrimental to accuracy. If you ask any of the big companies that make both, flat base and boattail, they will tell you that the flat bases have a greater accuracy potential. I have staked my reputation (and financial future) on providing a bonded core bullet that is accurate. I will not put anything into the equation that has the potential of deviating from that goal.

    Why don’t you make the tip (meplat) smaller, so the bullet would have a sharper point? The answer to this one contains two parts. The first has to do with length of the bullet and the weight distribution over the length of the bullet. The second has to do with the velocities at which the bullet will open. When the tip of the bullet is brought to a small point, becoming a spitzer, rather than a semi-spitzer, the bullet would become longer, for the same weight. The pointed nose of the bullet would also mean a lesser amount of the mass of the bullet will be outside the case, obviously necessitating that a greater amount of the mass be inside the case, taking up powder space.
    Four things determine the minimum velocity at which a bullet will open.

    • 1. The jacket material.
    • 2. How far that material was moved from it’s original, annealed position.
    • 3. The thickness of the jacket at the mouth.
    • 4. The “affective” meplat size.

    • 1. The basic characteristics of the jacket material, primarily, ductility and tensile strength will have an affect on what the minimum velocity would be, to initiate rupture and begin the mushroom process.
    • 2. How far the material is moved from the original position is linked to #1, in that, the farther it is moved, the harder the material will become. Copper and copper based alloys are hardened by working them. The more pointed (smaller meplat) the bullet is made; the farther the jacket material that makes the point is moved. The farther the material is moved, the more it is worked and the harder it gets. The harder the material is, the higher the impact velocity must be to rupture it and begin the mushroom.
    • 3. The thickness of the jacket at the mouth is determined (in my case) by the initial machining process (which has practical lower limits on how thin the material can be machined) as well as a direct relation to #2 above. When the jacket material that forms the mouth of the jacket is moved to the degree necessary to form a small point, it also becomes thicker. The farther it is moved the thicker it becomes and again the higher the impact velocity needs to be for the bullet to mushroom.
    • 4. The “ effective” meplat size is defined by the diameter of the tip of the bullet at the immediate end of the jacket. The meplat, in conjunction with the thickness of the jacket at the same point, will define the area, of lead, that will be exposed to initial impact. Think of looking at the end of the bullet with any lead at the tip cut flush with the mouth of the jacket. This area of lead is what the flesh of the quarry would act upon to initiate expansion; sort of like a hydraulic piston with the flesh acting as the fluid. When the point of the bullet is forced to a smaller size, this area is doubly affected. First, it becomes smaller in area due to the reduction in diameter and, second, the jacket material, at this point has become thicker, further reducing the area. Any reduction in this area will require a higher impact velocity to initiate expansion. Lastly, I know this is contrary to what folks are told but we have found plastic tips on competitive products may hinder reliable initial expansion.

    In summation, the reduction in the size of the tip of a bullet will reduce the affective hydraulic area for flesh to act upon, the jacket material at the tip would become thicker, and the same material would be strengthened due to work hardening. All these affects are detrimental to the reliable function of the bullet at low impact velocities. Again, a price I am not willing to pay for a slight increase in BC.

    Do you have a loading manual or loading information for my cartridge?
    At this time, we do not have a manual or a compilation of loads for many different cartridges. If your cartridge of choice happens to be one that we have accumulated pressure data on, in the course of testing our bullets, we could, at your request, offer some starting points and do not exceed points.

    We do intend to put load data on the website, when we have had more time to compile data with several brands of powders. At this point, we are only trying to confirm maximum pressures and velocities with an eye toward attempting to induce bullet failure and then engineering to preclude any such failure.
    What manual would you recommend?
    Virtually all of the manuals, from the larger companies, give reliable and safe information. If you can afford to, we recommend having several to refer to, if for no other reason than to see how much loads and pressures can vary with different components and different rifles, even when using SAAMI techniques.
    If you have no load information, can I just use my old ”favorite load”?
    Come on folks. When you change one of the most important components of a load, there is no longer anything that’s “favorite” about your “favorite load”. Even thirty years ago, when all we had were conventional bullets made by Hornady, Speer, and Sierra, trading components wasn’t a wise thing to do; unwise yes, but generally not hazardous.

    Today, with all the different styles of bullets with different lengths, surface contact area, materials, and construction designs, it behooves the reloader to use his noggin even more than in the past. It may be likely that your rifle likes a certain weight bullet when launched by a certain brand of powder but that affinity would, more than likely, be linked to the launch velocity. The chance that your “favorite load” would give that same velocity is very remote. When you change to a different bullet (any bullet), reduce your loads and work back up. It takes very few shots to find out where you are at, with the new bullet.
    How does one assemble a powerful and safe load with these bullets?
    Chronograph. Chronograph. Chronograph. It is the most useful tool available to the average loader, at a reasonable price. In every box of bullets sold there is a slip of paper that recommends firing factory ammunition, with the same weight bullet, through your rifle, to check the velocity. Using a reputable manual, choose an appropriately slow powder for the cartridge and reduce the max load by, at least, eight percent. If that load does not give the same velocity, then increase the powder charge, a grain at a time, until it does match the velocity of the factory load. Obviously, watching all the time for any of the classic pressure signs. When you achieve the same velocity, as the factory load, you will have an equal pressure. Notice that I said an “appropriate” powder. Also on the paper in the box, I state that, on average, North Fork bullets require 3 to 4 percent less powder to achieve factory (or manual) velocities and pressures. In some guns it’s only 1% less, in others, it is the full 8% less. I would like to say here that I have not run across a case where I was not able to achieve the same velocity as a factory load at factory equivalent pressures or the stated velocity, from a reputable manual, with a particular bullet weight, in a particular cartridge, at the same pressures. It just usually happens at a slightly lower powder charge.

    To confirm that pressures are the same as factory loads, we use the Oehler 43 system of pressure measurement. Even with over 30 years of reloading behind me, it has been a revelation. Just remember, if you are generating more velocity than a factory load, or loads from a manual (considering the weight of bullet, powder type and quantity, and the length of your particular barrel), then you are generating more pressure than that factory or manual load. I have found in my testing that when dealing with cartridges from .277 through .338, at velocities of 2700 to 3100fps (which covers 95% of all cartridges), that if a load is reduced to produce a 100fps reduction from factory muzzle velocity, that the pressure is reduced around 4 to 5000psi. Adjusting the load to produce a 100fps increase, over factory velocity, takes an increase of around 7 to 8000psi. In a lot of cartridges, that would put you well over 70,000psi. If you are comfortable with that, then so be it. Just don’t kid yourself that you’ve come up with some magical loading, or that you own some magical rifle, that is producing that velocity gain; the gain is coming from increased pressure, period. The gun may handle it, the brass may handle it, but the pressure is there.

    There are cartridges that are currently factory loaded below, what is now considered, standard factory pressures. Such cartridges as the 45-70, 9.3x62, and 404 Jeffery, come to mind. These will be dealt with later, on a case-by-case basis when load data is put on the site. There has been one exception to the velocity equals pressure rule. When the chamber, throat, or barrel dimensions are severely out of spec, velocities cannot be trusted to give relative pressures. On one occasion, I was dealing with a barrel that was grossly out of spec (undersize). That barrel would generate excessive pressures long before factory velocities could be achieved, and that was with conventional lead cored bullets. Whether this particular pressure response to this particular variation should be considered normal or not, I do not know. It scared me sufficiently that I have no desire for further investigation.
    Can, or should, the grooves be used for crimping?
    Well, yes and no. Some bullets have a groove that is located at the proper crimping point, others do not. For instance, the 458-350FP has the forward groove located at a point that would make it proper to use as a crimp groove. Doing so would provide a 45-70 cartridge OAL that is suitable for current Marlin and Winchester lever guns. Of course, if you wish a longer OAL, you can crimp in any groove that you choose to. Whether you can increase the OAL, will be determined by the throat in your rifle. Heavy recoiling calibers, 40 and above, are provided with a groove that would serve as a crimp groove.

    The proper procedure for crimping in a groove is as follows.

    1. First, the grooves are fairly narrow, so the casings should be trimmed to a uniform length.
    2. Next, with the die backed off so that it can’t crimp, adjust the seater plug so that it seats the bullet until the groove, that you desire to crimp into, just about disappears into the case.
    3. Then, readjust the die to crimp at this point.

    Due to the narrowness of the grooves, it is preferred that the seating and crimping be carried out as a two-step process as described above.

    On the smaller calibers, it is not feasible to carry the grooves far enough forward, for the front groove to be used for crimping. If the smaller calibers need to have a tighter fit in the case neck, it is usually advisable to take a few thousandths off the expander ball. If you still prefer to crimp the smaller calibers, a crimp can be performed on the body of the bullet, ahead of the grooves, with the use of a Lee Factory Crimp die. Just seat to the desired OAL and apply the crimp with the die. Don’t expect to see the case mouth indent into the body of the bullet; that isn’t going to happen. What will happen is the case mouth will tighten on the bullet, increasing the bullet pull. This you can test by using an impact bullet puller to try and pull both crimped and uncrimped bullets. The crimp does indeed increase bullet pull; you just won’t be able to see the crimp. I have tested bullets that have been crimped VERY hard with the Lee die and no detrimental affects have been found, as far as terminal performance.
    What is considered normal weight variation on North Fork bullets?
    Every attempt is made to keep the variation to no more than plus or minus .5 grains from the mean bullet weight for a particular run. In general, 90% of the bullets in a run will have a variation of no more than plus or minus .25 grains. Variation between runs is usually less than .25 grains.
    Since your bullets are bonded, can I use one that is lighter than normal, for a given caliber, and expect enough penetration?
    That all depends on how much lighter you are talking about and what you consider “enough” penetration. This is one of the areas where you can’t fool Mother Nature. Sectional density still counts. Yes, bonding the core of a bullet does greatly decrease the likelihood of bullet failure and that will definitely result in greater penetration compared to a bullet that breaks up, but in truth, the survival of the bullet’s structural integrity, and it’s penetration, has more to do with the internal design than whether it is bonded or not. For instance, if a bullet is basically designed to be a bomb, then you take that bullet and put in a bonded core, it will still be a bomb; it’s just that now it will be a bomb that won’t throw off shrapnel. The depth of penetration will be affected very little. One simple rule can be counted on; if you take two bullets of the same caliber and identical construction, AND impact them at the same velocity, the higher sectional density bullet will always penetrate further. Where the fuzzy area comes in is when the bullets aren’t constructed the same and, also, rarely are the two bullets of different weights impacting at the same velocities because they were not fired at the same muzzle velocity.

    In conventional (full length core) bullets, the faster their impact velocities, the larger they expand, which has the result of greater drag and reduced penetration. On the other hand, North Fork bullets have reached their maximum frontal area in the 2000 to 2200fps impact range. If they impact at higher speeds, the frontal area increases very little, if at all. This relatively constant frontal area, over a wide range of impact speeds translates into increased penetration, at those higher impact speeds; same frontal area and higher momentum. Notice I said impact speeds, not muzzle velocities; the two are not the same. So, in some instances, velocity itself can mitigate the lower sectional density of the lighter bullet, but in general, I will always recommend the highest sectional density, when large and/or dangerous game is involved. That rule will always give you the most options when less than optimum shot angles are presented.

    More detail as to the proper use of the different weights offered in the different calibers, can be found under those specific calibers.

    A special word to those of you headed for Africa. We manufacture a line of heavy game (HG) bullets (308-200, 338-240, 358-270, 375-300) that are primarily designed for that use. They are more heavily constructed than the standard line and will hold up under the most severe of tests.

    All of them will open, even on the lighter animals so there is no reason to be taking the wrong weight and design on your African trip. Use the right bullet.
    Have you ever tried using moly on your bullets?
    I have experimented with moly and found it to be of no benefit. It will do the same thing that moly will do to any other bullet. It will reduce pressure and velocity which, in order to get the velocity back up, requires an increase in powder charge. When the charge is increased enough to get the pressure back to normal, the velocity is back up to where you started. Unless you own stock in one of the powder companies, I don’t see the point. It yields no increase in velocity over the bullets without the moly, given equal pressures. It also does not decrease fouling because that is why the grooves are there in the first place. One other point, to work at all, the moly must be peened into the surface of the bullet, either by steel shot or by the action of bullet-to-bullet contact. The problem is that there is no way to get the moly to peen in the grooves. This leaves a lot of free moly in the grooves, which causes a mess. This moly would have to be removed by some method (toothbrush)? or eventually you would have moly particles everywhere. Sort of like rolling the bullets around in a coal bin; they come out pretty filthy.

    If you are one of those that are of the opinion that moly increases barrel life or lengthens the time between cleanings, then by all means, give it a try. If you think that it will increase velocity, don’t waste your time. And to you inveterate experimenters that have a mind to put some sort of lube in the grooves, that won’t do anything, either. Ross Seyfried tried that by putting bee’s wax in the grooves. He said he couldn’t help himself; he had grooves and he had to put something in them. I asked him what happened and he said “it made everything smell like burnt bee’s wax”. There was no increase in velocity and, if anything, a decrease in accuracy.