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Alf, Gerard's "new rules" is just sales-speak for his new application of old rules. You can indeed have it both ways if you use the 300 grain .375 bullets in a faster .375. Not too fast like a .378 Weatherby, which is just excessive, but .375 Weatherby or .375 /.404 Saeed at 2700 to 2800 fps would be just right with 300 grainers. That "greater damage" only occurred in the first two compartments of the Iron Buffalo. Thereafter the faster bullet was slowed down to penetrate equally as well as the slower bullet. This pattern was repeatable, reliably. 200 fps extra made for a bigger splash and greater board breakage only in the first 2 compartments of 11 traversed. This was using 300 grain FN's at 2500 and 2700 fps. They both bounced off the 11th wood layer. The 270 grain FN at 2900 fps was stopped by the 9th layer of wood. Sectional density is funny that way, no joke, just funny. Bullet weight beats velocity for penetration, as you agree, and Saeed has certainly proven that .375/300 grain Walterhogs are not too long to be stable. Any solid with a round nose was keyholing after the second compartment and stopping or going out the side of the fifth compartment, reliably. I had to stop using the round noses of any type due to damage to the Iron Buffalo's ribs. | |||
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In the old days with round nose solids, too much velocity made them yaw much sooner, and penetrate less. Too fragile softs also would penetrate less with too much velocity, of course, and make a mess of the meat. FN solids stay straight and penetrate as deeply or more deeply as velocity goes up between 2100 and 2700 fps impact speeds, this I am sure of. You can have your cake and eat it too, with the higher velocity FN solids. Same applies to the new softs like the HV that blow off their nose petals with higher velocity and become very stable shorter cylinders, as Alf has pointed out. Alf, Admit it. You can have your cake (high velocity wound on entry) and eat it too ( stable straight line penetration as deep or deeper than slower bullets), with either a soft or a solid, thanks to Gerard's "new rules." Now we must stop bad mouthing the 300 grain .375 caliber monometal bullets at 2700 to 2800 fps MV, or impacting around 2700 fps.  Eat right up to the bullet hole, as long as it is not a Portuguese-Texan heart shot on that buff or ele.  | |||
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Gerard, Quite so and only true for shooting overly short bullets in long-throated calibers. That means one goes against the design parameters for a specific cartridge. The condition that you describe generally falls outside the design spec. Let me illustrate practically with the 9,3 x 62 mm: The specified cartridge AOL per CIP is 83.7 mm. The case is 62 mm long. Thus the external bullet length is 21.7 mm. Soft bullets in 286 grain class run from 30 to 33.3 mm's. Using the 286-gr Rhino Semi-Spitzer @ 33.3 mm as an example, the bullet is seated (33.3 mm less 21.7) 11.6 millimeters deep into the case. To touch the lands (to seal the bore) I have to move the bullet forward by 2.5 mm. I have 11.6 mm vs the 2.5 mm slack. Even if the shorter 286 gr Woodleigh bullets is used, the bore is sealed before the base of the bullet leaves the neck of the case. Thus the combination of hot loads (high flame temperature) and high pressure systems are in the main to blame for throat erosion. So the condition that you punt cannot happen with a 9.3x62 mm, or any well designed caliber for that matter. Everything in a 9,3x62 mm seems to gell so perfectly, there is just nothing that can be improved upon to yield a practical improvement. Much better designed than a 375 H&H in my opinion. Over time more and more people are discovering the genius and adequacy of the 9,x62 mm. A 286 gr Woodleigh Steel-jacketed RN FMJ goes traight through an elephant's head. For additional insurance, a FN solid design will yield even further straight-line penetration. Chris | |||
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Here you say:
Over on the Ruger 375 thread you say:
You want Ruger to long throat the caliber for a bullet that will see use in less than a fraction of a percent of use and the rest of the time the throat will be subject to flame cutting from bullets that are too short? What were you thinking? Or are you just here again to differ on principle? You should pull your head out of that 9.3x62 and look around a bit more.  | |||
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Gerhard, Throat erosion is actually present in all calibers, be they short or long-throated. The fact is that over-bore calibers suffer more severe throat erosion than those that are not; for example, the 22 Swift vs the 500 Jeffery, even though its powder capacity is much less than the 500 Jeffery. So, the ratio of powder to diameter is a critical factor. In addition, hot loads (more powder through the same hole) causes a further increase in flame temperatures - the scorching flame that 'melts' the steel away. We also know that the powder burns well into the barrel, and as such, unburned granules run over the throat area like sandpaper and assists the erosion process. Throat erosion has therefore more to do with hot loads and the ratio between the amount of powder to bore diameter, as opposed to the length of the throat. That's why we see far less throat erosion in the long-throated 7x57 mm and the 9,3 x62 mm than those calibers with much shorter throats but far higher velocity - consider in this regard the various over-bore magnums. Further more, throat erosion can be exacerbated if many rounds are fired in quick succession, when the barrel is hot and thus becomes softer. Gerhard you should pull your head out of the clouds of high velocity when we deal with calibers that are meant for DG hunting at short range and look around a bit more at the virtues of calibers such as the 9,3 x 62 mm - an engineering marvel. 320/325 Grainers (Woodleigh & Rhino)can be comfortably shot in the 9,3 and there is a specific reason/application for it, and I would like to think that a similar benefit can be had with heavier bullets in a 9,5 mm caliber (any .375" bore). Just get the design right. Chris | |||
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RIP, The first two paragraphs Kwiff wrote above has been common knowledge for decades and I have not stated otherwise. Kwiff sets up his replies to make it appear so. He is in fact arguing with himself. This is to draw attention away from his blunder on long throating the 375 Ruger, no doubt. No, I have not forgotten how his name is spelled, just belabouring the point that his attention to detail is so poor that, after six years of picking petty arguments with me, he can't even get my name right. As for getting my head out of the clouds of high speed: I like it here. The times of flight are short, wind drift is low, trajectories are flatter and all this makes shot placement so much easier and enhances the forces applied to the target. Kwiff should try it some time. With that taken care of, consider this. The 22-06 Easling and other similar overbore wildcats were not popular in their time because of the throat erosion issue. Now I have built two 22x64s which are essentially the same thing as the Easling and I know of two that have been built in the US as well. Throat erosion in these rifles is not a problem. Mine is now pushing 2700 shots. It has been fired almost exclusively with drive band bullets coated with very high grade moly. Of course there will be erosion eventually but the indications are that it will be on a par with mundane stuff like 270 Win and 7mm RM. Times they are a'changing. Alf, you took the words right out of my mouth about the 9.3. What a grand caliber it is and so much more versatile with the addition of some speed. It has lost nothing, only gained. | |||
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Now there is something I can get excited about. If it will push a 250gr lead core bullet at 3250, the 230gr HV will cruise nicely at about 3400fps. There is nothing that walks the planet that cannot be taken with a machine like that. It would not matter if it is at muzzle blast distance or out as far as you are comfortable to shoot. Squeeze the trigger and watch it fall down. | |||
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Gerard, You don't get off so easy. Just one question please: Is the .375 Weatherby more prone to throat erosion with this kind of throat: freebore parallel-sided for 0.3700" long freebore diameter of 0.3755" leade angle of 1.5 degrees Hmmm? Also please see second question below. Alf, Thank you for getting into the concept of "African Sheep Rifle," or ASR. Mr. Chadwick did it with a .404 Jeffery in Canada in the 1920's. GSC 320 grain HV's are manna from heaven for a .404 Jeffery ASR. Think 2800 fps. BTW, the .404 Jeffery has no freebore, just a reasonbly tight leade. I would love to hear Gerard recommend a 9.3 mm bullet for use in the 9.3x62 mm Mauser, as an ASR. What weight and how fast? | |||
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RIP, As I have said before: Throat erosion increases when the base of the bullet leaves the case mouth before the bore is sealed. The dimensions of the freebore/throat are immaterial, as long as the condition is met. From a pure design point of view, increased freebore should reduce the onset of erosion but the longer the freebore, the more limited the choice of bullet becomes. A way of taking advantage of increased freebore is to tighten the rate of twist. Tighter twist allows the use of longer bullets and increases the tolerance for increased freebore. 9.3 ASR will be good with a 230gr HV at 2800fps if built on the standard 1:14" twist. Lilja for one, makes a 1:12" barrel and that should be used with a 260gr HV at around 2600fps. | |||
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Gerard, So you are claiming that gas cutting ahead of the bullet occurs, if the bore is not fully sealed by the time the full diameter base of the bullet clears the case mouth edge. This has got to be minimal since much worse soon follows as the burning powder comes right after. This is much more abrasive and hotter by then and much larger in volume. Theoretically you may have a minor point, but I think it is insignificant. Still, it is easy to meet your criteria with a .375 Weatherby throat and a 300 grain monometal. However, the 300 grain Barnes TSX, flat base, works better than a boat tail HV of 265 grains! You are making a case against a shorter boat tail bullet in some applications, like a .375 Weatherby loaded long for a 3.8" box. Anyway, it is trivial in effect and would take thousands of rounds to make any difference if any could be seen, IMHO. 300 grain bullets of any make are more efficient than lighter ones in any .375 caliber rifle with case capacity bigger than a .375 H&H. Period. Your 265 and 270 grain bullets are most efficient in a .375 H&H. As has always been the case, the 270 grainers of any make are the energy champs for the .375 H&H. This is a balance point phenomenon between bullet weight, case capacity, propellant burn rates, and pressure limits. No new rules here. On to the 9.3x62mm ASR, thank you:  CZ's model 550 Medium FS has a 20.5" barrel of 1:9.5" twist. I fired a couple of fouling shots from a new one then aimed for group at 100 yards, 3 shots: Norma 232 grain Vulkan soft point Factory load: Chronographed: 2547 fps 2533 fps 2556 fps average = 2545 fps 3-shot group: 0.306" center to center, 9x scope (Advertized at 2625 fps, probably right on for a 24" barrel.) I am amazed that anyone would be afraid of fast twist barrels at hunting ranges of less than 1000 yards! You should just recommend that everyone use a 1:10" twist barrel, or at slowest 1:12" for anything of .375 caliber or larger. Any unhappy campers with your bullets will likely come from those with too slow twist barrels, if not those with over-sized bores/bad barrels. Why dither around with twists slower than 12" on any hunting rifle to be used with monometal bullets? I am not just stirring the pot. I am really puzzled by all this fiddling over matching twist rate to a specific bullet weight in a hunting rifle. 1:10" twist is not excessive on any hunting rifle I can think of. Another example: A Kimber Montama M84 It has a 1:12" twist and does not like bullets heavier than 150 grains. Shoots 150 grainers well, but with any bullet heavier than that, the groups are never as small. Seems to me you are still hung up on some OLD RULES about barrel twist. New Rules: .308 to .366 caliber: preferred twist is 1:10", or faster if you dare, never slower. .375 to .510 caliber: slowest allowed twist is 1:12", simply because it works, but so does the faster 1:10". Of course this covers all useful hunting rifles, with useful bullets on either side of that old joker, .300 SD. Smaller than .308 is for varmints: Fiddle with twist rate to heart's content. Larger than .510 is for plinking with rocks, rocks on the ground and in the head. | |||
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If you have ever worked with an oxy acetylene gas welding set, you wil know that you are dead wrong on this. Running a welding or cutting flame through a small aperture cuts the steel much more quickly. Shorter conventional bullet yes. Shorter HV or FN bullet not applicable to the same extent. Testing at Somchem Proof Lab confirmed that the engraving pressure of our drive band bullets is low enough, so that the primer going off will move the powder and bullet forwards, so that when the charge starts burning, the font drive band is into the rifling. A seal is effected quicker than with ogives that terminate at barrel groove diameter. This is why we recommend magnum primers regardless of powder type or charge weight.
Reality is that the number of fast twist custom made rifles are such a small group that we have to make recommendations for and accommodate factory rifles built to CIP/SAAMI specs as well. The longer the bullet, generally, the better the BC. The best bullet choice (from our range) is firstly the longest bullet that will meet our stability factor requirement in the given twist. This is tempered with the requirement of enough speed for acceptable terminal ballistics, given the capability of a cartridge as dictated by the case capacity and the weight of the HV bullet. A good example is the 308 Win with a 1:10" twist. It stabilises a 160gr HV (designed for the 300 magnums) but terminal ballistics is spotty. The 150gr HV is better but not as good as when used in a 30-06, which is what the 150gr HV is intended for. Now if you want a 308 win to come alive and turn into a real good grief rifle, use the 130gr HV at 3150 to 3200 fps. Our last field trials with that bullet included 7 eland, from 80 to 200m and bush shooting on black wildebeest, down to as close as 30m. What have you been smoking, your socks?  Every owner of a 7mm will tell you how wrong you are. You have opened the door to some serious flaming and I suggest you shut it quickly.  I use a 40gr .224 bullet on everything up to blesbuck at around 150 to 200lbs live weight. After that, I use my 7x57 with a 130gr HV up to eland. On eland I will not shoot over 200m but anything closer, or smaller and further, is meat in the freezer, if I am confident of placing the shot where it must be. Only after this do I exceed the .30 calibre mark with a 375. I have been thinking about a 416 but since 1993, these thoughts have been fading. Sd........ What can one say about Sd? I suppose it is a relic from the era of bullets that contain lead in some proportion. I fear it has no place in monometal bullet technology, but there is a cure: Pour yourself a good one or two, make yourself comfortable in a quiet place and repeat for 20 minutes, "Sd is a crock and sent to mislead me, Sd is a crock and sent to mislead........" Do this once a day until the silly belief goes away. | |||
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Gerard, The primer going off will move any bullet and powder charge forward into the lands. That first rush of gas ahead of the bullet is just low temperature air that was ahead of the bullet and between the powder granules, but starting to warm up from flash of gas from the primer pushing it ahead. It is by no means a cutting torch before the bullet engraves, and that means any bullet, not just yours. Well, I see I have stirred your pot with the "less than .308 is for varmints" thing. Now we just need someone to take offense at the "greater than .510 is for rocks" thing. Sectional density is only funny because it describes a bullet of square cross section. However it is directly proportional to reality, and directly important in many fundamentals of all areas of ballistics. Alf has tried to tell you that too. We worship at no altar to SD. We just have a good chuckle over your attempts to totally scrap it. It will never happen. I know you are working in the limits of making your bullets work in all manner of existing firearms, antique and modern, some with very slow twists. Still, 10" twist would be better on any .308 to .510 caliber hunting rifle for any game within hunting ranges, especially with monometal bullets such as yours. Looks like I am righteous on all points, except for the pot stirring outside of the .308 to .510 caliber range. Please forgive me. I know you sell a lot of small caliber bullets. I would definitely rather have an HV in my .223 if I took it after blesbuck. BTW, a 300 gr .375 HV or TSX or Walterhog at +2700 fps MV will seal the throat well ahead of the "cutting torch" in a .375 Wby, will work great in a 12" twist, and will penetrate significantly better than a 265 grain HV at 2900 fps (if possible in a .375 H&H, though certainly more easily done with Wby or RUM at safer pressures) and will deliver plenty of permanent and temporary WOK along the way. | |||
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So it is not really Sd in the sense of "This 500gr 458 bullet sitting on the bench over here will kill better than that 330gr 416 bullet sitting on your bench over there." Rather it is something more sophisticated and better related to momentum, cross sectional area and kinetic energy? They also do not call them Sectional Density weapons but rather Kinetic Energy weapons. The latest technology again replaces depleted uranium dart of 4.6kg at 1570m/s with a tungsten dart of 4kg at 1740m/s, increasing the capability from 3000m to 5000m. I guess the extra speed is worth more than the extra weight.  | |||
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Please define momentum density. | |||
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So when do we get fin stabilized, saboted darts in caseless ammo to use in our smoothbores for hunting? With no brass to worry about, maybe pressures to 75K psi and velocities of 5000 fps will be obtainable in a man-portable, shoulder-fired weapon of the proper design? | |||
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RIP, Now, now, I have never said Sd does not exist, only that there are better ways of estimating and comparing the potential capability of bullets than Sd. In fact, Sd (the correct formulation, not the square bullet one) is useful in some of the math involving the deforming of bullets. But that is where it ends. Jim Carmichael said: "All things being equal, which they almost never are in the ballistics universe, bullets with a high SD maintain their momentum better and penetrate deeper than lighter bullets of the same caliber. But don't take this to the bank, because when such variables as velocity, bullet shape and construction are tossed into the stew, terminal performances can vary widely." REPENT  Alf, I think Norbert spoke about momentum density but that was just a translation problem. However, you confuse me. If we replace the term momentum density with "the projectile mass and area to which velocity of the projectile is applied in order to penetrate", we are back to momentum applied to the cross sectional area. This is not the same as your old friend Sd but indeed what I said in my post 5 up from here. It is similar to (but still not the same as) Sd x V. That has been my point for the last 6 years. Sd on it's own is a poor measure to use for comparison. Sd has to lean on motion, construction and form. The moment we do that, it becomes Mo/Xsa or BC or morphed into something other than where it started and properly called something other than Sd. Why start over there with Sd and qualify it through several steps to here, when we can start over here where it makes more sense? Tell me this. If someone says a particular bullet will be better because it has more Sd than another, without any other qualification, is that a valid statement? | |||
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Gerard, O.K. I repent, again. But only until next time.  Seriously, what is a mental retard such as I to do rather than rely on the handy SD? It is very useful shorthand for dealing with bullets. Mo/XSA requires some sort of correction factor for velocity effect on drag factor and we shall have to use calculus to integrate our way through the various tissues the bullet encounters in its passage at declining speed through the critter.  Life was so much easier when we had SD.  | |||
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Mental retard  There are no flies on you.  | |||
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Every publication uses Sd because it contains the weight and cross sectional area of the bullet. Together this is used with the speed and other factors to calculate penetration. Sd ON ITS OWN means nothing and that is my problem. Those who say Sd is an indicator WITHOUT QUALIFYING IT with construction shape and speed are wrong. It is as wrong as saying that a high Sd number always results in a high BC number. Querschnittbelastung is the workload on a cross sectional area. You cannot load an area with Sd, it requires motion and mass (momentum). I found where Norbert first referred to it in this thread that dates back to 2003. In a nutshell, that thread was summarised as: Art S said: "If you simplify the formula, you will find that the fundamental relation is proportional to the momentum divided by the area." Norbert said: "This number, called "momentum density" is a basic value calculating the penetration of solid materials by warheads etc. including "bazookas" and the like." Since then the term has been used incorrectly. More than a year later Norbert said regarding penetration: "Momentum density ( momentum per area ) is the key figure... " So we know he means momentum applied to an area (Querschnittbelastung) but the translation is not correct. There is no blame assigned here, it is a translation error and one that is made easily. Still the term was bandied about until February 2005 when RIP asked for a definition of momentum density and it was discovered that it has zip to do with ballistics. By that stage all of us had in fact agreed that the real pointer to likely penetration was Mo/A (aka momentum density). With it, any amount of it, as much as you like of it, on it's own, you also have no penetration. Place a concrete pole 30m high and 1m in diameter on a concrete slab and, despite a massive Sd number, it just sits there until the wind blows it over. Specifically, in many of the penetration tables I have seen, the Sd number on it's own bore little relation to the penetration depth or other test results. And mass GOING TO WORK over a certain reference area is Mo/A. Mass over a reference area is Sd. You have just proved the worthlessness of Sd as a free standing number. | |||
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Gerard, O.K., let's try the new way of looking at things: The reason that a 300 grain bullet is so much better in a .375 Wby is because the .375 Wby can do the same velocity-wise with the 300 grainer as the the .375 H&H can do with 270 grain bullets, and that is a fact. It is also a fact that there are no instability problems with the 300 grainer at higher velocity and slightly higher rps from a 1:12" twist. It is true that the .375 H&H is most efficient with a 265 or 270 grainer. It is also true that the .375 Wby is most efficient with a 300 grainer. SD has nothing to do with it. It is simply a function of the case capacities, bore ratios, bullet weights, and available powders and pressure limits. XSA is constant, and in this case, so is the velocity achieved by the two being compared. If you use a .375 H&H, use 265 HV's and 270 grain FN's. If you use a .375 Wby, use 300 grain HV's and 300 grain FN's. It is as simple as that. The .375 Wby will be a better killer because it delivers both higher momentum and higher kinetic energy to the same frontal area, it will make a deeper wound of the same profile and go on out the other side more likely. How am I doing? A minor point might be that the 300 grainer at the same velocity will have more momentum and energy to open up the hollowpoint sooner (some say SD drives this, but we know it is really the energy and momentum), so the petals might blow off sooner and alter the wound profile a wee bit, but likely making the bullet convert to a cylinder sooner and devastate on along. This stuff really can be complicated.  | |||
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No argument from me on anything so far. Taken care of. The nose profile volume to hollow point volume ratio is adjusted to allow expansion over a similar time frame as the 265gr HV. It nicely compensates for the additional Sd/momentum/energy. | |||
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Amazing. You have designed the perfect bullet combo for the .375 Wby, 300 grain HV and FN, as well as the perfect combo for the .375 H&H, 265 grain HV and 270 grain FN. If only the heavier HV was 295 grains, its SD would be exactly .300, but who cares about that anyway. Numerology of SD is hogwash. | |||
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Heh, heh. I finally talked Gerard into seeing a use for his .375/300gr HV and FN. Heh, heh. | |||
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When it comes to throat erosion, only Gerard is allowed to read to us from the pulpit from the book of "Secrets of Ballistics". RIP knows nothing about what a flame can do, and I guess I know even less. When it comes to free-bore, only short ones will do, despite the evidence of the 9,3 mm caliber - what makes a 9.5 mm caliber (.375) so different, and that despite all the explanations of the major factors in throat erosion that culminates in high flame temperature. When I say "Gerhard you should pull your head out of the clouds of high velocity when we deal with calibers that are meant for DG hunting at short range ... " I get a reply like this ... "The times of flight are short, wind drift is low, trajectories are flatter and all this makes shot placement so much easier and enhances the forces applied to the target." Did I not state specifically "DG hunting at short range."? We can argue all the SD points over and over again; a futile exercise as we have seen in the past. Everyone can do his own tests as far as I am concerned and believe whatever he wants. When I have a choice of 3 Barnes-X bullets, say a 120 or a 140 or a 160 grainer, and I ask the salesman behind the counter to hand me a box of 160 grainers for my 7x57, I have made a conscious decision in favour of the high SD bullet without saying it. So SD will always be with us when we buy bullets. The argument that a high SD does not guarantee a high BC is really a silly one, as we all know that a form factor, indicating the sleekness, is involved. SD is useful when used correctly, as I have explained previously, but a high SD is not always necessary - not on small soft game. Longer distances typically dictate lighter bullets with better BC's at higher velocities. So there is always a trade-off situation. So, if I only own a 7x57 rifle and I want to go shoot springbuck at 350 yds, I will opt for the 120 gr bullet, the lowest SD bullet - horses for courses. Why would Woodleigh offer a 320 gr FMJ in addition to a 286 gr FMJ for the 9,3? Does it mean that the higher SD bullet has no niche in DG hunting? Or would a 230 gr FMJ be more appropriate in line with the silly answer I got about times of flight, low wind drift and flatter trajectories? Different applications call for different load combinations - shooting plains game at longer distances is a totally different matter. However I do recognise that a 230gr HV bullets can be useful in the 9,3 especially if it is your only gun and longer distance plains game hunting is on the cards - horses for courses. Chris | |||
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A .243 Win and a .308 Win are both based on the same case, but the .308 will last longer because it has a larger bore. This underlines the importance of the ratio of powder to bore size. Also, hot loads in small-bore magnums will erode the throat of a barrel much faster than milder loads in the same cartridge. The above points us to the single most important aspect of barrel erosion, namely the intensity of the flame temperature. It is a well known law of physics that with increase in pressure, the temperature also increases. Low pressure cartridges generally has a much longer barrel life than high pressure cartridges - more than 10,000 shots are atainable with a 30-30 Win. It is on record that some magnums, such as the large-cased but small bore Weatherby .30-378 Mag, needs a barrel replacement after only 500 rounds - this calibre must have one of the worst records out there. A friend of mine, involved in benchrest shooting, had to replace the barrel of his 6 mm Rem (a slightly bigger case than a .243 Win) before he got 3,000 rounds, whereas his coleques got around 6,000 with their 308 Winchesters. The 7 mm Rem Mag will yield around 1,500 shots, but barrel life can be extended by using moderate loads for practice, and not overheating the barrel by rapid firing. Interesting comment from Lilja ... " Any fast varmint type cartridge can burn out a barrel in just a few hundred rounds if those rounds are shot one after another without letting the barrel cool between groups." The US Army conducted tests and they found that 'boat tail' bullets are assisting in barrel erosion. Some sources say the use of boat tail bullets cause twenty percent faster throat erosion than flat base bullets. Another interesting aspect is that a faster twist rate causes the pressure curve to peak sooner, as more torque is being imparted to the bullet during the highest loading phase of the interior ballistic cycle, with the result that throat erosion is quicker - the US Marine Corps found this out when they re-barreled the M16 to have a 1 in 7" twist instead of the standard 1 in 12" twist. The Swiss opted to use a 1 in 10" twist in their service rifles to prolong barrel life. Chris | |||
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RIP, You are a troublemaker. Now we have to keep explaining to 375H&H shooters why the 300 combo is not the right one for them. The 300combo is stunning in a 378 Weatherby though. I did not have access to a 375 Weatherby and will take your word for what is possible. Chris, How much work have you done with oxy-acetylene welding? How many repairs have you effected with gas welding and silver solder? How many gunsmiths have you apprenticed through your workshop? How many rifles have you had on your books that return year after year from professional culling operations and that require barrel replacement? How much experimenting have you done with long throats, short throats and undersize / oversize / short / long and exactly right bullets? When I finally stopped smithing for customers in 2004, my registers reflected a customer base of around 6000 jobs done. So it is just possible that I may know a little bit more about the subject than you. Maybe. Just a little. So you missed the bit I said about freebore above. Here it is again: "From a pure design point of view, increased freebore should reduce the onset of erosion" You are back to the same old sordid habit of picking an argument with half truths and putting words in my mouth. If you think that shorter time of flight, flatter trajectory and more momentum and energy is unimportant in the frenzy of a charge or when taking a shot at a DG animal at 80m with a 500gr bullet, you have not thought this through. Your ignorance shows again. ..........he won't give you any one of those weights because they have been discontinued. As silly as your point of view that high Sd leads to better terminal performance. That was the point of my using that example. You are as thick as a brick, as usual. And that would be the wrong choice, but it is yours to make. Go forth and err, I could care less what mistakes you make. Because it is the right length. Six years of futile nitpicking and you have learned nothing. Where do you get this from? The 243 will typically use 4gr less of a slower burning powder than a 308. The SAAMI pressure standard for the 243 is 60,000 psi and for the 308 it is 62,000 psi. So you are barking up the wrong horse, you are so far off the mark with this one. You have friends?? That is incredible.
In 1996 I burned out a 7x57 doing exactly the same thing, with jacketed lead core 170gr bullets. It has little to do with speed but I do not expect you to understand that. Show us the reference to this interesting piece of information........ if you can. No doubt these "sources" live on that farm in the Eastern Cape of South Africa that no one can find because it does not exist? You know, the one where no one is allowed to hunt with GS Bullets. Do I have to keep repeating myself? Johan Loubser proved this to be unfounded with experiments he did at Somchem Proof Labs. But if you will reveal the source of this statement........ You would actually be funny if you were not so completely misguided and serious about it too.  | |||
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Gerard, Hey Gerard, your response was really awesome, man. Just a pity that sharing varying viewpoints with you are always turning into a fiasco. If I am as "thick as a brick as usual" as you say, you must be as thick-headed as an old Cape Buffalo ... you just need the horns to round off the 'boss' between your stubborn ears. You just won't listen to RIP's sensible explanations and then you talk down to him from cloud number 9, as he has no clue about the mechanics of throat erosion. Since you raised this question of thickness, let me illustrate your thickness - the 3 Barnes-X bullets were just used as an example, and we all know that they have been replaced by the newer TSX bullets, although we still have the old style floating around - that was not the point, but you want to derail the debate as allways. Then your silly comment that a 120 gr Barnes-X bullet (@ high velocity) in a 7x57 would be the wrong choice for springbuck hunting. Your pompous and godly remark from your self-elevated position has no boundaries ... "Go forth and err, I could care less what mistakes you make." My goodness! Trying to impress this way is typical of you - always side-tracking and putting another spin on things to create a cloud of smoke. You must be thinking that you deal with retarded children to speak such utter nonsense. Consider this the end of this fruitless and futile conversation. Chris | |||
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Chris, Apart from you goading Canuck into calling you a pompous ass and eventually slapping you down, this was a good and civil discussion. I refrained from responding to most of the drivel you came up with. Even when you started with your all red post, implying that I said things I did not and completely contradicting yourself, I kept a civil tongue. When you post in a manner that implies I have never seen a 9.3, I replied with good humour. Clearly I was right when I asked whether you were here just to nitpick and differ on principle. Your very next post about throat erosion, again makes me out to have said a number of things I did not. Once again you take the tone that I have no knowledge of the subject and I corrected the false impression you left, with fair restraint. When you open your next post with: "When it comes to throat erosion, only Gerard is allowed to read to us from the pulpit from the book of "Secrets of Ballistics", you show the true colours that have been lurking all along and then whine that you are only "sharing a varying point of view". Do not accuse me of turning things into a fiasco when you openly pursue your agenda of damage and lies regarding GSC and myself. You are a despicable individual, making out that you are something you clearly are not. That is loathsome.
That is a very convenient but also very transparent ploy to avoid being cornered about the lies about research and opinions of throat erosion caused by boat tail bullets. I asked for references and sources. Where are they? | |||
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Hopefully this can shed a little more light on the subject of throat erosion/barrel burn-out. This is how the US Military looked at the situation as recently as in April/May 2006:
Now, if a M4A1 Carbine Barrel can do 4 000 rounds in harsh firing schedules, then surely my 7mm Rem Mag using GSCHV boat tail bullets, magnum primers and large loads of S365 Somchem powder, yielding high velocities through it's 1:9.5" twist barrel can also do just that! That would mean at a rate of 200 rounds p.a. I have 20 years of accurate shooting out of it. Considering that my hunt shooting takes place on a much milder firing schedule than any military weapon, and I will possibly end up with 40 years of happy, accurate hunting!!!!! Go out and burn those barrels, guys! They can take it! OWLS My Africa, with which I will never be able to live without! | |||
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Wow! Never seen a wooden trigger guard being part of the stock - such a funny shaped stock either! Ja, what shall we, the ordinary biltong hunter say, limited to our 3 hunting rifles and one handgun only - just look and dream! But we live in sunny South Africa with lots of hunting opportunities and that compensates for the lack of having rifles as many as you wish, I think. Alf, that's a beautiful rifle, ou vriend! OWLS My Africa, with which I will never be able to live without! | |||
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