in my neck of the woods sometimes things are hard to get a hold of. i was just getting started developing loads for the 130 grain sierra match king (stock no. 1903) well the local supply dried up. i have 'em on back order everywhere, to no avail.
so, i went to plan b, and looked for another bullet. i wanted to try some 120 grain .284 speer/federal fusion bullets, but there are none to be had in the local stores.
so, i went to plan c, and decided to take a chance with some 120 grain nosler ballistic tips, .284 caliber. now, there is nothing wrong with the nosler. as a matter of fact, bullets they sell as "hunting bullets" often group as accurately a bullets described as "target" or "match," plus the perform dependably on game. but, they do suffer one deficiency, insofar as my particular purposes go. and, that is, nosler has designed the bullet with considerable taper in it, e.g., in other words, the bullet begins to diminish in diameter along its shank much earlier than the ogive starts, e.g., they get narrow before the official start of the pointy part.
as an example of what i am talking about, the 130 grain sierra stays at .284" until a point along the shank .473" from the base of the bullet, and remains at .283" in diameter for a considerable distance past that towards the tip. i can seat this bullet at an overall cartridge length of 2.260" with "jj's brit," ™ although the case neck grip is not as firm at the case mouth as at the tip of the bullet.
the nosler is quite another story. it is not a true .284" in diameter, measuring only .2835" at its base, the point of its greatest diameter. at the point at which the sierra first begins to imperceptibly narrow, the nosler is only .282" in diameter, and very quickly past that point has narrowed to .280 to .279" in diameter. the case neck of my cartridge simply will not grip it adequately if i attempt a seating at 2.260" overall depth, and the bullet simply falls into the interior of the case if pressed.
but, at 2.440" overall seating depth the case neck of "jj's brit" ™ grips the nosler very securely, and it just so happens it is at this overall cartridge length where the nosler begins to make contact with the barrels lands, evidenced by a scuff on the bullet when chambered in the rem-chester.
so, when in rome, do as the romans do. i decided to test the nosler seated at 2.440" overall length.
i started simply. i just used the powder charge i'd used for the 130 sierra for the 120 nosler, and made some cartridges with the nosler bullet seated at 2.440". i drove out to the range, uncased the rifle, put a round or two over the chrony, and noted the speed at around 2550 fps. this is slower than the heavier bullet achieves with the same powder charge, but the result is hardly surprising. being a shorter bullet seated longer, there is more room in the cartridge case available for powder, and since no more powder was placed in it, the chamber pressure is lower. also, the nosler is not as thick in diameter as the sierra, and not as much area of the bullet shank bears against the walls of the barrel's interior. again, less pressure.
less pressure, less velocity.
i shot three rounds. no warm ups, no mulligans.
i went down to examine the target with a friend who witnessed the shooting, and when i saw the group i had shot, i said, "oh, shit."
it was a very small cluster of three holes measuring .584" between the holes farthest apart. that's good. but, i said oh shit because i want higher velocity from this bullet, and my very real concern was that as i obtained velocity the groups shot by the rifle would expand. that's the way it works in my world.
so, to the range today.
with the 120 grain nosler bullets loaded in front of 29, 29.5 and 30.0 grains of h-4198, and seated to an overall cartridge length of 2.440". i put the 30 grain load across the chrony first, and it registered 2670 fps in muzzle velocity, the chronograph about 15 feet in front of the gun's muzzle. i then shot a group with that load, and it measured 2.000" across exactly (as exact as it gets in my world), with horizontal "stringing." this means that while the bullets were within .250" of each other on the vertical axis, on the horizontal axis the middle round had a bullet about 1.000" on either flank.
next i shot a group with the 29 grain powder charge, and it made a nice little round cluster, (actually, pretty much an equilateral triangle) measuring .885" between the two farthest bullet holes. the group center was about 2.500" above the point of aim, and directly above it.
perfect, in my world. that means a shot taken at 300 yards with that load, bullet and speed, will hit about dead on at 300 yards, and about 4 to 5" high at 200 yards, or so. in other points, point and shoot.
finally, i shot the load propelled by 29.5 grains of h-4198 over the chronograph, and it measured about 2650 feet per second in velocity. this confirmed to my suspicion that the load with 30 grains of powder was "stringing" perhaps because of pressure problems. too much powder, ... , probably. with a bit of a caveat on that. i will want to speak with my friends who do the quick load analysis, to make sure the "vibration nodes" were simply not in order.
trust me, this is a bit more technical than you want to hear about.
to conclude the festivities, i shot on final group, and it measured around 2.095" in another string. was i disappointed? nope, because i new that when i fired the second shot, that i had entered into "brain fart" mode, and that i was paying attention, and that i was moving when i fired the shot. even while one part of your mind knows that it is doing wrong, the other part has committed to a course, and completes it. (this is true. people who look into human performance note that when a baseball pitcher commits to throwing the curve ball, all of the sequences which have been pre-programmed are going to be carried out, even if the pitcher knows he has begun badly. it sort of like when you put the boat into the water in the grand canyon, you are committed to the trip. physiologically speaking, of course.)
the two bullets nearest each other in this group were about .608" from each other, and i suspect that had i not "brain farted" on the second shot, that this group would have been quite similar to the first group of the day.
i am pretty confident that if i fiddle with this load just a bit, going up or down a .1 of a grain or so from 29.5 grains of powder used in it, that i will arrive sooner or later at a "shooter."
i may fiddle with some different powders over the next 3 months or so, as finances permit, but, for the most part i am inclined just to accept the fact that this has been a pretty painless endeavor finding a load that will shoot well.
why fix it, if it ain't broke? not all rifles and loads shot .584" and .885" groups the first two times out of the chute. i am not inclined to look a gift horse in the mouth.
i think this cartridge will shoot. it shot a .950" group with the 130 grain sierra bullet, and .584" & 885" with the 120 grain nosler bullet. who knows what it shot with the 100 sierra hollow point bullet, i never found the holes? laughing. (when in fact a young man, i had a ruger model 77 rifle in .22-250 remington that would shoot all day long inside a dime, with a very cheap bushnell scope, any combination of brass & powder i could think of, as long as it was using 52 grain speer hollow point bullets. i sold that rifle, much to my everlasting regret. it's been 40 years ago, and i regret it, so that is pretty close to ever lasting in my book.) i thought that all rifles and all loads shot so well. *sigh* if i had only known.
caption: this is the same target from an earlier shooting session, using the 130 grain sierra match king, .284 caliber, for evaluation. you've seen it at, http://wintersoldier2008.typepad.com/summer_patriot_winter_sol/2012/05/beginning-ballistics-jjs-brit-preliminary-accuracy-testing-w-the-130-grain-sierra-.html . i've just reused it.
you can see the little group, at .584", just to the left of my signature. it was the first group i shot w/ the 120 grain nosler ballistic tips. the next day, near the bottom of the target, i shot another good group, at .885", the center of aim being the bottom orange ball. larger groups shot that next day, as noted in the text, were with powder charges of 29.5 and 30.0 grains of h-4198, and with increasing pressure the groups began to spread a bit. still in all, compared to the "standard" set by the 7.62x39mm russian, this is good grouping indeed.
velocities with the larger doses of powder averaged above 2650 feet per second, pretty sprightly for such a small case.
well, enough of this.
for right now, this is the last of the "jj's brit" ™ articles for a while.
i am satisfied it is a doable concept. i don't mean the .30/280 british as adopted by great britain and then abandoned to keep favor with america. the validity of that program, and the .30/280 british was established nigh onto 60 years ago.
no, what i mean is, it is a doable concept for you to get some reloading dies, and to fabricate a virtual replica/duplicate/facsimile of the .30/280 british cartridge as i have outlined and described in the pages of this blog, and to find yourself with a very tractable (by that, i mean it has no unpleasant surprises, at least as i have found, with high pressure or other disagreeable traits in a hand-load cartridge), and exceptionally accurate rifle cartridge that is a snap to reload when the initial chore of fabricating cases is done.
simple as that.
the little dear is easy & quite predictable to reload, and it is accurate and potent to boot.
john jay @ 05.25.2012
p.s. i think britain should readopt the .30/284 british, or the "jjs' brit" ™ if they would like, and load it into a scaled down fn fal rifle with provisions for a good optical sight. they would have, quite simply, one of the best, if not the best, rifle and cartridge combinations of any nation on earth.
"invented here," as they say. re-invented here, as i say.
and, much credit should be extended to louis potter, and english gun smith, member of the gun trade, and well respected firearms authority and author who still plies his trade in england. and, who still extols the virtues of the .30/280 british.
i deeply regret that he has never seen fit to contact me about the whole matter, and i made considerable effort to achieve that on my end.
more's the pity. i would like to talk to him about this, my elbows drowning in the overflow from a couple good pints of beer. it is apparently not intended to be.