Might be worth looking at the Palma shooting team since they shoot a lot of 600m stuff.
http://www.palma.org/USA/basics.htm
I have shot a fair # of LONG distance groundhogs and prairie dogs and the ability to read wind and thermals has a LOT to do with how well you will shoot. Start by reading an awesome article on the Houston Warehouse below. It will give you a lot of food for thought. Expect to dump a LOT of money into this pit and no looking back. There are a LOT of 1500M+ shooters out there and many of them are long distance varmint hunters. Might be worth reading Varmint hunter Magazine
Here I am shooting a nice custom 22br which is a 6mm necked down to a 22. Neseika Bay action, bumped Nightforce scope, 1.5 ounce Jewell trigger, Lilja barrel, custom stock with fire breathing dragon blowin flames down the stock and prairie dogs trying to get out of the way... Money pit.
Secrets of the Houston Warehouse
by Dave Scott
(Editor’s introduction: Many, many years ago, when the earth was young, and the oceans still covered much of the land, and dinosaurs were to be found on every street corner... okay, if you insist on a date, it was 1993... we published the first of five Special Issues... and in a burst of creativity, we elected to call this one “Special Issue No. 1”. Unfortunately, the first two Special Issues are long since sold out, and those few that infrequently come on the market often carry price tags that look like the Gross National Product figure of some third world countries. That first issue carried an article by Dave Scott that we still receive a dozen or more calls a month asking for copies of. After a half dozen calls this week, we have decided to save ourselves a lot of wear and tear on our photocopier, and reprint the article... one of the most popular, and most quoted pieces that we ever carried.)
In 1975, when a Houston concrete contractor opened the doors of his new business venture, the event didn’t exactly make ripples among the benchrest community. The project, an enormous warehouse on Houston’s east side, was built solely to be leased for industrial storage. And if the event went unnoted, its builder, Virgil King, was equally unknown to group shooters. No one could have predicted that the Houston Warehouse and Virgil King would write one of the more fascinating chapters on the subject of extreme rifle accuracy.
From the beginning, the warehouse was utilized as planned. First, tons of telephone directories were stacked on its floor; then an oil company leased the structure to store plastics.
All the while, Virgil and a neighbor, veteran shooter Bob Fisher, were kicking around an interesting idea. Even though the building was in full use, it had an unobstructed fire lane that was 30 feet wide and ran the full length of the mammoth structure — 325 yards. Moreover, although employees of the leasing oil company were in and out during the work day, the building was deserted nights and weekends. Virgil saw an opportunity to test his most accurate gun, a Shilen-barreled .25/06 hunting rifle, in ideal shooting conditions.
Bob Fisher, a benchrest shooter, had other things in mind. He was awed when first he stood in the enormous warehouse. The floor was thick concrete, poured to withstand hundreds of tons of storage. The walls were 6" concrete without windows. The roof soared 45 feet above floor level. In short, it was obvious to Bob that this building had the potential of becoming the best shooting environment an accuracy fanatic ever popped a primer in. It literally was a benchrest shooter’s dream come true, the Camelot of shooting ranges. Here, the breezes never blew, the mirage never shimmered, the sun never set and the rain never fell. Even the harshness of the weather, either heat or cold, was moderated by the insulating properties of the walls and steel roof.
The two shooters began by constructing a combination bullet trap and target holder utilizing sand contained between walls of 1 1/2" steel plate and a face of 3/4" plywood. Although the heavy device was mounted on casters, Virgil decided it would remain stationed against a wall at one end of the warehouse. To change shooting distances, the bench would be moved along the fire lane.
The warehouse already had fluore-scent lighting throughout, but special illumination would be needed at the target. Bob Fisher, an electrical contractor, wired a mix of mercury vapor and quartz lighting. In combination with the fluorescent lamps, it faithfully reproduced normal outside lighting at the target. With the exception of a portable floor lamp used to eliminate shadows, the lights were mounted on the ceiling to prevent their heat from interfering with sighting.
The two shooters built a sturdy, wooden bench but quickly abandoned it when they discovered that placing a hand on its top displaced the crosshairs at the target. They also committed a major error in constructing the bench and stool as a single unit. Every bodily movement was transmitted to the rifle. The shooters correctly decided there was no point in having a million-dollar shooting range with a two-bit bench.
Determined to convincingly rectify his initial mistake, Virgil poured a massive 700-pound concrete bench consisting of a 6"-thick, steel-reinforced top perched on three legs of 6" steel pipe. To be on the sturdy side, he ran iron rods inside the legs and filled them with concrete. The stool was also three-legged and independent of the bench.
Since this ponderous shooting platform was a tad hefty to be manually hauled about, a heavy industrial caster was mounted on an eccentric at the foot of each leg. Rotated down, the casters allowed the bench to freely roll. With the casters raised, the bench sat solidly on its legs.
With the range now perfected, a minor and somewhat nagging difficulty had to be overcome. In the sealed environment of the warehouse, there was no breeze to dispel the mirage rising from a heated barrel. Because a scope tube’s bulk may damage a fragile scope, or the tube itself may heat up and introduce mirage, fanning the barrel with a piece of paper became for standard procedure for a while.
Finally, in a bold stroke of technological innovation, Bob brought in a small electric fan. Carefully directed over the barrel, the puny appliance effectively cleared away the barrel mirage. Care was exercised, however, not to allow errant air movement to invade the sensitive muzzle area and thereby deflect the bullet from its true path.
And so began perhaps the most insightful, revealing experimentation into practical rifle accuracy ever conducted. Over a period of six years, the levels of accuracy achieved in the Houston Warehouse went beyond what many precision shooters thought possible for lightweight rifles shot from sandbags and aimed shot-to-shot by human eye. For the first time, a handful of gifted, serious experimenters — armed with the very best performing rifles (with notable exceptions) — could boldly venture into the final frontiers of rifle accuracy, a journey made possible by eliminating the baffling uncertainties of conditions arising from wind and mirage.
Under these steel skies, a shooter could, without question, confirm the absolute limits of accuracy of his rifle, or isolate the source of a problem. In the flawlessly stable containment of the Houston Warehouse, only four general categories of accuracy problems were possible: the rifle, the scope, the load or the shooter. For the first time, a very few exceptional rifles would display the real stuff, drilling repeated groups measuring well below the unbelievably tiny .100" barrier. The bulk of rifles, however, embarrassed their owners.
For the most part, shooters arrived at the warehouse with troubles. Their rifles were inconsistent — one group in the teens, the next in the .3’s — for reasons they could not fathom. Others had consistent .25" to .30- something rifles, an accuracy level guaranteed to put a competition shooter down near the bottom of the pack. With the list of potential problems significantly narrowed by the elimination of moving air and dancing heat waves, the answers were easier to isolate in the warehouse, and shooters drove hundreds of miles or flew into Houston to get to the source of their tribulations.
Some of the best benchrest marksmen in the nation showed up with rifles they hoped would somehow perform much better in Virgil’s concrete sanctuary than out there where the flags flutter. Still others wanted merely to shrink the bullet dispersion of a superb rifle a few additional thousandths of an inch by careful tuning, a task that could not be accomplished at an outside range cursed with the vagaries of natural conditions. Some departed enlightened. Others stalked away disgruntled.
The discoveries made there, some reported in Precision Shooting by T.J. Jackson, were sometimes controversial, but always fascinating. Circulating around at that time were mutterings that the warehouse conditions were flawed and the shooting there invalid. From what I knew about the warehouse, I wondered how anyone could fault it. After all, some of the shooters were firing numerous consecutive groups measuring “in the zeros”. Flawed conditions, indeed!
For those of us who are strangers to groups “in the zeros”, we’re talking about 5 shots at 100 yards that are, at first glance, indistinguishable from a single shot. The bullets sizzling through the same hole merely worry away the tortured edge of the target paper in varying degrees until the hole is enlarged less than .100" over bullet diameter. Often much less.
For years, many of us expectantly thumbed through the pages of Precision Shooting, searching for more information from the Houston Warehouse. Col. Jackson, a highly respected benchrest shooter and gunsmith who frequented the warehouse, occasionally dropped us a crumb — and sometimes a bomb. But it was never enough. In late 1985, two years after the warehouse mysteriously passed into obscurity, a frustrated Dave Brennan confessed that one of the great disappointments of his editorship was that he had never received a comprehensive write-up on the shooting that went on there.
In 1983, as suddenly as it all began, the Houston Warehouse shut its doors to the men who mysteriously arrived in the night. The gunshots faded away. And with them died the hopes of many of us. Now we might never know what happened behind those sturdy concrete walls. Gone was the possibility, however remote, that any one of us would ever sit at the massive bench and launch a bullet into perfectly still air. With sinking hearts, we realized it was the end of an era that might never come again.
In June of this year, I contacted T.J. Jackson in Austin and asked if he would consent to an interview on the Houston Warehouse. T.J. graciously offered to help, but suggested I contact Virgil King, since only Virgil was present every time shooting occurred in the warehouse. T.J. had reported in PS that Virgil was the primary shooter. Col. Jackson described him as having a superior delivery — “delivery” meaning bag technique, or the mechanical ability to return, position and fire the rifle identically each time. Unfortunately, T.J. had no idea how to contact Virgil.
Three nights after I talked to T.J., the phone rang at 9:45. The caller introduced himself as the caretaker of the Houston Warehouse. Virgil had read my recent Precision Shooting article on neck clearance and wanted to discuss some of his thoughts on that subject. Somewhat stunned at this fortunate coincidence, I listened intently for over an hour as Virgil spoke of case necks, shooters and the Houston Warehouse experience. Finally I asked if he would be agreeable to an interview. He was reluctant, but at least I managed to obtain his phone number.
A couple of weeks later, after several abbreviated conversations with his answering machine, I reached him again. This time, Virgil kindly consented to sparing me a couple of hours to tape a conversation on shooting and the warehouse. In order that neither of us spend all morning driving, Virgil suggested we meet about halfway between our homes — at Shilen Rifles in Ennis, Texas.
On the appointed day, Ed Shilen, a mutual friend of Virgil’s and mine, introduced us, then departed for an afternoon of sailplane soaring. In the quiet of Ed’s office, Virgil began to vividly sketch what many of us had tried to envision. He spoke with great clarity and sharp memory of events that concluded a decade ago.
“The shooting would generally start about 10 at night,” he began. “Everything settled down, and the air got real still. It just felt right. Then it was like shooting outside, except there was no wind or mirage. If you had a rifle that would shoot, it would shoot. If you didn’t, you found out pretty soon that you had a problem.”
“Downrange at 100 yards,” he continued, “if a rifle was really cooking, through the spotting scope you’d see the hole in the target open up black when the bullet passed through, then the paper would spring back and close a little bit. And if the group was .035" or so, you couldn’t see the difference between it and one bullet hole through a 36X spotting scope.”
A unique feature of the Houston Warehouse was the fact that it indeed had similarities to shooting outside. Unlike shooting tunnels, where the shooter must wait between shots for powder gases and heat to clear, firing in the vast expanses of the warehouse could be conducted at any pace. The offending products of combustion rapidly floated to the roof, high above.
As already indicated, of the handful of riflemen who ever fired in the warehouse, a high percentage had problems. On occasion, experimentation would continue all night or all weekend, as a shooter refused to accept the fact that his rifle simply was not going to perform. When this occurred, Virgil and his shooting guest spread cardboard on the hard warehouse floor and rested periodically, then went back to it again.
“It was pretty frustrating,” Virgil admitted, “because in the warehouse I could fire three groups in any rifle and tell you if that rifle was going to shoot really well.”
“Still,” Virgil explained, “I felt that I owed any shooter who either drove hundreds of miles or flew into Houston the opportunity to prove to himself that his rifle just was not going to shoot. If that took hours or days, that’s the way it was going to be.”
Numbered among those who showed up with rifles not measuring up to expectations were distinguished personages such as Don Geraci, Harold Broughton, Ed Shilen, Frank Wilson, Henry Christman, John Jones, Wilbur Cooper, Col. Jackson, Jim Goddard, Jim Williams, and Bob Fisher. Most of the disappointed shooters reworked their equipment and returned. Those who returned generally trotted out vastly improved guns.
That’s not to say that the bulk of rifles showing up there — even the reworked ones — would shoot in the zeros. Virgil estimated he could count on his fingers the rifles he had seen that would consistently shoot to this awesome accuracy level. T.J. Jackson owned two such rifles, both chambered by him for 6BR. One of his rifles, a Heavy Varmint class gun, consistently shot .050". The other, a lighter rifle, would hold at about .060". T.J. also built an exceptional 6PPC for a customer, which T.J. later purchased. Why? We can assume part of the reason is that it grouped at the .050" level. Frank Wilson had two rifles that would shoot in the zeros, but only after they had been reworked.
“We figured any gun was really shooting,” Virgil explained, “when it would shoot five consecutive groups that were identical in shape and less than .080”.
The most accurate rifle ever to punctuate the stillness of the Houston Warehouse happened to be Virgil King’s own 10 1/2-pound Light Varmint benchrest rifle. The rifle was built around an action made to Virgil’s specifications by Houston shooter Wilbur Cooper, a mechanical engineer, master machinist and fanatical perfectionist. The action was machined from #416 stainless steel and had an integral sleeve extending 5/8" forward around the barrel, but not touching it, to provide additional bedding surface. Virgil said the tolerances were held so close in this action that he estimated, as an example, that the clearance between the bolt and boltway measured perhaps a minuscule .0001" on all sides. Consequently, simply inserting the bolt took a measure of concentration.
T.J. Jackson chambered its Shilen Select Match Grade 8-groove barrel for a .050"-shortened version of the 22PPC. He also turned the outside of the barrel to ounce-saving dimensions which permitted an oversized #7 contour to be used without the rifle exceeding the weight limit for Light Varmint class. The barrel was cut to 21 3/4" and target crowned.
Lapping compound was then smeared on the barrel threads, and by applying outward pull, the barrel was lapped into the action threads for full, positive contact. Virgil pointed out that if this procedure is not accomplished, only one thread or parts of one or several threads may be making contact. Anything less than full thread contact, he underscored, is destructive to finest accuracy.
During the lapping operation, great care was exercised to align the barrel straight with the receiver. Virgil used no mechanical means. He simply used his hands and a delicate degree of “feel”. He stressed that this step should be done with great moderation. A little lapping here goes a long way.
Part of the reason for lapping-in the barrel and receiver threads is to help center the barrel in the precise middle of the receiver. The superb precision gunsmiths who build benchrest rifles correctly cut the barrel threads slightly loose. While this serves several essential purposes, there is no guarantee that the barrel will “center” when it’s run up and tightened. Lapping helps eliminate this uncertainty.
Virgil confessed that lapping would not have been necessary on his rifle if he, Wilbur Cooper and seasoned shooter John Jones had not been tardy in developing an important innovation in the mating of the barrel to the receiver. Too late to benefit Virgil, the three jointly conceived the idea of undercutting a 45-degree slope on the inside edge of the receiver ring, leaving about two-thirds of the receiver shoulder untouched and square. Another 45-degree slope, cut farther inside the receiver (on a Cooper action), terminated at the locking lugs. With the barrel precisely cut to snug up against the two sloped areas, as well as the receiver shoulder, perfect barrel centering became absolute and positive.
With the lapping done, Virgil next disassembled his Burns conversion Remington trigger and polished it to a mirror-smooth finish, setting it at a delicate 1/4 ounce. He also specified that the firing pin spring inside the bolt be as strong as feasible.
The barreled action was zero-tolerance bedded and then glued in a McMillan stock. Two action screws were also installed in place. In tuning this finely accurate rifle, Virgil firmed up the middle screw to correct a tendency for slight vertical dispersion.
He mounted a Lyman-Siebert 30X scope in Bausch & Lomb rings that had been painstakingly lapped so only a tiny amount of crosshair correction was needed to bring the gun on target. The rings were set on Weaver bases.
The finished rifle made its weight limitation by the skin of its teeth, which did nothing for the appearance of this exceptional gun. Spraying the stock would have catapulted it into the Heavy Varmint ranks. Therefore, the stock permanently retained its unfinished fiberglass appearance.
If the rifle looked like the devil, it shot like the hammers of hell. “Day after day, week after week”, Virgil recalled “it would NOT shoot a group in the warehouse bigger than .070". You had to cheek it or thumb it to get it to shoot that big. Generally, it shot .035" to .050", with most groups holding around .035". But now and then you’d sneak one in a little better than that.”
Friends, we’re talking about firing group after group approximately the same size as the gap on your spark plugs. This, with the barrel cleaned between every six shots — one group plus one fouler. But didn’t he get an occasional larger group? Something really horrible, something maybe in the (shudder) teens? “Not unless you did something wrong,” Virgil responded indignantly, flinching at the implication of his rifle sinking to that dismal level.
How could the rifle and the man behind it be that consistently accurate? Virgil told me in great detail. “First, you shoot free-recoil. After a while, after all the thousands of rounds I fired in the warehouse, I developed a technique that was practically infallible. I did exactly the same thing every shot. I was like a machine, and once you find out what works, you don’t change anything. We discovered that if you want a gun to really shoot, you can’t cheek it, you can’t shoulder it, you can’t hand it, you can’t thumb it. The only thing you touch is the trigger, and I tried to put my fingerprint on the trigger exactly where my last fingerprint was. I didn’t even touch the bench. I planted my feet solidly on the floor and kept them right there.
“Your shoulder should be 3/16" to 5/16" from the stock so you can catch the rifle immediately when it recoils back,” Virgil advised. “Otherwise the rifle will get back too far and disturb the rear bag.”
The rear bag and the way you manage it is crucial, Virgil explained. First, he positioned the rifle on the bench so the stock barely protruded from the “V” of a rabbit-ear bag, then he pounded the stock firmly into the bag. As already mentioned, when the rifle recoils, it’s important that the bag stay put. With proper bag technique, when the rifle is returned to its firing position, any sight corrections should be slight and made by tiny manipulation of the rear bag. The less bag adjustment, the better. Consistency is everything.
Virgil packed his rear bag very firm with casting sand, which is about 33% heavier than common sand. He then applied water and formed the “V” to the rifle stock by pounding the stock into the bag and allowing the leather to dry. Done only once, this step hardens the leather and makes the stock slide smoother. A mixture of equal amounts of talcum powder and white graphite applied to the back and front bags provided smooth sliding of the rifle, even in very humid conditions.
He packed the front bag as hard as iron. Here he employed a one-to-three mixture of Portland cement and casting sand. The cement doesn’t set, but it does help hold the bag shape by resisting the twisting force imparted to the fore-end by bullet torque.
Virgil fired his many zero-level groups without any side support for the front bag, but he strongly advocates the pedestal fore-end stop. He adjusted the stop so the front bag supported the fore-end about halfway from the end of the fore-end to the receiver. He said if the bag is positioned farther forward, this part of the stock is too springy, and accuracy will suffer.
When Virgil returned his rifle after firing, he bumped the fore-end stop and then pulled the rifle back “one-millionth of an inch”. In the warehouse, he found that contact between the stop and stock tended to deteriorate accuracy.
The Houston Warehouse was the perfect setting for building a load. In years of watching his rifles and a few others punch microscopically enlarged holes in targets, he recorded some interesting observations. “In the summer,” Virgil noted, “the sharpest groups we could get out of the 6PPC was with Winchester
748 powder. But when the temperature fell below, say 70 degrees, it wouldn’t shoot. We’d have to go to H322.” His Gilmore-chambered Shilen 8-groove 6PPC barrel on the Cooper action produced groups a bit looser than the 22PPC barrel, averaging about .070".
In this shortened 22PPC, he used IMR4198 exclusively. He adopted this powder after Don Geraci, an advocate of 4198, visited the warehouse. Although 4198 has a reputation for varying considerably from lot to lot, Virgil never bothered to lay in a big supply of any particular batch. “I just went out and bought some when I needed it,” he said. “Lot number didn’t make any difference.”
Within limits, neither did powder charge. Virgil threw his charges from a Culver conversion, and the grain-cutting operation obviously gave him reasonably consistent results with the long, little kernels, considering the excellence of the resulting groups. He did, however, later use a Belding & Mull powder measure in order to lessen the grain-cutting problem.
Powder charges, as long as they were fairly consistent and bracketed within a couple of grains, were not important, he said. On one occasion, as an experiment Virgil shot one group with his 6PPC barrel on the Cooper action using a 53 Culver setting of Winchester 748, the next 52 and the third 51. All three groups were identical.
01-01-2010, 10:46 AM
Great day on the range
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