BY AL ASHTON ment of the DASHER. The most
Transcription
BY AL ASHTON ment of the DASHER. The most
PRECISION SHOOTING - FEBRUARY 1999 BY AL ASHTON Dan Dowling is the proprietor of Accuracy Gunsmithing, in Palisade, Colorado. His name is well known to many readers of Precision Shooting, as the developer of the WALDOG cartridge. Dan is a superb riflesmith. all-around good guy, and he enjoys a well-deserved reputation for high quality work. One of Dan's outstanding traits is his willingness to work with his customers. He has a really good feeling for what works, and what doesn't. Dan has generously given me advice and guidance on my projects. His wealth of experience has certainly been a benefit, helping guide my decisions. Dan built several fine rifles for me; all shoot exceptionally well. The roots of the Dasher project started about five years ago. On several occasions, as Dan and I were discussing future projects, he praised the virtues of the .22 PPC cartridge. I was a hard sell, but Dan persisted, finally convincing me to build a.22PPC. He fiued a Schneider #'7 barrel (27" length, l:14 twist) to a Remington 700 action. The action was bedded into a McMillan A2 stock, using Marine-tex compound and Parish pillars. A Leupold 12X scope, with target turrets and a Jewell varmint trigger completed the package. After extensive testing, a load was selected using a moly-coated 50 grain Nosler Ballistic Tip, at 3535 fps. The rifle is superbly accurate, and, to the detriment of the Wyoming rodent population, very effective at long ranges. I've been 13 shooting the rifle for four years now, with excellent results. when I bedded the .22 PPC, I installed Parish pillars in the fiberglass moly-coated bullets are increased accuracy, and longer barrel life. stock. Several stock makers. McMillan benefits which are substantially more among them, say pillars aren't necessary with their stocks. However. I obtained some improvement with pillars installed. The groups seem to be more round, and the rifle is slightly more repeatable. to me: increased cleaning interval, and reduced barrel heating. The use of moly-coated bullets permits many more shots to be fired, before accuracy deteriorates. This point was clearly demonstrated by an experiment I conducted last year. The objective of my experiment was to determine how Based on the performance of the .22 PPC. I went back and instailed the Parish pillars in all of my varmint rifle stocks. However, fiom the standpoint of practical varmint shooting, there are two other important In retrospect, I believe the results completely justified the effort. The .22 PPC is a fine cartridge, but it has a few shorlcomings. The odd sized rim diameter requires bolt face modification in most rifles, the brass is quite expensive, and it has a relatively small case capacity. Its ballistic performance is very similar to the .223 Remington. On varmint hunting trip to Wyoming for this test. At the time, my Remington 700 Varmint (.22-250) had an old factory barrel, with several thousand rounds through it. Since the barrel wasjust about shot out, I didn't care if it was damaged ofthe during testing. There were 290 rounds of the plus side, the inherent accuracy PPC case is legend in benchrest circles. The PPC's short, wide powder column, small rifle primer, small diameter flash hole, and high quality brass lend to its inherent accuracy. My .22 PPC loads do have lower standard deviation (SD) values than comparable loads for my .223 Remington. This may be one of the for the excellent long range accuracy of the .22 PPC. At this point, it is necessary to digress for a moment, to mention some benefits of moly-coated bullets. The moly coating process has strongly influenced developreasons ment of the DASHER. The many rounds could be fired, without cleaning, before accuracy deteriorated. A presented an ideal opporlunity ammunition available, all I wouldn't recommend shooting any barrel that much without cleaning, but it clearly demonstrated that moly-coated bullets do significantly increase the number of shots which may be fired before accuracy deteriorates. Apparently, my experience was not that unusual. Dick Wright, in his August 1998 most commonly proclaimed advantages of loaded with moly-coated bullets. All 290 rounds were fired in one day, without ever cleaning the barrel! To my pleasant surprise, the rif'le shot just as well at the end of the test, and no decline in accuracy was observed. Continued on next page 7 PRECISION SHOOTING 14 immediatelY obvious that a considerable gain in BR Improved Continued case capacity could be achieved Precision Shooting article on moly coating, tells of shooting a Highpower match, where he fred212 rounds through his match rifle, without cleaning the barrel. His arlicle also mentioned Eunice Berger firing an entire benchrest match without cleaning. is an ever present for many varmint shooters. It isn't uncommon for a heavy batel .22Barrel heating problem 250 to become uncomfortably warm after only five or six shots. After switching over to moly-coated bullets, a significant reduction in barrel heating was noted. Compared to uncoated bullets, nearly twice as many moly-coated bullets may be fired before reaching the same barrel FEBBUAFY 1999 times during the next two years. It was my tum to be persuasive, and finally, in February 1998, Dan agreed to underlake case. It was Dasher Project - bY the project. pushing the shoulder forward, and utilizing a 40 degree shoulder with a minimum case taper. After some measurements and calculations, I concluded it would be Possible to I made a drawing of the proposed case dimensions, and mailed it to Dan for his evaluation. He suggested one change, a slightly longer case neck. After some discussion, the dimensions were agreed upon. In selecting a name for approach .22-250 performance. using a I called Dan Dowling and described my concept. Dan was interested; he felt the concept our new carlridge, we took the D from Dowling, ASH from my name, and the blown out BR case. Inspired, DASHER project was born. Dan sent the drawing off to Pacific had merit and the goal seemed achievable. Unfortunately, Dan was swamped with work, and was unable to take on any Precision, to have the chambering reamer and headspace gage fabricated. He specified dimensions for the chambering special projects at that time. Dan and I discussed the project several reamer which provide an optimum fit for temperature. In past years, I had a strong preference for the smaller .22 callber cartridges, such as the .223 Remington and the .22 PPC, because they generated less heat. This is a real advantage for prairie dog hunting, where the weather is often very warm, and many shots are fired in a single day. Compared to the larger .22 caliber cartridges, the .223 could be fired nearly twice as many times before reaching the same temperature. My .22-250 and .22- 250 Ackley Improved weren't used as much, because they would get too hot, too fast. I'd fire five or six shots, and then have to put the gun in the cooling rack. After switching over to moly-coated bullets, the reduced barrel heating made using the larger .22 caliber cartridges somewhat more practical. I thought what I really needed was a cartridge that could duplicate the performance of a .22-250, but with a smaller case capacity. The advantages of the PPC, with its outstanding accuracy, led me to take a long look at a similar cartridge, the a standard rim diameter, less expensive brass, and a slightly larger case capacity. Its performance falls about midway between the .22 PPC and the .22- 250. There were some comPlaints regarding the quality of BR brass, but the recent availability of superbly-made Lapua and Norma brass eliminated that problem. I was examining a 6 BR case, and it to the .22-250 AckleY compared "170" ZZ Drnatsttt: -t\xL{ rgot"l DASHES l\ FlgE rosrE} cA65 .22 Remington Bench Rest. The .22 BR has many of the same attributes as the .22PPC, plus a few additional advantages, including .75A Don Gmtner's bullzts .... the 6mrn bulbts that haue set so nxany World B mchrest recor^ are f'nally aaailnb lz ! Gmtns Bulles on bencbrest-Prouen Detsclt carbide dies, Tbese extraordinary bullets are offered in 7 or I ogiue, flatbase at $75.0O Per 5OO;boattail at $85.00 Per 500. 22 caliber are Mad.e nou auailable at tbe aboue Prices. PRECISION SHOOTING - FEBRUARY 19S9 Lapua cases. Neck diameter was set at .254" , and overall case length at 1.56". In due time the reamer and headspace gage arrived. In the interim, we had acquired the other components required to build the rifle. Dan built the rifle to my standard varmint rifle formula: Schneider 2J" #7 contour barrel. 15 Remington 700 action, McMillan A2 stock, and Jewell trigger. He also modified a set of Redding.22 BR compe- tition dies to handle the Dasher case. In mid August, I visited Palisade and DASHER case is quite simple. Because the DASHER shoulder is moved forward in the forming process, the 6 BR case will not headspace properly in the DASHER chamber. It is necessary to leave a step in took delivery of the rifle. Dan and I wanted to fire form a case, so we could the case neck, to maintain the proper position of the case during fire forming. have a look at our creation. Makins the This is accomplished by sizing jusr the front parl of the neck down to .22 caliber. Run the 6 BR case part way into a 22 BR sizing die, then try the case in the rifle chamber. Adjust the sizing downward, until the bolt will just close on the case, with moderate resistance. This ensures the of the cartridge case is held firmly against the bolt face. Warning - This causes substantial rearward thrust on the bolt. Make sure the rear of the bolt lugs are well lubricated with grease, to prevent galling. For a hre forming load, we started with 30 grains of H-322,behinda 55 grain bullet (a maximum load for a .22 BR). Pressure was too low, resulting in rounded case comers. The load was increased to 32 grains of H-322, which worked very well, giving sharp, fully formed corners with no base The Dasher, on the bench during load testing at the cororaito Rifte club. evidence of excessive pressure. We measured the case capacity of the DASHER and found ir held 40.5 grains of water. That is an I I percent increase over the 6 New... from Switzerland! Green-X Lubricator Greases seated BR! The case capacity of the DASHER falls just about midway berween the .22-250, at 45 grains of water, and the 6 BR, at 36.5 grains of water. bullets ""$:. d"':'{;;e' Continued on page 17 CLAY SPENCER cal. 3O8 or 223 or 244 available Used by Swiss national Team Used by German national Team Used by Palma Team USA Used by 1998 IBS 10OO yard Champion Reduces Barrel fouling and throat errosion Cuts cleaning time by 5O% Price USD 80.OO a Setincludes Shipping an Handling in the lower 4g States Baity's Gunworks 2623 Boone Trail, 28GSg North Wilkesboro, NC 336667 87 85 336€38 17 58 e-mail: [email protected] We accept Visa- and Mastercard www.echo. ch/-kstadl in/baity NC Residence add 696 Sales Tax Benchrest Rifles 7,000-yard Rifles Silhouette Pistols Liae Varmint Rifles High Grade Hunting Rifles Benchrest Handguns SPENCER'S CUSTOM GUNS Precision Stainless Rifle Barrels 4107 Jacobs Creek Driue Scottsuille, VA 24590 (804) 293,6836 Shop Phone (804) 293-6836 Shop Far PRECISION SHOOTING - FEBRUARY 199S Dasher Project prepare the rifle prior to departing for a varmint hunting trip. Since I much prefer fire forming in the field, I hastily mounted a 6.5 X 20 Leupold on the barreled action and carried it along to Wyoming. After arriving, I pulled the stock off my .22-250 and mounted it on the DASHER action. The rifle was sighted-in exactly one inch Continued from page 15 In August, Lapua 6 BR brass was in very short supply. A good friend took pity, loaning me a hundred cases, to get started. The fire forming loads were prepared, but I 17 was unable to completely high at 100 yards. After setting the elevation, I switched to a new target and fired three rounds. I was rewarded with a nice triangular group, just over 3/8" center to center an auspicious start for - the DASHER. There are some days when things just go really well, and this turned out to be one of them. Since the barrel was new. it was to go through the break-in process. For the first ten rounds, the necessary barel was cleaned after each shot. The barrel was scrubbed with a Kroil wetted patch, followed by two or three dry patches. No brush was used. Subsequently, the barrel was cleaned after every three rounds, until thirty more rounds had been fired. Finally, it was cleaned after every five shots, until the remainder oi the ammunit ion was exhausted. Schneider Rifle Barrels, of Scottsdale, AZ, make excellent barrels. They are extremely accurate, with very little tendency to fbul. Schneider barrels shoot well right from the beginning, not First outing with the Dasher, in Wyoming. Continued on page 19 Wessinger Gustom Guns & Engraving . lbe NEW BAI;D EAGLE Live Vormint Rifles Single Shot Rifles High Grode Hunting Rifles Built to Benchrest Stondords Muzzle Brokes Custom Mode Motch Grode Borrels Troditionol Engroving Chombers for most stondord, wildcot ond l7 colibers . 268 Limestone Rd, Chopin, SC 29036 803-345-5677 FAX 803-345-9845 Call or write for descriptive brochure . ';-^Tr?rf#1"" $85 This is a gage to measure consistency of rim thickness on .22 rimfire ammunition (a .22 timtue rille's headspace is determined by case rim thickness). The more consislent the rim thickness, the more I consistent the ignition of the t primer and the powder charge in the case. ln other words, the firing pin will fall the same distance every time if the same rim thickness is used on every case being fired for a particular group. By sorting the shells into various groups by rim thickness, a reduction in group size of up to 25% can be realized in some lF NOT MOST rimfire rifles. This information aboul group reduction comes from the .22 rimfire benchrest participants who compele in the extremely difficutt BR-sO matches. All of the top shooters sort their shells into groups by checking rims and weighing lhe unfired carlndoes. BAI,D EAGII.E -A Allison St. /.<il\ /"2-*k\ Lock Haven, PA17745 Preclrlon Machlne Company '101 t(v)., \E / lli8iliff-sn:" Bill Gebhardt, Owner (NRA Patran Member - IBS Life Member) PRECISION SHOOTING Dasher Project - FEBFUARY 'I9S9 Cantinued from page 17 requiring an extensive break-in period. This barrel was no exception, it perlbrmed splendidly from the very start. The highlight of the day was two consecutive hits at 600 yards (measured with my Ban & Stroud rangehnder). An impressive :irst outing, to be sure! The Lapua cases formed very well, and only one case was lost due to a split in the shoulder. The cases were cleaned and primed, and it was off to the Colorado Rifle Club near Byers, for load testing. Since this is a varmint rifle, I prefer using polymer tip bullets like the Hornady V-Max, Nosler Ballistic Tip, and Sierra 19 BlitzKing. All bullets are moly-coated. Powders selected tbr preliminary testing were Varget, Reloader 15, and IMR-4895. These powders were chosen because their burning rate should give maximum velocity with high loading density. This assumption proved correct; the listed loads filled the DASHER case to the bottom of the neck. I believe this is ideal, since it permits throwing charges directly from the measure. This is a great time saver when loading several hundred rounds at a time. Velocities were measured using an Oehler Model 35 chronograph, set up with 2 foot screen spacing. Screens were placed 15 feet ahead of the muzzle. A starting load of 35.0 grains of Varget Continued on next page Cleaning the Dasher during fire forming. Barrel cleaned only with Kroil and patches. Working setup in Wyoming. Most of the prairie dogs are in the dark bsnd ut the base ofthe hills, between 400 and 600 yards off. S#* Vm*ar Sflghts,,, #ile i3Ka* ffi*sf ffiqarr 1. Six Enterprises' stocks - the strongest and most stable hand laminated stocks on the market...Specificalty designed for the serious vafmintef. 2. Nightforce scopes. 3. Six Enterprises'adjustable rings & mounts. 6"+**"ffies 32O-D Turtle Creek Ct. Phone . SanJose, CA 95].25 . Fax 408 999-OZt6 4OS 999-O2O1. Call or write for.brochure waiting for!! Increase intemal scope adjustments 40 percent while adding a minimum of 20 m.o.a. of upward travel to your scope. . All steel construction . Torx Head sctews . Two piece design . Matte Finish . $65 per set . Accepts any Weaver style ring . Multiple mounting positions . Available lor Rernington Model 700 and Winchester M70 actions . Custom orders accepted Nightforce Custom Tapered Bases Proudly Distributed by LIGHTFORCE, USA 19226 66thAve., S, Bldg. L-103 Kent, Washington98032 Call (425) 656-1577 .Fax (425) 656-1578 PRECISION SHOOTING 20 tially in the late afternoon, as a thunderstorm moved in. A total of 28 grouPs were fired. The average spread for all Dasher Project Continued behind a 50 grain Sierra BlitzKing produced an average velocity of 3850 fps, with moderate pressure. The next load, 35.0 grains of Varget behind a 55 grain Ballistic Tip, produced an average velocity of 3750 fps, with a Standard Deviation of 1l Again, pressures were groups was .442" . The largest group fired was less than one inch. I believe this is particularly impressive, considering the rif-le had not been bedded into the action at the time of testing. - FEBRUAFY 1999 We met our goal of matching .22-250 performance. Dan Dowling rebarreled my .22-250 last year, installing a 21" Schneider barcel, #1 contour, with a 1:14 twist. This rifle makes an excellent basis for comparing the .22-250 against the DASHER. since both have the sam" length barrel, with the same twist rate. moderate. Accuracy was in the vicinity of 1/:" for 3-shot groups. Switching to IMR-4895, 35.3 grains of 4895 behind a 55 grain Ballistic Tip, produced an average velocity of 3870 fps. The second load was 36.5 grains of 4895, behind a 50 grain Ballistic tip, for an average velocity of4040 fps. Pressure for both loads was near maximum, with accuracy in the 3/+" range. At this point, the groups started to open up. Next I tried Reloader 15, with miserable results. A 3shot group measured nearly one inch. I suspected that switching powders, with the resultant mixing of residue in the barrel, caused the poor accuracy. The barrel was cleaned thoroughly, and the loads re-lested. My assumption was correct, the difference was remarkable. A load of 36.0 grains of 4895 behind a 50 grain Ballistic Tip averaged 4000 fps and shot into a one hole group. The load for the 55 grain bullet remained the same, at 35.3 grains. It produced an average velocity of 3850 fps, and it Left to right: .223, .22 PPC, .22 BR, .22 Dasher, .22-250, .22-250 Ackley Improved 40 deg. MIL.DOT RANGING COMPUTER Set size designated 1. SMALL. FITS IN SHIRT POCKET APPBOX 4'DlAMETER also made a nice one hole group. The barrel was cleaned again, then the Varget powder loads were re-tested. A load of 36.5 grains ofVarget, behind a 50 grain BlitzKing averaged 3975 fps, with excellent accuracy. Switching to 55 grain Ballistic Tips, 35.5 grains of Varget averaged 3825 fps, also with excellent accuracy. Pressure on both loads was good. The fire forming loads (32.0 H-322 with a 55 grain Ballistic TiP) were chronographed, averaging 3715 fps with good accuracy. Alter seeing how well the ire forming loads groupea dn pap.r. it was no surprise that they had performed so well in the field. I planned to re-test Reloader 15, but a massive thunderstorm moved in, and I departed the range in haste, just ahead of a torrential downpour. I was delighted with the results of the first day's testing. Wind conditions at the range were excellent during the morning and early afternoon, with just the slightest breeze. Wind speed increased. substan- HANDY SCALES s19.50 ptus 3.00 snipplng Texas residents please add $1 86 State Sales Tax HOW FAR ? 2. Read distance ne)d to mils subtended. DURABLE CONSTRUCTION E REAR DISK FOR METERS SUPER FAST. EASY TO USE Police Dept. PO's accepted 1(888) 920-2468 (oFoERSoNLY) M-F 8:30-s:30 of object on outer wheel. CSr or send CHECKS / MONEY ORDERS to FlEl NG.--ll l- (817) 568-8778 (ouESrloNS) (817) 568-8784 (FAX) DIRECT FIR"E TECHMCAL, INC. 2836 S.E LOOP 820. FORT WORTH, TEXAS 761 40 Benchrest and varmint rifles built with Remington or custom actions, M-16 extractors installed in Remington bolts, action trueing, cuslom dies made, rechamberin g, muzzle brakes, and all other types of custom work. Specializing in QUICK turnaround. Stop using the expander ball in your sizing dies. I will convert your dies to accept nJOOing or Wilson sizing bushings, as pictured. Keeps the necks straight and reduces case lengthening. PRICE REDUCED, $25.00 per die, plus $5.00 shipping. PRECISION SHOOTING - FEBRUARY 1999 from the same manufacturer. The best load fbr the .22-250 pushes a 50 grain Nosler ballistic tip at 3950 fps, while the best 50 grain load for rhe DASHER fps. In the same manner, the best load for the .22-250 had a velocity of 3175 fps, compared to 38-50 fps for the DASHER. The referenced loads for the .22-250 and the DASHER reached 4040 produced similar sized groups. After bedding the action, and with more load development, the average 21 group size has been reduced to the mid .3s. The working loads have been reduced slightly, from those listed above. The current loads are very accurate. My best load fbr the 50 grain Nosler Ballistic tip is 36.3 grains ofVarget, for a velocity of 3985 fps. The best Ioad for rhe 55 grain Nosler Ballistic tip is 35.2 grains of Varget, giving a veiocity of 3800 fps. Is the Dasher Proiect a success? We certainly believe it is. The velocity goals were achieved, while maintainins a hish degree of accuracy. And it was accomplished using less powder than the .22250. What's nexr? A 6mm DASHER is on the way. In fact, as Dan and I were admiring the tirst DASHER case (it was about two minutes old, and still warm), he commented that it would make a superb little 6mm cartridge. I just wonder how close we can come to .243 perfbrmance. The 6 DASHER reamer is on order, as well as a 6mm Schneider barrel, with a 1:14 twist. That will be my winler project this year. Accuracy Gunsmithing '];lt E& -ffi pffi "sfiD #re ffi ffi ffi ffi ffi iw ffiw ffffi-: ,,t#ffi, ,'it &' .sry"' #ffi i&i ffi M, : & Dan Dowling 260 Road 33r/: Palisade. CO 81526 910-434-0525 Al Ashton 1122 S. Penrose Ct. Littleton. CO 80122 303-798-0 I 89 Jewell Triggers 3620 Highway 123 San Marcos, TX 78666 s12-353-2999 :IL !l*{]::l]]r,iry' .,{ .@@s* "&M**li Left to right: Basic 6 BR case; 6 BR case partially necked to .22, with headspacing step; Case, ready to fire form; Fire formed .22 Dasher; Loaded .22 Dasher. Attention: McMillan Fiberglass Stocks 21421 N. 14th Ave. Suite B Phoenix. A285021 (t02-582-9635 Schneider Rifle Barrels 12202 N 62nd Pl. Scottsdale. A285254 602-948-252s Accuracy minded owners of factory rifles If you are the owner of a Remington SS, BDL, ADL, 700 VS, or Browning A-BoIt, Winchester M-70 or any other factory rifle, you can benefit from our Accurizing service. For just $22b.00 we will recrown the barrel with a match grade crown, adjust the trigger, pillar bed, float the barrel, lap the locking lugs on the bolt, lap the scope rings, and properly remount the scope. Your rifle can benefit from this work which brings it up to where it should have been from the factory. Give your factory rifle a chance to deliver the accuracy that you expect. Phone: (803) 827-2069 FAX: (803) 827-3908 1200 Old Jackson Hwr'. Jackson, SC 29831 G ary's Gun shop .doRcEqe^ z.s-t ox - 12-42x ua ap ;f r-iSr',"d Ranging netictes Corpbt" Mntory-Same $ day shipping I :- Dealer ffi;,- utv-oilntt @ *""'u6oo-444-1og7 Jtl @ www.start.aUgarysguns