257 roberts reloading data

Reloder 16. Select A Caliber or Gauge Below To View Recipes. 243 Win. 25-06 Rem. 257 Roberts. 260 Rem. 270 Win. 270 Win. Short Magnum.

257 Roberts Brass: We Offer Both New and Once Fired Brass in 257 Roberts Once Fired Brass : The once fired brass has been magnetically screened, machine sorted and meticulously hand inspected. Brass is comprised of mixed headstamps, both nickel and brass casings. They are packaged in vacuum sealed in bags. The vacuum sealed bags …Printed from Shooter's Reference on 04/20/2024: https://www.shootersreference.com/reloadingdata/257-roberts/ Remarks: COAL: 2.750 inches; maximum load. .257 Roberts (using Sierra bullets) reloading data with 391 loads. Using bullets from Sierra HP, Sierra SPT, Sierra SPT , Sierra HPBT, Sierra SPT, SBT or HPBT MatchKing, Sierra SPT or SBT, Sierra SPT or SBT , Sierra SPT or SBT . Powders include IMR, Hodgdon, Accurate, Vihtavuori, Ramshot, Alliant. Wt. .257 Roberts reloading data with 8 loads. Using bullets from Sierra jacketed hollowpoint, Hornady jacketed hollowpoint, Speer jacketed hollowpoint, Nosler Solid Base, Nosler Partition, Sierra spitzer boat-tail, Hornady hollowpoint. Powders include IMR, Norma, Hodgdon, Winchester.May 20, 2023 ... I've shot one box and reloaded it with 100 gr spitzers. The two targets show 6 rounds of the factory ammo and 6 of the hand loads.The Hornady Handbook and Nosler Reloading Guide show maximum reloads for the .257 Improved (either version) achieving muzzle velocities (MV) of about 3600 fps with a 75 …Load Data for .257 Roberts . Bullet: 80 gr TTSX BT (Barnes) Diameter: 0.257" Powder: IMR 4451 (Improved Military Rifle) Starting Powder: 43.2 gr. Max Powder: 48.6 gr ....257 Roberts Loads reloading data with 7 loads. Using bullets from Sierra hollowpoint, Nosler Ballistic Tip, Hornady Spire Point, Nosler Partition, Barnes TSX. ... .257 Roberts Loads: Warning! Notes: Source: Handloader Issue #247 - June, 2007: Be Alert: Publisher cannot be responsible for errors in published load data. Wt. Bullet: Powder ...

Today we're choosing a load and we're going to select our bullet, powder, brass, and primer. And we're not just choosing a load for accuracy but a lot that w... The .257 Roberts was the premier combination varmint/deer cartridge until the .243 Winchester and .244 Remington were introduced in 1955. These cartridges were highly touted by Warren Page, the Shooting Editor at Field & Stream magazine, and appeared to be ballistically superior to the .257 Roberts.The 6.5/257Roberts is the ballistic twin to the 6.5X57. Much the same way the 30/338 is to the 308 norma. Interstingly, I have a barrel from a Winchester featherwieght, that was rechambered to the Ackley version. I often thought of possibly of boring and rifling it to a 6.5mm,hence a 6.5X257 Roberts Ackley Improved..257 Roberts Handloads +P Pressure reloading data with 31 loads. Using bullets from Hornady Spire Point, Barnes TSX FB, Hornady SST, Sierra softpoint, Speer softpoint. Powders include IMR, Winchester, Hodgdon, Vihtavuori, Alliant, Ramshot, Norma, AccurateSep 20, 2023 · The .257 Roberts started life as a wildcat, devised by gunwriter and tinkerer Ned Roberts in the 1920s who tried his hand at necking down a case to shoot a smaller bullet. The idea, as always, was to decrease recoil and gain ballistic advantage through sheer velocity. The parent case is 7x57mm Mauser.

Hornady Manufacturing Company develops and publishes reloading data for the Handbook of Cartridge Reloading. Occasionally, we will temporarily publish load data on this page when a bullet becomes available and is not yet listed in the latest edition of the handbook. 6.5mm .264" 100 gr. ELD-VT™ [PDF] 22 ARC (Bolt Gun) [PDF] 22 ARC (Gas Gun) [PDF] .257 Roberts (Hodgdon Data) reloading data with 122 loads. Using bullets from Hornady SP, Hornady HP, Barnes TTSX BT, Hornady GMX, Sierra HPBT, Speer SPBT, Nosler Part. The slower powders work better with heavy bullets for me in the 257 Roberts.. 48gr of RL26 with WLRM primers and win cases gets about 3120fps for 5 shots using 115gr Nosler partitions. RL23 with 48.2gr with 110gr Accubonds CCI250 mag primers win cases 3157 fps. All in a model 70 Winchester.Remember, any loading data is a guide, not an absolute. You may find your individual rifle may shoot the same loads as those published faster or ...Refer to the current SPEER® Reloading Manual for handloading instructions. Be thoroughly familiar with those instructions before using these loads. As Vista Outdoor Operations LLC has no control over individual handloading practices or the condition of firearms in which ... 257 Roberts +P 3290 3386 3381 3367 3295 3226 3187 3184 3170 3163 3153 ...

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Warning! Notes: .257 Roberts, Ruger M-77 long action 24-inch barrel; Remington cases, 186 grains; CCI No. 200 primers; Oehler M-31 Chronotach, Oehler M-50 photoelectric screens; velocity at 15 feet converted to MV; temperature 70 degrees; this rifle had a rather loose chamber and would handle more powder than most rifles with every bullet ...Use TBBC and TBSS data ONLY for TBBC and TBSS bullets; maximum loads should be used with CAUTION. Be Alert: Publisher cannot be responsible for errors in published load data. Wt. .257 Roberts +P (Speer Reloading Manual #14) reloading data with 116 loads. Using bullets from Speer FNSP, Speer Spitz SP or TNT HP, Speer Spitz SP, HP or Spitz BTSP ...Overview. Nosler 257 Roberts +P Rifle Reloading Brass - 50 Count. Nosler Premium Brass is designed for those who want to take finding the perfect load into their own hands. Fully prepped and ready to load, Nosler's gone ahead and done the meticulous case prep work for you. Each piece is chamfered, deburred, checked for proper alignment, sized ...257 Roberts +P and H4350. Am going to try H4350 in my 257 Roberts as the powder should work better in the conditions I hunt (Alberta, Canada, where the temp during hunting season can be 10 above or 30 below). I have been using 115 gr Nosler BT with IMR 4350 and am getting great groups (44 grains, which is over max. does not …

Remarks: maximum load; 57,100 psi; col (inch): 2.775. .257 Roberts +P (Ramshot Data Edition 4.5 - 2011) reloading data with 10 loads. Using bullets from Sierra Hollow Point, Nosler Ballistic Tip, Sierra SPBT. Powders include Ramshot.257 Roberts +P with 100 gr HP. speer-ammo.com Alliant Reloder 23 Federal Federal 210 43.9 2767 48.8 C3064 Hodgdon H380 Winchester CCI 250 38.0 2566 42.0 2842 Hodgdon H414 Winchester CCI 250 40.0 2657 44.0 2878 Hodgdon H4350 Winchester CCI 200 43.0 2795 47.0 C3055The .257 Roberts Improved. The two most popular "Improved" .257 Roberts cartridges are the Ackley and RCBS versions. They are quite similar except for the shoulder angle, which is 40 degrees for the Ackley version and 28 degrees for the RCBS version. The Hornady Handbook and Nosler Reloading Guide show maximum reloads for the .257 Improved ....257 Roberts Handloads Standard Pressure reloading data with 40 loads. Using bullets from Hornady Spire Point, Berger HP, Barnes TSX FB, Hornady SST, Sierra softpoint, Speer softpoint. Powders include IMR, Winchester, Hodgdon, Vihtavuori, Alliant, Accurate, Ramshot, Normakleanbore 1. Oct 31, 2020. #1. Any long time shooters of the 257 Roberts, a question for you. What powders do you prefer for the heavier bullets, say 90gr-120gr I have IMR 4350, 4064, 3031, Varget , Reloader 15 and others. I know, what shoots good in your rifle may not in mine. Looking for a consensus on where to start.The content on this website (including videos, articles, ammunition reloading data, technical articles, gunsmithing and other information) is for demonstration purposes only. ... November 14, 2021 Tyler Hale Hunting, Reloading Blog 25 Creedmoor, 25-06, 257 Roberts, Athlon, Ballistics Gel, Berger Bullets, ...I am shooting a 20" suppressed Ruger Hawkeye chambered in 257 Roberts. I have had real good luck and accuracy with both IMR and H 4831. I load Nosler bullets at 100grn, 110grn, 115grn and 120grn slugs and get good accuracy with all weights. I used the Hogdon reloading data to get a starting point and worked up from there..257 Roberts (Hodgdon CFE 223 Data) reloading data with 6 loads. Using bullets from Hornady SP, Hornady HP, Barnes TTSX BT. Powders include Hodgdon Reloder 16. Select A Caliber or Gauge Below To View Recipes. 243 Win. 25-06 Rem. 257 Roberts. 260 Rem. 270 Win. 270 Win. Short Magnum.

The .257 Roberts Improved. The two most popular "Improved" .257 Roberts cartridges are the Ackley and RCBS versions. They are quite similar except for the shoulder angle, which is 40 degrees for the Ackley version and 28 degrees for the RCBS version. The Hornady Handbook and Nosler Reloading Guide show maximum reloads for the .257 Improved ...

Load Data for .257 Roberts . Bullet: 115 gr PART (NOS) Diameter: 0.257" Powder: StaBALL 6.5 (Winchester) Starting Powder: 38.5 gr. Max Powder: 43.0 gr .The current SAAMI spec for the .257 Roberts Maximum Average Pressure (MAP) is 54,000 psi. Winchester introduced a +P version with a MAP of 58,000 psi in the mid-1980s. That’s still less than the typical 60,000 to 65,000 psi of comparable modern rifle cartridges. The .257 Roberts was pretty popular for a few years before and after World …May 11, 2022 · The .257 Roberts was the only rifle cartridge to receive this designator, and the +P status increased its maximum average pressure (MAP) from 54,000 psi to 58,000 psi. For comparison, the .30-06 has a MAP of 60,000 psi. Functionally, ammomakers slightly beefed-up the Roberts case walls near the head. 257 Rob +P - 100 grain Version 9.0 4" Lilja BARREL Twist 1-10" Expansion Tip® 0 .4 0 9 D u e to in te rn al co n stru ctio n d i˜ e re n ce s, alw ays b e g in w ith startin g lo ad s w h e n u sin g Exp an sio n Tip ® products. 81% 96% 72% 92% 81% 7% This data was developed to the 257 Roberts +P pressure level of 58,000 psi, and should only Revised 12/2009 Indicates most accurate load. Bullet Weight:80 grCase Trim Length:2.223"S.D.0.173. Bullet Style:TTSX BTPrimer:Fed 210B.C.0.316. …*To fire-form brass, use the faster-burning powders and loads from standard .257 Roberts data. *To properly chamber a rifle for .257 Ackley Improved cartridges, a gunsmith must set the original barrel back about 0.004”. The chamber distance from the bolt face to the junction of shoulder and neck is shorter in Ackley Improved rifles than in ...Never will understand folks fishing for reloading data on the Internet. There are so many documented loads out there, if you search even a little bit. ... Accuracy has come at the top of the loading charts for my 30.06 with 168g bullets and .257 Roberts with 75g bullets with 760. The sensitivity issue concerns me now that I read about it. I'll ...Load Data for .257 Roberts . Bullet: 80 gr TTSX BT (Barnes) Diameter: 0.257" Powder: IMR 3031 (Improved Military Rifle) Starting Powder: 36.0 gr. Max Powder: 40.3 gr ...This question is about the NetSpend® Visa® Prepaid Card - Pay-As-You-Go @lisacahill • 06/27/19 This answer was first published on 06/27/19. For the most current information about a...

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The .257 Roberts started life as a wildcat, devised by gunwriter and tinkerer Ned Roberts in the 1920s who tried his hand at necking down a case to shoot a smaller bullet. The idea, as always, was to decrease recoil and gain ballistic advantage through sheer velocity. The parent case is 7x57mm Mauser.MISSISSIPPI DELTA. I purchased an Arisaka custom rifle for a song at a gun show. After the first shot I realized it was a wild cat and had the gunsmith check the chamber. A previuos owner had rechambered to 6.5x257 Roberts. I ordered a $125.00 set of dies from RCBS, and reloaded using 6.5x55 data to start. I got zero accuracy and so I … Remarks: COAL: 2.750 inches; maximum load. .257 Roberts (using Sierra bullets) reloading data with 391 loads. Using bullets from Sierra HP, Sierra SPT, Sierra SPT , Sierra HPBT, Sierra SPT, SBT or HPBT MatchKing, Sierra SPT or SBT, Sierra SPT or SBT , Sierra SPT or SBT . Powders include IMR, Hodgdon, Accurate, Vihtavuori, Ramshot, Alliant. .257 Roberts (Hodgdon Data - Winchester Powder) reloading data with 14 loads. Using bullets from Hornady SP, Hornady HP, Barnes TTSX BT, Sierra HPBT, Speer SPBT, Nosler Part.*To fire-form brass, use the faster-burning powders and loads from standard .257 Roberts data. *To properly chamber a rifle for .257 Ackley Improved cartridges, a gunsmith must set the original barrel back about 0.004”. The chamber distance from the bolt face to the junction of shoulder and neck is shorter in Ackley Improved rifles than in ...6.5x257 Roberts: Warning! Notes: rifle: Japanese type 38 (rechambered); barrel: 24"; twist: 1-8 3/8; cases: R-P; primer: CCI-200 (except where otherwise specified in remarks); data for 87 grain Spitzer bullet may be used with the 87 grain Hollow Point; this data may be used to load 6.5x57mm Mauser; maximum loads listed should be used with caution (Speer ….257 Roberts - Published Manufacturer Loading Data Shellholders: Hornady #12971. Remarks: max load. .257 Roberts (Berger Bullets Data) reloading data with 38 loads. Using bullets from Berger Match FB Target, Berger Match VLD Target or Match Grade VLD Hunting. Powders include IMR, Hodgdon, Alliant, Accurate, Ramshot, Vihtavuori, Winchester, Norma.*To fire-form brass, use the faster-burning powders and loads from standard .257 Roberts data. *To properly chamber a rifle for .257 Ackley Improved cartridges, a gunsmith must set the original barrel back about 0.004”. The chamber distance from the bolt face to the junction of shoulder and neck is shorter in Ackley Improved rifles than in ...By 2050, 66% of people will live in urban areas. Smarter data-driven urban planning will help make that possible. In the middle of the 20th century, a war waged for the soul of New...Reloading data is available as low as 99¢ per cartridge or as a subscription for $19.99. Below you’ll find some basic data for each cartridge to help get you started. Basic Load Data. Hornady Manufacturing Company develops and publishes reloading data for the Handbook of Cartridge Reloading. Occasionally, we will temporarily publish load ... ….

.257 Roberts Select Handloads reloading data with 6 loads. Using bullets from Hornady V-Max, Nosler Ballistic Tip, Sierra Spitzer, Barnes Triple-Shock, Remington Core-Lokt PSP, Remington Core-Lokt PSP Ultra Bonded. Powders include Hodgdon, AlliantLoad Data for .257 Roberts. Bullet: 115 gr PART (NOS) Diameter: 0.257" Powder: Hybrid 100V (Hodgdon) Starting Powder: 42.0 gr. Max Powder: 46.0 gr. Primer: REM 9½. Case: …Load data with 94 loads for .257 | 100gr | Sierra SPT Pro-Hunter bullet in caliber .257 Roberts.257 Roberts reloading data with 8 loads. Using bullets from Sierra jacketed hollowpoint, Hornady jacketed hollowpoint, Speer jacketed hollowpoint, Nosler Solid Base, Nosler Partition, Sierra spitzer boat-tail, Hornady hollowpoint. Powders include IMR, Norma, Hodgdon, WinchesterSafety Data Sheets; Shipping & Delivery; Warranty; Login 0. 0. My Cart. 0. 0. Search suggestions. Site Search. Cartridge Selector (Tap to open) ... .257 ROBERTS IMPROVED 40° RELOADING ESSENTIALS .257 ROBERTS RELOADING ESSENTIALS .257 WEATHERBY MAGNUM RELOADING ESSENTIALS .25 AUTO (25 ACP) … The 257 Improved is a fi ne performer, adding up to 100 fps velocity over its factory cousin. One of its advantages, Ackley noted, is the fact that 257 Roberts factory ammunition can be used in an improved rifl e if necessary. Other 25 caliber wildcats are not this fl exible. The 257 Improved is all that the 257 Roberts is—and a bit more. Remember, any loading data is a guide, not an absolute. You may find your individual rifle may shoot the same loads as those published faster or ...This question is about the NetSpend® Visa® Prepaid Card - Pay-As-You-Go @lisacahill • 06/27/19 This answer was first published on 06/27/19. For the most current information about a... 257 roberts reloading data, The .257 Roberts has (finally) been updated to piezoelectric pressure measurements, with standard pressure loads listed at 54,000 psi while +P loads are listed at 58,000 psi. The maximum loads in the accompanying data are almost all +P pressures. However, for handloaders wanting standard pressure data, starting and maximum loads should be ..., Printed from Shooter's Reference on 05/03/2024: https://www.shootersreference.com/reloadingdata/257-roberts/ , .257 Roberts (Hodgdon Data - Winchester Powder) reloading data with 14 loads. Using bullets from Hornady SP, Hornady HP, Barnes TTSX BT, Sierra HPBT, Speer SPBT, Nosler Part., .257 Roberts +P Handload Data (50,000 CUP) reloading data with 19 loads. Using bullets from Hornady V-Max, Speer flat softpoint, Hornady Spire Point, Nosler Ballistic Tip, Nosler Partition, Speer spitzer boat-tail. Powders include Hodgdon, Accurate, Alliant, Vihtavuori, For a performance comparison, let’s put current .257 Roberts +P handloads next to its more modern challenger, the .25-06 Remington (1969). Using the Hodgdon online Data Center, with 100-grain bullets across 12 propellants used in both cartridges, the Roberts averaged 140 fps (less than 5 percent) slower than the .25-06., We place limited powder inventory for sale on a regular basis on our website. When we are sold out, we are sold out. We do not take backorders and our Tech Services team cannot take orders via email or phone. The max order quantity of any powder SKU is 5 and we will only accept one order, per customer, per calendar month with a maximum weight ... , Reloder 16. Select A Caliber or Gauge Below To View Recipes. 243 Win. 25-06 Rem. 257 Roberts. 260 Rem. 270 Win. 270 Win. Short Magnum. , May 11, 2022 · The .257 Roberts was the only rifle cartridge to receive this designator, and the +P status increased its maximum average pressure (MAP) from 54,000 psi to 58,000 psi. For comparison, the .30-06 has a MAP of 60,000 psi. Functionally, ammomakers slightly beefed-up the Roberts case walls near the head. , Remember, any loading data is a guide, not an absolute. You may find your individual rifle may shoot the same loads as those published faster or ..., Refer to the current SPEER® Reloading Manual for handloading instructions. Be thoroughly familiar with those instructions before using these loads. As Vista Outdoor Operations LLC has no control over individual handloading practices or the condition of firearms in which ... 257 Roberts +P 3290 3386 3381 3367 3295 3226 3187 3184 3170 3163 3153 ..., Load Data for .257 Roberts. Bullet: 115 gr PART (NOS) Diameter: 0.257" Powder: StaBALL 6.5 (Winchester) Starting Powder: 38.5 gr. Max Powder: 43.0 gr. Primer: REM 9½. Case: …, I am shooting a 20" suppressed Ruger Hawkeye chambered in 257 Roberts. I have had real good luck and accuracy with both IMR and H 4831. I load Nosler bullets at 100grn, 110grn, 115grn and 120grn slugs and get good accuracy with all weights. I used the Hogdon reloading data to get a starting point and worked up from there., 1. Never begin loading with the maximum powder charge shown in these reloading data tables, regardless of your experience. 2. Never exceed maximum loads because excessive chamber pressure will result. 3. Discontinue firing at the first sign of excessive pressure or upon noticing a change in the. report of the firearm., Printed from Shooter's Reference on 05/13/2024: https://www.shootersreference.com/reloadingdata/257-roberts-ackley-improved/, Load Data for .257 Roberts. Bullet: 80 gr TTSX BT (Barnes) Diameter: 0.257" Powder: IMR 4451 (Improved Military Rifle) Starting Powder: 43.2 gr. Max Powder: 48.6 gr. Primer: …, .257 Roberts Handloads reloading data with 18 loads. Using bullets from Hornady FP, Speer FP, Hornady V-Max, Nosler Ballistic Tip, Partition, Hornady, Hornady boat-tail. Powders include IMR, Winchester, Accurate, Hodgdon, Ramshot, Alliant ... .257 Roberts Handloads: Warning! Notes: All groups are an average of three shots at 100 yards ..., Well, I'm about three weeks into reloading for the .257 Roberts +P. So far I have three good loads worked up and have loaded but not test-fired another batch. The results so far: Common components. Win brass, CCI 250 primer. 75g Hornady VMAX. COL 2.8025". 42.0g Varget. 3187fps, 7.0fps STD, 16fps E.S., Load data for 39 loads in caliber .257 Roberts with .257 | 100gr | Sierra SBT GameKing bullet including underlying parameters such as bullet length, ..., .257 Diameter Bullets 75 gr. HP 87 gr. SPT 90 gr. HPBT 100 gr. SPT 100 gr. SBT 117 gr. SBT 117 gr. SPT 120 gr. HPBT.264 Diameter Bullets 85 gr. HP 100 gr. HP 120 gr. SPT , The history of the .257 Roberts dates back to the 1920's, when a wildcatter by the name of Ned Roberts began to experiment with the .257” caliber. It has been suggested that Charles Newton persuaded Roberts to settle on the 7x57 case design and that close friend Col. Townsend Whelen suggested a 15 degree shoulder., Load Data for .257 Roberts . Bullet: 115 gr PART (NOS) Diameter: 0.257" Powder: StaBALL 6.5 (Winchester) Starting Powder: 38.5 gr. Max Powder: 43.0 gr ., Mar 10, 2011 ... Looking for loads for a 257 Roberts, the rifle is used for elk, deer, and antelope. Thinking a 110gr Nosler ACCU-bond or 100gr Partition will be ..., 257 Roberts +P 117 gr SST® Superformance® ; IT IS VERSATILE: This new breed of ammunition is available in 17 Hornet to 444 Marlin, and is safe for use in all ..., It is considered to be about the maximum capacity for the .25 bore and still produce satisfactory performance and good barrel life. The Improved .257 can be readily recommended. (Handbook for Shooters & Reloaders/Vol. 1 - P.O. Ackley, 1962) NOTE: USE THIS DATA WITH EXTREME CAUTION. Be Alert: Publisher cannot be …, .257 Roberts Improved (RCBS Version) reloading data with 49 loads. Using bullets from Sierra HP, Sierra spitzer, Hornady SP, Nosler SB, Nosler Partition, Speer HP, Speer SBT, Sierra FB, Hornady HP. ... Notes: Test rifle: Enfield sporter with 24-inch Buhmiller barrel (rechambered from .257 Roberts to .257 Improved, with 28-degree RCBS chamber ..., Utah. QuickLOAD agrees with the others that 45.5g is WAY over pressure for the standard 257 Roberts. With a 24" barrel and a COAL of 2.775" the estimated pressure is 67,220 psi with 3,081 fps estimated muzzle velocity. QuickLOAD predicts that 41.5g to be max with that combo (@ 2.775" COAL & 24" barrel) for 2,822 fps., 257 Roberts Ackley Improved Load Data. 85 Grain. 100 Grain. 110 Grain. 115 Grain. 120 Grain. Explore the world of Nosler, renowned for crafting the finest bullets, ammunition, rifles, and brass. Discover our extensive lineup, including Partition, AccuBond, E-Tip, Ballistic Tip, Custom Competition, and more. Experience superior quality and ... , 257 Roberts Load Data. Using Hornady reloading data with the 257 Roberts bullets creates a great round that is popular with hunters who like its low recoil rates. The .257 Roberts dates way back to around the 1920's but many still use it to this day. Be Alert: Publisher cannot be responsible for errors in published load data. , Load Data for .257 Roberts. Bullet: 120 gr HPBT (Sierra) Diameter: 0.257" Powder: IMR 4350 (Improved Military Rifle) Starting Powder: . Max Powder: 41.5 gr. Primer: REM 9½. Case: REM. Trim Length: 2.223" Cartridge Overall Length: 2.775" Starting Velocity: Starting Pressure: Max Velocity: 2,780. Max Pressure: 45,000 CUP., Rifle Data. Rifle Data. Here you will find load data for some of the most recent cartridges on the market, with more being added each week. We are currently populating the cartridge drop-down menu with updated cartridge renderings, new propellants and bullets, and links to complimentary product pages. Cartridge., .257 Roberts Improved Data reloading data with 40 loads. Using bullets from Hornady, Sierra HP, Rem. Power Lokt, Sierra, Hornady Spire Point, Hornady Round Nose, Barnes., I have a Howa 1500 that has been rebarreled by E.R.Shaw to .257 Roberts with a 24" magnum contour barrel with 1:10 twist. It is topped with a Weaver V10 scope in Leupold mounts. I'm planning to make this my main deer rifle and hopefully print tiny groups with it too. I'm planning to use heavier bullets of 110-120 grains at modest velocity, 2600 ..., Load Data for .257 Roberts . Bullet: 90 gr GMX (HDY) Diameter: 0.257" Powder: IMR 4064 (Improved Military Rifle) Starting Powder: 35.0 gr. Max Powder: 38.5 gr .