.257 Roberts modern data


March 23, 2012, 11:17 AM
I have asked similar before, but now I am about to load my test loads this weekend and hate going in blind.

Here is the loading data from Hodgdon's website for my selected powder and bullet for .257Roberts. Notice that it is a conservative load meant to be safe for older Mausers. I am loading for a modern action and with +P Brass. I am looking for loads to make the most of the round's capabilities. I would like to see if 3200fps (maybe 3250?) is attainable with this bullet/powder for a longer range predator/deer load.

Bullet wt/ type- 100 GR. SPR SPBT
Powder - Hodgdon H414
Caliber- .257"
OAL- 2.770"
Starting load/ Velocity/Pressure- 44.0/2919/33,600 CUP
Max Load/ Velocity/ Pressure- 45.0/3098/44,500 CUP

I know precision will dictate the final load, but I would like a good modern maximum. I want to load for the strongest load that holds a decent group. If I can go up .1gr and give up just .1" in group then I would if I can put a bit (worthwhile and noticeable via chrony) more energy on target.

Just looking for input.

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March 23, 2012, 03:47 PM
I have never loaded for that cartridge, however given the bore size and capacity relative to the 243 Win, I would be astounded if you could not do a good bit better than 3098fps with a 100g bullet.

You will need to work upwards in increments no larger than 0.5 grains at a time, and chrono the speeds and check for those well documented signs of pressure. Use only new brass that has been prepped properly.

In a modern bolt action chambered for modern high intensity rounds, with good brass, 44500cup is very mild. You would be well aware many people exceed that in the 257, but those that do should only do so very carefully and methodically.

Make sure you log everything meticulously of course.

When I start to push beyond published maximums looking for more power, I try whenever possible to use the slowest recommended powder for that cartridge and bullet weight, as these can be more forgiving.

Would you mind posting your results for interests' sake mate?

March 23, 2012, 05:24 PM
I own and have hunted deer with a .257 R. I had no trouble getting 3200fps with a 100grn bullet. My barrel is 24" and IIRC 48grns IMR4350 gave 3031fps and 49grns IMR4831 gave 3200fps. Both loads appeared mild in my rifle and I could go up a couple grains but I haven't loaded for that nice gun for a few years.

March 23, 2012, 05:49 PM
While we're book lookin', notice that Hybrid 100V already lists 3205fps for a max load, and seemingly has the potential to take the 257 Roberts further than H414/Win760 would, because it's a high energy, actual hybrid, spherical/extruded powder, according to Hodgdon, and is a bit slower burning.
I would not be surprised if Rel-17 would give some top velocities too, but data is sparse.

Here's a link to the REAL Guns site testing +P reloads in a 22" barrel.



March 23, 2012, 09:21 PM
I'm not going to list the actual load for personal reasons, but I have gotten 3500 fps from 75 gr. V-max bullets in my .257 with no signs of any problems. I used Re-15 powder and I would think that 3200 with a 100 gr. bullet wouldn't be a problem with Re- 19. That sure beats the creeping along factory loads at about 2600 fps. I have found that the Hornady regular velocity load performs really well in my rifle too. I like it better than the light magnum load.

March 25, 2012, 04:17 AM
I've loaded and shot the .257 since 1983.
Generally, the Hodgdon data is really good with the .257.

However, every gun is a rule unto itself.
I had a Ruger M77mkII, that generally, was at max with the Hodgdon data, and gave slightly lower velocities as would have been expected from it's 22" bbl.

So, I would let the rifle dictate the loads. I've used the 45.0gr load of H414 in my custom M98 Mauser w/E.R.Shaw bbl. It's a good one, and essentially duplicates the classic load of 45.0gr of IMR4350.

I would be really cautious of using myamoto's loads given above. Those will be somewhat above what my rifle(s) will tolerate.

FWIW; I found that the listed load of 48.0gr of H100V was "MUCH, MUCH" too hot for my gun. It gave a badly cratered/extruded primer, and very stiff bolt lift, w/case head burnishing (and chrono'd at 3,300+fps!). My rifle's max with my lot# is 44.0gr for 2,950fps. or, not as good as the H414 or H380 loads where the max loads give the approximate pressure listed and are actually "mild" loads in my rifle......... (if 3,100fps is "mild"!!!) FWIW; with a Sierra 100gr bullet, they kill deer all out of proportion to what you'd expect. Think .270 w/130gr bullet for comparison....

also, for what it's worth, my Ruger's favorite load was the 100gr bullet with 38.0gr of IMR3031. A classic load for the "Bob" from back in the '30's and '40's. It gave right at 3,000fps and moa accuracy. And 39.0gr gave 3,200fps with the 87gr Speer's and equally good accuracy.

FWIW; I found 3,500fps easy with the 75gr Hornady over H414 at the Hodgdon recommended load of 52.0gr for 3,350fps, and likewise 48.0gr of H380 from my Custom M98. But the Nosler 85gr BallisticTip over 50.0gr of H414 is an even better long range P-dog load. I shot 96rds of this on a p-dog town in BigSandy, MT in 1993. Got hits to over 400yds with ease. Not bad for a 7lb rifle with a 2x-7x scope.....After taking a mule deer doe at over 350yds.... the other three rounds were for checking zero....

March 25, 2012, 06:21 AM
Speer #12 lists a starting load of 40 grains H-414 @2657 fps and a max load of 44 grains @ 2878 fps for a 100 grain bullet out of a 24" Ruger 77.

Their fastest 100 grain bullet load is a max charge of 45 grains of Olin 760 powder @ 3113 fps.

March 25, 2012, 01:13 PM

I just looked up the .257 Roberts +P data in Speer #14. The rifle used to produce the data was a Ruger 77 with a 24" barrel. Cases were Winchester & the H414 data used the magnum primer. The start was 40 grains at 2657 fps & the max was 44 grains at 2878 fps. Sorting by velocity, as Speer does, this is the eighth powder down the list, indicating that it's not particularly efficient according to their data. For instance, 49 grains of RL19 gives 3094 from the same gun.


March 25, 2012, 04:57 PM
CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

With that 100gr Speer 1408 SPBT bullet, 2.77", and H414 in the 257 Roberts I would expect in a work up:

1) 51.7 gr 77kpsi 3560 fps 26" barrel, 3430 fps 22" barrel, easy insertion of the next primer in one firing on all the brass, difficult bolt lift.

2) 50.2 gr 72kpsi 3500 fps 26" barrel, 3360 fps 22" barrel, most brass lasts 5 firings and primer pockets still good.

3) 49.2 gr 67kpsi 3425 fps 26" barrel, 3300 fps 22" barrel, after years of trying to get the highest velocity and much shooting, this is the hottest load that always gives long brass life despite changes in temperature and other problems.

4) 46.3 gr 55 kpsi 3230 fps 26" barrel, 3100 fps 22" barrel, after years of going to the range, you have found this reduced load to give two full 5 shot groups under an inch, while the hot hunting loads only gave one good group before Copper fouling occurred. You have decided this load is what you will shoot.

5) You grow tired of the temperature affecting velocity in long range hunting and switch to a different powder.

March 25, 2012, 11:32 PM
I have loaded some rounds ranging from 45gr to 47.4 in .1gr increments. I know my rifle tends to be a little fast, probably due to its 26" barrel. I will shoot them off over my chrony next weekend just to look for a max. I will let you know what I see. Might write it up.

March 28, 2012, 03:13 AM
What is interesting about the Speer data is that H414 and Win760 are the EXACT same powder, but from different lot#'s.

I use the Hodgdon data and find that with my E.R.Shaw barrel on my M98 action, that the data corresponds very closely to what I get. With the Ruger M77 I had, the Speer data was closer as the Ruger had a very short throat, and tight chamber. I had to segregate the brass because of the differences. Hence, my admontition that you needed to let the RIFLE dictate the loads.
In my rifle, the Hodgdon loads are indeed NON +P. But in the Ruger, were right up against maximum..... I've gone as high as 47.5 (as did Clark, and then some) but found that the Hodgdon load was where accuracy was best. This was with Federal #210 and Win Large Rifle primers and Winchester, Remington, and Federal .257Robt brass.

Reformed 7x57 and 8x57 brass had thicker necks and lower case volumns but functioned properly at the "Hodgdon" load levels.

FWIW; the Speer data with both the .257wby and .300RUM is "low" compared to Lyman, Sierra, Hornady, and Nosler data...... but, they used 24" bbls and CCI primers and Federal brass with the .300RUM. Tells you something about Speer's data.... and choice of components being an ATK company.

April 7, 2012, 10:00 AM
I am loading Bobs with 37.5 grains of H335 with 100 gr. Nosler ballistic tips and getting single hole accuracy at 25 yards (no outdoor public ranges available). Hogdon says that 39 grain max load gives 3042, and my M77R only has a 21" barrel, so I'd guess I'm around 2900 fps (no chrono either...). However, I'm noting a lot of muzzle flash, as in the scope whites out like a night sight (unburned powder?), and what seems like excessive noise and more visible shockwave greater than my .30-06. Anyone have suggestions for other less flashy powder that would give similar velocity? I don't see a need for much more, as Kentucky deer shots are mostly under 200 yards and the rifle/round are already more accurate than I am.

April 7, 2012, 04:43 PM

You may find the following data useful.

Hornady #6, uses a Winchester model 70 with a 22" barrel for the following data:
Hornady 100gr #2540, 42.3 gr RL19 to 48.5 gr RL19 max. Velocity 2600 - 3000 fps.

Speer #14 uses a Ruger 77 but with a 24" barrel, and with 100 grain bullets gets:
RL19 start 45.0 grains at 2804 & 49.0 grains max at 3094 fps.

For comparison, Nosler #6 shows RL19 min-max to be: 44 - 48 grains at 2827 & 3052 fps.

I prefer either Speer or Hornady because they use real world guns, not test barrels. I'll also note that because of different jacket thickness's & ductility, you should never just swap bullets & expect the results to be within safe parameters at max or near max loads.

Hope this helps,


April 8, 2012, 02:39 AM
re: Less "flashy" powder. I noted this characteristic of H335 while loading some in the .358win recently. With 180gr bullets and less than 50,000cup loads, the H335 was giving some remarkable flash. I'm told that at yet higher pressures and heavier bullets that the "flash" goes away.

In the .257Roberts, the IMR4350 with 100gr bullets, IMR4831 w/115-120gr bullets, as well as H4831 are hard to beat. I've not gotten as good of results with RL22, or RL17 with the 'Roberts as I have with other cartridges such as the .30/06 or .260 or .270.

And, I've never seen the "velocities" or accuracy attributed to RL19 in any cartridge EXCEPT with the .338/06 and 225gr, and 250gr bullets. Even then, the velocities were still 50-75fps slower than "predicted" by the data.

H380 and H414 performed well in my rifle, but I gravitated back to H4831 and IMR4350 with bullets 100gr and heavier.

April 10, 2012, 06:13 PM
Goose Gestapo - thanks, I've seen a lot of other sources since I posted for H4831in the caliber, so it looks like another order from Midway... I avoided it at first since it uses significantly higher powder weight for similar velocity.

September 1, 2012, 09:54 PM
CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.
(Thanks for the easy warning to copy and paste, Clark)

Ok it took a long time to get out there and try them out, but I easily got my 3200fps without any sign of pressure issues. In fact, I only pushed the max listed by Hodgdon's data by .1gr. to get it out of my rifle.

I went ahead and fired the rest and was at 46.8 gr before I got my first sign. By then I had pushed well beyond my goal at any rate. Extraction was still good and no primer issues either. Just an increase in head expansion over previous loads.

The loads were loaded to test pressure/velocity not accuracy so I was going to disregard group sizes, but 45.4gr gave an awesome .82" @ 3280fps (average velocity of 5) for me. This was without me going through and doing my usual OTL (off the lands) testing and any special brass prep. I will be loading more of that to check out.

I plan to re-bed and re-scope the rifle as it is my project gun as well and was wearing a Konus 1.5-5 shotgun scope and I plan to shoot to 500 on varmints with this thing eventually. Maybe I can get .5 out of this old thing then?

September 2, 2012, 12:49 AM
CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

The 257 Roberts uses the 1989 7.65x53mm Mauser or 7x57mm Mauser case head built with a large Boxer primer pocket and so is only good for handloaders to ~ 67 kpsi for long brass life with margins [in strong rifles]. The 22-250 Rem, 6mmRem, and 270 Win use this case head and are SAAMI registered at 65 kpsi. They are really pushing the limit of pressure for any commercial ammo working in any gun.

So this year I am trying to build a 257 Roberts Ackley Improved Rimmed rifle to go to higher pressure ~ 80kpsi. I have tried it by using a Mauser bolt I modified for 7mmRemMag in a VZ24 that I have converted to 257RAI. But if I can get off the dime and build a rifle for hunting 2012, I want to do it in falling block. It seemed like such a good idea, a Google search reveals, it has been done before.

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