Who knows about 257 Roberts?

[Potashminer]

So, looking for some information - thought maybe to ask here. I am aware a guy named Ned Roberts was playing with adopting 7x57 into using .257" bullets, for a number of years. Then Remington picked up a version and named it ".257 Roberts" in honour of that guy. From various purchases on CGN, I have acquired some R-P brass with headstamp "R-P 257 ROBT". And then some headstamp "W-W Super 257 Roberts". And then some other W-W that has headstamp "W-W Super 257 ROBT +P". And lately, some "FC 257 ROBT +P".

Can anyone explain what is the thing about the "+P"? I know it should mean increased pressure, but did R-P ever do that? Was it just a marketing ploy that W-W changed it into +P? I have not confirmed, but expect there is weight difference / perhaps volume difference between the brands? In perhaps true CGN fashion I do not yet have the 257 Roberts barrel screwed onto a receiver - so is no way, at the moment, for me to even fire it. Is all new, and some previously fired, brass that is here or on the way to me.

 

[todbartell]

I'm not sure on the back story on the +P brass, but Quickload software has the MAX PSI for the standard 257 Roberts @ 51,488psi and 58,000psi for the +P version {56.00grs h2O case capacity for both)

Here's some 117gr load predictions for each style of 257 Roberts when loaded 2,000psi below their respective maximums :

Cartridge          : .[B]257 Roberts[/B]
Bullet             : .257, 117, Hornady BTSP 2552
Useable Case Capaci: 48.362 grain H2O = 3.140 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length      : 24.0 inch = 609.6 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching [B]Maximum Pressure: 49488 psi[/B], or 341 MPa
or a maximum loading ratio or filling of 104 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

56 loads produced a Loading Ratio below user-defined minimum of 80%. These powders have been skipped.
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Alliant Reloder-26                  95.7     45.9     2.97    2906    99.4    49488   11025   1.227  ! Near Maximum !
Vihtavuori N560                     97.5     44.4     2.88    2835    93.3    49488   10759   1.234  ! Near Maximum !
Alliant Reloder-17                  85.5     40.0     2.59    2835   100.0    49488    9750   1.214  ! Near Maximum !
Alliant Reloder-23                  99.5     43.4     2.81    2835   100.0    49488    9798   1.216  ! Near Maximum !
Alliant Reloder-22                  97.8     44.1     2.86    2824    95.6    49488   10509   1.217  ! Near Maximum !
Alliant Reloder-16                  89.8     39.0     2.53    2821    99.6    49488    9719   1.211  ! Near Maximum !
IMR 7828SSC                         96.3     44.1     2.86    2821    93.7    49488   10446   1.227  ! Near Maximum !
Vihtavuori N555                     95.7     41.8     2.71    2803    99.6    49488    9882   1.241  ! Near Maximum !
Ramshot Hunter                      89.7     41.3     2.68    2782    98.0    49488    9816   1.228  ! Near Maximum !
Alliant Reloder-19                  94.1     42.0     2.72    2777    95.5    49488    9941   1.223  ! Near Maximum !
Winchester 760                      84.4     39.8     2.58    2769    97.2    49488    9758   1.233  ! Near Maximum !
Hodgdon H414                        84.4     39.8     2.58    2769    97.2    49488    9758   1.233  ! Near Maximum !
IMR 4831                            93.3     39.8     2.58    2748    99.3    49488    9318   1.245  ! Near Maximum !
Hodgdon H4831SC                     95.7     43.1     2.79    2747    92.8    49488    9689   1.221  ! Near Maximum !
Alliant Reloder-15                  80.4     35.8     2.32    2729    99.6    49488    9029   1.248  ! Near Maximum !
Hodgdon H4350                       91.1     39.7     2.57    2714    96.5    49488    9186   1.238  ! Near Maximum !
IMR 4350                            89.4     39.6     2.57    2714    96.6    49488    9174   1.238  ! Near Maximum !

 

[todbartell]

Cartridge          : .[COLOR=#ff0000][B]257 Roberts +P[/B][/COLOR]
Bullet             : .257, 117, Hornady BTSP 2552
Useable Case Capaci: 48.355 grain H2O = 3.140 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length      : 24.0 inch = 609.6 mm

Predicted Data for Indicated Charges of the Following Powders.
[B]Matching Maximum Pressure: 56000 psi[/B], or 386 MPa
or a maximum loading ratio or filling of 104 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

46 loads produced a Loading Ratio below user-defined minimum of 80%. These powders have been skipped.
Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Alliant Reloder-26                  99.5     47.7     3.09    3024    99.9    56000   11271   1.167  ! Near Maximum !
Norma MRP                          100.2     46.6     3.02    2984    98.5    56000   11217   1.173  ! Near Maximum !
Vihtavuori N560                    101.8     46.3     3.00    2961    95.2    56000   11249   1.173  ! Near Maximum !
Alliant Reloder-17                  89.5     41.8     2.71    2948   100.0    56000    9977   1.160  ! Near Maximum !
Alliant Reloder-22                 102.0     45.9     2.98    2946    97.2    56000   10936   1.161  ! Near Maximum !
Alliant Reloder-23                 103.8     45.3     2.93    2946   100.0    56000    9990   1.161  ! Near Maximum !
IMR 7828SSC                        100.4     46.0     2.98    2945    95.6    56000   10902   1.165  ! Near Maximum !
Alliant Reloder-16                  94.2     40.9     2.65    2937   100.0    56000    9996   1.155  ! Near Maximum !
Vihtavuori N555                    100.0     43.7     2.83    2919   100.0    56000   10128   1.184  ! Near Maximum !
Ramshot Hunter                      93.9     43.2     2.80    2899    99.1    56000   10178   1.172  ! Near Maximum !
Alliant Reloder-19                  98.4     43.9     2.84    2898    97.0    56000   10377   1.166  ! Near Maximum !
Winchester 760                      88.6     41.7     2.71    2891    98.5    56000   10159   1.175  ! Near Maximum !
Hodgdon H4831SC                     99.8     45.0     2.91    2866    94.7    56000   10132   1.165  ! Near Maximum !
IMR 4831                            97.8     41.8     2.71    2865    99.9    56000    9602   1.187  ! Near Maximum !
Ramshot BigGame                     84.2     40.0     2.59    2861   100.0    56000    9340   1.180  ! Near Maximum !
IMR 4895                            83.8     37.4     2.42    2855   100.0    56000    9343   1.188  ! Near Maximum !
Alliant Reloder-15                  84.7     37.7     2.45    2847   100.0    56000    9331   1.188  ! Near Maximum !
Hodgdon H4350                       95.6     41.7     2.70    2834    97.9    56000    9591   1.178  ! Near Maximum !
IMR 4350                            93.8     41.6     2.70    2834    98.0    56000    9576   1.178  ! Near Maximum !

 

[9.3mauser]

The Roberts was loaded quite conservatively in deference to older rifles, much like it's parent, the 7x57. The +P version was to give a little boost in modern rifles. I think both Winchester and Remington had +P loadings, but I can't recall the ballistics or how much the pressure was increased.

 

[Longwalker]

Weigh your brass. Weight = internal volume, for practical purposes. Sort accordingly, and work up loads for each weight category of brass. I shot a Win M70 push feed .257 Roberts for many years as my primary deer rifle. Great round, but factory loads are not so great. Underloaded, even in the +P versions in my opinion. I easily achieved 2800 fps with 120 gr. bullets/ IMR 4350. Good brass life and no pressure signs.

 

[nowarningshot]

The Roberts was loaded quite conservatively in deference to older rifles, much like it's parent, the 7x57. The +P version was to give a little boost in modern rifles. I think both Winchester and Remington had +P loadings, but I can't recall the ballistics or how much the pressure was increased.

Pretty much this. So many ancient, pre M98 mausers rechambered to 257 Bob. Take a shot out 7x57, spin on a 257 bob barrel, bobs your uncle. Any modern rifle in the x57 family, you can push some fast loads.

Personally never owned one, had several 7x57. Like pushing light for 7 bore bullets, 100 and 120gr, even faster than a Bob+p, slightly worse bc, but I hunt thick places so it doesn't matter.

 

[Potashminer]

The Roberts was loaded quite conservatively in deference to older rifles, much like it's parent, the 7x57. The +P version was to give a little boost in modern rifles. I think both Winchester and Remington had +P loadings, but I can't recall the ballistics or how much the pressure was increased.

I found them in the SAAMI 2015 document - likely where I should have looked first - as you likely know, CUP units come from using the Copper Crusher test method and PSI come from the Pieziometric test method - even though both are reporting the same pressure, in that cartridge. I see SAAMI sets limit of 45,000 CUP (54,000 PSI) for 257 Roberts, and then 50,000 CUP (58,000 PSI) for 257 Roberts +P - so about 11% increase using CUP system; about 7.4% increase using Piezometer system, in that cartridge. Drawings later on in the document seem to show that the exterior dimensions of the two cartridges, and the chambers, appear to be identical. Velocities appear to increase up to 200 fps, or more, with 117 grain bullets.

The receiver in question is a Mauser 98 and used to be 8x57 - the bore was allowed to severely pit and corrode. It might have been sporterized in Germany, 1920's or earlier from the proof stamps - done up as a very slim little rifle. The replacement barrel is "long chambered" by McGowen - 24" long (?). I have a stash of 75 grain V-Max and 115 Partition that I intend to load for it - once I get off me arse and screw that thing together - then do something about that wood, so the new barrel will fit.

 

[Potashminer]

Weigh your brass. Weight = internal volume, for practical purposes. Sort accordingly, and work up loads for each weight category of brass. I shot a Win M70 push feed .257 Roberts for many years as my primary deer rifle. Great round, but factory loads are not so great. Underloaded, even in the +P versions in my opinion. I easily achieved 2800 fps with 120 gr. bullets/ IMR 4350. Good brass life and no pressure signs.

Yep - duly noted!! It has been my practice to load up batches with same head stamps - I had not previously mixed case head stamps too often. I read an article by John Barsness where he pretty much demonstrates, at Western Powder lab, that the "home done" "pressure signs" can be false - one of his loads that he used for many years was well over the SAAMI limit, yet he had not experienced any "signs" with it. But, regardless of pressure, I really do not like a "tight to open" bolt, flattened primers, etc., so has been my practice to do up a "pressure test series" - start low and work up in small increments of powder - often 0.5 grain or 1.0 grains past a book's Maximum - to "sneak up" on symptoms, rather than have the bolt frozen shut on the first shot. Usually I am "sighting in" a new-to-me scope for that rifle at the same time.

I have enough choices of rifles and cartridges that I have seldom gone looking for a second load after I find one that is "good enough" for the purpose. This 257 Roberts will be my first attempt to try to get two decent loads, from the same rifle, with two different bullet weights.

 

[Longwalker]

I agree with you on your pressure signs comments. Barsness suggests carefully loading to a certain max. velocity level for a certain combination of barrel length and components as a practical "max" and I agree. I also stop way before sticky bolts or leaky flattened primers. Another test I do is shoot and reload at least five times with the same small test lot of 3-5 cartridge cases. If the primer pockets stand up to those five shots & reloads without getting loose, the load is not stressing the case head too much. Good luck with your project!

 

[Potashminer]

Is laudable to want to "stop" before tight opening bolt or really flattened primers, but I do not know how to do that unless I find where that level is - at least one rifle and component combination was well below various reloading manual's maximum, and a Weatherby 7 mm Magnum went a full grain past the Nosler book's maximum without symptoms. I do not find any point to "pushing" pressure - if a 30-06 is not enough, is why there is 300 H&H, 308 Norma Mag, 300 Win Mag and 300 Weatherby Mag here - can do about what is needed without overly stressing the rifle. If the 7x57 is "not enough", then get a 280 Rem, 284 Win or similar - is no point, for me, to "push" a 7x57, for example, to make it into something else - although I have been very tempted by some of the AI conversions - is not real clear to me, though, how much improvement is due to case shape / powder volume, or due to higher operating pressures.

 

[Eagleye]

I have 2 rifles chambered in 257 Roberts at present. Both are in modern, strong factory configuration.
[M70 Featherweight (22" barrel)] [M700 Classic (24" barrel)]
Factory ammunition is lethargic, IMHO. Even the +P ammo does not exploit the potential of this fine
chambering.
In a 24" barrelled rifle, 120 grain bullets can be safely driven to 3000 fps with several slow burning
powders. 100 grain to 3150 fps.
Quite effective on game up to 200 kgs, if the right bullet is used. Dave.

 

[Potashminer]

Since reading about it in a John Barsness article - I always wondered about pressure limits in the same brand / model of rifle. If it is being chambered for 270 Win (MAP of 65,000 psi), why would there be a lesser limit on other cartridges, using same brass case heads (?) and same receiver / barrel sources?? I do not know of any factory 1893 Mauser that were factory chambered for 270 Win - so that part makes sense - but what about Win Model 70 or Rem 700, various CZ, Tikka, etc. ??

If I recall correctly, he had a CZ rifle of some sort in 9.3x62 - he either had or knew of same factory rifle made in 30-06. I think was why he went to Western Powder lab - to confirm that his "hot" 9.3x62 loads were actually equivalent pressure to 30-06.

 

[bearhunter]

I've had several 257 Roberts chambered rifles at one time or another. Everything from lovely little custom built 95 Mausers to custom Model 30 Remington, custom Mod 98 Mausers, M38 Arisaka, BSA U9 type, Winchester Mod 70 and now a lonely Remington 700.

The M38 Arisaka was built by PO Ackley and his version had a sharper shoulder.

Factory rifles were within SAAMI specs but the custom rifles were often just a bit different when it came to chamber dimensions and had to be fireformed, if they even accepted factory ammunition.

This has led to a lot of confusion over the decades when it comes to this very efficient little cartridge.


The early rifles had a very slow twist rate for the most part 1-14 and seldom shot anything over 100 grains well. An early Rem 721 I had with a 1-14 twist from the factory wouldn't stabilize bullets over 90 grains, no matter how fast I pushed them.

Depending on when the rifle was built or who built them you had to be careful to check twist rate or the rifle may not shoot the bullets you want to hunt with.

My present Remington 700 Classic is straight from the factory and it has a 1-10 twist rate. It shoots whatever weight bullets it's fed well, even off the shelf factory fodder.

The +P designation is IMHO promotional hype for the most part, other than they do weigh more and are stronger. The hype I'm alluding to is that it wasn't necessary, but did make people feel better.

In strong rifles, such as the M98 Mausers, M38 or 77 Arisakas, Remington, Winchester, Ruger and other modern bolt rifles there isn't any reason this cartridge shouldn't be loaded to higher pressure levels to wring out its true potential. Again, IMHO.

We're now blessed with some excellent powders for the 257 Roberts that weren't available even 10 years ago.

I shoot three different bullet weights through my Remington. 87 grain Speer HP "TNT", 100 grain Hornady IL flat base and Hornady 110 grain Interbond.

I have shot heavier 117 and 120 grain bullets out of the Roberts and even took a few Moose, clean and quick, with them but there are better choices for this type of game.

I've been through times when you just couldn't find 257Rob cases and 25 calibre bullets were just as hard to find.

I've necked down 6.5x57, 7x57, necked up 6mm Rem to make the cases and they worked very well.

Due to the extreme litigation issues in the US, manufacturers came up with the +P cases and in all honesty it wasn't a bad idea.

I have a few hundred factory cases of both the regular "thin wall" cases and the heavier "thick wall" cases and load both of them, with different weights of powder, in cases fireformed to the chamber in my rifle.

I load them on the HOT side, which is still safe in my rifle using both weights of cases.

My load for the 87 grain Speer TNT is 42.0 grains of W748 over CCI 250 primers to get 3200fps

100 grain Hornady IL is 46.0 grains of W760/H414 over CCI 250 primers to get 3000fps

110 Hornady IB is 45.0 grains of Superformance over CCI 250 primers for 2900fps.

All of the loads listed above are for the +P case, which has slightly less capacity than the regular cases.

I use the standard cases for the 87 grain bullets with different powders that take up more space but give close to identical results, accuracy and velocity wise.