Where to start - 256 Newton yet again

Ok, I've got the rifle. Finally got some dies. Making brass out of .270 cases (I've got 25-06 rifles). I have H & I 4831, I4350, RL23 and others. Just trying to figure out where to start a load.
I have a few of the 123 gr Scenars to play with as well as nearly 2 boxes of 129 gr ABLR. Any suggestions or guidance will be appreciated.

First off Bear, I never noticed your Signature line. Sorry for your Pop's and I assume he is a Marine.

And secondly, I am jealous as all get out you get to work with a 256 Newton! If it were me, I would probably take a case capacity measurement and use Swede data along with QL data to tweak it. I can't see you having a bit of trouble starting with upper end Swede data and then working up, if need be from there. Out of the ones you list I would have to think bore/case ratio is similar to a 270 so the H4831, IMR4831, RL26, and RL23 would all work excellent. I use RL26 in my Swede and it works really well.

Please put all of the pictures you can of this project. It is a sorta long range dream to get an original Newton rifle someday. I would absolutely die to have an original 30 Newton! That my friend is the ultimate 300 mag probably designed before Doc Mike :lol:

Good luck and please let me know if I can help at all. Cannot wait to hear how it turns out!

Ken Waters Pet Loads has data for the .256 newton.
Paul B.

Cartridge : .256 Newton
Bullet : .264, 129, Nosler AccuBond LR 58943
Useable Case Capaci: 59.160 grain H2O = 3.841 cm³
Cartridge O.A.L. L6: 3.400 inch = 86.36 mm
Barrel Length : 24.0 inch = 609.6 mm

Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 43745 psi, or 301 MPa
or a maximum loading ratio or filling of 105 %
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 !

15 loads produced a Loading Ratio below user-defined minimum of 40%. 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 90.5 53.0 3.44 2849 99.5 43745 12593 1.343 ! Near Maximum !
Vihtavuori N570 102.1 58.7 3.80 2833 89.0 43745 13376 1.332 ! Near Maximum !
Hodgdon Retumbo 105.0 57.6 3.73 2829 97.9 43565 12803 1.328 ! Near Maximum !
ADI AR 2225 105.0 57.6 3.73 2829 97.9 43565 12803 1.328 ! Near Maximum !
Alliant Reloder-33 104.2 61.6 3.99 2820 89.4 43745 13272 1.334 ! Near Maximum !
Alliant Reloder-25 98.1 53.2 3.45 2820 99.2 43745 12167 1.330 ! Near Maximum !
Bofors RP30 100.9 55.0 3.56 2813 95.1 43745 12578 1.342 ! Near Maximum !
Norma MRP 2 100.9 55.0 3.56 2813 95.1 43745 12578 1.342 ! Near Maximum !
Norma MRP 90.8 51.7 3.35 2813 97.5 43745 12345 1.340 ! Near Maximum !
ReloadSwiss RS 60 81.3 46.5 3.01 2803 100.0 43745 11142 1.328 ! Near Maximum !
ReloadSwiss RS 70 87.6 50.9 3.30 2801 98.0 43745 12008 1.325 ! Near Maximum !
SNPE Vectan SP 12 96.0 55.9 3.62 2800 95.0 43745 12364 1.328 ! Near Maximum !
PB Clermont PCL 517 96.1 55.9 3.63 2800 94.9 43745 12376 1.328 ! Near Maximum !
ReloadSwiss RS 80 105.0 62.1 4.03 2799 89.6 42863 13211 1.344 ! Near Maximum !
Vihtavuori N560 92.1 51.3 3.32 2793 93.7 43745 12285 1.336 ! Near Maximum !
Accurate MAGPRO 92.9 53.8 3.49 2784 91.9 43745 12324 1.344 ! Near Maximum !
IMR 7828 SSC 91.1 51.0 3.31 2782 94.3 43745 11978 1.325 ! Near Maximum !
IMR 7828 96.3 51.0 3.31 2782 94.3 43745 11978 1.325 ! Near Maximum !
Alliant Reloder-23 94.7 50.5 3.27 2779 99.9 43745 11281 1.346 ! Near Maximum !
Alliant Reloder-22 92.3 50.9 3.30 2779 96.0 43745 11973 1.342 ! Near Maximum !
Bofors RP5/NP ~approximation 92.3 50.9 3.30 2779 96.0 43745 11973 1.342 ! Near Maximum !
Raufoss RA15 92.3 50.9 3.30 2779 96.0 43745 11973 1.342 ! Near Maximum !
Elcho 17 80.4 46.0 2.98 2778 100.0 43745 11055 1.337 ! Near Maximum !
Alliant Reloder-17 80.4 46.0 2.98 2778 100.0 43745 11055 1.337 ! Near Maximum !
Winchester WXR 94.7 51.1 3.31 2777 95.8 43745 11969 1.342 ! Near Maximum !
Bofors RP15 94.7 51.1 3.31 2777 95.8 43745 11969 1.342 ! Near Maximum !
Ramshot Magnum 93.6 55.6 3.60 2774 96.8 43745 11757 1.334 ! Near Maximum !
ADI AR 2218 105.0 61.0 3.95 2773 86.5 43129 13222 1.332 ! Near Maximum !
ADI AR 2213 91.8 50.6 3.28 2768 94.1 43745 11803 1.324 ! Near Maximum !
ADI AP 2214 96.2 54.5 3.53 2764 94.3 43745 11822 1.323 ! Near Maximum !
ADI AR 2217 101.2 54.6 3.54 2762 94.3 43745 11789 1.323 ! Near Maximum !
Hodgdon H1000 101.2 54.6 3.54 2762 94.3 43745 11789 1.323 ! Near Maximum !
Somchem S365 86.2 46.7 3.03 2752 100.0 43745 10604 1.356 ! Near Maximum !
Alliant Reloder-16 85.8 45.6 2.95 2752 99.8 43745 10925 1.351 ! Near Maximum !
ReloadSwiss RS 62 83.4 47.7 3.09 2745 99.2 43745 11133 1.363 ! Near Maximum !
Rottweil R905 93.4 50.6 3.28 2744 93.7 43745 11549 1.343 ! Near Maximum !
ADI AR 2209 88.4 48.0 3.11 2740 95.7 43745 11258 1.328 ! Near Maximum !
PB Clermont PCL 518 85.2 48.0 3.11 2740 98.0 43745 11205 1.346 ! Near Maximum !
PB Clermont PCL 511 81.7 47.5 3.08 2738 98.2 43745 11146 1.347 ! Near Maximum !
Ramshot Hunter 84.5 47.6 3.08 2738 98.2 43745 11134 1.347 ! Near Maximum !
Alliant Reloder-19 88.6 48.3 3.13 2735 95.8 43745 11289 1.339 ! Near Maximum !
Hodgdon H414 79.6 45.9 2.97 2730 97.5 43745 11087 1.349 ! Near Maximum !
Winchester 760 79.6 45.9 2.97 2730 97.5 43745 11087 1.349 ! Near Maximum !
Bofors RP5 NT ~approximation 95.0 52.8 3.42 2730 91.4 43745 11456 1.328 ! Near Maximum !
Norma 217 105.0 56.4 3.65 2730 95.3 38359 12718 1.425
Bofors RP14 ~approximation 89.3 48.7 3.16 2730 95.8 43745 11217 1.340 ! Near Maximum !
Norma URP 83.8 45.2 2.93 2723 99.4 43745 10771 1.354 ! Near Maximum !
Bofors RP19 ~approximation 83.8 45.2 2.93 2723 99.3 43745 10768 1.354 ! Near Maximum !
Accurate 4350 83.6 45.6 2.96 2721 99.4 43745 10847 1.379 ! Near Maximum !
Vihtavuori N550 81.2 45.3 2.93 2719 99.2 43745 10837 1.360 ! Near Maximum !
Norma 204 84.1 47.3 3.07 2713 95.6 43745 10988 1.340 ! Near Maximum !
Raufoss RA4 86.8 47.3 3.07 2713 95.6 43745 10988 1.340 ! Near Maximum !
Bofors RP4 ~approximation 86.8 47.3 3.07 2713 95.6 43745 10988 1.340 ! Near Maximum !
Hodgdon H4831 SC 90.4 49.8 3.23 2713 93.4 43745 11072 1.335 ! Near Maximum !
Hodgdon H4831 94.0 49.8 3.23 2713 93.4 43745 11072 1.335 ! Near Maximum !
IMR 4831 88.1 46.0 2.98 2709 99.5 43745 10593 1.366 ! Near Maximum !
Somchem S385 89.0 49.1 3.18 2706 96.9 43745 10940 1.365 ! Near Maximum !
SNPE Vectan SP 11 77.8 43.8 2.84 2705 99.8 43745 10352 1.351 ! Near Maximum !
Accurate 3100 92.6 50.5 3.27 2705 98.3 43745 10879 1.383 ! Near Maximum !
Lovex S071 97.9 50.5 3.27 2705 98.3 43745 10879 1.383 ! Near Maximum !
Vihtavuori 24N41 103.8 60.3 3.91 2705 81.4 43745 11584 1.333 ! Near Maximum !
ReloadSwiss RS 52 75.7 42.6 2.76 2702 100.0 43745 10083 1.361 ! Near Maximum !
Winchester Supreme 780 88.4 50.8 3.29 2701 95.8 43745 10853 1.345 ! Near Maximum !
Ramshot Big Game 75.3 43.8 2.84 2701 99.8 43745 10265 1.351 ! Near Maximum !
Hodgdon Hybrid 100V 86.3 45.5 2.95 2700 100.0 43745 10072 1.351 ! Near Maximum !
Hodgdon CFE223 71.0 43.1 2.80 2700 99.9 43745 10209 1.352 ! Near Maximum !
Vihtavuori N165 94.2 50.8 3.29 2697 96.5 43745 10724 1.350 ! Near Maximum !
Hodgdon H870 105.0 59.1 3.83 2697 88.7 38623 12551 1.418
Bofors RP4 NT ~approximation 84.6 46.9 3.04 2697 97.3 43745 10717 1.356 ! Near Maximum !
IMR 4895 74.6 40.7 2.63 2691 99.9 43745 10194 1.361 ! Near Maximum !
Vihtavuori N170 103.8 56.0 3.63 2688 87.6 43745 11241 1.362 ! Near Maximum !
Alliant Reloder-15 75.3 41.1 2.66 2684 99.7 43745 10165 1.360 ! Near Maximum !
Bofors RP11 ~approximation 75.3 41.1 2.66 2684 99.7 43745 10165 1.360 ! Near Maximum !
Raufoss RA11 75.3 41.1 2.66 2684 99.7 43745 10165 1.360 ! Near Maximum !
Rottweil R904 87.4 47.0 3.05 2684 94.4 43745 10645 1.342 ! Near Maximum !
Norma 203B 75.7 41.3 2.68 2683 99.9 43745 10098 1.362 ! Near Maximum !
Hodgdon H4350 85.7 45.7 2.96 2680 96.8 43745 10421 1.344 ! Near Maximum !
Hodgdon H380 77.0 42.9 2.78 2680 99.1 43745 10306 1.366 ! Near Maximum !
Hodgdon BL-C2 71.4 42.5 2.75 2679 100.0 43745 9966 1.367 ! Near Maximum !
IMR 4350 84.1 45.6 2.96 2679 97.0 43745 10406 1.344 ! Near Maximum !
Lovex S070 83.4 45.0 2.91 2679 97.7 43745 10503 1.367 ! Near Maximum !
Bofors RP7 NT ~approximation 78.9 43.4 2.81 2679 97.9 43745 10176 1.328 ! Near Maximum !
Norma 203 old 77.2 42.6 2.76 2678 100.0 43745 10015 1.381 ! Near Maximum !
Bofors RP3 77.2 42.6 2.76 2678 100.0 43745 10015 1.381 ! Near Maximum !
IMR 4320 77.3 41.5 2.69 2677 99.8 43745 9855 1.339 ! Near Maximum !
IMR 4955 Enduron 90.5 48.0 3.11 2675 93.7 43745 10615 1.341 ! Near Maximu

Wow. Nothing wrong with those especially considering the low pressure.
Cool cartridge and rifle.
If it's one of the originals check the twist. I believe they were 1-10. If so, up to and including 130s should be good imo.

It has the 'Metford' rifling. Kind of an oblong looking view down the pipe. Running a cleaning rod with patch & jag I counted 1-10" twist. Wanting to run the 129 ABLR.
The 1st model Newton's were all built by Mauser though there aren't any markings I've seen on this one to say so.
SJB, you asked, here are some pictures. The D/T was done by the previous owner. (smh) on a square-bridge Mauser no less.









The ol' girl has definitely been used before. At those pressures shown on the QL by muleman, It looks to be a mate in velocity to my 6.5x55 SE.

Bbear, thank you so much. My good hearted jealously is through the roof with this one! Newton is my all time favorite cartridge designer and to own one of his rifles would be incredible.

I think you’d be doing it right with some 140’s as well. I’m betting a Partition, AccuBond or A-Frame would work just fine as well with the 10 twist. Either way, you’ve got a cool danged rifle. I’d do backflips to have that rifle in the Rocky’s chasing elk!

That is one cool rifle!

Oh my my my. If I had that gun I'd kick the house dog out and set that rifle on the chair next to me and reach over and pat it now and then. Lol.

What a cool gun, and like you said on a square bridged mauser no less. Truly a fantastic find. Much respect that you're planning on letting it stretch its legs and not just making it a collector safe queen.