A Ruger M77 Hawkeye in 257 Roberts Part 2

Bear with me while I ramble through some of this. I promise to eventually get to the part where the rifle goes boom and I measure the holes in the target. I like firearms, so the research interests me and, sometimes, the information acquired makes it to the page… where it gets in the way of the pictures.

When Remington homologated the 257 Roberts, the original Roberts’ design was altered. The case shoulders were sharpened from 15º to 21º, which: made the case a straight neck down of the 7x57mm cartridge1, reduced production tooling investment and provided an improved surface for more positive headspacing. It also prevented chambering the Remington sanctioned round in earlier custom firearms marked for the same cartridge.

No, I don’t think Remington was hatching a nefarious plot. I think it was Remington’s acknowledgement that, in those days, wildcat cartridge dimensions tended to follow the preferences of whomever made the chamber reamer, so they needed to shied their customers from the possibility of sticking an almost right cartridge into an almost wrong chamber. I have read that Remington changed the cartridge but retained the name to pay homage to Roberts. It might also have something to do with getting some winds in the cartridge’s sails from a decade of preexisting good will. So I had this great little Ruger M77 and some boxes of factory ammo…

Factory ammo performance

SAAMI references two Maximum Average Pressure specifications for the 257 Roberts; standard @ 54,000 PSI and +P at 58,000 PSI. Both are currently produced with a ballistic differences that are notable. As an example, standard pressure Remington Express ammunition is rated at 2,650 fps of muzzle velocity and 1,824 ft-lbs of muzzle energy while Winchester Super X +P is rated at 2,780 fps of muzzle energy and 2,009 ft-lbs of muzzle energy. Both ratings are based upon a 24″ test barrel standard. Reviewing published specifications from other manufacturer, this difference between the two types of loadings is fairly consistent.

+P Cartridges	Weight Grains	Bullet Type	MV 24″ Rated	MV 22″ Actual	Δ
Nosler Custom	110	AccuBond	3000	2933	-67
Hornady Superformance	117	SST	2945	2836	-109
Winchester Super X	117	Power Point	2780	2735	-45
Federal Premium	120	Partition	2800	2675	-125

The barrel length comparison can be used for whatever it might infer as a relative indicator, however, it is an apple to bicycle chain comparison as these are rated 24″ numbers and not recorded live fire.

What would that look like… if I could see small things far away?

Nosler Custom 110 Grain AccuBond
Yards	0	50	100	150	200	250	300
Velocity – fps	2933	2820	2710	2602	2497	2394	2294
Energy – ft.-lbs.	2101	1942	1793	1653	1522	1400	1285
Momentum – lbs-sec	1.43	1.37	1.32	1.27	1.22	1.17	1.12
Path – in.	-1.5	0.5	1.4	1.2	-0.3	-3.3	-7.7
Max Ordinate 3″ Point Blank Range 215 Yards

Hornady 117 Grain SST
Yards	0	50	100	150	200	250	300
Velocity – fps	2836	2717	2602	2489	2380	2273	2169
Energy – ft.-lbs.	2089	1918	1758	1609	1471	1342	1222
Momentum – lbs-sec	1.47	1.41	1.35	1.29	1.23	1.18	1.12
Path – in.	-1.5	0.6	1.5	1.1	-0.7	-4.0	-9.1
Max Ordinate 3″ Point Blank Range 214 Yards

Winchester 117 Grain Round Nose
Yards	0	50	100	150	200	250	300
Velocity – fps	2735	2553	2379	2212	2052	1899	1754
Energy – ft.-lbs.	1943	1693	1470	1271	1094	937	799
Momentum – lbs-sec	1.42	1.32	1.23	1.15	1.06	0.98	0.91
Path – in.	-1.5	0.7	1.5	0.8	-1.7	-6.3	-13.2
Max Ordinate 3″ Point Blank Range 197 Yards

Federal 120 Grain Nosler Partition
Range	0	50	100	150	200	250	300
Velocity – fps	2675	2563	2454	2347	2243	2142	2044
Energy – ft.-lbs.	1906	1750	1604	1467	1341	1223	1113
Momentum – lbs-sec	1.42	1.36	1.30	1.25	1.19	1.14	1.09
Path – in.	-1.5	0.7	1.5	0.9	-1.3	-5.2	-11.0
Max Ordinate 3″ Point Blank Range 203 Yards

I’m not sure who at Winchester should be thanked for the round nose bullet. There are plenty of spire types in that weight range that Winchester could have loaded. Perhaps it is a hold over from Winchester producing a round nose for the old 25-35 WCF and lever action rifles? It is also a way to get to a heavy bullet by thickening its ogive without adding bullet length… or… or… it be a hold over to the old brush buster notion of round nose bullets.

Anecdotal support of the latter – Hornady’s Eight Edition reloading Manual, under 25-35 WCF data there is a comment about the 117 grain round nose bullet. “…our 117 grain Round Nose, a very deadly game bullet preferred for hunting brush and a bullet that will expand easily even at low remaining velocities.”. It is rated for 2000 to 3300 fps MV in their bullet listings… which is actually the same as all of their other 100+ grain 0.257″ bullets. Oddly, the same bullet is listed for the Roberts and Roberts AI without comment. Anyway…

Almost had a 4×4 picture….

Cold or hot barrel, the Ruger M77 Hawkeye put up the same group sizes within an ammunition type. From a steady rest and through a substantial scope: 1) Nosler 1/2″, 2) Hornady 1 5/8″, Winchester 1/2″, Federal 1″. If there was a shocker here for me it would be that ugly flying frying pan of a Winchester bullet.

No, I don’t know what’s up with the Superformance ammo and, no, I don’t think that is typical of the product as I have considerable experience with it delivering excellent accuracy. Maybe it’s just this cartridge and this rifle’s barrel harmonics? There are results here that are just… well

Personality

For as mundane as the name “Roberts” may make this cartridge sound, as opposed to,,, Fireball or Ultra, it is anything but. Recoil is modest, as is muzzle rise, but the combination has a sharp… bark. And why not? It has about the same case capacity as a 308 Winchester hot rodded down to 25 caliber.

Very nice rifle, very balanced combination with a lot of versatility. All things preferable in a hunting rifle. For more information, check in at Ruger.Com.

1) The Handloader’s Manual of Cartridge Conversions – Donnelly & Handbook for Shooters and Reloaders – Ackley

A Ruger M77 Hawkeye in 257 Roberts Part 1
A Ruger M77 Hawkeye in 257 Roberts Part 2

A Ruger M77 Hawkeye in 257 Roberts Part 2

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