For those that shoot a .257 Roberts..re: powder

[rifleman]

Two points: remember, the group size right @ the muzzle would of course be VERY impressive! At 25 yds, a lot of things have yet to sort themselves out. A bullet that close in could not yet stabilize or worse; de-stabilize. That 100 yd range is a good starting point, but then take it out to 250 or so.

Having said that, I initially had good accuracy, but not such luck with the velocities I'd hoped to see, with 4350, in my similar-case-capacity 250-3000 Ackley Improved, with 100 gr and even 117 grain bullets ,at about 3100 and 2900 fps respectfully. I'll have to go and find my other Alliant Reloader powder loads, since they did a lot better, they always have in most of my rifles. Very consistent powders. And the newer Varget will likely work very well; it leaves no residue and is very temperature independent.

As for pressure increases: many of the original re-chambered rifles in .257 Roberts were based on rechambered but questionable or older military rifles, which may have been being case-hardened by "Fritz" when zah bombs vehre falling out of those pesky B-17 hordes above it all, undt vhen he thoughtfully ran for "zah bombé shelter"! So they may have "variable" metallurgical strength.

Now if you have a modern Ruger or converted Rem 700 or Win 70, then you can safely up the load pressures from the original Roberts 48 - 50k psi up into a still-safe 52 - 54k range. This means slower powders. That's also the only advantage of an Ackley, BTW: not so you can happily magic-jack the pressures way up, but rather so you can place more of a slower, longer-acting powder behind a bullet. (They also tend to work well with a longer bbl, if you can afford to re-barrel your favorite smokepole) (Powders like the new consistently-controlled burn rate RL-17, BTW. So far, I've gotto experiment more with that one...)

As in: Longer push=more velocity. The action was not made any stronger by Ackley-izing it; it just increases case capacity. I personally know of one chump who, upon rechambering his Mauser '06 to a 35 Whelen Ackley Imp, proceeded to load 'er up with a nice fast-rate powder but then he blew the rifle apart quite convincingly on the second-only round that he ever fired in it.

He shoulda noted the complete case separation of the first round, right at the base, on a first-load cartridge, but Noooooooo... he always said "there's lots of safety margin engineered into these rifles!" Yup; there is, but I'm betting he'd moved his special loads up into the 70k+ psi range. and the Mauser just wouldn't take it! And told him so. Lucky he didn't also suffer some base separation himself!

Go slow, read a lot, and experiment a bit, but always carefully. I'll try to find some RL-17 info, and also my Alliant loads for yah later today!

PS: I also do commercial custom reloading, and then you start to really think about liability and safety, since you don't want to blow your customer's grandson's arm off down at the public range, now do you? All to prove some magic über-velocity theory?

Take Care, and Shoot Safely! YrHmblSrvnt: rifleman™

[rifleman]

Here's my experience with loads in the .257 Roberts.

Try the Alliant RL 19 and RL 22 powders for sure! As noted above, they do burn extra-clean and provide excellent pressure characteristics. Note: only use the RL 22 powders on the lighter 90 & 100 gr bullets: it burns too slowly for bullet weights over 100 grains.

BTW, this data assumes you have a bbl length of about 22". A 24" bbl will return a possible additional 40 to 60 fps.

90 gr bullets:

Start @ 46 gr RL 19, or 47 gr RL 22; ≈ 2900 fps.

Work up to max 49 gr RL 19, or 49 gr RL 22 for ≈ 3050 fps.

100 gr bullets:

Starting: 47 gr RL19 ≈ 2900 fps

Max: 49 gr RL 19 ≈ 3000 fps

Starting: 47 gr RL 22;

Max: 49 gr RL 22 ≈ 3050 fps

110-117gr bullets:

Starting: RL 19: 45 gr = 2800 fps;

Max RL 19: 47.5 gr, for ≈ 2840 fps.

120 g bullets:

Start: 44 gr RL 19 ≈ 2650 fps.

Max: 46 gr RL 19 ≈ 2800 fps.

All purt-good 'nough for elk work!

BTW, the .257 Roberts Ackley will do this with those same powders:

100 grain bullets:

Max load: 51.5 gr RL 19: 3120 fps.

117 gr bullets:

Max loads: 50 gr RL 19: ≈2920

120 gr bullets:

Max 49.5 gr RL 19: ≈ 2890 fps

Also quite Elk-effective! The Ackley obviously provides about 100 to 120 fps more velocity, but also prefers a 24" bbl.

NOTE: the author is not responsible for possible data inaccuracies listed here I'm tired and a bit sleepy tonight! The reloader thus takes full responsibility for correctly assembling and firing these loads. If anything looks "odd", stop and PM me or check with others!

Loads may react differently in each rifle; it's the full responsibility of the shooter and handloader to take all reasonable precautions and also to thoroughly inspect & clean his rifle before testing any reloads.

It's also strongly suggested that you consult a commercially published hand-loading manual, such as the latest Hornady or Sierra publications, for comparative loads and velocities. You may not achieve the velocities listed here or in a manual, but do not exceed max listed loads in search of some "magic velocity" loads!

Always be on the lookout for signs of excessive pressure (flattened primers, bulged cases, cracked case necks, action hard to open, etc.)

(There! That ought to make the lawyers unhappy if you blow your nose off.)

Enjoy!

[NICKG914]

I own a 257 roberts and improved version ,i found for light varmint bullets 75 grain i use varget powder only 49 gr,improved and 47gr in the original , all very accurate v max, sierra , velocity 3500 and 3700 respectfully . For the heavier bullets i go with h4350 47 gr, 115 barnes tsx in the improved version ,it will do the job like you would not believe on deer size game .i use fed 210 or wolf primers