I am considering a Ruger M77 MkII Ultra Light in .257 Roberts. The only thing I am concerned about is the short 20" barrel. Does anyone here have any experience with the .257 Roberts in short barrels? I am curious as to what kind of ballistics I can expect. Also, some people have warned me that the twist rate of the Ruger rifles chambered in .257 Roberts is too slow to stabilize the heavier bullets. I looked it up on the Ruger website, and the twist rate is 1:10. That sounds like a pretty fast twist to me, but I could be wrong.I would love to hear from anyone who has any experience with the .257 Roberts, especially in Ruger rifles. Thanks.

My 77 is a 22" barrel.

I'm shooting 100gr. Rem PSP-CL and 100gr. Nosler Solid Base bullets at about 2900fps with 38.0gr. of Varget. That load is straight out of the Hodgdon manual, only about 45,000CUP or so and well under what the Ruger will take. It shoots good and will kill pigs, deer, javelina, and the occasional varmit so I let well enough alone and keep using it.

At 500 yards the Solid Base bullets can hit a gallon milk jug full of water. They won't expand anymore, just poke holes through it, but you can hit them :D So I'd not recommend the .257 with that combination to shoot game animals at 500 yards.

A benefit to not running your bullets at screaming velocities is not having so many issues with bullet blow up, by the way....

With book loads, the 75gr. Sierra HP goes out around 3,100fps and will dispatch prairie dogs without any issues. By chance that load shoots to the same point of impact as my 100gr. load.

Anyway I'm perfectly satisfied with the combination. Good luck.....

I have a pre-64 M70 Win in 257 Robts. The barrel is 24"
with 6 grooves and a twist of 1 in 10".

The gun shoots just fine with 1" groups, with a sand
bag rest, at 100 yds. With a better rest I"m sure I could
even improve a little.

The factory ammo has been Remington and Winchester.
Both 117 Gr. PP.

I wouldn't think a 20" barrel is much different; maybe a tad bit slower, but nothing to worry about. In fact the shorter barrel might be nicer to pack around in the bush. Don't
suspect there would be any difference in muzzle blast either.

I'm about to start a new 257Roberts project. I'm going to build one on a Mauser VZ-24 action and plan to put a 21" barrel on it. The 1-10" twist is supposed to shoot the heavier bullets better. Thus making it a perfect deer rifle setup using 100-120gr bullets. The 20-22" barrel is perfect for the Rob in my opinion. To get more speed and range in a 25 cal, jump up to an '06 or 25WSSM or WBY.

Used to own a M77 UL (tang safety model) with the 20" thin barrel. It was rechambered in Ack. Imp., but was still comparable to what you're asking about.

The rifle loved the 95 gr Nosler BT's and a loading of IMR4895. The accuracy was great for the first 3 shots from a cold barrel. Any more after that and they began to walk around the target. If you pace your shots, I think you'll really like this rifle/cartridge combo.

Ballistic performance of a given cartridge in a 2" or 4" shorter barrel is, to me, a non-issue. Yes, generally speaking, you'll lose a bit of velocity and as a consequence a bit of "flatness" in the trajectory, but even at extended ranges the energy and trajectory loss will be so minimal as to be pretty inconsequential. 100 ft-lbs and an inch or 2 at 300 yards -- no big deal.

My now-gone .257R was a Mauser M93 with a 24" Douglas Sporter barrel, 1 in 10" twist. It shot 100 gr bullets quite well, 87 gr even better and readily put 75gr Hornadys into 3/4" at 100 yds.
Bud W

JasonH, I have the Ruger M77RL MKII in .257 Roberts & absolutely love it. The twist rate is no problem for the Hornady light magnum 117 gr. SST ammo I use with sub M.O.A. accuracy at 100 yds. Now like Kdub stated, the thin 20" barrel will heat quicker than a standard sporter weight barrel. I have found that 3 shot strings with a cooling period between works well for me & in the field hunting you'll rarely shoot more than 3 shots in a row anyhow. Purchase the rifle with confidence & it'll become your favorite also.

Not a problem with these little ones; 257 Roberts, 260, 7-08, they are all good to go with a 20” pipe, you will lose about 100fps compared with a 24” and standard is a 22’ so you will lose less than would be expected! I like the 260 because I can shoot 120 and 140 gainers, but the 257 have the advantage with the lighter projectiles.
Good luck

Like everybody else said, don't worry about the twist rate, 1:10 is standard for the .257 bore. My old Ruger 77 round top in .257 Roberts with a 1:10 24" barrel would shoot well under 1" and when I had it rechambered to .257 Ackley Improved and glassed bedded it shot one load into .350"! Load it with 100 grain Barnes XLC or TSX bullets and you can take some fairly large critters. The 10 inch twist in my rebareled Remington handled the 117 grain Hornady factory light magnum loads very well averaging under 3/4" at 100 yards, and that was fire forming to Ackley Improved. Yes indeed, the Roberts is one sweet cartridge and it kills way out of proportion to it's size and lack of hype. Deer drop like they were electrocuted and varmint disappear. Enjoy!

I built my Roberts on a 95 mauser with a Adams & Bennet 21" barrel. I shoot 100 grain Noslers at 2850 fps. That's a low pressure load safe for the small ring mausers. You could do considerably better with the Ruger.

I have a 257 R made in the republic of Columbia serial number 7427. can anyone tell me about this gun and where I might find more info. Thanks, I'm a brand new user but have put this site in favorites so I'll be back. Thanks in advance for any help.

Sounds like a customized Columbian military Mauser. Used to be a 7x57mm chambering. The 257 R (Roberts) is this cartridge case necked down to accept 257 bullets.

Like everybody else said, don't worry about the twist rate, 1:10 is standard for the .257 bore. My old Ruger 77 round top in .257 Roberts with a 1:10 24" barrel would shoot well under 1" and when I had it rechambered to .257 Ackley Improved and glassed bedded it shot one load into .350"! Load it with 100 grain Barnes XLC or TSX bullets and you can take some fairly large critters. The 10 inch twist in my rebareled Remington handled the 117 grain Hornady factory light magnum loads very well averaging under 3/4" at 100 yards, and that was fire forming to Ackley Improved. Yes indeed, the Roberts is one sweet cartridge and it kills way out of proportion to it's size and lack of hype. Deer drop like they were electrocuted and varmint disappear. Enjoy!

Once you re-chambered to .257 Ackley Improved can you still shoot factory .257 ammo?
If so, I am going to have my 700 Mtn Rifle re-chambered and then start reloading.

Yes, you can still fire standard 257 Rob'ts cartridges in an AI chamber. That's how you fireform cases for reloading. There's a slight velocity loss when doing so, somewhere around 100 fps in my former Ruger M77 Ultralight, as I recall.

Short barrels make sense only to reduce weight. Is weight more important to you than using all the powder in the cartridge?
-Ed

Here's my 700 Mtn Rifle chambered in .257 Roberts.
I'm going to refinish the stock and slap a scope on it for this years deer season in SC.
http://i172.photobucket.com/albums/w22/WFR11B/RemJun07019.jpg