257 ai

[shiredude]

Hey fellas, I have a buddy who just bought a 257 Roberts that is ackleytized. He doesn't know where to start and I have never loaded for this round. Any pet loads out there? He doesn't care about a long range load yet, just somewhere to start. Maybe some 100 gr BT's? I am not sure what twist his barrel is.
Any help would be appreciated.

 

[Winchester 69]

I seem to remember a rule of thumb of increasing standard starting loads by 5%.
.

 

[308sako]

Depending upon his twist, the 100 grain bullet should have no problems at all with IMR or H 4350 or the 4831 from either manufacturer.

85/87 grain bullets best velocity: IMR 4064

100 grain : 4350/4831

110 grain Accubond R22 hands down!

115/117 accuracy 4831 or R22... power 7828

120: R22 or 7828

That's what works for me, as a side note, the 7x57 mauser brass sometimes makes the best cases. 6 Rem, 257 Bob, 7 x57 all same basic, and it is a different shell holder than the .30-06 family.

 

[Clark]

I have a 257RAI that I headspaced to 257R [mistake].
So by the time I get some brass fire formed, I have too much invested to get loose primer pockets.

So I load kind of wimpy with 42 gr IMR4895 [a lot that acts more like H322] pushes the 100 gr at 3220 fps.

 

[TAP]

I run 49.0 gn of H4350 with GM210M primers, and Nosler 100gn BT and get sub-MOA easily. Get around 3200fps with these loads. Very nice shooting rifle. I like this cartridge alot. Good luck.

 

[MagnumManiac]

Shiredude,
I have a 257AI on a Mauser 98 action and a lot of data for it.
It generally runs 100fps more than the standard 257 in a 24" barrel.
I start with max loads for the standard 257 and work up from there.
If you're not comfortable with starting at max 257 loads, although I have never run into problems doing this, you can reduce those loads by 2 grains and start there.
I ALWAYS use standard primers in this cartridge, I have had problems using magnum primers with this round.
If you would like loading data, PM me the bullet weight,brass and powder you would like to use.
I found H4350 to be one of the best powders with 100gr bullets in this cartridge, RE19 and RE22 work well with heavier bullets (110gr,115gr and 120gr.)
Cheers.
MagnumManiac.
gun)

 

[Clark]

Four of us guys got a 257 Roberts Ackley improved reamer.
We bought (4) Lothar Walther 26" light varmint .257 barrels from Brownells
RIFLE BARRELS at Brownells

Mine has shot a .45" 5 shot group at 100 meters, but averages:
0.8" average with 72 and 75 gr bullets
1.0" average with 100 gr bullets
1.2" average with 115 and 117 gr bullets.

Mine and another are on a surplus VZ24 actions.
Two others are on surplus Turkish Mauser actions.

One of the other guys is getting sub moa with the heavy bullets and not so good with the light bullets.

I don't know why, but I have noticed the heavy bullets group an inch to the left of the light bullet groups.

 

[badhabit]

I use 55gr. 7828ssc and 100gr nosler BT will shoot 10 shot groups under 1" in mine.

 

[MagnumManiac]

Four of us guys got a 257 Roberts Ackley improved reamer.
We bought (4) Lothar Walther 26" light varmint .257 barrels from Brownells
RIFLE BARRELS at Brownells

Mine has shot a .45" 5 shot group at 100 meters, but averages:
0.8" average with 72 and 75 gr bullets
1.0" average with 100 gr bullets
1.2" average with 115 and 117 gr bullets.

Mine and another are on a surplus VZ24 actions.
Two others are on surplus Turkish Mauser actions.

One of the other guys is getting sub moa with the heavy bullets and not so good with the light bullets.

I don't know why, but I have noticed the heavy bullets group an inch to the left of the light bullet groups.

My rifle is also built on a VZ24 action, they are one of the nicest and strongest of all the military actions available, I replaced the original bottom metal with an aftermarket one with a dropped floor plate and a magazine length of 3.400". It also has an aftermarket trigger and safety, 3 position Model 70 style.
Cheers.
MagnumManiac.
gun)

 

[Clark]

I like the M70 safeties.
I heard of a man stationed in Iraq who's daughter wanted a rifle, so I spent two months and built her a 243 on a Mauser auction. I sent emails with pics every night, it kept me away from the TV at night in May and June 2007. I had a great time, but I slit sawed and milled and drilled and ground until I got a $20 Chapman M70 type safety to fit. Never more, it is $30 Wisner M70 type safeties for me from now on. That extra $10 will mean allot more TV time for me.

I like VZ24s.
BIG5 had 1903 and 1938 Turks on sale often enough in 1999, 2000, 2001 for $50 + $4 WA state sales tax = $54 out the door.
I bought allot of those.
Then BIG5 in 2001 and 2002 had VZ24s on sale for $70 + $6 WA state sales tax = $76 out the door.
I bought allot of those.
Now 2008 Century sometimes has VZ24s on sale for $115 + shipping + FFL.
I have not bought any yet.

I killed 3 deer this year with 130 gr 270 at 400, 400, and 500 yards with Nosler Ballistic tip bullets.

Next year I want to use the 257RAI.
It is every bit as flat shooting, and might make a little less meat damage.

 

[WyoHunter]

My .257 Ackley Improved is built on a pre-64 Win M70 action and a Douglas Premium barrel. It loves 50 grs. IMR4350 and 100 gr. Nosler Partitions. Typical 3 shot groups at 100 yards measure 1/2" - 3/4". This is an excellent whitetail and antelope load.