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Reloading Berger Bullets


257 ai

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Unread 11-12-2008, 10:38 AM
Silver Member
Join Date: Aug 2007
Location: Oklahoma
Posts: 170
257 ai

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.
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Unread 11-12-2008, 04:52 PM
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Join Date: Mar 2007
Posts: 430
Re: 257 ai

I seem to remember a rule of thumb of increasing standard starting loads by 5%.
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Unread 12-03-2008, 09:42 PM
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Join Date: Aug 2004
Location: LV NV
Posts: 59
Re: 257 ai

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.
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Unread 12-03-2008, 11:18 PM
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Join Date: Oct 2006
Posts: 652
Re: 257 ai

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.
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Unread 12-21-2008, 01:10 AM
TAP TAP is offline
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Join Date: Jan 2008
Location: Central Az.
Posts: 152
Re: 257 ai

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.
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Unread 12-23-2008, 06:22 AM
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Join Date: Feb 2008
Posts: 994
Re: 257 ai

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.)
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Unread 12-23-2008, 12:00 PM
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Join Date: Oct 2006
Posts: 652
Re: 257 ai

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.
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