257 Roberts pet loads

[JohnD386]

I have a Browning A Bolt in 257 Roberts with a 20" barrel. I have played around with 110gr Accubonds and 115gr BTs using 4350, 4064, and H4350. COAL is 2.780. Groups are about 2" to 2.5". I was thinking about playing with COAL to see if that's keeps. Any suggestions? This gun shoots 1" groups with factory 117gr Hornady custom. This gun has me scratching my head. I am no expert and still a newbie to reloading but have great success with all of my other cartridges.

 

[DrMike]

If standard deviations are less than 1%, it would indicate that adjusting OAL will give you the accuracy you seek.

 

[Oldtrader3]

My .257 Roberts is a full length magazine and is freebored to allow seating to a COAL of 2.920 with a 24 inch barrel. I shoot the 110 Accubonds with Hodgdon Hybrid 100 V. However I am not getting good results with this rifle and the 110 AccuBond using the long COAL. With the 85 and 100 grain Nosler's, this rifle easily shoots between .5 and 1 MOA at 100 yards. I need to shorten my loads somewhat for this 110 AB bullet. The Accubonds seem to shoot better with a shorter COAL, shorter even than the 2.780 SAAMI COAL because I have factory Nosler loads for the 110 AB and they are not that accurate in my rifle.

 

[bobnob]

If all else fails you could trade your current stock of bullets for some of the Hornady Interlocks, as they seem to work well in the factory ammo. Its worth trying different seating depths or varying the charge weights first though imo.

 

[Oldtrader3]

I have some Hornady Interlocks in .338. They are not as accurate as Partitions, if you weigh them and not nearly as accurate as Ballistic tips. I am pretty consistently shooting close to 1/2 inch groups with the Ballistic Tips, no reason to change!

 

[JohnD386]

Best I can get in the factory magazine is 2.792 OAL. I'll try them at that length and see what happens. If that does not work I may try 100gr Partitions.

 

[Oldtrader3]

The 100 grain Partitions are great for accuracy and kill game very well. Problem is that I can shot the AccuBond's 110 gr 100 fps faster then the Partition's 100 gr. It does not make sense?

 

[truck driver]

If you can find it mine likes 760 Win ball powder. I've tried the longer grain 4350s in the Roberts and have found the shorter grain powders give the best performance. IMR 4895, IMR 4320 and Win.760 give me the most accurate loads with commercialy available powders. There are some custom blends that work well also but unless you are a chemical engineer I would not try to blend my own powders. My rifle was custom barreled in the late 70s using a 1-12 twist 26" Douglas XX air guage barrel and likes everything from 117gr round nose to 75gr hps. with the 100gr Hornaday Spire Points being the most accurate.

 

[wildgene]

...try the 120gr. Sierra HPBT GameKings...

 

[Oldtrader3]

I have been working with Hybrid 100V but no results yet. I also want to run some handloads with IMR 7828 SSC before I decide which powder is best for the 110 AccuBond.

 

[Bruce Mc]

My Bob had always performed best with very slow powders like H4831 and Reloder 22. My first "good" load was the 117 Sierra SBT with H 4831. It my very well be a good choice for you because it is a much shorter bullet than the Noslers. It will load a shorter OAL for your shorter magazine length but still likely give you some flexibility for distance off the lands. I do not believe the shorter throats and magazines in some rifles are a negative for the Bob. You just have to load em different.