257 Roberts AI starting load with 134 ELDM's

[Philly]

Just built a Roberts Ackley 7 twist and would like some starting loads to try with these heavies if anyone has any info. I do have a new lb of Hunter that I wouldn't mind trying as well. thanks!

 

[SD guy]

Sounds like a neat project, mind if I ask what action this is built on & what brass you intend to utilize? have you looked at extrapolating 25 creed data?

 

[Philly]

Sounds like a neat project, mind if I ask what action this is built on & what brass you intend to utilize? have you looked at extrapolating 25 creed data?

I had a bad chamber in a 25-06 AI I built a while ago so I cut a couple inches off and rechambered it to the Roberts. It's built on a 700 LA. I thought about using the CM data to start but if someone has the info, I'd rather save some powder and lead working up my own load. lol. I scored 100 new pieces of Winchester 257 Roberts brass.

 

[SeabeeKen]

I have a lot of loads ive tested in 257ai but unfortunately, none with bullets that heavy

 

[LCazador]

Use any of the plus P loads in the latest Sierra manual.

 

[Philly]

I just tried 43g hunter. No pressure signs. .763” first 5 shot group wasn’t bad shooting from an eBay bipod at a box at 100. My chrono had a dead battery so wasn’t able to check velocities. I will load more with a hotter load later this week.

 

[Philly]

Use any of the plus P loads in the latest Sierra manual.

Does the sierra manual list the heavy bullets?

 

[LCazador]

I just tried 43g hunter. No pressure signs. .763” first 5 shot group wasn’t bad shooting from an eBay bipod at a box at 100. My chrono had a dead battery so wasn’t able to check velocities. I will load more with a hotter load later this week.

A 43 grain? I'm sure that's a typo but personally a think you're wasting time trying to shoot anything heavier than 115 grains. Been there done that. You need a bigger case to do that.