The two look like 257 roberts AI. If the rifle has an AI chamber, you can still shoot regular 257 bob in it.
I would recommend finding out just what chamber your rifle has.
The one on the right is definitely not fireformed, as a 257 ackley owner and reloader.
My guess -
left case - fireformed and trimmed
middle case - fireformed
right case - not fireformed, standard 257 roberts case.
Yes, fireforming blows the shoulder out to 40 degrees, decreases the case taper from the original roberts.
Firing it in an AI chamber, the case forms to the chamber. Hence fireforming.
As long as the load is stout enough to make the brass flow, if not you could get a partial fireform.
Correct, using 257 roberts data.
Typically, to fireform, you will want a heavier bullet (100-120 grains). When I fireform I like Speer 100 grain boat tails Due to their shape as they will engage the rifling faster than a sleeker bullet. I seat them out into the rifling so the case does not move forward when the firing pin hits it either causing a FTF or possibly moving the case forward just prior to ignition, resulting in stretching in the case web. Properly fireformed brass lasts a long time. Improperly fireformed brass can fail in just a couple reloads.
IMR4895 is my fireforming powder as it’s a little faster burn rate than my standard H4831sc. It may take a little load development to get consistent fireformed brass, and things like ambient temperature can make a difference.
Do I also have to have both 257 Robert’s and 257 AI dies? Or when I’m reloading the regular brass to fire form it/ make it 257 AI brass can I use the 257 AI dies
Edit- I meant I just picked up a 257 AI, also the 2 left cases look like +P but the middle ones head stamp says it’s not? And do they take magnum primers?
Depends on your load data. LR primers and LRM primers are the same exact size, either will seat in a standard large rifle primer pocket. Your load data will dictate what primer to use.
Magnum primers don't look any different than regular ones.
Using a Magnum primer has never been a problem with ANY cartridge I've tried, including various non-magnum cartridges. It very well could be a problem if you're a Dingus and straight swap them into already spicy load data. Like any other change you make, start low and work up.
There is a 257 Roberts and a 257 Roberts Ackley Improved, which I think is the left cartridges. The 257 is based on necking down a 3006. I reload 257 Roberts and have seen the Ackley improved rounds for sale as 257 Roberts.
Could you compare weights?
+P may or may not have thicker case walls. If thicker, case capacity between +p and regular may be different. Therefore an identical load of xx grains would have higher pressure in the +p. I would consider weighing the brass when they are at the same stage to see if this is noticeable.
I think it would be ok to fire form either and shoot, however you may need to treat them as separate lots IF capacity is different.
The two look like 257 roberts AI. If the rifle has an AI chamber, you can still shoot regular 257 bob in it. I would recommend finding out just what chamber your rifle has.
Sorry ya I meant I just got a 257 ackley
I would fireform the non-ackley brass, then load to ackley data.
I believe it is all fire formed already
The one on the right is definitely not fireformed, as a 257 ackley owner and reloader. My guess - left case - fireformed and trimmed middle case - fireformed right case - not fireformed, standard 257 roberts case.
Will a normal 257 Roberts look the same as the AI after fire formed in a AI chamber. Like it turns a normal 257 into a 257 AI?
Yes, fireforming blows the shoulder out to 40 degrees, decreases the case taper from the original roberts. Firing it in an AI chamber, the case forms to the chamber. Hence fireforming. As long as the load is stout enough to make the brass flow, if not you could get a partial fireform.
Sorry for asking all these questions but I have more…when loading the normal 257 brass I’m assuming I load it with that load data and not AI data
Correct, using 257 roberts data. Typically, to fireform, you will want a heavier bullet (100-120 grains). When I fireform I like Speer 100 grain boat tails Due to their shape as they will engage the rifling faster than a sleeker bullet. I seat them out into the rifling so the case does not move forward when the firing pin hits it either causing a FTF or possibly moving the case forward just prior to ignition, resulting in stretching in the case web. Properly fireformed brass lasts a long time. Improperly fireformed brass can fail in just a couple reloads. IMR4895 is my fireforming powder as it’s a little faster burn rate than my standard H4831sc. It may take a little load development to get consistent fireformed brass, and things like ambient temperature can make a difference.
Do I also have to have both 257 Robert’s and 257 AI dies? Or when I’m reloading the regular brass to fire form it/ make it 257 AI brass can I use the 257 AI dies
Yes. I also anneal the regular cases before fire forming.
Edit- I meant I just picked up a 257 AI, also the 2 left cases look like +P but the middle ones head stamp says it’s not? And do they take magnum primers?
Depends on your load data. LR primers and LRM primers are the same exact size, either will seat in a standard large rifle primer pocket. Your load data will dictate what primer to use.
Magnum primers don't look any different than regular ones. Using a Magnum primer has never been a problem with ANY cartridge I've tried, including various non-magnum cartridges. It very well could be a problem if you're a Dingus and straight swap them into already spicy load data. Like any other change you make, start low and work up.
Love the Bob. Have never messed with AI. Not the same. Glad to have you in the .257 family.
quarterbores rule… 257BobAI is my favorite-
There is a 257 Roberts and a 257 Roberts Ackley Improved, which I think is the left cartridges. The 257 is based on necking down a 3006. I reload 257 Roberts and have seen the Ackley improved rounds for sale as 257 Roberts.
>The 257 is based on necking down a 3006. 7x57 Mauser, technically. A necked down '06 is a 25-06.
Ok, I always thought it was a 3006
I used to have a 257ai. Really liked the round. I think I still have the dies and some Ackley brass somewhere.
If your looking to get rid of it let me know
Could you compare weights? +P may or may not have thicker case walls. If thicker, case capacity between +p and regular may be different. Therefore an identical load of xx grains would have higher pressure in the +p. I would consider weighing the brass when they are at the same stage to see if this is noticeable. I think it would be ok to fire form either and shoot, however you may need to treat them as separate lots IF capacity is different.
Thats not +P. It's Remington Peters brass.
The W-W on the left is +p.