257 Rob Brass ?I

[OneNdone]

I recently got a Rem 722 in 257 Rob, Let me also say I'm new to reloading and this will probably be one of many questions I will have. I purchased the Lyman 50th edition handbook and read thru all the chapters on reloading. Had I done this before purchasing brass I may have done something different. So onto my question I bought some once fired mixed headstamp brass from capitol, something the Lyman manual recommended you not do. What are your thoughts on this. I know I probably need to sort these and load to there specs, is that correct? There is some Hornady +p brass and some that are stamped R . P 257 ROB who is this MFG? Does the P mean it can be loaded to +P data? I also bought some new 7mm Mauser brass from privi partrizan. I read some where it was thinner but harder brass and should be fine loaded to +p, is that correct? Where could I find load data for the privi brass?
Sorry if this got long and any suggestions on how to better post will be appreciated.

 

[Dusty Stevens]

RP is remington brass

 

[Dusty Stevens]

Welcome to the forum. Sort the brass by headstamp and keep em together. Go by the loading manual and ask a lot of questions. Best reloaders on earth are right here

 

[shoot4fun]

Well it's a get what you can get world right now so just having 257 Roberts brass is a stroke of luck.
Don't worry about it in the beginning because ruining a stick of the mixed brass won't make you cry as much as the brand new stuff.
Do as Dusty recommends and you will be fine.
Welcome to our group!

 

[NETim]

You have a classic rifle in a timeless caliber there. Congratulations!

Recollecting back to my youth and the time I spent devouring Jack O'Conner's writings, it seems the 257 was originally loaded "down" (IMR3031 had just hit the market and was the latest, greatest thing, but it's not the powder to use in the 257 as it's too fast). Then too, the 257 was usually chambered in short action rifles back then. It really needs to be in a long action so the OAL can be longer, increasing powder space, therefore boosting ballistic performance.

That's what gave rise to the +P loading of the 257. It needed to catch up to the .243. And there's no reason it can't catch the up with the 243 and 6mm.

Anyway, keep reading and follow the suggested loads, watching for signs of pressure.

Have fun with that classic rig!

 

[Orr89rocz]

. Then too, the 257 was usually chambered in short action rifles back then. It really needs to be in a long action so the OAL can be longer, increasing powder space, therefore boosting ballistic performance.

I disagree here unless you also throat the chamber longer. I have a 257 roberts and i cant load the 115-120 grain stuff very long before running into the lands. I assume mine is saami chamber. Oal remains short enough for short action. 2.88 and less mostly.
It would love more freebore and load it out some. My savage short action can handle 2.97” oal. Not sure where that puts bullet base with neck and shoulder but def would help improve powder space.

but i find my loads are well above Most book in velocity But do not seem to have any pressure signs. Im very happy with it. Its a great round when loaded to its potential

 

[Kurz]

RP stands for Remington-Peters which is the earlier headstamp for centerfire cartridges and shotgun shells.

+P is an attempt to separate loads used in modern rifles which were built using modern material and modern manufacturing which were tested to manage 58,000 PSI and higher. The original loads were represented to be used in WWI and WWII lower quality actions such as the Mauser M1916 converted to use the .257 Roberts with a lower pressure rating of 51,000 PSI.

It is all modern manufactured brass simply separated by suggested pressure to afford care when using slighter weaker actions. +P is a marketing point.

 

[SeabeeKen]

I have a 257 improved on a mauser 98 and its my favorite deer rifle. I drive it hard. PPU brass is very good brass. I use it in my 7x57AI and its on its 7th loading so it holds up well.

 

[Orr89rocz]

Couple load books say +P brass is thicker than regular roberts brass and may require less powder for same pressure. As always work your way up

 

[gdbleb]

I always wondered why Remington kept the “P” in the “RP” head stamp long after Peters was removed from the corporate ammo branding.

 

[std7mag]

Welcome to reloading the 257 Roberts!
I'm using the 7X57 PPU brass.
Simple run through a 257 Roberts full length sizing die.
I'm using it for both standard 257 Roberts, and Ackley Improved.
Both of which i'm at +P pressures, shooting everything from 75gr Varmint through 120gr Partitions.
The standard 257 Roberts really seems to shine with 100-115gr bullet weights. Although the 117gr Hornady SST is a known excellent bullet for deer & up.
With the 100-115gr bullets, Hodgdon Hybrid 100V gives great velocities.

 

[Dusty Stevens]

Couple load books say +P brass is thicker than regular roberts brass and may require less powder for same pressure. As always work your way up

I think it was more about the gun itself from what i remember. Reminding you to not use it in whatever antique gun there was back then that was a 257rob

 

[ncageneral]

Welcome to the Roberts. I have used 7 Mauser PPU brass , Winchester 6mm Rem brass, and lucked up into about 150 WW 257+P cases. I found a Browning A Bolt in 270 and had it barreled with a Bartlein with the throat cut long enough for 120 gr Speer SPBT's. It replaced the Ruger M 77 Hawkeye that refused to shoot worth a darn with every known combination of bullet and propellant known to man. Stick to the manuals for information, take your time , read alot. You will do well. Std7mag is correct about the H100V, excellent powder for the Roberts.

 

[SweaterDood]

A good suggestion for the OP is to obtain the Richard Lee manual. Everything should be used as a reference, of course, but his manual lists tested pressures for loads. This is especially useful for older cartridges that arrived on the scene at the time that smokeless powder came about.

As others have stated the “+P” moniker is to designate use in new stronger actions, rather than the actions from the late 1890s through the World Wars.

Powders in burn rate from roughly 4350 to 4831 work well.

 

[Orr89rocz]

I think it was more about the gun itself from what i remember. Reminding you to not use it in whatever antique gun there was back then that was a 257rob

That makes sense, but my latest hornady book says some cases are designed for +P pressures and have less Powder capacity.
Speer book says in 1980’s winchester made an effort to update the roberts with a stronger heavier cartridge case and increase in max allowable pressure. They called it 257 roberts +P. They mention winchester offers +P cases and remingtons are standard. So take it for what its worth. Modern guns i suppose start at min and work up.

i find reloder 23 to be awesome in it

 

[std7mag]

That makes sense, but my latest hornady book says some cases are designed for +P pressures and have less Powder capacity.
Speer book says in 1980’s winchester made an effort to update the roberts with a stronger heavier cartridge case and increase in max allowable pressure. They called it 257 roberts +P. They mention winchester offers +P cases and remingtons are standard. So take it for what its worth. Modern guns i suppose start at min and work up.

i find reloder 23 to be awesome in it

I've seen the same reference.
I've been given Winchester, Hornady, Frontier (Hornady), and Remington cases from several people. Along with the PRVI Partizan (PPU) cases i bought. Not a one has "+P" stamped on them.
Most of them i have 5-7 reloads on, plus the original firing.
Follow standard loading practices, aka start low and work up.
Your rifle will tell you when pressure is starting to get too high.
Hard bolt lift, ejector mark or swipe on the case head.

I've found data for RL26 with the 120gr bullets. Tried it. Didn't care for it.
RL19, IMR 4831, Ramshot Hunter seems the sweet spot in burn rate for them.
For my 75gr & 90gr bullets H414, W760, RL17.
And as already stated, Hybrid 100V for 100gr - 115gr bullets.

 

[Orr89rocz]

I have federal and winchester brass that all have +P on them. Curious what the weights are on non P brass

 

[RGRobinett]

If you have some, RL-17 will make you wonder why "they" keep it buried under the piles of rubbish . . . RG

 

[CaptainMal]

Been using IMR 4350 for decades. One is built on a old Mauser action, the other a Remington Mountain rifle. In both rifles the 115 Nosler- 117 gr.Hor. bullets work great with loads higher than what is shown on that copy of a loading page.

My favorite deer cartridge of all time in a bolt. My favorite ??? One of or all of my Marlin 30-30's.

 

[358WCF]

Curious what the weights are on non P brass

It may be more about better (stronger) metallurgy & a thicker web slightly decreasing capacity than weight, but here's four I dug out of the box of doom in the basement.

A piece of white/red box W-W Super not marked +P but this one may be from long after the change. Lot #003VD3 with unfired primer weighs 179.9 gr.

A piece of Super-X (pre +P Win) brass with an unfired primer weighs 188.5 gr.

A piece of Super Speed (pre +P Win) from a yellow box marked "Winchester Roberts" of 100gr. Silver Tips with unfired primer weighs 192.6 gr.

A piece of REM-UMC from a green/red Kleanbore box marked 257 Roberts Express with unfired primer weighs 188.3 gr.

FWIW, while 4350 was good, IMR4064 in the above W-W Super brass shot little tiny groups at various charge weights from c.2900 up close to 3100fps with 100 gr. Sierra spitzers & 100 gr. Ballistic Tips. That 3100fps was a warm load, & likely over what the (conservative pressure) book called for, in a 700 Classic that I wish still lived here. Start low & work up.