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Discussion Starter #1
I have a new (old stock) Browning A bolt in 257 Roberts. (actually two, one in youth model and one in full size)
I plan on using the Speer 87 TNTHP bullet though I may work up a load with the 120 SPBT for game.
I have been doing some research on the brass trying to find the best brass to use. I ran into a problem right off the bat.
The only new brass I can find is all +P brass. This brass has thicker base and walls than the original brass. (according to the information on Winchester's +P brass development) The +P cartridge has just over 1% increase in SAAMI pressure limits but has a lower internal volume due to thicker base and walls. (over 4% decrease). I would like to use new brass to work up loads but I would rather use the original brass and not +P. Since the cartridge was originally a 7x57mm case necked down to 25 caliber is there any good reason I shouldn't use it?

An extended question is whether more velocity is achievable with the use of proper slow powders at the lower pressure? As a general rule more powder of a slower burn rate in a case with more volume will give higher velocity.
I am considering H414 or H4895 as they are listed as the powders that have higher velocities with lower pressures. I use H414 in my 3006 with very good results. the case capacity to bore diameter in the Roberts is close to the same as the 3006.

The load work-up will be done in small increments starting at minimum listed loads. The chronograph I use is a LabRadar and I will measure high, low and average velocity with extreme spread and standard deviation for five shot groups of each load. The base to shoulder length will be measured before and after the new brass is fired and the case length will be held at 2.23" with overall length at 2.78". I will watch for any sign of excessive pressure as I go up the ladder. Groups will be recorded for each 5 shot load at 100 yards. I am looking for groups under MOA that are consistent over a wide range of temperatures and conditions. (as I always do)

Any helpful thoughts?
 

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7x57 brass works just fine. The Roberts is a natural for 100 grain bullets and 4895 or 4350. 4350 for heavier than 100 for sure.
 
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Just curious, does your Abolt have a 1/10" barrel?
 

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The Hog Whisperer (Administrator)
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Did you check the actual case volume? Some old Winchester .257 Roberts brass I have is identical whether stamped "+p" or not. Granted it is a few decades old.
 

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Elk Whisperer (Super Moderator)
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Any new production brass I've been buying has been Hornady anyway so whether it's +P or not I've worked with it and not worried about what Winchester or anybody else says about their brass.

That being said, work up your load according to your brass in hand and how it reacts. Just make sure it all the same headstamp, which will likely mean close enough in volume that you couldn't shoot the difference in a hunting rifle. Goodness knows I try and do it all the time in my varmint rifles and can't.

RJ
 

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The Troll Whisperer (Moderator)
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Have about 100 new cases that I bought years ago and planned on offering them to you, but upon inspection, they are all W-W and +P marked. Sorry I couldn't be of help.
 

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The Shadow (Super Mod)
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I have a new (old stock) Browning A bolt in 257 Roberts. (actually two, one in youth model and one in full size)
I plan on using the Speer 87 TNTHP bullet though I may work up a load with the 120 SPBT for game.
I have been doing some research on the brass trying to find the best brass to use. I ran into a problem right off the bat.
The only new brass I can find is all +P brass. This brass has thicker base and walls than the original brass. (according to the information on Winchester's +P brass development) The +P cartridge has just over 1% increase in SAAMI pressure limits but has a lower internal volume due to thicker base and walls. (over 4% decrease).

An extended question is whether more velocity is achievable with the use of proper slow powders at the lower pressure? As a general rule more powder of a slower burn rate in a case with more volume will give higher velocity.
I am considering H414 or H4895 as they are listed as the powders that have higher velocities with lower pressures.
As Mike said, actually measure the volume difference in Winchester brass against their +p, and you'll find a distinction without difference.

Anything you read about "Winchester" products on the "Winchester" site, is a historical thing not what actually happens anytime in the past several decades.
In the sense of design, production, and company focus; "Winchester" was Olin. They were the driver in serious design work and production of spherical powder, C260 alloy, case production, rifles, etc.
That lovely little dream began to crumble long ago, and Olin started selling off production capability and rights to use their Winchester name to various people.
Winchester branded brass is least cost bidder produced, and has come from at least 3 different suppliers in the past decade alone. Whatever magic they tell you it was on the website, it isn't anymore. Use whatever brass you want, but don't do it because of a Boogeyman story from 50 years ago.

As far as the burning rate thing, it doesn't work remotely that simply. More, slower, doesn't just magically give more speed at lower pressure. If you look up my post about FlatLine bullets, this was pressure tested out. Of the claims surrounding that product, some were about burning speeds and "signs" claims about pressure.
Like all good charlatans, they used "signs" to justify unsubstantiated claims.
The reality about the burning speed difference in that setting, was that the "fast" and "slow" powder produce the same results. Somewhere in the results you could have a technical argument about a difference, but it would be minutia and not possible with signs.

Cheers
 

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Discussion Starter #9
Did you check the actual case volume? Some old Winchester .257 Roberts brass I have is identical whether stamped "+p" or not. Granted it is a few decades old.
Mike,
I only measured the used cases I had collected but out of the 200 cases the Winchester were the smallest capacity. Other +P cases were similar in volume but to my surprise most of the cases were close to the Winchester +P but varied a lot. Remington cases have more volume than any of the others by at least 2.5 grains. (measuring to the case mouth)
Hodgdon's #25 manual has a warning to reduce listed loads by 10% for +P cases and their data has a starting load that is 1 to 1.5 grains higher than the maximum loads listed in the Speer #13 manual. If you used the starting loads from the Hodgdon manual you would see pressure signs (I did) in most of the cases. The exception was the Remington brass. They showed no bolt impressions on the case head and the bolt lift was normal.
I started segregating out the +P brass but some of the brass not marked +P was just as heavy and had similar volume to the +P brass. It was a waste of time and energy.
I did load the Remington brass to try to work with but it is well used brass so I have pretty much decided to order the 7x57mm brass and start from scratch.
 

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Discussion Starter #10
Darkker,
I know that you have a lot of knowledge but I have measured the volume of cases. I have loaded some of these cases and there is a BIG difference in the volume and the pressure they generate. This isn't just my beliefs but tested verifiable information that seems to be backed up by the loading information in the manuals and in my gun. When I first inspected my brass I found many that had impressions in the base of the cases. Some were expanded to the point they would not fit in a shell holder. After culling the questionable cases I separated the cases stamped +P and started with the others using starting loads. Some of the cases were causing hard bolt lift and showed impressions from my bolt face. Remington cases were the only ones that I didn't have problems with. The two problems were that they were used when I got them and I like to use new brass to work up loads. The only brass produced now are all +P. I am absolutely sure that I will get more powder space from the 7x57mm brass than I can with any 257 brass. Time will tell as I am going to order 200 cases today.
I will treat the brass like it is a wildcat load (as it was once) and work the loads up from low to max listed in the Hodgdon manual. That way I can see if there are any indications of over-pressure at any point in the load workup.
 

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Discussion Starter #11
Have about 100 new cases that I bought years ago and planned on offering them to you, but upon inspection, they are all W-W and +P marked. Sorry I couldn't be of help.
Thanks Kdub, you are kind to make the offer. I am hoping that the source I found for the 7x57mm cases will be around for a while.
Paul
 

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The Hog Whisperer (Administrator)
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Wouldn't it just be easier to work up loads with whatever cases are the most plentiful that you can fnd? :confused:

At the end of the day there might be all of 1 or 2 percent difference in the velocity potential, comparing the cases with the most capacity, to those with the least.
 

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Elk Whisperer (Super Moderator)
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Not a 257 Rbts, but I have a 788 in .223 that still shoots three head stamps ( Fed. WW and RP) picked at random from a 50 cal. Ammo can into 1/2 moa. Olde Granny is not picky once the powder charge is figured out.

RJ
 
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MontyF,
No, the A-bolt has a 1:9.5 inch twist. It should be fine with most of the longer bullets.
Paul
Just curious on the twist since I have seen .257s with a 1/12". Some time back there was a discussion about 25-06s having trouble stabilizing 120 grain bullets with a 1/10". My opinion it was the particular barrels that didn't like those bullets since at the time I has 3 of them that could manage respectable groups with long bullets.

All the better for that Abolt because of the added insurance of faster twist.
 

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The Hog Whisperer (Administrator)
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Right. I have three .25 cal rifles that all stabilize 120 and 117gr. bullets just fine with 1-10" twists. In fact two of them are very slightly slower than 10". I don't know that anyone claming problems with a 10" twist actually measured to see what they had.
 

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The Shadow (Super Mod)
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I have loaded some of these cases and there is a BIG difference in the volume and the pressure they generate. This isn't just my beliefs but tested verifiable information that seems to be backed up by the loading information in the manuals and in my gun.
Nice try. We aren't doing a reboot of the Illuminati conspiracy nonsense thread.

The facts are you have only misguided beliefs.
Just like the last thread, you are referencing obsolete data because of a false belief about powder. Here a 34 year old and 19 year old manual gets trumped out.
They give general cautions about what is possible, not what will be in 34 years if someone is using different components.

Next you read a historical account and caution from "Winchester" about brass. Further ignoring the fact that they haven't actually made brass in a long time, and it doesn't apply anymore. You add up all those possible cautions, and it fits the confirmation bias slot in the prayer to the alter of signs nicely.

Still doesn't tell you anything about what actual pressures are.
In This test of Sierra bullets, I also had difficult extraction and difficulty resizing one brand of brass.
Rather than cherry picking cautions and confirmation bias in "signs", I actually measured the pressure and velocity.
Another link you'll no doubt ignore for your beliefs...

I have no doubt you measured a volume difference, I have no doubt it can make a pressure difference. I doubt very much that it matters as much as you are pretending it does.
 

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Discussion Starter #17
Darkker,
Well since I have actually looked at the manuals, loaded the rounds and gotten the results I have more of an idea what the results were than you do. Your test was the difference between two bullets in the same 243 brass it has no correlation to the test that I did in my rifle. I am using the same bullet in different cases, all sized the the same base to shoulder length in the same die, all seated to the same OAL, using the same powder and primer.
The Hodgdon manual (#25) says the starting load is 46 grains of H414 and a maximum load is 50 grains. The caution at the bottom of the table says "CAUTION: Reduce this data 10% when using +P Winchester brass."
The Speer manual lists data for 257 Roberts +P and has a starting load of 42 grains of H414 and a maximum of 46 grains. The Remington cases did not experience hard bolt lift or imprints of the bolt face on the cartridge head even at 47.5 grain loads while the Winchester, Federal, and others showed hard bolt lift and or bolt face impressions on the head of the case at 46 grain loads.
Since you have obviously no experience with these cartridges you are the one pretending to know more than you do on this subject. When you have actually tested the data please feel free to comment. Until then don't try to belittle my research, experience or my personal results.
You are right about me not knowing actual pressures but as a result of that I stay away from loads that leave imprints of the bolt face on my cartridges and have hard bolt lift after firing. Those are uncharacteristic in my rifle with factory loads.
 

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Shooter Paul-- It would be interesting to measure base to shoulder (headspace) on those case before firing. OLD Western brass is 'longer' in that dimension than newer brass and R-P is shorter than R-P+p. Or at least the batches I've measured. The same holds true with 6mm Rem factory loads and brass. That's (another reason) why I resize 7x57 brass to 'zero' HS in my guns. I'm with you. I don't need numbers if I have the brass speaking to me.

The Roberts is as perfect an all-round North American big game caliber that's ever been made, IMO. Light enough for women and kids and big enough for elk and moose with good shot placement. I wish I had back the Model 30S Roberts. :(
 

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The Shadow (Super Mod)
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1) Well since I have actually looked at the manuals, loaded the rounds and gotten the results I have more of an idea what the results were than you do.
2) Your test was the difference between two bullets in the same 243 brass it has no correlation to the test that I did in my rifle. I am using the same bullet in different cases, all sized the the same base to shoulder length in the same die, all seated to the same OAL, using the same powder and primer.
3) The Hodgdon manual (#25) says the starting load is 46 grains of H414 and a maximum load is 50 grains.
4) The caution at the bottom of the table says "CAUTION: Reduce this data 10% when using +P Winchester brass."
5) The Speer manual lists data for 257 Roberts +P and has a starting load of 42 grains of H414 and a maximum of 46 grains.
6) The Remington cases did not experience hard bolt lift or imprints of the bolt face on the cartridge head even at 47.5 grain loads while the Winchester, Federal, and others showed hard bolt lift and or bolt face impressions on the head of the case at 46 grain loads.
7) Since you have obviously no experience with these cartridges you are the one pretending to know more than you do on this subject. When you have actually tested the data please feel free to comment. Until then don't try to belittle my research, experience or my personal results.
You are right about me not knowing actual pressures but as a result of that I stay away from loads that leave imprints of the bolt face on my cartridges and have hard bolt lift after firing. Those are uncharacteristic in my rifle with factory loads.
1) An Idea, not a known high pressure situation. It's an important difference you confused earlier.
2) Clearly you still aren't reading links. It is correlated in that there was different brass, loaded with each type of bullet. Sign's tell you something is different, not WHAT is different.
3) The Manual which is 34 years old, doesn't tell you anything about the powder back then, nor what it is currently.
4) Fine for brass actually built by Winchester 34 years ago. You follow a brass caution, but pretend powder and components don't change. That's playing both sides.
5) The 19 year old manual, which doesn't have the caution or maybe is specific to the +P situation. If holding your belief of that powder doesn't change, the load difference doesn't math out.
6) Another link and tons of threads you've ignored is that Federal cases are known to be soft. Further since the pressure testing of Ackley's charlatan claims in the 1950's, it's well known that "Signs" aren't reliable or accurate indicators of pressure. No doubt you have signs of brass problems, but the much more reliable indicator of actual pressures; you continue to keep a secret.
7) The entire point isn't belittlement, it's education. Yet you continue to hold on to false beliefs of "Signs" and unchanging components. When shown info or data explaining things don't work that way, you continually ignore them or cherry pick certain things out of context.

Have I pressure tested the Bob? No, on that we are on equal footing.
The difference is that I have pressure tested very similar sized cases, and a bunch of different sized cases. Similarly I have read a bunch of pressure testing about various cases including the volume and pressure differences in the 5.56 Nato, over the dropped primer issue. I understand that, while case volume can very well lead to some large pressure swings, you will never understand what is actually happening by relying upon "signs".
 

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The Hog Whisperer (Administrator)
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Paul, do us all a favor a take say 5 each of the Rem, Fed, and Win brass, and measure the FIRED capacity in grains of water. 5 each won't take long and that will give some confidence in what is happening, with regards to case capacity. That will go a long ways to figuring out if you really have a serious discrepancy in brass volume, or if one or the other batches is soft.
 
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