Opinions on loading for Rem Rolling Block, 7x57

[flintlocke]

A late production Roller in 7mm I have acquired recently needs now to be shot. I guess it is a late one, "Remington Arms, pat date 1901", Frank DeHaas says that is late production smokeless steel. The action is tight and crisp, the face of the breechblock is square with the breechface. Firing pin fits the hole in the breechblock. Main pins are tight in the action. It appears to be ready. Unfortunately, it was shot with corrosive priming, neglected, and the bore is dark, with some light pitting. Bad enough I suspect cast bullets will be a heartbreaker.
I made a crude chamber cast and the neck is slightly oversize, and of course the shoulder is a few thou longer than SAAMI specs. To address this, I reformed to 7x57, annealed GI .30-06 brass to headspace correctly and a little extra neck thickness will help the generous chamber.
So, finally to my questions:
Is there any reason I can't/shouldn't concoct a load of slow burning 4831 shoving 175 gr jacketed round noses to original velocity, circa 1900's, to match the sights? I think Guru John Taylor mentioned the action is capable of 50,000...which seems way over what would be needed for 175's at 2,100 fps.
Is there a GC bullet style, lube, alloy that might just work in a rough bore...something that could be pushed to 2,100 ish?
Is there any point to firelapping? I did thirty or so strokes with some 400 Clover compound...with noticeable improvement in appearance, and a much smoother 'push' with a tight dry patch. Thanks flintlocke.

[marlinman93]

A late production Roller in 7mm I have acquired recently needs now to be shot. I guess it is a late one, "Remington Arms, pat date 1901", Frank DeHaas says that is late production smokeless steel. The action is tight and crisp, the face of the breechblock is square with the breechface. Firing pin fits the hole in the breechblock. Main pins are tight in the action. It appears to be ready. Unfortunately, it was shot with corrosive priming, neglected, and the bore is dark, with some light pitting. Bad enough I suspect cast bullets will be a heartbreaker.
I made a crude chamber cast and the neck is slightly oversize, and of course the shoulder is a few thou longer than SAAMI specs. To address this, I reformed to 7x57, annealed GI .30-06 brass to headspace correctly and a little extra neck thickness will help the generous chamber.
So, finally to my questions:
Is there any reason I can't/shouldn't concoct a load of slow burning 4831 shoving 175 gr jacketed round noses to original velocity, circa 1900's, to match the sights? I think Guru John Taylor mentioned the action is capable of 50,000...which seems way over what would be needed for 175's at 2,100 fps.
Is there a GC bullet style, lube, alloy that might just work in a rough bore...something that could be pushed to 2,100 ish?
Is there any point to firelapping? I did thirty or so strokes with some 400 Clover compound...with noticeable improvement in appearance, and a much smoother 'push' with a tight dry patch. Thanks flintlocke.

Personally I would never push even a later smokeless action Roller to pressures that high! I think most feel that 30,000 psi is fine, and maybe push them to 35,000 psi.
I prefer 4198 as it operates at lower chamber pressures, and gives my loads very tight groups, and low deviations over the chronograph.

[flintlocke]

Thanks for the comeback.
No, no, I had no intention of pushing pressures up. I just quoted the 50K as an indicator of the action's steel and design strength. With our modern powders and published pressures it shouldn't be too difficult to duplicate turn of the century military load velocity with a large margin of safety. As a matter of fact Frank deHaas claims many 1902 Rollers were rebarreled to .257 Robts., lol, that's a little scary.

[RustyReel]

As a matter of fact Frank deHaas claims many 1902 Rollers were rebarreled to .257 Robts., lol, that's a little scary.

I have one of those. But, I never load hot.


And a 219 Zipper Imp around here somewhere

[ascast]

Not sure of the dates, but I have one of those, minty, and it is an oversized base. Cases last about two shots with full power loads before head separation.( with full resizing) You might want to look into that base demention before rolling up a bunch of loads. good luck

[flintlocke]

Thanks, I noticed the wide chamber mouth and had hoped by using GI '06 brass at .473 instead of 7x57 at .470 I would get away without case head ruptures. Maybe I'll even have to go to 6.5 Swede brass at .477.
I can see why a lot of guys just gave up on the original and rebarreled.

[marlinman93]

Frank DeHaas is one of my favorite sources for rolling Block info, but some of the guns he built, or knew of are sketchy as to chamberings he did or others did. As much as I admire his work, I've often found myself questioning some of his choices.

[Bigslug]

My experience is slightly secondhand, and a sample of one, so take it with a hefty chunk of salt...

My Dad tinkered with one and eventually got it to shoot, but ended up naming the rifle "Job" in the process. Took several attempts at a custom mold as I recall, which ended up being significantly oversize to what we think of as normal 7mm diameter. I came away with the impression that Remington was still feeling their way with the transition from black to smokeless, and left an amount of space in the chamber appropriate to working with black powder fouling in a military environment. . .even though that was not what they were shooting anymore.

So, even after you get the gak scrubbed out to the degree possible, it's definitely one I'd do the full round of pound casts, bore slugs, pin gauge, etc... on before ordering a mold.

[flintlocke]

Bigslug...LOL....a rifle named Job. Love it.
My bore is so bad, I think cast is a forlorn hope at best. If I can get jacketed to perform to some degree of accuracy, I might try cast.
Nobody responded to my third query in the OP...firelapping...anything to be gained there?

[atr]

4831 shoving 175 gr jacketed round noses to original velocity,

I use this combination a lot with my RRB #5....no problems, no issues....the action on my #5 is tight, no slop and locks up tight
the throat on the RB can accommodate that large weight RN slug
shooting cast also works well with the heavier and longer gas checked slugs

and yes I have also used resized GI 30-06 brass in lieu of standard 7x57 brass

[JHeath]

I have one of those. But, I never load hot.


And a 219 Zipper Imp around here somewhere

When were those .257s made? I'm curious about whether it might explain the oddly low factory max pressure for the cartrdge. The assumption I have seen was that (perhaps) Remington was worried about existing small ring Mausers chambered for the wildcat, plus the issue of wildcat variants. The issue has been a bit of a mystery.

But if RB .257s were a "thing" that would explain it.

[leadman]

From my experience with one of these I owned long ago and other posts on the various forums it seems like the long chamber is the norm. 8mm X 57 has the shoulder farther forward so might reform easier to a long 7X57. I use it for my 7.7X58 brass.
My rifle had BATJAK stamped on the buttstock. Was told it was John Wayne's movie company.

[Bigslug]

Bigslug...LOL....a rifle named Job. Love it.
My bore is so bad, I think cast is a forlorn hope at best. If I can get jacketed to perform to some degree of accuracy, I might try cast.
Nobody responded to my third query in the OP...firelapping...anything to be gained there?

What firelapping will do for you is scour more at the chamber end, and less toward the muzzle as the bullet gets compressed. This could be a positive in that you'll end up with a very slight tapering of your bore that will cause your bullets to grip tighter / seal better as they get farther down the tube.

Given that you're already addressing the oversize headspace and throat with custom brass and presumably neck sizing, I'd probably keep firelapping as another stone you can throw at the problem. My order of progression would go something like this:

1. Will it shoot with jacketed? Given the throats, I probably would start with 175 grain round noses and seat them just off the lands. If that doesn't deliver, it probably won't play well with cast.

2. Will it shoot with cast using bullets from an on-hand mold? If no, it could be the barrel pitting, but it could be a throat fit issue.

3. Seek out samples of cast bullets that might fit without having to risk a mold purchase finding out.

4. I'd probably fire lap BEFORE checking measurements preparatory to ordering a custom mold.

5. Stand by to re-barrel, because at the end of the day, rolling blocks are FUN!