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Thread: shooting a 7mm Mauser Remington Rolling Block Model 1902

  1. #41
    Boolit Mold brian1's Avatar
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    Quote Originally Posted by vzerone View Post
    Maybe deer kills?
    That's my guess, as I see no evidence anywhere on the rifle that it was military.

  2. #42
    Boolit Mold brian1's Avatar
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    I fired it, unexpected results

    Well, after getting all my brass cut down and annealed, I formed a couple and trimmed them to 2.255". I loaded one up with a 175 gn RN Hornady over 20 gn IMR 4198. My Speer loading book from 1979 was the only one that mentioned a reduced load for old guns. They said 22.0-26.0 of 4198 for the reduced load, and said that should give me 1633-1915 fps. I initially seated the long bullet WAY out, like only about 1/3 down the neck, just to see if it would touch the lands when I chambered it. It did not. I decided to think about bullet jump distance later, and seated it to just short of the cannelure, which was about 80-90% of the way down the neck.

    I fired it this morning. The chrony said 1336. All seemed fine, but when I ejected the case, I was surprised that one side of it was all blackened. I've never seen this before, so I really don't know what it means. It certainly appears that gases were going back, but not all the way to the head. It also didn't blow the case out much, as I can still see impressed in the neck how far the bullet was seated. I could add a couple grains of powder, to bring it up to the starting load; I just wanted my first shot to be very conservative.

    Before I go any further with this, I'd like to hear your opinions on my observations, especially the blackening. The fact that the charge didn't even fully blow out the neck may be because I started a bit under the starting load. But I don't want to add more powder until I know what's up with the blackening and if it's safe to continue. These cases were all tumbled overnight, and were all shiny and like new before I fired.

    Clean side of brass:
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    Closeup of neck:
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    Blackened side of case:
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    Closeup of blackened side of neck:
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    It's pretty clear how far down the bullet was seated, and it didn't expand the neck at all, other than where the bullet expanded it.

    I annealed before forming; should I have also annealed again after forming?
    Last edited by brian1; 11-19-2017 at 03:56 PM.

  3. #43
    Boolit Master marlinman93's Avatar
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    It means one of two things (or both). It is usually a sign of too little pressure and the case isn't sealing in the chamber. It can also be caused by brass that's too hard and might need annealing. I'd up the charge first, as 1336 fps is pretty low for the bottleneck 7x57 cartridge.
    Might consider a little faster burning powder also to bump the pressure up.

  4. #44
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    Quote Originally Posted by brian1 View Post
    That's my guess, as I see no evidence anywhere on the rifle that it was military.
    It's possible that it was used during the long period of 20th century revolution in Mexico.

  5. #45
    Boolit Master Texas by God's Avatar
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    The brass did not seal against the chamber wall. More powder is needed badly.

    Sent from my SAMSUNG-SM-G930A using Tapatalk

  6. #46
    Boolit Mold brian1's Avatar
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    Well, I loaded up a couple more. One with 22 grains of IMR 4198, one with 22 grains of AA 5744. My chrony didn't record the first shot with 4198. It opened up the neck more fully than the last time, but not completely, and there was only a small amount of blackening on the neck. On the second shot, with 5744, I recorded 1650 fps, less blackening than the 4198, and it fully opened up the neck. Maybe another 0.5-1.0 grains.

    I am having a hard time understanding the whole low pressure loading thing. We use reduced loads to keep pressures low for old guns. But it appears to me that the reduced loads are done with faster powders, like 4198 and 5744. This doesn't make sense to me. I would think we'd be using much slower powders for reduced loads, not faster ones. All the more so with the long barrels in rifles like the Rem RB. It seems to me that a fast powder is going to produce much more of a shorter, higher pressure spike, that may not even last until the bullet is out of the barrel, than a slow powder that starts off slow, without a quick pressure spike, then continues burning and maintaining pressure as the volume (bullet going down barrel) increases. I suppose there must be some fallacy in this logic, as all the reduced loads I've seen recommended call for small amounts of faster powder, but I just don't see where the error in thinking is.

    Here's a simple graph I made of what I'm talking about; blue is a fast powder, red is a slow powder. Wouldn't it happen like this, and if so why wouldn't we be better off with slow powders when we want to reduce pressure, especially in a long barrel?
    Click image for larger version. 

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    Last edited by brian1; Today at 03:58 AM.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check