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Thread: 3800 fps, 110gr Accubond, 257 Wby

  1. #1
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    Default 3800 fps, 110gr Accubond, 257 Wby

    Those in the know will know...the only way to achieve this is if something goes wrong. Well, I got close (3785fps) and something IS wrong. Let me tell the tale.

    I've been working up loads for my 257 Wby for several weeks. I've gone through four different powders and 3 different bullets, and shot about 200 rounds. About 2 weeks ago I figured I had arrived when I shot two consecutive, side by side 3 shot groups that you could have covered with a dime. As a matter of fact, even though there was 1/2 grain of powder difference between the two sets of three, had I shot all six bullets at the same spot you still could have covered the six-shot group with a dime. The magic combination was 72.5 grains of RL 25 behind a 110 grain Nosler Accubond, which yielded about 3550 fps. A little on the warm side, but no pressure problems. Although the Nosler manual lists no data for RL25 with the 110 grain Accubonds, it lists 72 grains of RL 25 as max for all of their 115 grain bullets. Since the data for the Accubonds is always the same as for their other bullets, I figured I was safe. And initially I was!

    Before I started I was down to about 1/2 pound of the one pound canister of RL 25 I had purchased this fall, so I located another pound a few months ago and poured what remained of the "old" RL25 into the new canister. I was VERY careful to make sure I was not mixing two different powders, just two different batches of RL 25. I only ever put one kind of powder on the table at a time, and I carefully checked and rechecked the lables before, during, and after. I don't recall making any special effort to shake up or mix the two batches, but I may have since my intent was to have one fairly uniform batch.

    I used about half of the RL 25 in the canister to work up loads for my 7RM, and then switched to the 257 Wby. No problems. Then, after shooting the two groups I loaded ten of bullets a 72 grains of RL 25. Imagine my surprise when I started shooting them and started seeing numbers above 3700 fps on my chronograph! Along with those numbers came blown primers and stuck cases. Same batch of primers, same cases, same canister of powder, same box of bullets, same seating depth. Outside temperatures were within 10 degrees on both days. Not a thing I can think of was different. After the third stuck casing I quit and went home, pulled the remaining bullets, and thought about it for a night.

    Before starting over I mixed the canister of RL 25 thoroughly, checked my scale with the test weights, recalibrated it, rechecked it, and carefully measured out new charges, this time of 71 grains of RL 25.

    I expected to see a reduction in pressure and speed. No such thing. More pressure, higher speed, more stuck cases. I went home early again.

    Today I went back to the range with 69 grains of RL 25 loaded with the same primers, behind the same bullets, in the same cases, with similar weather. Almost four grains less than the loads that has yielded 3550 fps and no extreme pressure signs. After the first shot the chrono read 3785 fps, and before even trying the bolt I knew I was screwed...again.

    SO WHAT GIVES? In working up loads I started at 71 grains of RL 25 and got speeds in the 3400 range and no pressure. I shot 71, 72, and 73 grains, no problems. Now I'm down to 69 grains and up to massive pressures...and speeds. If it were just pressure going up, OK, maybe a rough bore, but this is a custom Pac-Nor barrel with maybe 250 rounds through it, and it has been treated and cleaned very carefully. The only thing I can think of is that the batches of RL 25 were radically different, or that somehow the retardent is wearing off. Both of those theories seem really weak though, since certainly over seven or eight pourings into the powder measure the two batches would have mixed, and they shouldn't be THAT different to begin with. That is...unless the factory screwed up and mis-labled. Visually, I see no difference in the granules; they look like "normal" Rl 25 granules. Same shape, color and size. Also note that neither of the two cans of RL 25 I mixed was more than a year old, probably much less. I wish I had a fresh pound of RL 25 to try out, but you know how tight the powder supply is lately! I'm definitely NOT going to use ANY more of this canister, unless one of you can shed some light on this.

    Frankly, I'm stumped. Ideas?

  2. #2
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    Default Ideas????

    Hard to say... I suscpect we'll read a bit more detailed report in the ADN if you continue down this road.

    All jocking aside. You need to stop blending powders of dif. lots. Buy powder a couple pounds at a time and use it all up, then repeat. Also it sounds like you did a poor job of working up a safe load. Maybe I am coming across a little harsh, but it sounds like some of your basic reloading fundamentals are a bit lacking.

    Be safe, and keep your nose in the books,
    Jake

  3. #3
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    Default

    This is an interesting story. I'm not sure what is going on with your .257WBY handloads, but I do know where I'd start...

    One thing that you have learned is that mixing together powders of different lots has added a new variable to consider and now you must rule it out. IMO the primary goal of handloading for accuracy is consistency and uniformity within the batch from one finished case to the next. Consistency and uniformity is compromised when mixing lots together. Although I personally don't mix lots of the same powder, mixing lots can and reportedly does make a difference. Does it make the kind of difference you're describing? I don't know for sure, but I suspect not. However, I consider mixing lots to be poor practice when striving towards accuracy (which requires consistency and uniformity). Take a look at your situation...whether the fact that you mixed lots together made a difference or not, you now have to rule it out.

    I suggest that you wait and see what others have to say. They may offer hypotheses to explain your pressure differentials. Either way, I encourage you to stop mixing lots when seeking accuracy, wait until you acquire a new pound of RL-25 ("non-homogenized type"), and start over following safe standards of practice for progressive load development. See what happens as you progressively build up, and please let us know what you find.

    Good luck sir.

    Doc

    BTW, my .257WBY really likes RL-22.

  4. #4
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    Default I wonder ?

    Is it possible that the cases streched out a wee bit and although you are using the same overall length you are getting a little more bullet to neck tension ?
    Little bullets might expand ! But big bullets never shrink !
    When you swim with big fish try not to act like bait !

  5. #5

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    This is a very interesting story and I am very puzzled by it. Sure, powders can vary from lot to lot, but this much difference seems to be way out of bounds.

    I sure wont be mixing my powders, and I will always start low with a new lot, especially after also reading a report on some newer H1000.

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    Default figured it out!

    KCasey, you nailed it! It was NOT the powder!

    I had set the 257 Wby aside after all the troubles, partly waiting to get my hands on a new batch of RL25, and partly to think about it and ask other experts questions. Then one day we have our nephews over for our youngest son's birthday, and my wife's brother mentions that his father, who is a long-time gun nut and reloader, once blew up a rifle due to case neck stretching. As he put it: "No problem on the first reloading of the brass, the second was fine too, but on the third go-round he ruined the rifle. It sounded too familiar, so I checked my brass. Sure enough, not all my cases were over max, but most were!

    I trimmed them all, and while I was at it I turned the necks just enough to even out neck wall thickness.

    Of course then I was faced with the dilemna: Do I hope that was it, and try again with the same (suspect) powder? Naturally, I was kind of spooked. I thought about it for another week, and today I decided to give it a try. I looked up the minimum load and started there, even though that's about the same amount of powder that resulted in 3800fps, popped primer, and a stuck case last time.

    My first shot: about 3400 fps. YAHOO! I worked back up another two grains and got it back to near 3500 fps with no pressure. Furhtermore, the two three-shot groups I shot were both right at 1/2". Back in business.

    What surprises me is not that I got high pressure, but how much speeds went up when the necks got long. Had it not been for those stupid-fast speeds, I might have suspected neck length earlier.

    Judging from the fact that most on here were as baffled as I was, here's the lesson we can all learn this: ESPECIALLY WITH A CUSTOM BARREL (tighter tolerances) KEEP YOUR BRASS WELL TRIMMED.

    Thanks for your thoughts, and way to go KCASEY!

  7. #7
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    Default

    Quote Originally Posted by AKArcherdaddy View Post
    KCasey, you nailed it! It was NOT the powder!

    I had set the 257 Wby aside after all the troubles, partly waiting to get my hands on a new batch of RL25, and partly to think about it and ask other experts questions. Then one day we have our nephews over for our youngest son's birthday, and my wife's brother mentions that his father, who is a long-time gun nut and reloader, once blew up a rifle due to case neck stretching. As he put it: "No problem on the first reloading of the brass, the second was fine too, but on the third go-round he ruined the rifle. It sounded too familiar, so I checked my brass. Sure enough, not all my cases were over max, but most were!

    I trimmed them all, and while I was at it I turned the necks just enough to even out neck wall thickness.

    Of course then I was faced with the dilemna: Do I hope that was it, and try again with the same (suspect) powder? Naturally, I was kind of spooked. I thought about it for another week, and today I decided to give it a try. I looked up the minimum load and started there, even though that's about the same amount of powder that resulted in 3800fps, popped primer, and a stuck case last time.

    My first shot: about 3400 fps. YAHOO! I worked back up another two grains and got it back to near 3500 fps with no pressure. Furhtermore, the two three-shot groups I shot were both right at 1/2". Back in business.

    What surprises me is not that I got high pressure, but how much speeds went up when the necks got long. Had it not been for those stupid-fast speeds, I might have suspected neck length earlier.

    Judging from the fact that most on here were as baffled as I was, here's the lesson we can all learn this: ESPECIALLY WITH A CUSTOM BARREL (tighter tolerances) KEEP YOUR BRASS WELL TRIMMED.

    Thanks for your thoughts, and way to go KCASEY!
    Thanks for the report and keep check on case OAL.

  8. #8
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    Default

    Ditto...thanks for the follow-up.

    We're always learning, and you gave a great example of pressure differentials from untrimmed brass causing inordinate neck tension. Your report of the observations and corrections were especailly instructional and helpful.

    Thanks again, sir.

    Doc

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