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.270 Wby, 140 Accubond and Retumbo

.270 Wby, 140 Accubond and Retumbo
« on: November 28, 2017, 01:48:02 PM »
New member here.... Trying to get away from RL 22 to a more stable powder with 140 accubonds. I am definitely going to try IMR 7828 scc. I was told Retumbo is a good stable powder to try but have been unable to find a starting load in the manuals (red flag?). Hoping to find a node in the 3275-3300 range in order to keep current turret. Any help would be greatly aprreciated. Great wealth of knowledge on this site, thank you all in advance... Jay

Re: .270 Wby, 140 Accubond and Retumbo
« Reply #1 on: November 28, 2017, 03:56:28 PM »
Welcome to the nation.
 I assume you have a 26" barreled Mark V. A fairly new powder I tried in my 24" barreled 270 Bee was RL 26. I worked up to a max load of 74 grs with a 150 gr Hornady interlock. My vel was 3194 ft/sec, so I assume your goal of 3275-3300 with a 140 gr projectile is realistic. I found this powder to be fairly temp stable, but did not pursue it much, as in my rifle, the accuracy just wasn't there. IMR 7828 is also a great powder giving good velocity although not known for being as stable as Hogdon's extreme line.  I have also gotten good results in my 270 with several bullet weights with Norma MRP.

dubyam

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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #2 on: November 28, 2017, 06:00:13 PM »
Retumbo is really outside the window of ideal burn rates for the 270Wby's case capacity to bore ratio. Better choices are IMR7828ssc, H1000, RL19, Accurate MagPro, and Ramshot Magnum.

Unfortunately, unless you have some older manuals, the data currently available for most Weatherby cartridges, including the 270Wby, is dismal, at best. Consider the Nosler and Barnes data the only remotely realistic data available currently.
I believe this is a practical world, and in it I can count only on what I can earn.  Therefore I believe in work, hard work. - The Auburn Creed
The older I get, the less stock I place in what men say, and the more I place in what men do. - Andrew Carnegie

Re: .270 Wby, 140 Accubond and Retumbo
« Reply #3 on: November 28, 2017, 06:08:04 PM »
Thank you for the response.  Correct, it is a 26" Accumark. Great shooting gun for last 20 years with 150 Barnes tsx bullets and RL 22. But lately I have wanted to start practice extending my range and doing a little more 600+ yard shots (my .270 Roy deserves it. Lol) Never had a problem with Barnes on deer/elk less than 400 yards, just a little scared on their expansion performance at longer ranges. Hearing great things about Accubonds along with better BC and would like to give them a whirl with a less temp sensitive powder like Retumbo. Will start with 7828ssc, H1000 & Magpro... Thnx Jay

Re: .270 Wby, 140 Accubond and Retumbo
« Reply #4 on: November 28, 2017, 07:21:16 PM »
You are very wise to get away from heat sensitive powders as RL 22 and inconsistents from lot to lot.I found the same to be true with 7828ssc in other calibraters.Give H1000 a try.The Barnes will perform.
« Last Edit: November 28, 2017, 07:23:41 PM by terminator »
Roger
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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #5 on: November 29, 2017, 11:16:32 AM »
Another temp stable powder for you to consider is IMR7977. It is in the same burn-rate range as 7828 and H1000. I have tried all 3 of these powders with the 150 ABLR and the 145 ELDX. I found a good combo with 7977 and the 145ELDX averaging 3265 fps.
Good luck!

dubyam

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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #6 on: November 29, 2017, 12:03:18 PM »
I'd be very interested to hear more about your work with 7977. If you're not comfortable describing the work up you did here, can you PM me your email and we can chat off the board about it?
I believe this is a practical world, and in it I can count only on what I can earn.  Therefore I believe in work, hard work. - The Auburn Creed
The older I get, the less stock I place in what men say, and the more I place in what men do. - Andrew Carnegie

Re: .270 Wby, 140 Accubond and Retumbo
« Reply #7 on: November 29, 2017, 03:45:41 PM »
Thanks for the tip with the IMR 7977. Not familiar with it yet but will definitely give it a shot if 7828 or H1000 doesn't pan out. Nosler lists H1000 for the 7mm WBY 75-79 grains for a 140 grain Nosler bullet as their most accurate powder but doesn't even list it for the 270 WBY 140 grain load. Would it be safe to say the 270 WBY would have a VERY close starting point (of the 7 mm wby) for the powder charge if using a 140 grain Nosler bullet as well? Same case right?  Jay

dubyam

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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #8 on: November 29, 2017, 04:14:16 PM »
Very hard to extrapolate like that. Hodgdon lists some pretty anemic H1000 loads for the 270Wby on their site, which oddly enough run from 75-80gr for the 140gr. Peak velocity is in the neighborhood of 3250, which is a hundred or so feet per second off the normal pace of the 270Wby 140gr loadings.
I believe this is a practical world, and in it I can count only on what I can earn.  Therefore I believe in work, hard work. - The Auburn Creed
The older I get, the less stock I place in what men say, and the more I place in what men do. - Andrew Carnegie

Re: .270 Wby, 140 Accubond and Retumbo
« Reply #9 on: November 29, 2017, 11:02:46 PM »
I'd be very interested to hear more about your work with 7977. If you're not comfortable describing the work up you did here, can you PM me your email and we can chat off the board about it?

Nothing fancy really. Data is available for H1000 and 7828 and according to the relative burn rate chart I have, 7977 is the next fastest powder than H1000 and 7828 is 5 places faster than H1000.
I already discovered the Hodgdon values listed on their website were high in my rifle for H1000 charges (from 75-79 gr for 150 gr bullet) due to my previous load development with the 150ABLR. This was also reported by many others on various websites. I could only get to about 76.5 gr before pressure signs said stop.
Regardless, I found my max with that powder and did some load development with 7828 starting just under Nosler starting loads. I used this data to validate how my rifle behaves with the respective powders vs. the published values. I then did a pseudo-interpolation for the starting charges of 7977. I did the same calculation/analysis with 7977 and other popular magnum cartridges to see if the data fell in line with those published 7977 loads. In most cases 7977 charges fell between 7828 and H1000 values. This gave me confidence to safely start with the charges I calculated for 7977 in my 270WBY.
I worked up several loads with the 150ABLR (sample data attached if I uploaded it correctly) then the 145ELDX came out. I had good on-game performance with the ELDX before in other cartridges and wanted to try it in my 270WBY so I did load development for the 145ELDX with 7977 and H1000. I arrived at a more accurate load with 7977 vs H1000 and ended up loading 7977 with the 145ELDX for my hunt that starts Friday 12/1.
I leave tomorrow so if there are more questions, I will not be able to respond until I get back.
Safe shooting...............looserowels

Re: .270 Wby, 140 Accubond and Retumbo
« Reply #10 on: December 09, 2017, 12:23:43 PM »
Just returned from the range after loading up some 140 Accubonds in my .270 Roy.  Thank you to all with the powder selections... IMR7828 was the hands down winner.  5/8" groups @ 3300fps. Groups started to open up near max charge. You all were a huge help, thanks a ton!
Jay

dubyam

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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #11 on: December 09, 2017, 02:40:44 PM »
Glad to hear you had good results. You should be all set now!
I believe this is a practical world, and in it I can count only on what I can earn.  Therefore I believe in work, hard work. - The Auburn Creed
The older I get, the less stock I place in what men say, and the more I place in what men do. - Andrew Carnegie

224KING

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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #12 on: December 09, 2017, 04:40:14 PM »
Hell,with that kind of speed from a 140 who needs the 6.5-300?
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dubyam

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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #13 on: December 09, 2017, 11:03:05 PM »
Hell,with that kind of speed from a 140 who needs the 6.5-300?

That's what I've been saying for a while.
I believe this is a practical world, and in it I can count only on what I can earn.  Therefore I believe in work, hard work. - The Auburn Creed
The older I get, the less stock I place in what men say, and the more I place in what men do. - Andrew Carnegie

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Re: .270 Wby, 140 Accubond and Retumbo
« Reply #14 on: December 10, 2017, 05:00:32 AM »
Maybe what Jay is actually saying is that with his newly developed hand loads(140gr@3300)he has achieved Weatherby ballistics which are proprietary, and hand loaders aren't usually able to match Weatherby factory loads? Unless 3300fps isn't a Weatherby mythical number anymore in 270 Wby.
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