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Post by seancass on Apr 23, 2014 22:11:18 GMT -5
I snagged a couple pounds of AA#9 powder the other day and was wondering if it could run in the JRH. Accurate's website provides good data for big bores, including a good list of data for AA#9 and 475 Linebaugh. Curious if there is any general guidelines on converting 475 to 500. Is starting at the listed starting load prefered or a little lower? I know it's been said that the data is basically transferable, but "basically" leaves a lot of room for things to go wrong. I would be shooting this using 440gr Leadheads GC, and a 400gr Missouri bullet works slug that seats deep into the case(deeper than the 440!). Looks like something in the 21gr department would be an appropriate start, but hard to say considering the seating depth. (I can measure that length)
Thanks for any thoughts or experience share!
Here's the data from Accurate:
475 LINEBAUGH
Barrel: 8.0” ¦ Twist: 1-18” ¦ Primer: CCI 350 ¦ Bullet Diameter: 0 .475”
Case: STAR ¦ Max Case Length: 1.400” ¦ Trim Length: 1.390”
ACCURATE NO. 9
275 BARNES XPB 27.9 1,559 31.0 1,732 48,540 1.814
325 HDY XTP 27.0 1,430 30.0 1,589 49,340 1.739
400 HDY XTP 21.2 1,227 23.5 1,363 48,610 1.739
355 (L) TS WFPGC 26.1 1,436 29.0 1,596 49,010 1.775
375 (L) CP LFNGC 23.9 1,356 26.5 1,507 49,940 1.740
395 (L) CP WFPGC 22.0 1,290 24.4 1,433 47,890 1.794
405 (L) MTB KSPB 21.4 1,258 23.8 1,398 49,600 1.821
410 (L) CP WFNGC 21.4 1,253 23.8 1,392 49,900 1.739
420 (L) CP LFNPB 20.9 1,228 23.2 1,364 49,690 1.808
425 (L) CP LFNGC 18.9 1,134 21.0 1,260 43,360 1.731
Other powders of interest include Unique and 2400 for the same bullets. I've got H110 for the heavy stuff behind the 440, looking for something a little more mild. Something to stand the ground between Trailboss and H110. But this thread is mostly about the use of the new-found AA#9.
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Post by subsonic on Apr 24, 2014 5:21:49 GMT -5
The .500jrh has a little more case capacity than the .475.
The same weight of bullet will take up less case capacity in the .500 when compared to the .475 because it won't be as long - it will be more short and squatty. Keep actual seating depth (location of the crimp groove) in mind when considering this.
The .475 holds about 50gr of water.
The .500jrh holds about 55gr.
The .500S&W holds about 65gr.
Doing simple ratios of capacity will get you real close to the correct charge. You can extrapolate from .500s&w data too, but be very cautious.
In general, you SHOULD be able to SLIGHTLY exceed the max listed charges for the .475 when using that data in the .500jrh.
Start low, work up. Starting loads for the .475 should be safe. I would not reduce them anymore than that with slow ball powders like #9, H110, 296.
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Post by Encore64 on Apr 24, 2014 6:30:40 GMT -5
I spoke to Jack about this when I got my first 500 JRH. Subsonic is spot on with his advice.
My experience with AA#9 shows it works great in the big magnum rounds. It is easy to ignite to boot. Sounds like you are on the right track.
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Post by AxeHandle on Apr 24, 2014 7:47:54 GMT -5
For your mild loads don't forget Trail Boss. JT wrote about it in American Handgunner. Just fill the case to the bottom of the bullet. DO NOT compress the powder. Makes for a wonderful all day shooting load.
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Post by Encore64 on Apr 24, 2014 8:12:03 GMT -5
I have used the 475 Linebaugh Unique powder data from the Speer #14 manual in my 500 JRHs. It works great and a pound goes a long way. Been around for a long time, but still works well for reduced loads.
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Post by seancass on Apr 24, 2014 9:11:52 GMT -5
Axe, I use trailboss for my light loads already, but its such a great powder I don't expect to see it in stores for a long time and I don't want to use it too fast.
Also, I'd like something in the middle. Trailboss has an impressive amount of thump when launching 400+ grs but the H110 is such a hammer. I need something between them so the H110 loads aren't such a shock to the system.
Subsonic, thanks for the great reply, really appreciate it! You too, encore!
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Post by Encore64 on Apr 24, 2014 9:51:31 GMT -5
For midrange loads try HS-6 or Longshot. Both work great. I rarely use full power loads in my 454s, 475 LB or 500 JRH.
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dmize
.401 Bobcat
Posts: 2,825
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Post by dmize on Apr 24, 2014 10:49:54 GMT -5
10 grains of 231 is a hard one to beat in my BFR.
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Post by seancass on Apr 24, 2014 11:51:30 GMT -5
I'm on the hunt for HS6 and i think 231, but have never seen them for sale.
Any particular bullet over that charge of unique? Or about anything?
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Post by Encore64 on Apr 24, 2014 12:56:44 GMT -5
I use 13.0 grn of Unique with a 400 grn cast bullet and 15.0 with a 335 grn cast lead bullet, Works great...
Keep in mind 231 and HP-38 are the same powder with different labels.
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dmize
.401 Bobcat
Posts: 2,825
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Post by dmize on Apr 24, 2014 15:46:09 GMT -5
My mistake Sean. I meant 10 grains of 231/HP38 in mine.
Changed my post.
Don't know what I was thinking.
I use it with 400 grainers in mine.
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Post by trueat1stlight on Apr 24, 2014 22:58:57 GMT -5
I've gotta say that HS6 is my "unicorn" powder. I have not been able to find it ANYWHERE in the entire Midwest, nor at any single retailer on the web. you could also use IMR 4227 for some slightly-less powered loads than H110, albeit possibly negligible in recoil intensity.
-John
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Post by seancass on Apr 30, 2014 8:56:49 GMT -5
Is AA #9 a twin to another powder? For example H110 and 296 are the same.
Does AA#9 have a renamed twin?
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Post by subsonic on May 2, 2014 5:23:43 GMT -5
AA9 isn't an exact twin.
It is very close to 2400, but a hair faster so in some applications you can't safely reach the max load listed for 2400.
I beleive Ramshot Enforcer is also pretty close, but load data is a little different.
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Post by AxeHandle on May 2, 2014 6:03:47 GMT -5
Seem that I've seen some reasonable loads for the big bore revolvers with H/IMR 4227. Doesn't it have a reputation for not having the low temperature sensitivity of H110?
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