6.5/300 Rum load Help

Trig

Active Member
Joined
Dec 15, 2013
Messages
29
Location
Central NSW Australia
I have just bought a 6.5/300 Rum and looking for some people with experience with this chambering to help me out here.

I live in Australia so dont have access to the slow burning ball powder in the American market...

I know that powder bridging is a problem with cases this large and steep shoulder angles.

The case still has a 30 degree shoulder so i am hoping the powder bridging will be minimal as the only powder i can get that is even remotely suitable is ADI AR2218 powder wich is similar to Hodgdon 50BMG which is slightly slower then AR2218 as far as i can tell.

My plan is to run 120-129gr bullets out of this case.

Anyone got any experience with this combination?

Regards Sam.
 

jfseaman

Well-Known Member
Joined
Apr 8, 2012
Messages
4,171
Location
California Central Coast
Be safe, I recommend QuickLoad as a tool.

Cartridge : 6.5-.300 Remington Ultra Magnum
Bullet : .264, 129, Nosler AccuBond LR 58943 G7
Useable Case Capaci: 101.599 grain H2O = 6.597 cm³
Cartridge O.A.L. L6: 3.600 inch = 91.44 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : ADI AR 2218

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.099% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-11.0 81 81.00 2884 2382 36658 16251 92.8 1.629
-09.9 82 82.00 2926 2452 38053 16531 93.6 1.596
-08.8 83 83.00 2968 2524 39506 16802 94.4 1.569
-07.7 84 84.00 3011 2596 41017 17062 95.2 1.540
-06.6 85 85.00 3053 2670 42591 17311 95.9 1.512
-05.5 86 86.00 3096 2745 44228 17548 96.5 1.485
-04.4 87 87.00 3138 2821 45935 17773 97.2 1.458
-03.3 88 88.00 3181 2898 47712 17984 97.7 1.432
-02.2 89 89.00 3223 2976 49564 18181 98.2 1.406
-01.1 90 90.00 3266 3055 51493 18364 98.6 1.380
+00.0 91 91.00 3308 3134 53506 18532 99.0 1.355
+01.1 92 92.00 3350 3215 55603 18684 99.3 1.331 ! Near Maximum !
+02.2 93 93.00 3392 3296 57793 18820 99.6 1.307 ! Near Maximum !
+03.3 94 94.00 3434 3378 60077 18940 99.8 1.284 ! Near Maximum !
+04.4 95 95.00 3476 3461 62462 19043 99.9 1.260 ! Near Maximum !
+05.5 96 96.00 3518 3544 64951 19129 100.0 1.238 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 91 91.00 3510 3529 66891 17995 100.0 1.230 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 91 91.00 3028 2627 42234 17556 91.1 1.513
 

DUSTY NOGGIN

Well-Known Member
Joined
Mar 18, 2015
Messages
749
Location
salt lake city
I know that powder bridging is a problem with cases this large and steep shoulder angles.

??? i would like to understand what you mean by this ,can you explain what you know about this powder bridging and how the these large cases or steep shoulder angles relate to that bridging ???

dump slower , like 30 to 45 minutes per case , :rolleyes: if that doesnt work , youll have to try the tweezer method from at least 3 ft over the funnel ... :D:
 

Trig

Active Member
Joined
Dec 15, 2013
Messages
29
Location
Central NSW Australia
hello Dusty,
I think you are referring to powder bridging in the powder funnel as were are charging the cases.
What i am meaning by powder bridging is the powder in these stupidly over bored cases bot being able to flow through the neck of the case and causing erratic pressure spikes.

This has been an ongoing topic on this forum regarding the .257 and 6.5 Allen mags.
These 2 cartridges have steeper shoulder angles then the standard rum case so I am keen to know if the 30 degree shoulder angle will mitigate this problem enought to safely run log style powder that is available to me.

Sam.
 

FEENIX

Well-Known Member
LRH Team Member
Joined
Dec 20, 2008
Messages
16,392
Location
Great Falls, MT
hello Dusty,
I think you are referring to powder bridging in the powder funnel as were are charging the cases.
What i am meaning by powder bridging is the powder in these stupidly over bored cases bot being able to flow through the neck of the case and causing erratic pressure spikes.

This has been an ongoing topic on this forum regarding the .257 and 6.5 Allen mags.
These 2 cartridges have steeper shoulder angles then the standard rum case so I am keen to know if the 30 degree shoulder angle will mitigate this problem enought to safely run log style powder that is available to me.

Sam.

Kirby Allen might be too busy building LR rifles at the moment, otherwise he'll chime in.
 

yobuck

Well-Known Member
Joined
Aug 23, 2008
Messages
1,673
Location
east central fl. /n.c. pa.
Realize if you will that 45/50 years ago the 6.5x300 weatherby cartridge was considered the ultimate long range cartridge by most long range hunters.
Back then of coarse most long range hunters would have been found in N C PA.
Reason being the 139 gr Norma bullet was considered the best of the very few good bullets. There were then as now a few who wanted more of a good thing and tried using larger cases. The 378 weatherby was one being experimented with by a few of these people.
The only really suitable powders available then were h870 which is a ball powder, or h570 which was a stick ww2 surplus. Im not sure which was used but id assume h870.
When Hornady brought out the 162 match bullet, most guys rebarreled their 6.5s to the 7x300 weatherby. And the same few were also fooling with that bullet in 378 cases.
That case was also being necked down to 30 cal of coarse during that time frame.
The big case never caught on except for 30 cal and there it became dominant among the serious hunters.
Today if you were to check around NC PA you probably wont be finding many 6.5s of any configuration being used for long range deer hunting.
 

RockyMtnMT

Official LRH Sponsor
Joined
Mar 25, 2007
Messages
6,033
Location
Montana
Did a lot of work with 6.5-300rum that we built last summer. For what we were doing the brass seemed to be the weakest link. US869 had the best results, but the temp sensitivity would not allow for top end loads. Found some Ramshot Magnum last fall on a hunting trip and will be trying it when we can. This is the powder choice for Kirby and his 6.5. We will be making a trip to see Kirby in the near future to have him rerchamber one of our 6.5 Ultracats into a 6.5 Lapcat. We just got the reamer for 6.5-338 Lap imp. Hoping we can get where we want with this one.

Hunting rifles that run near 4000fps are a blast. Have fun.

Steve
 

longrangebo

Well-Known Member
Joined
Oct 8, 2005
Messages
229
Like Yobuck, I live in that area and also went the 6.3 300 and 7x300 the latest one I tried was a 276 Baer(7mm 416 Rigby) wow 3700fps with 162,s fun to shoot, but the 7step neck down prosess was a bitch HaHa Came to my senses now and rechambered into 338-408 much , much better in the wind Still have the barrel , dies and bolt for a switch barrel, but doubt i will go back!
 

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