375 RUM guys

[Tikkamike]

I have been out of the 375 game for a while. I have a freshly rebarreled 375 sitting in the safe that has a scope on it just needs broken in and a load worked up. I plan to keep using the 270 TSX. just wondering if any of my fellow 375 rum groupies have been seeing cool results with any new bullets or powders? I have come to really like Hunter powder because the burn rate matches up really well with large capacity cases with big bullets. just a little faster than the popular slow burners and its spherical so you can get a little more in than with a stick powder before you start to compress. It has worked well in my 338 win and 416 rigby. We will see how it is in the rum. May also try RL33

 

[benchracer]

I ran some basic QL numbers and it looks like Ramshot Hunter is one of the better choices available for the RUM and 270 TSX (I ran the numbers with a 26" barrel). It looks like you could pick up about 50 fps or so with RL-22 or IMR 7828 SSC. Velocity drops off pretty quickly with powders slower/bulkier than those.

If I knew your fired case capacity, barrel length, and the COAL you load to with the TSX, I could give you better numbers.

I have done some initial testing with 350g SMK's and RL-22 in a .375 H&H, with promising results. I plan to try IMR 7828 SSC also. You have the case capacity to make those powders work with lighter bullets in your RUM. I have to go to faster powders if I back the bullet weight off.

The reloading manuals all specify much faster powders for the .375's, even the larger cased ones. I consider that to be a reflection of the lack of long range type research in the larger bores.

 

[Tikkamike]

barrel length is 28" coal I can get for you but its close to 3.880 I believe. fired case capacity. is that h20 at the trim to length?

 

[benchracer]

is that h20 at the trim to length?

Yes. Trimmed and not resized.

 

[memtb]

Mike, I just sent you a PM and then find this post. I guess that your sticking with the 270 pretty much answered my PM to you!!! Todd

 

[benchracer]

barrel length is 28" coal I can get for you but its close to 3.880 I believe. fired case capacity. is that h20 at the trim to length?

Here is a sample list of powders recommended by QL, given the above information, a default case capacity of 117.01 grains, and a minimum load density of 97%. When I did my initial estimate (using a 26" barrel and default values for COAL and case capacity), Ramshot Hunter was among the top powders on the list. Using the supplied COAL of 3.880 and the 28" barrel length has shifted the optimum burning rate powders a notch or two toward slower powders as seen below:



Cartridge : .375 Rem Ultra Mag
Bullet : .375, 270, Barnes 'TSX' 37556
Useable Case Capaci: 107.549 grain H2O = 6.983 cm³
Cartridge O.A.L. L6: 3.880 inch = 98.55 mm
Barrel Length : 28.0 inch = 711.2 mm
Predicted Data for Indicated Charges of the Following Powders.
Matching Maximum Pressure: 62000 psi, or 427 MPa
or a maximum loading ratio or filling of 105 %
These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !
33 loads produced a Loading Ratio below user-defined minimum of 97%. These powders have been skipped.
Powder type Filling/Loading Ratio Charge Charge Vel. Prop.Burnt P max P muzz B_Time
% Grains Gramm fps % psi psi ms
--------------------------------- -----------------------------------------------------------------
Norma MRP 101.7 105.2 6.82 3055 100.0 62000 9827 1.276 ! Near Maximum !
Vihtavuori N560 103.4 104.8 6.79 3051 99.0 62000 10166 1.272 ! Near Maximum !
Accurate MAGPRO 103.7 109.2 7.08 3039 98.1 62000 10227 1.280 ! Near Maximum !
IMR 7828 SSC 102.1 104.0 6.74 3035 99.3 62000 9812 1.263 ! Near Maximum !
Bofors RP5/NP ~approximation 103.7 103.9 6.73 3025 99.8 62000 9739 1.279 ! Near Maximum !
Raufoss RA15 103.7 103.9 6.73 3025 99.8 62000 9739 1.279 ! Near Maximum !
Alliant Reloder-22 103.7 103.9 6.73 3025 99.8 62000 9739 1.279 ! Near Maximum !
ADI AR 2213 103.1 103.3 6.69 3021 99.2 62000 9751 1.262 ! Near Maximum !
SNPE Vectan SP 12 105.0 111.1 7.20 3011 99.4 59572 9866 1.287 ! Near Maximum !
PB Clermont PCL 517 105.0 111.1 7.20 3006 99.4 59222 9878 1.290 ! Near Maximum !
Ramshot Magnum 103.4 111.7 7.24 3000 100.0 62000 9228 1.273 ! Near Maximum !
Rottweil R905 104.9 103.2 6.69 2989 98.9 62000 9527 1.281 ! Near Maximum !
Winchester WXR 105.0 103.0 6.67 2984 99.6 59188 9687 1.306 ! Near Maximum !
Bofors RP15 105.0 103.0 6.67 2984 99.6 59188 9687 1.306 ! Near Maximum !
ADI AR 2209 99.9 98.5 6.39 2983 99.7 62000 9255 1.270 ! Near Maximum !
Alliant Reloder-19 100.4 99.6 6.45 2980 99.7 62000 9303 1.279 ! Near Maximum !
Bofors RP14 ~approximation 101.2 100.3 6.50 2973 99.7 62000 9234 1.280 ! Near Maximum !
Raufoss RA4 98.4 97.6 6.32 2956 99.6 62000 9074 1.280 ! Near Maximum !
Bofors RP4 ~approximation 98.4 97.6 6.32 2956 99.6 62000 9074 1.280 ! Near Maximum !
Hodgdon H4831 SC 101.6 101.9 6.60 2954 98.6 62000 9207 1.278 ! Near Maximum !
IMR 7828 105.0 101.2 6.55 2952 98.6 56358 9653 1.317 ! Near Maximum !
Somchem S365 97.5 96.2 6.23 2952 100.0 62000 8270 1.296 ! Near Maximum !
ADI AP 2214 105.0 108.1 7.00 2950 99.0 57931 9482 1.300 ! Near Maximum !
Somchem S385 100.6 100.8 6.53 2940 99.9 62000 8835 1.300 ! Near Maximum !
Bofors RP5 NT ~approximation 105.0 106.1 6.88 2936 97.2 58796 9528 1.299 ! Near Maximum !
Hodgdon H4831 105.0 101.2 6.55 2933 98.5 60555 9164 1.291 ! Near Maximum !
Winchester Supreme 780 99.0 103.5 6.71 2929 99.7 62000 8825 1.287 ! Near Maximum !
IMR 4831 100.2 95.1 6.16 2928 100.0 62000 8349 1.302 ! Near Maximum !
Alliant Reloder-25 105.0 103.5 6.71 2928 100.0 53154 9291 1.354
Rottweil R904 99.2 97.0 6.29 2926 99.1 62000 8871 1.284 ! Near Maximum !
Accurate 3100 103.7 102.8 6.66 2923 100.0 62000 8521 1.315 ! Near Maximum !
Hodgdon Hybrid 100V 98.1 94.1 6.09 2901 100.0 62000 7864 1.294 ! Near Maximum !
Vihtavuori N165 105.0 103.0 6.67 2899 99.8 60279 8596 1.308 ! Near Maximum !
Somchem S361 98.2 103.7 6.72 2892 98.6 62000 8692 1.297 ! Near Maximum !
Vihtavuori N160 105.0 99.8 6.47 2884 98.9 60309 8645 1.303 ! Near Maximum !

 

[benchracer]

Here is what QL spit out for Accurate MAGPRO, IMR 7828SSC, and RL-22:

Cartridge : .375 Rem Ultra Mag
Bullet : .375, 270, Barnes 'TSX' 37556
Useable Case Capaci: 107.549 grain H2O = 6.983 cm³
Cartridge O.A.L. L6: 3.880 inch = 98.55 mm
Barrel Length : 28.0 inch = 711.2 mm
Powder : Accurate MAGPRO
Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.465% 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
-04.6 97 102.50 2840 4836 49526 9708 95.5 1.413
-04.2 98 103.00 2855 4886 50348 9752 95.8 1.403
-03.7 98 103.50 2870 4937 51187 9796 96.0 1.393
-03.3 99 104.00 2884 4988 52043 9838 96.2 1.382
-02.8 99 104.50 2899 5039 52912 9879 96.4 1.372
-02.3 100 105.00 2914 5090 53801 9920 96.6 1.362
-01.9 100 105.50 2929 5142 54703 9960 96.8 1.352 ! Near Maximum !
-01.4 101 106.00 2943 5194 55626 9999 97.0 1.342 ! Near Maximum !
-00.9 101 106.50 2958 5246 56565 10037 97.1 1.332 ! Near Maximum !
-00.5 102 107.00 2973 5298 57518 10073 97.3 1.323 ! Near Maximum !
+00.0 102 107.50 2987 5351 58488 10109 97.5 1.313 ! Near Maximum !
+00.5 102 108.00 3002 5404 59474 10144 97.7 1.303 ! Near Maximum !
+00.9 103 108.50 3017 5457 60477 10178 97.8 1.294 ! Near Maximum !
+01.4 103 109.00 3032 5510 61497 10211 98.0 1.284 ! Near Maximum !
+01.9 104 109.50 3046 5564 62535 10243 98.1 1.275 ! Near Maximum !
+02.3 104 110.00 3061 5618 63592 10274 98.3 1.266 !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 102 107.50 3145 5931 71720 9923 100.0 1.208 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 102 107.50 2776 4619 46365 9702 90.3 1.450



Cartridge : .375 Rem Ultra Mag
Bullet : .375, 270, Barnes 'TSX' 37556
Useable Case Capaci: 107.549 grain H2O = 6.983 cm³
Cartridge O.A.L. L6: 3.880 inch = 98.55 mm
Barrel Length : 28.0 inch = 711.2 mm
Powder : IMR 7828 SSC
Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.481% 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
-04.8 97 98.87 2884 4986 52218 9498 97.9 1.362
-04.3 98 99.37 2899 5037 53093 9534 98.1 1.352
-03.8 98 99.87 2914 5089 53984 9569 98.2 1.342
-03.4 99 100.37 2928 5141 54892 9602 98.4 1.332 ! Near Maximum !
-02.9 99 100.87 2943 5193 55817 9635 98.5 1.322 ! Near Maximum !
-02.4 100 101.37 2958 5246 56761 9666 98.7 1.313 ! Near Maximum !
-01.9 100 101.87 2973 5298 57722 9697 98.8 1.303 ! Near Maximum !
-01.4 101 102.37 2988 5351 58703 9726 98.9 1.293 ! Near Maximum !
-01.0 101 102.87 3002 5404 59700 9754 99.0 1.284 ! Near Maximum !
-00.5 102 103.37 3017 5457 60718 9780 99.1 1.274 ! Near Maximum !
+00.0 102 103.87 3032 5511 61756 9806 99.3 1.265 ! Near Maximum !
+00.5 102 104.37 3046 5564 62815 9830 99.4 1.256 ! Near Maximum !
+01.0 103 104.87 3061 5618 63893 9853 99.4 1.246 !DANGEROUS LOAD-DO NOT USE!
+01.4 103 105.37 3076 5672 64993 9875 99.5 1.237 !DANGEROUS LOAD-DO NOT USE!
+01.9 104 105.87 3090 5726 66116 9896 99.6 1.228 !DANGEROUS LOAD-DO NOT USE!
+02.4 104 106.37 3105 5780 67259 9915 99.7 1.219 !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 102 103.87 3168 6019 75132 9406 100.0 1.171 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 102 103.87 2837 4826 50159 9656 93.8 1.387



Cartridge : .375 Rem Ultra Mag
Bullet : .375, 270, Barnes 'TSX' 37556
Useable Case Capaci: 107.549 grain H2O = 6.983 cm³
Cartridge O.A.L. L6: 3.880 inch = 98.55 mm
Barrel Length : 28.0 inch = 711.2 mm
Powder : Alliant Reloder-22
Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.481% 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
-04.8 99 98.87 2883 4984 52518 9469 99.0 1.375
-04.3 99 99.37 2898 5033 53395 9501 99.1 1.365
-03.8 100 99.87 2912 5083 54287 9532 99.2 1.355 ! Near Maximum !
-03.4 100 100.37 2926 5132 55192 9561 99.3 1.345 ! Near Maximum !
-02.9 101 100.87 2940 5182 56112 9590 99.4 1.336 ! Near Maximum !
-02.4 101 101.37 2954 5232 57046 9617 99.5 1.326 ! Near Maximum !
-01.9 102 101.87 2968 5282 57995 9643 99.6 1.317 ! Near Maximum !
-01.4 102 102.37 2982 5332 58959 9669 99.6 1.307 ! Near Maximum !
-01.0 103 102.87 2996 5382 59938 9693 99.7 1.298 ! Near Maximum !
-00.5 103 103.37 3010 5432 60936 9716 99.8 1.289 ! Near Maximum !
+00.0 104 103.87 3024 5483 61951 9737 99.8 1.279 ! Near Maximum !
+00.5 104 104.37 3038 5534 62984 9758 99.9 1.270 ! Near Maximum !
+01.0 105 104.87 3052 5585 64035 9777 99.9 1.261 !DANGEROUS LOAD-DO NOT USE!
+01.4 105 105.37 3066 5636 65106 9796 99.9 1.252 !DANGEROUS LOAD-DO NOT USE!
+01.9 106 105.87 3080 5687 66195 9813 100.0 1.243 !DANGEROUS LOAD-DO NOT USE!
+02.4 106 106.37 3094 5738 67305 9829 100.0 1.235 !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 104 103.87 3148 5943 75046 9333 100.0 1.186 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 104 103.87 2843 4845 49536 9730 95.7 1.404

 

[benchracer]

I really don't like the way QL data converts when using cut and paste, so I tried to make some JPEG's that might be easier to read. Here they are:

 

[Deleted member 46119]

Tikkamike,

I've had very good results with the 7828 powders.

 

[Tikkamike]

Interesting results thanks for doing that. The velocities seem slow, with a factory 26"I was getting 3200 FPS with 102 gr of rl 22... Maybe it was a fast barrel... Maybe my chrono was off... I'll be working on a load very soon and using the magneto speed so I'm looking forward to comparing real world results... Have you found quick load to give you pretty accurate estimates when working up a load?

 

[benchracer]

I am just getting started with using it, but so far, I have found QL to be in the ballpark. Typically, its estimates are within + or - 50fps or so.

For instance, I was recently working with RL-17 and 300 SGK's in my H&H. My accuracy load came in at 80.0 grains. Accounting for barrel length, COAL, and measured case capacity, QL predicted a velocity of 2755 on the edge of pressure limits.

My actual 10 shot average came in at 2780 in 90*+ weather, so I would consider the QL estimate to be fairly close. I got sticky bolt lift from a few of those shots at that temp. I had shot the same load a few days earlier in 75* weather with no pressure signs, so I would say that QL is correct about that load being right on the edge of pressure limits.

On the same day, I shot a few test rounds loaded with RL-22 and 350 SMK's. QL predicted that combo would top out at 2549. I actually got between 2600 and 2648 with no pressure signs and smooth extraction. I only shot a couple of rounds at each powder charge, though, because I was only trying to establish MIN and MAX at that point. I need to shoot some more rounds to be confident of my numbers. If the initial numbers hold true, it looks like I will see best accuracy around 2570 or so, based on the VERY consistent velocities I was seeing at that level.

So, I had one set of loads that came in right on the money and one set of loads that looks to be about 100fps faster than predicted. Not a large set of data to go on, but I would consider QL to be ballpark accurate in terms of MV.

Where I have found it to be most useful is with powder selection. These days, I mostly find myself using bullets and COAL's that are not covered in published data. Having QL has been very helpful in gauging which powders will give me the best performance using non-standard bullets and non-SAAMI lengths.

So far, the trend has been that the optimum powders for the way I am loading are much slower than those recommended in the manuals. Before I acquired a Magnetospeed and QL, I did a lot of stumbling around in the dark when it came to trying to figure out what would work with some of the combinations that I wanted to try. With much better estimating tools, I find myself able to be more efficient in my testing and I am not wasting my money buying powders that won't yield the results I am after. It doesn't take long for tools like that to pay for themselves.

BTW, all the above loads were chronoed using a Magnetospeed, which I am also just learning how to fly.

 

[benchracer]

Interesting results thanks for doing that. The velocities seem slow, with a factory 26"I was getting 3200 FPS with 102 gr of rl 22... Maybe it was a fast barrel... Maybe my chrono was off... I'll be working on a load very soon and using the magneto speed so I'm looking forward to comparing real world results... Have you found quick load to give you pretty accurate estimates when working up a load?

I ran the above numbers using an OAL of 3.880 and QL predicts 2900ish. It will be interesting to see what your Magnetospeed tells you when you start your load workup.

I would expect a spread between actual and predicted that large to yield something valuable on the learning curve. I look forward to seeing your shooting results.

 

[Engineering101]

benchracer

If you have QuickLoad check out Chris Long's paper on optimal barrel timing at:

Optimal Barrel Time Paper

 

[benchracer]

benchracer

If you have QuickLoad check out Chris Long's paper on optimal barrel timing at:

Optimal Barrel Time Paper

Pretty interesting stuff. It may take me some time and repetition to digest all of the information there. I am thinking that it may be interesting to compare my known accuracy loads to the data presented there to see where they fall vs the predicted nodes.