I wonder if any forumites can offer any suggestions as to how to develop loads for the 585 Nyati with 900 grain bullets.

There is data on Saeed's site for both the 750 grain jacketed bullet and the 1200 grain cast. Does anyone have a suggestion as to how to start developing for the 900 grain jacketed slug?

Data for the 750 grain jacketed is as follows: from 140 to 156 grains of IMR 4350 giving 2125 to 2310 fps.

Data for the 1200 grain cast bullet is as follows: from 100 to 110 grains of IMR 4350 giving 1550 to 1570 fps.

For the 900 grainer, I was thinking of starting at 120 grains of IMR 4350 and working up possibly to 140 or 145 grains.

The 585 Nyati is not in Quickload, but if you will give me the case volume in grains of water, the trimmed case length and the cartridge loaded overall length with the 900 grain bullet I will see how the modelling goes.

Don

500 grains, I reduced the powder charge 15.0 grains under what I was using for 750 gr. bullets in my t.rex. when I developed 900 grain loads for my t.rex. This is more reduction than nessesary but it is better to be on the safe side. You could also go to a slower burning powder(such as RL. 19) with the heavier bullets in the Nyati.

Don, The Nyati case holds 183.0 to 185.0 grains of water, trim lenth is 2.790.

[This message has been edited by Mitch (edited 06-13-2001).]

Don G.,

Thanks for the modeling!

Mitch,
Can you tell me what the cartridge overall length is?

And I forgot I needed bullet length and barrel length. If anyone has the barrel length and bullet lengths for the 750 and 1200 grain bullets that Saeed used I can test my model.

Don

[This message has been edited by Don G (edited 06-13-2001).]

500grains,
One SLIGHT computer glitch, when I revised the bullet weight to 900 grains in the custom bullet definition, the program updated the file, but not the setting it was using. That was a long 750 grain bullet, not a 900 grain bullet. The revised numbers are (I hope) more nearly correct.

Remember this is speculative BS only for comparison purposes, etc, etc.

QuickLoad does best with bottleneck cases, so you will probably get both lower pressures and lower velocities, but start 10% below these loads and work up. Remember when you see pressure signs you are probably already at 65,000-70,000 PSI.

I used Saeed's barrel length of 23.5 inches.
Type mc (gr) fill (%) vel (fps) Pmax (psi) Z (%) t (ms) Pmuz (psi)
Hodgdon H4350 153 101 2180 52500 100 1.4004 8779
Norma 204 155 103 2173 52500 99 1.4094 8877
Vihtavuori N560 161 104 2168 52500 96 1.4039 9175
Somchem S365 151 102 2166 52500 100 1.4086 7951
Acc.Arms XMR4350 151 103 2162 52500 100 1.4055 7920
Hodgdon H414 150 93 2162 52500 99 1.4164 8715
Alliant Reloder-19 154 105 2148 52500 97 1.4072 8735
Hodgdon H4350 SC 153 102 2146 52500 97 1.3994 8711
Winchester 760 147 91 2145 52500 99 1.4169 8463
IMR 4350 148 100 2143 52500 98 1.4098 8451
IMR 4831 156 105 2141 51998 99 1.4268 8497
Vihtavuori N550 145 94 2137 52500 100 1.4279 8253
Vihtavuori N160 159 104 2137 52500 99 1.4088 8425
Norma MRP 160 105 2130 45524 98 1.4796 9359
Alliant Reloder-22 158 105 2127 47766 97 1.4578 9077
Somchem S385 157 104 2126 52500 98 1.4290 8406
SNPE Vectan SP 11 141 92 2120 52500 100 1.4239 7770
Hodgdon H4831 SC 161 105 2116 50667 95 1.4228 8805
Hodgdon H380 141 96 2112 52500 100 1.4483 7981
IMR 4895 130 87 2103 52500 100 1.4111 7173
Vihtavuori N160 ,fast lot 145 96 2103 52500 100 1.4276 7687
Norma 203B 132 89 2103 52500 100 1.4391 7432
SNPE Vectan Sp 7 142 89 2100 52500 100 1.4370 7611
Alliant Reloder-15 132 89 2099 52500 100 1.4392 7569
Norma 203 old 137 94 2096 52500 100 1.4520 7456
Winchester 748 131 81 2086 52500 100 1.4355 7108
IMR 4320 133 88 2086 52500 100 1.4238 7301
Vihtavuori N165 161 105 2083 45586 99 1.4923 8461
Ramshot Big Game 133 86 2080 52500 100 1.4370 7336
Hodgdon BL-C2 134 80 2080 52500 100 1.4470 7271
SNPE Vectan SP 9 133 87 2079 52500 100 1.4373 7325
Vihtavuori N150 137 93 2072 52500 100 1.4422 6874
Somchem S341 137 86 2069 52500 100 1.4393 7162
Somchem S321 131 83 2067 52500 100 1.4485 7110
IMR 3031 123 86 2065 52500 100 1.4468 6662
Norma 202 131 89 2064 52500 100 1.4439 7018
IMR 4064 129 89 2062 52500 100 1.4396 7120
Hodgdon VARGET 129 86 2061 52500 100 1.4353 7116
Hodgdon H335 129 77 2060 52500 100 1.4436 6896

I am emailing this also, as it might be easier to read.

If it was me, I'd try H4350. I like the fact that the H4350 uses a compressed caseful (keeps the bullet from seating itself deeper due to recoil while in the magazine), and is close to 100% burnt.
Don

[This message has been edited by Don G (edited 06-13-2001).]

Don, The lenth of the 750 Barnes Super Solid is 1.450 the lenth of the 900 gr. Woodleigh is 1.400. The cannelure on the 900 gr. bullet is really too far foward, if you seat the bullet to the cannelure the overall lenth would be about 3.390 which is about .100 less than it should be with other bullets. I could not find the 585 Nyati case that I have, so I seated the bullet in one of my t.rex cases and then subtracted the .190 extra lenth of the t.rex. case. I hope this helps.

Mitch,

I extrapolated the 900 grain to be 1.445, so I should be close enough.

Thanks,
Don

Very interesting guys. The 585 Nyati can be a real dinosaur gun with the 900 grainers, if Don G's data is anywhere near close. I will have to put thoughts of the 510 Nyati away and go back to the standard 585 Nyati.

------------------
Good huntin' and shootin',
RAB

If you are still alive, and your brains don't pour out your nose after shooting one of these, let me know how the actual data turns out.

Any resemblance to reality is purely coincidental!

Don

Dear 500grains:

Please arrange for your next of kin to post your loads to this board!

Man, if you get the velocities predicted by that modelling that is going to be some recoil in a heavy rifle!

Please keep us informed...

jpb

I store these threads so I can re read them before shooting my 375s at the range

Mike

I had the model messed up. When I loaded the program to check the run this morning I got completely different numbers!

It turns out the program was still using the old bullet weight of 750 grains last night, even though I'd updated the bullet definition file properly.

When I reloaded the program the new number (900 grains) actually took effect.

If you had used the old run of 154 grains XMR4350 you'd have actually gotten 56,000 PSI.

Just a minor computer glitch, eh?

Don

Mitch,

> "I reduced the powder charge 15.0 grains under what I was using for 750 gr. bullets in my t.rex.
when I developed 900 grain loads for my t.rex."

Did you choose that as a 10% reduction of the powder charge, or how?

Don,

That's some impressive data, but I worry about starting anywhere near those loads.

Will the software let you stipulate a max PSI?

For example, if I wanted to limit my max pressure to 45,000 PSI, what would my charge of IMR 4350 or H 4350?

I am putting the data you modeled in my reloading notebook.

Thanks!

500grains,

You can see from these numbers that 10% down from the first batch is lower than this. I would start 10% down from the first batch. I would not run any load less than 80% of a full case. H4350 is still looking good to me.

Don

23.5 inch barrel, 900 grain bullet 1.445"
long, 45000 PSI max

Type mc (gr) fill (%) vel (fps) Pmax (psi) Burnt (%) t (ms) Pmuz (psi)
Norma MRP 159 105 2122 45000 98 1.4873 9329
Alliant Reloder-22 155 103 2087 45000 96 1.4971 8910
Hodgdon H4350 146 97 2081 45000 99 1.4987 8471
Somchem S365 144 97 2077 45000 100 1.5053 7760
Vihtavuori N165 161 105 2075 45000 99 1.5009 8438
Norma 204 148 99 2074 45000 98 1.5082 8524
Acc.Arms XMR4350 144 98 2073 45000 100 1.5024 7740
Vihtavuori N560 154 99 2064 45000 94 1.5036 8716
Hodgdon H414 143 88 2062 45000 98 1.5165 8352
IMR 7828 155 105 2055 44303 93 1.5049 8739
Ramshot Big Boy 167 105 2051 43148 93 1.5188 9054
IMR 4831 149 101 2050 45000 98 1.5199 8198
Alliant Reloder-19 147 100 2045 45000 96 1.5070 8308
Winchester 760 140 87 2045 45000 98 1.5165 8096
IMR 4350 140 95 2042 45000 97 1.5090 8070
Hodgdon H4350 SC 146 97 2042 45000 96 1.4998 8286
Vihtavuori N550 138 89 2040 45000 99 1.5286 7944
Vihtavuori N160 151 100 2039 45000 97 1.5077 8087
Hodgdon H4831 SC 156 101 2037 45000 93 1.5004 8458
Somchem S385 150 99 2028 45000 97 1.5299 8055
SNPE Vectan SP 11 134 87 2025 45000 100 1.5231 7515
Hodgdon H380 134 91 2015 45000 99 1.5527 7678
IMR 4895 123 82 2011 45000 100 1.5085 6926
Norma 203B 125 84 2010 45000 100 1.5403 7176
Vihtavuori N160 ,fast lot 138 91 2009 45000 99 1.5268 7426
SNPE Vectan Sp 7 135 84 2006 45000 100 1.5379 7357
Norma 203 old 130 89 2004 45000 100 1.5550 7226
Alliant Reloder-15 125 84 2002 45000 100 1.5419 7285
Winchester 748 124 77 1995 45000 100 1.5351 6857
IMR 4320 126 83 1993 45000 100 1.5220 7048
Hodgdon H1000 161 105 1990 42017 92 1.5468 8414
Vihtavuori N150 130 89 1989 45000 100 1.5391 6646
Hodgdon BL-C2 126 76 1987 45000 100 1.5491 7011
Ramshot Big Game 125 82 1985 45000 100 1.5384 7060
SNPE Vectan SP 9 126 82 1984 45000 100 1.5387 7050
IMR 3031 116 81 1978 45000 100 1.5457 6406
Somchem S341 129 81 1975 45000 100 1.5402 6917
Somchem S321 124 78 1974 45000 100 1.5510 6842
Norma 202 123 84 1972 45000 100 1.5452 6760
Acc.Arms 2520 125 80 1972 45000 100 1.5421 6520
Hodgdon H335 122 73 1969 45000 100 1.5441 6625
IMR 4064 122 84 1967 45000 100 1.5415 6846
Hodgdon VARGET 122 81 1966 45000 100 1.5366 6836
Norma 201 119 82 1960 45000 100 1.5656 6691
Acc.Arms 2230 119 75 1958 45000 100 1.5541 6513
Vihtavuori N140 126 86 1958 45000 100 1.5462 6510
Vihtavuori N540 129 83 1955 45000 100 1.5502 6890
Alliant Reloder-12 123 78 1953 45000 100 1.5449 6456
SNPE Vectan SP 10 116 73 1953 45000 100 1.5518 6367
Ramshot TAC 116 73 1952 45000 100 1.5519 6364
Hodgdon H322 112 73 1946 45000 100 1.5460 6171
Vihtavuori N135 120 84 1938 45000 100 1.5639 6048
Hodgdon H4895 119 80 1924 45000 100 1.5470 6359
Alliant Reloder-25 155 105 1922 34862 93 1.6704 8547
Somchem S335 118 81 1908 45000 100 1.5732 5934

[This message has been edited by Don G (edited 06-14-2001).]

Don, that is very helpful. I remain surprised that such heavy powder charges would be used with the 900 grain bullet.

Comparing the data for the 750 grain bullet, we see a max load of 156 grains of IMR4350 giving 2310 fps. A starting load with a 750 is 140 grains at 2125 fps.

With a 900 grain bullet, 148 grains of IMR4350 would give 2143 fps at max pressure, while 140 grains gives 2042 fps.

It seems that the extra 150 grains of bullet weight in the 900 grainer is not that hard to get up to high velocity (2100 fps), per the model.

Don,

Is that modeling software available on the net?

500 grains, when I reduced the powder charge 15.0 grains I was not thinking of a particular percentage of reduction. I just chose to drop the charge 15.0 grain because I was sure the load would be a very safe place to start. The reason for such a large reduction was prompted by my concerns about going over board with too much bolt head thrust.

[This message has been edited by Mitch (edited 06-14-2001).]

500grains,

You can get the software from NECO

Last I knew it was about $150. I have not tried the other internal ballistics programs, this one does fairly well.

It is always best to use data based on experience, I mostly use QuickLoad to help me choose which powder to buy. I based the model on Saeed's published 750 grain data, so I had a good starting point, but I'd still put more weight in Mitch's experience and Saeed's data than on QuickLoad.

By the way, I still get the same answers this motning!

Don

Sorry about the cannelure.I had them designed to allow feeding with my longer case in the CZ magazine,at which time I was not sure just how long the case was going to be.
- I played it safe and stuck with the same OAL as for the other woodleigh 585 bullets.

My gunsmith recommended 140gns of AR2209 which is bit slower than IMR4350 for the 900 grainers to start with.My case is a bit larger at 195-200 grains.

By the way, can I get a show of hands who is interested in another order. Woodleigh will be doing their 577 run in a couple of months hopefully.

Mike I guess you will looking at getting a few too?

Don, with 750grain woodleighs and the above powder capacity,what would be maximum velocity with IMR4350?
Forgot to add, 25" barrel.
Regards,
karl.

[This message has been edited by Karl (edited 06-16-2001).]

Karl,

That case is quite a bit bigger!

Using 197 gr case capacity and the 750 gr. Woodleigh, QL predicts an even 2400 fps at 166 grains of H4350. Peak pressure is predicted to ne 52,500 PSI. If you have it available to try, the Somchem S365 also looks good at 164 grains, same fps, slightly lower pressure.

The IMR4350 prediction was 2358 fps from 160 grains at 52,500 peak pressure.

Please remember, QuickLoad is a nice tool, it has saved me hundreds of dollars by putting me on the right powder quickly, but it does not do a good job on these big cases with small shoulders. Almost every time I have needed 3-5 grains more powder to get the predicted velocity out of my 416Rem.

I believe that once you load up to get the predicted velocity, you are also at (at least) the predicted pressure. So there is no "free" velocity.

An exception is when you shove the bullet into the lands. Peak pressure will go up faster than the velocity would indicate. These models use a start pressure based on a reasonable bullet jump - at least .005.

If you have actual data, no matter how far off from these predictions, please post it or send it to me. It helps to know when the model is wrong, and in which direction!

Don

Karl,

3 grains of added case capacity does not mean much at 200 total! For the 750 gr. Woodleigh my model showed 2440 fps at 167gr H4350, other powders went up roughly the same perecentage.

H414 looks pretty good also, 165 gr gets 2424 fps. But I'm not sure even a magnum primer would do a good job of lighting off that much ball powder.

Mike 375 told me that ADI AR2209 is the same as H4350SC, if that is true, my model shows 168 gr H4350SC yielding 2384 fps. That is not too shabby, but that is a 5% compressed load, so in actuality you will probably run out of case room before you get to 2400 fps. I'd use a long drop tube!

As always, work up carefully - these big cases never model well.

Let me know your range results.

Don

I would avoid ball powders in the 585 Nyati. I tried ball powder in my 500 A2 and got extreme spreads of nearly 200 fps. In the much larger 585 Nyati 3.0 case the problem would be even worse.

Mitch,

I was afraid of that.

You going to make it to GeorgeS's dinner?

Don