585 nyati
110 grains RE15
800 grain Bridger FN solid
100 yards

500,

that is an impressive group with a .585 for sure well done !!.

I like the idea of those solid style bridger bullets but I worry about the monometals like them and barnes x bullets being bad for your barrel. I reckon in the long term they could not be any good for the barrel I could be wrong and probably am, but thats the way I feel about them.

500grains
very nice this the gun you would take for jumbo? Waiting for my bridgers to arrive.
Dean

PC,

Since the Bridgers are grooved on the exterior, it takes very little pressure to engrave the rifling so I do not think they are a problem for the barrel. The Barnes are not grooved and it takes a pretty good pressure spike to get the rifling to engrave. The Barnes scare me a little.

Tonto,

Yes that is the rifle that shot jumbo, although I used TCCI and Woodleigh solids for that.

HI,

800 grains, I think it will get through. Kev

Very nice group!

One thing I noticed is that I don't get any metal fouling with the Bridgers.

I can't wait to smash a water buffalo with it in April!

George

Dan,

Any idea on the actual muzzle velocity? By the way, that was good shooting too!

Scott

Dan,

I calculated the following internal ballistics for your load:

Chamber pressure ~ 28900 psi
Muzzle velocity ~ 1600 fps
Muzzle energy ~ 4540 ftlb

Calculated recoil numbers:
Recoil velocity of bullet acceleration - 13 fps
Total recoil velocity (inclusive of gas effect) - 14.85 fps
Total recoil energy dissipated - 48 ft lb.
Assumes rifle mass of 14 lbm.

How close is the simulation?

Scott

Scott, Quickload seems to break down with the big bores. I have not chronographed the load above, but I have chronographed 130 grains Re15 with a 750 grain bullet and it averages 2267 fps. Move up to 140 grains Re15 with a 750 grain bullet and the velocity is 2320 fps. Therefore I would guess that 110 grains with an 800 grain bullet would be 2000 fps or just a tad less. Recoil of the 800 grain load is less than my standard 750 grain load, but I would say it is in the 80-90 ft lb area just based on feel.

Rifle weighs 13.25 pounds.

Dan,

Thanks for the information. The program isn't Quickload though. I have never been overly impressed with Quickload. I have had it predict low pressures and high velocities. The former being very bad in my opinion.

Scott

HI,

500 grains, how many of those round can you shoot from the bench before it starts to hurt a little, I like the accuracy you are getting with the Brids. Kev

Kev,



If I take Tylenol before going to the range, I can get in about 14 shots before a headache sets in, but I can still go to the office that day.



One day I shot 22 or 24 rounds without Tylenol and I had to go home and lay in bed the rest of the day.



I also took an updated IQ test and it puts me 10 points lower now that I shoot a .585.

500grains,
I have a 600 OK in the works... Reading this, when it gets finished I don't want to shoot it too much while I'm still in school or I might not graduate.
Rumor has it John Madden shoots a 4 Bore every day before breakfast.

500.



Based upon case length supplied by PC for the Nyati, the case capacity came out 183g and for 110g RL-15, 800g FMJ at 1.394" long seated for OAL = 3.525 in 24" barrel, Quickload showed 1960 fps @ 36,600 psi. I will post my 505 Gibbs results when i get my rifle.



rgds,



steve



PS. regarding the target, WOW!

You probably know this, but do NOT take aspirin or Ibuprofin before a range session. Both thin the blood and reduce clotting, making concussive damage more severe.

Steve,

If I use the 577 NE 3" model, which has been correlated to reality, I achieve a muzzle velocity of 1781 fps for 500grains load.

This load:

110 gr Rel 15
CCI 250 primer
750 Woodleigh
Bell Brass
577 NE 3"
Muzzle velocity = 1778 fps avg from chronograph. Software matches it 100%. This load is too slow.

115 gr of Rel 15 provides a muzzle velocity of 1940 fps. This load works well.

120 gr of Rel 15 provides a muzzle velocity of 2033 fps. This load is REAL hot!

The added mass of 500grains bullet increases the working pressure of the load and achieves the same velocity as the lighter bullet does even though the powder volume has not changed. This is actually quite common with the big bores.

Scott

Your case volume is too big if that is intended to be a 585 nyati simulation.

The case capacities I have used are (in grains of water):

577 NE 3" - 185.1 grains (avg from 5 cases)

585 Nyati - 182.5 grain (calculated)

They should be very close. I am using the burn curve from the 577 NE 3", which I have determined from actual shooting sessions over a chronograph for Rel 15. Personally, I like IMR4350 or IMR4831 better for this behemoth.

Scott

The problem is using the 577 case geometry for a bottle neck cartridge in Quickload. Quickload admits the simulation for straight wall, extreme capacity cases shows higher velocity than measured. I ran the 577 3" and compare to A^2 manual and the vel. is high by about 200fps. The 585 Nyati sim agrees more with the AR reloading data.

rgds,

steve

My 585 nyati cases are 178.9 grains water capacity.

I think the error here is that the Sweet simulator is not working correctly. But I have seen Quickload simulations fall apart for the 470 capstick and the 585 nyati too.

I suggest a test:

1. What velocity does the Sweet simulator predict with a 750 grain bullet ahead of 130.0 re15 in the 585 nyati?

2. What velocity does the Sweet simulator predict with a 500 grain bullet ahead of 84 grains IMR4320 in a 458 lott?

Dan,

The Sweet simulator suggests the following:

585 Nyati (using your case volume)
750 gr Woodleigh Solid
130 gr of Rel 15
24" barrel
Muzzle velocity - 2100 fps +/- 20 fps


458 Lott
500 gr Hornady
84 gr IMR4320
24" barrel
Muzzle velocity - 2271 fps +/- 31 fps.

Scott

For some reason the sweet simulator is giving artifically low velocities. 150 fps low for the 585 and about 100 fps low in the lott. Do you know why?

Dan,



I have GREAT confidence in the Sweet simulator (I kinda like that name thanks for coining it). The errors, as you call them, sound frightenly close to published reloading data error.



I have found that most reload manuals will have optimistic velocities publish for all their loads. Typically, these optimistic velocities are between 80 fps and 200 fps higher than reality. This seems to be methodology to reduce liability, since most reloaders do not chronograph their loads, they simply load to what the book says and are happy with there 3300 fps load (even though in reality it is closer to 3150 fps). I have had the pleasure of dispelling several reloaders dreams about the performance of their hotrodded handloads with the chronograph. Once in a while the opposite is determined, but that is a rare, rare occurence.



Of course your chronograph may not be reading properly, or the screen distance(s) are off, etc, etc.



Of course if you are using one of the commercial internal ballistics programs, you may well be falling victim to the marketing hype, which seems to permeate these programs. Specifically, I am referring to the overly optimistic mathematical representations of the powder curves in these programs. I do not necessarily fault the software producers, they are afterall only using the data provided to them by some powder manufacturer.



If your rifles actually are beating the Sweet simulator by the margin you suggest I see two plausible explanations:



1.) You are a very lucky man since you own two very fast rifles!



2.) Your rifles are in reality running VERY HIGH pressures for the loads you are using. This is a bad bad thing!



3.) You have been reloading with two seperate lots of two separate powders, which possess impressive, and I mean impressive, pressure v. distance curves!



Your 585 Nyati load should be in the mid to low 40 ksi range. Your 458 Lott load should be in the low 60 ksi range.



Scott



PS - I took a looksy at the AR reloading pages, and the data contained therein for the 585 Nyati matches closely to my simulation. The 458 Lott data in the reloading pages is lower than my simulation suggests.

Scott, I use a chronograph, not a calculator, simulator or loading manual, although the chrono has not been to the range for more than a year. I think it is a PACT (?) 3 screen model.

I wonder if altitude has anything to do with it. I shoot at 6000 or 6500 feet of elevation. Don't know if that would matter. However, in general I would tend to believe the numbers on a chronograph rather than out of a simulator.

How can you be sure that the mathematical model employed by the simulator does not break down at the edges of the envelope? For example, a complex mathematical function may be approximated by a simple algebraic expression within a certain range, but if your cartridge falls out of that range, then the algebraic expression will not longer be a good predictor. I suspect that the model was designed for 30-06, 270, etc. and may not be robust enough for the more extreme cartridges.

Your arguments may be worthy of Quickload or one of the other commercial packages, but to no apply to the Sweet Simulator.

The Sweet simulator was developed from big bore cases and correlated to actual measured pressures, velocities, bullets, and powders.

A list of the cartridges, which were directly utilized to achieve correlation are:
12 bore
577 NE 3"
500 Jeffery
500 AHR
505 Gibbs (minimal correlation work)
500 A Square
50 BMG
50 Beowulf
460 Weatherby magnum
458 Winchester magnum
45-120 Sharps
416 Rigby
405 Winchester
9.3X74 Rimmed
8X57 mm Mauser
7.62X39 Soviet
300 Winchester magnum
300 Weatherby magnum
30-06 Springfield
308 Win / 7.62X51 NATO
7.62X54R Soviet
303 Brit
30-40 Krag
30 US carbine
45 ACP
44 Remington magnum
22 LR

Numerous bullets and powders. Velocities were gathered with Oehler and Shooting Chrony chronographs.

I am immensely confident in the accuracy of this simulator from a velocity perspective. I do not trust ANY simulation with regard to pressure predictions. The accuracy of pressure measurements is typically no better than +/- 5% and more frequently more like +/- 10%.

Elevation will effect downrange velocities, but should not effect initial muzzle velocity significantly. Your 585 Nyati's quoted velocities are very close to Quickload simulations that I have seen published for this cartridge in the past. So your argument against the Quickload simulation actually appears to hurt your position.

Three screen chronographs are not necessarily more accurate, and there is significant potential for them to be less accurate, than a two screen chronograph.

Scott

Aaaah, but the defect remains.



The Sweet Simulator predicts my 585 will produce velocities 150 fps lower than I chronographed.



What am I to conclude? No scientist would conclude that a simulation is more accurate than the actual data.

Defect is not a correct term. Statistically speaking it is highly unlikely that your rifle would fire that projectile at the velocity you have stated, not impossible mind you, simply highly improbable.

I will believe your velocity claim only if I loaded the loads myself on my equipment, and shot these loads over my chronograph. Not calling you a liar, mind you, I am simply that much of a 'doubting Thomas'.

There is significant physics involved in these calculations, but a cursory examination of expansion ratios tells us that the 585 Nyati and the 577 NE 3" will have essentially the same performance.

The expansion ratio of the 577 NE 3" is ~ 11
The expansion ratio of the 585 Nyati is ~ 11.57

These two metrics merely say that the 585 Nyati will perform equivalently to the 577 NE 3" if loaded with a slightly faster burning powder than the 577 NE 3". However, the 585 Nyati has a small shoulder, which acts as a throttle. The throttle effect of this minute shoulder, from the perspective of the neck bore, does induce some small flow turbulence increase over the 577 NE 3". This restriction to flow, basically amounts to a small pressure amplifier, and brings the 585 Nyati back to using the same burn rate powder was used for the 577 NE 3" (the throttle has effectively eliminated the expansion ratio differential).

So in the final analysis, and this is based on a correlated mathematical model (meaning analysis matched to actual test results), the 585 Nyati will perform in a very similar manner to the 577 NE 3". I would say that the 585 Nyati may outperform the 577 NE by small margin, but with the mass of the projectiles these cartridges shoot it would not be anything massive with regard to velocity readings.

The biggest problem that the Sweet simulator has is with small, large bore cartridges, shooting light for caliber bullets, with fast powder i.e. the 50 Beowulf. Interestly, the Sweet simulator is quite accurate predicting the 50 Beowulf's ballistics when the 334 gr bullet is replaced with a 443 gr bullet (turned down Barnes Original, 450 gr SP). The reason for the inaccuracy with the lighter bullet is do to burn efficiency variation shot to shot, due to insufficient mass damping of the expanding gas column (too light of a bullet).

Like I said a few posts ago, if you are actually getting these velocities your rifle is either very fast or your load is way over-pressure. Again I will believe it when I shoot it over my chronograph.

Scott

Well my chrono avg was 2267 for 750 grains over 130.0 Re15. Pressures are moderate - some primer flattening but not much. Easy extraction.

I have no reason to doubt the chrono.

Roy Vincent's load for a 130 gr of similiar powder, 750 gr
solid, shows close to 500grains chronoed velocity, than to the simulator.What percentage of fill, compared to filling
to the bottom of bullet
is your 130 gr load.That is a major factor in making
a simulation come close.Vincent's info is
From reload pages on front of site.Ed.

Ed,

You are mixing powders. Roy Vincents powder is in the IMR3031 to IMR4895 burn rate. Which places it squarely between REl 7 and Rel 15. So the difference between Mr. Vincent's velocity and that achieved with Rel 15 would be approximately the same as the difference in velocity between Rel 15 and IMR4350.

Here are Mr. Vincent's loads:

Quote:

---

POWDER
VELOCITY
BULLET
ENERGY


140 IMR 4350
2125
BARNES MONO SOLIDS 750 GRAINS
7522

150
2240

8358

155
2290

8736

156
2310

8888

156 NORMA 204
2330

9043

120 S 341
2089

7269

125
2182

7931

130
2230

8284

135
2316

8935

140
2402

9610

150
2466

10130

152
2461

10088

153
2531

10671

75 H4831
1022
CAST 1200 GRAINS
2784

85
1150

3525

90
1259

4225

95
1351

4865

100 IMR 4350
1550

6403

110
1671

7442

110 NORMA 204
1680

7522

96 IMR 3031
1730

7977

100 S 341
1690

7612

---

500grains, I suggest you 'calibrate' your chronograph by firing the same loads your got 2267 fps with over two other chronographs and compare results. To be of any use you will need to fire at least 10 shots over each of those other two chronographs.

Scott

The part of the powder speed chart taken up by the powder Roy used and up to RE-15 is about 15%.Not a huge room

for variation.Lot to lot powder variations can take up half of that.I said a similiar powder, not an exact powder as there is no such thing. To many variables...And in my testing RE-15 speeded up a little as charges got over 110gr.IE,I graphed my load testing and the velocity curve steepened as load went up, in a faster amount compared to the actual wt of powder increases.If he has fast barrel that could be 50-100 fps there, fast lot of powder,50-100 there, powder speeding up as load increases

50-100 there, soon you have a bunch of factors that can give 150-200 fps extra above what is expected.Also are you figuring the speed and pressures of these bullets as a regular solid, as they are not.They in fact take the same pressures to get same speed as soft jacketed, not higher

pressures like regular solids.Ed.

I can't believe what I'm reading here! While imperfect, who in their right mind would trust a simulator( supposedely) developed by non other than Scott Sweet versus a chronoghraph? I too have a 585 NYATI and shoot the 130 gr RL-15 load. My results and 500 grs are within 15 fps of each other with two different guns and my chronograph ( an Oehler with 3 screens) is corrected for altitude. Sorry, but what exactly are Scott Sweets credentials as a software designer or ballistician? Let's see the supposed validation data on his simulator on each of the cartridges he claims to have used.Does he even know what Validation means? Did you follow a protocol Scott? If so let's see it! It must include verifiable Individual results, Number of replicates, statistical analysis program, his chronograph calibration records,balance calibration records, correlation with ballistic pendulum results etc. I want to see this data! Just another steaming pile of crap IMHO.
-Rob

Robert,



Lets see your calibration data. While we are at it, lets see all this supportive data from every single chronograph sold and each and every commercial software program.



Sad, very sad, counter argument. You aren't much of a debator are you.



By the way, why are you speaking to me. You are supposed to be ignoring my posts, remember!



Seems you feel you are riding to the rescue of a friend or two who have gotten in over their heads. The Sweet simulator will predict his 2267 fps (and yours too Robert) all I need to do is include the "Weatherby" factor. The "Weatherby" factor seems to be very evident with these three screen chronographs.





By the way, ballistic pendulum, that was too funny . Do you have any clue as to the uncertainty, statistically speaking that is, to the velocity prediction one acquires from an inelastic collision? A bullet strike against a ballistic pendulum is an inelastic collision, that is FACT.



Scott

I don't know why anyone gives ScottS (a known troll) the time of day. Block him (or her) out and when it responds to something all that comes up is:

*** You are ignoring this user ***

It has been much more pleasant on the board for me since I did that.

Have a good weekend.