Hi there,

Could someone with one of the better ballistic software packages give me a velocity/pressure prediction for the following:

.500 A2
525 gr bullet
IMR 3031 90 gr
23 inch bbl

Thanks,

I'm not aware of any software which can accurately predict fps and pressure from a given charge of a certain powder. Certainly QL cannot; it's known to miss by 10,000 psi at times. From what I've seen, 3031 is one of the powders not so well modeled in QL. An empirical approach, such as used by LoadTech, might with some powders do better than the simulation approach used by QL, but I wouldn't bet on it.

Software is able to estimate the velocity possible at a given peak pressure limit, and it can correctly predict which class of powders will let you attain such performance. That's not the same problem as predicting what a particular set of components will do. Software cannot predict what one powder will do; lot variations alone prevent this.

QL is an excellent tool for learning about internal ballistics, but it can't (reliably) do what you ask.

Thanks for the correction.

quote:

An empirical approach, such as used by LoadTech,

I checked Loadtech. It lists the 500asquare but it doesn't have the water capacity of the case.

QuickLoad will do it, but I'd need the length of the bullet and preferably seating depth or COL.

Eric

I will gladly measure the bullet length and COL tonight. Thanks for the help.

Water capacity is in the 141.5 to 143 range.

Load from a Disk says you can safely go up to 92.7gr of IMR4064, at 2145fps and 45,736CUP using Barnes TSX FB.

Or, 105.9gr max using Barnes banded solid, 2240fps, 45,863CUP.


LFAD lists a dozen appropriate powders, IMR 3031 is not included. Sorry.

LFAD predicts 2233fps at 100% load density with BLC#2 and the TSX bullet.

quote:

Originally posted by analog_peninsula:
Hi there,

Could someone with one of the better ballistic software packages give me a velocity/pressure prediction for the following:

.500 A2
525 gr bullet
IMR 3031 90 gr
23 inch bbl

Thanks,

Cartridge : .500 A-Square
Bullet : .510, 535, WDL FMJ 10
Cartridge O.A.L. L6: 3.740 inch or 95.00 mm
Barrel Length : 23.0 inch or 584.2 mm
Powder : IMR 3031

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0 75 80.00 1957 4549 27519 5915 98.0 1.624
-18.0 77 82.00 2000 4752 29231 6049 98.6 1.583
-16.0 79 84.00 2043 4957 31047 6174 99.1 1.543
-14.0 81 86.00 2085 5166 32974 6288 99.4 1.504
-12.0 83 88.00 2127 5376 35018 6393 99.7 1.466
-10.0 84 90.00 2169 5589 37190 6488 99.9 1.429
-08.0 86 92.00 2210 5803 39496 6571 100.0 1.392
-06.0 88 94.00 2251 6019 41943 6645 100.0 1.355
-04.0 90 96.00 2291 6236 44521 6716 100.0 1.320
-02.0 92 98.00 2331 6454 47233 6786 100.0 1.286
+00.0 94 100.00 2370 6673 50099 6855 100.0 1.254
+02.0 96 102.00 2409 6894 53132 6922 100.0 1.223
+04.0 98 104.00 2448 7117 56344 6987 100.0 1.193 ! Near Maximum !
+06.0 99 106.00 2486 7341 59745 7051 100.0 1.164 ! Near Maximum !
+08.0 101 108.00 2524 7567 63350 7113 100.0 1.136 !DANGEROUS LOAD-DO NOT USE!
+10.0 103 110.00 2562 7795 67172 7173 100.0 1.109 !DANGEROUS LOAD-DO NOT USE!

Use the numbers with care, analog_peninsula. The QL results at 90 gn show a pressure low enough that you should not have problems, even with a hot lot of 3031. Do not expect the fps estimate to be accurate. Lot variations are significant in any powder, and QL's author clearly states that the results become more inaccurate as the simulated peak pressure drops.

Trying to run to near full power is where the problems start, and I regret not running your numbers first to see if it was indeed near max. Most people asking for QL numbers are trying to predict maximums, which it will not reliably do.

I appreciate the advice from everyone; all of it.



I'm using the 525 gr Cast Performance bullet. I measured it last night and it was 1.054 inches in length. The bullet was designed for one of the old sharps cartridges, so the crimp is very high on the bullet, 0.635 up the bullet, so 0.419 remains exposed. My case was 2.867 inches in length, so the OAL was 3.286.

For those numbers, the estimated pressure is on the order of 40,000 and the velocity 2200 fps, but (for one more time) neither estimate is at all likely to be right on. QL estimates you won't be getting pressure concerns until about 2400 fps.

Thank you for the update, asdf. I'm using this load for case forming and practice; I'm not going to push the envelope with this one.

Quite frankly, I have very little desire to shoot maximum loads out of my A2. If I can get comfortable with a 570-600 grain bullet at 2200-2250 fps, I'll call it quits there.

You should be fine with your 3031 load. I use 3031 with the Barnes 570gr TSX and it works fine. I am getting 2200+ fps without any undue pressure. Quickload says my 570gr TSX load is running mid 50 ksi range.

By the way, it doesn't appear to me that anyone has posted any QuickLoad data on this thread so far.

POP, what simulator was your data created with?

ScottS, both POP and I have posted QL data for the question asked, POP's promptly, mine belatedly.

asdf,

What if you were to substitute his bullet for a Barnes 570gr TSX at a COL of 3.64". Everything else remaining the same (barrel length, cartridge, powder, etc). What does QL provide for a muzzle velocity and pressure?

Thanks!

If someone can give me the water capacity of the case I'll see if Loadtech will use 3031. I can't force a powder to be used.

Ammoguide.com lists the estimated water capacity at 133 grains.

Sorry Loadtech is of no help.

Thank you for checking, just the same.

ScottS: 39 ksi and 2000 fps at 90 gn, but my copy of QL only had dimensions for the 570 XLC, which should be close enough given the limited accuracy of such predictions.

I’ve said many times in a number of different forums that Quickload is not “God’s gift to reloading†and always check it’s results against published data.

Quickload is not a pressure-tested electronic reloading manual, it’s a computer model (simpler but no different than the global warming computer model). Quickload is not a program for the neophyte reloader or even the casual reloader.

Quickload is a “what is my possibly†program. It’s Lies all the time but it gives valuable information too.

If you haven’t been reloading long enough to have a feeling (gut feeling) that something is wrong here. You have no business owning the Quickload program. You don’t have enough experience, or enough resources to published information.

asdf,

My chronograph says that my load is running 2230 fps (90gr of 3031 and a 570gr Barnes TSX out of a 23" barrel). Can you tweak the QL simulation to get an estimated pressure?

quote:

It’s Lies all the time but it gives valuable information too.

No, Mick, it gives rather poor estimates all the time. It never lies. I try to make it clear that these numbers are only estimates, and estimates can be useless. ScottS, perhaps below there will be enough to let one see why Mick's warnings must be heeded.

For your case, ScottS, I had entered "90" in the wrong field. I was suspicious of the numbers I had listed earlier, but I was in a hurry and didn't think it through. Running it again, QL predicts over 70 ksi, but at 2350 fps. A 120 fps difference is a big error where pressure is concerned. As I tried to stress earlier, trying to predict what a given charge of a certain powder will do is impossible. No software can be aware of all the powder lot variations, nor does any of them try to adjust for different primer effects, nor do they know about the condition of your chamber. When QL is reporting pressures near the cartridge's limit, the pressure estimates cannot be safely used. As I mentioned in a post above, QL is known to be off by 10,000 psi at times.

QL will try to predict what pressure corresponds to the fps you're seeing. This is a somewhat better bet than trying to predict what pressure a certain charge will produce. For 3031, it estimates your 2230 comes from 84.5 gn (not 90 gn) and it predicts pressures on the order of 60 ksi. However, while I have not used 3031 in reloads myself, I have noticed that QL's predictions with 3031 are quite rosy when compared to pressure tested data, and I would never trust 3031 estimates from QL. Comparing to other powders of similar characteristics, you get estimates of mid-60's to low 70's. Based on my experience with QL when making comparisons to loadbook data, I'd hazard a guess that you're running hot at 2230 fps, say around 70 ksi.

Lastly, I ran QL the way it's author recommends. Here I see that powders similar to 3031 are the best performers, but QL is not accurate enough to predict which one of them will give you the top performance. From the QL numbers, I'd say 2150 fps is likely to prove safe with some powder and primer combination, but QL cannot tell you which combination. I would not be surprised if better performance than 2150 can be safely attained, perhaps with one of the denser, spherical powders.

Such ballpark estimates are where QL comes in handy. You can get an idea of what sort of performance a cartridge can give at a certain pressure and which powders are good candidates, but you most certainly cannot predict what a particular combination of primer and powder will do for you.

analog_penisula, I checked the numbers for your case again and got the same values, and I again offer the same warnings.

I'm a QL fan; I own the 3.3V and, untill now, it gave to me useful and quite accurate predictions about the pressures, on several calibers, as long as I check the EXACT brass capacity and EXACT bullet length (some of the data included are slightly erroneous); I almost exclusively use Vithavuori powders, that are really consistent. Asking QL to exactly predict the V/0 of a load is somewhat excessive; for this purpose it needs a chronograph.

LFAD lists full case capacity (not useable, mind you) at 141.45 for 500 A Square.

asdf,

Thank you for running that analysis for me. Now you have me concerned. I have shot that load for quite sometime without the least indication of pressure. It also happens to be the most accurate load in my rifle by far.

I take it from your posts that your feel I am definitely exceeding the envelope and should most likely back the load off a few grains.

My A2 brass measures between 141.4 and 143 gr depending if it is sized, fired, at max case length or trimmed back.

ScottS, I do not know your load is hot. I suspect it is, but it is not possible to say from QL numbers. There's been times when a load book showed a safe load that QL thought would be hot, and vice versa.

If you have the exact bullet length (I used an estimate), I'd be happy to run QL numbers again. (If it's a boat tail, I'd need the diameter of the base and the length of the tail.) From the numbers currently at hand, if I had only the condition of the brass and a chronograph to go by, I wouldn't go over 2150, and frankly I'd probably go slower than that. With a strain gauge available, I might go for a bit more. Others would interpret the tea leaves differently; this is not an exact science.

Lastly, some food for thought: I just went and ran some QL numbers for the type of load tested in the A-Square manual. Assuming the 600 gn bullet is 1.29" long, QL tells me 2300 is about all one could get, maybe over 2380 if you want to stretch it. The tested loads run safely to 2500--a big difference.

Well, one more thought: a strain gauge rig is worth more than QL. If you're worried about your loads, get one, and calibrate it with factory loads.

asdf,

The Barnes TSX is 1.563" long and is a flat base design.

Thanks again for the help.

Nearly the same results; I wouldn't care to go beyond 2150 without the aid of a strain gauge. Actually, with just the chrono, I'd stop at 2100. Call me chicken. As a reminder, my QL results seem to be pessimistic when compared with the A-Square book.

Completely agree with all the folks recommending against putting any faith in the Computer Software as it predicts Velocity and Pressure. It might be way off, or relatively close, the problem is you just don't know which way the "prediction"(Mathematical Model guess) went.

quote:

Originally posted by asdf:
... a strain gauge rig is worth more than QL. If you're worried about your loads, get one, and calibrate it with factory loads.

Normally agree with asdf, but we do disagree on the value of any HSGS. When the HSGS can not be Calibrated, the Chamber measurements must be guessed at, a PT Barnumed Fudge Factor must be entered into the Software, you are Haphazardly gluing a Strain Gauge to a surface that it really doesn't want to adher to, and you only get 3rd Hand "Haphazardly Guessed-At" results, a HSGS just doesn't seem worth the $500-$3000 to me.

Seems to me it would be much better to use the time-proven, venerable, CHE & PRE Pressure Detection Methods which work for every cartridge in existance, and provide first-hand information directly from the weakest link in the firing process, to know when it is time to Stop dumping in the Powder.

Once you know where the Upper Pressure Limit is, shoot some Cartridges to develop the Drop Chart. And with these DG cartridges that should go rather quickly due to the Limited Range they are typically used.

Then use your Software Mathmatical Models to estimate the Velocity and Pressure for grins. As a nice side Bonus, you can manipulate the Software to give you any Velocity you desire since it is just a guess anyhow. Same as you can manipulate the PT Barnumed Fudge Factor in the HSGS to give any Pressure you desire.

Best of luck to you all.

asdf,

I wouldn't put too much faith in that A2 manual. I think my rifle would explode if I tried anything near their max loads!!! I get sticky bolt with their starting IMR4064 loads and 600 gr bullets! Personally, I think the 500 A2 pressure data is erroneously cited in the A2 manual as psi when in fact it is CUP! Not only that, but I have blown primers in the 308 using A2's data, and gotten sooty primers in the 300 Win mag!!!

Having said that the A2 manual's data for the 460 Weatherby seems to be very accurate.

Hot Core, what would the acceptable maximum CHE/PRE be for a 500 A2?

Hello again Hot Core. We've discussed this use of factory ammo before, and I recall you found it reasonable. I used the word "calibrate" for lack of a better, simple term. I was not trying to imply you'd have a true pressure calibration. Forget the accuracy of the psi computation. Instead use the indicated psi from the factory load as your limit for handloads. As long as the strain is no greater than what factory loads produce, you should be as safe as with factory loads. It would be nice if the software produced a strain or voltage number instead of a psi estimate. I think people would be less likely to confuse this with true pressure. As for the cost, luckily I have access to a portable 'scope from work. A few resistors, a battery, and a strain gauge, and I should be in business (when I get back to the US).

ScottS, thanks for the info on the A-Square data. I was a bit surprised the QL numbers were that far off. I've never used A-Square data in my own handloads.

quote:

Originally posted by asdf:
Hello again Hot Core. We've discussed this use of factory ammo before, and I recall you found it reasonable. I used the word "calibrate" for lack of a better, simple term. I was not trying to imply you'd have a true pressure calibration. Forget the accuracy of the psi computation. Instead use the indicated psi from the factory load as your limit for handloads. As long as the strain is no greater than what factory loads produce, you should be as safe as with factory loads. It would be nice if the software produced a strain or voltage number instead of a psi estimate. I think people would be less likely to confuse this with true pressure. ....

Hey asdf, Yes we are in agreement - complete agreement.

The HSGSs tend to mislead folks in many ways. When they show 52,619psi, if it said "5Xk guessed-at-psi, with maybe a variance of +/- 4-8Kpsi", they would be a lot less misleading. Probably not help the $500-$3000 selling of them though.

A pressure computation that's withing 4 ksi of the true value is still useful information, I feel. Regardless, you can do a lot with just a plot of micro-volts. Combine a voltage plot with a chronograph, and there's little you can't do.