Before I buy Quickload....

[miningshawn]

Does Quickload work for wildcat cartridges? I have been using Gordon's Reloading Tool but I would like to compare my figures.

I am developing a new cartridge and can get accurate case volumes, would Quickload do these?

Thanks in advance for your input!

 

[MagnumManiac]

Simple answer...YES.
Do not expect real world numbers to match though without some serious tweaking.
I have a Pressure Trace II, I could not get numbers to match actual pressure testing.

Cheers.

 

[miningshawn]

Thanks for the tip! The Pressure Trace II may be the winner over Quickload... That looks like a pretty skookum system.

 

[mikecr]

PT and QL are different things all together. They don't replace one another.
And with either, without a 'test barrel', neither is more accurate than a good chronograph confirms.

You can calibrate QL to ANY cartridge, barrel, and powder lot.
You can run what-ifs with QL to aid in new design. This is the true value in it.
And like any ballistic software (internal or external) junk in = junk out. You have to learn how to use it well.

 

[jelenko]

I think I got it, but to confirm.
If I get a load in Gordon's Reloading Tool to match Bullet Lead Time with the Optimum Barrel time, it may, or may not, be an accurate load - and, it probably won't be an accurate load.
Would the predicated accurate load from Gordon's be close? I.e., within a couple tenth's of a grain?
Thanks

 

[MagnumManiac]

Predicted Optimal Barrel Time is hit and miss in my experience.
It only takes ONE parameter being off and the OBT is out the window.

I am bald...because of trying to match real world with predicted.
Mikecr is correct, one doesn’t replace the other, but using the Pressure Trace gives me ACTUAL RAW DATA. I don’t calibrate, my rifles aren’t to SAAMI spec, so what is spit out is what it is.

I have taken some loads well passed proof loads with nary an issue...in brass capable of such pressure.
But none of my loads exceed the max average for any given cartridge but one, I run my 222Rem at 223/222Mag pressure because it can be.

Cheers.

 

[dcali]

Pressure trace (which I don't own, to be clear), is a strain gauge pressure measurement system - all it does is measure the stretch of the barrel in the chamber - that stretch will be proportional to pressure *experienced by the chamber*. That is, it will read zero if the brass is capable of holding the pressure without expanding to the chamber wall (an unrealistically low pressure, but it illustrates the concept). What it doesn't do is have a good way to calibrate that stretch into an absolute pressure reading, which is a major consideration *if* you want be confident that what you're measuring is really what you're seeing. You can half-ass it by using a factory round to calibrate, but that's not an option with a wildcat. The best you can really do is to use quickload to calibrate the pressure trace, which is really the opposite of what you want. (Tests ought to validate analysis, not the other way around). Harold Vaughn used high pressure oil to calibrate his strain gages in "Rifle Accuracy Facts" (well worth a read if you can find a copy).

QuickLOAD is interior ballistics prediction software that uses measured values of the thermodynamic properties of powder, along with cartridge dimensions, to predict the pressure and motion of the bullet while in the barrel. They're different tools for different jobs. QuickLOAD is surprisingly good in my experience and has largely replaced reloading manuals for me. I still sanity check with the manuals, but it's never been a problem. But yes, it will work for your wildcatr. Assuming sane parameters, QuickLOAD doesn't really distinguish the geometric details of a case - it basically uses internal volume and a handful of fudge factors.

You might also look into QuickDESIGN, which is the wildcat design software - I don't have any experience with it.

Side note: OBT nodes don't exist. That's my story and I'm sticking to it. That's a whole 'nother thread, but it suffices to say that there are a lot of serious problems with the theory.

 

[mikecr]

Side note: OBT nodes don't exist. That's my story and I'm sticking to it. That's a whole 'nother thread, but it suffices to say that there are a lot of serious problems with the theory.

I agree

OBT 'nodes' are not tuning nodes (like powder plateaus and barrel whip positions).
OBT only attempts to place bullet muzzle release furthest from one particular barrel vibration.
It doesn't predict best load or anything near that.

I believe 'optimum' in OBT is a misleading, as there is nothing optimum about ANY barrel vibration.
The best you can do with OBT is see, as predicted, that certain timings are detrimental to whatever else you have going on. Better coined as Bad Vibration Time, BVT.

 

[chop house]

Harold Vaughn used high pressure oil to calibrate his strain gages in "Rifle Accuracy Facts" (well worth a read if you can find a copy).

a link to electronic copy of this work was published on AS about 6 months back

 

[chop house]

(like powder plateaus and barrel whip positions).

whip i can understand.... powder plateaus i have occasionally observed but can not understand (yet). what are the leading theories for why they exist....?

 

[dcali]

whip i can understand.... powder plateaus i have occasionally observed but can not understand (yet). what are the leading theories for why they exist....?

Depending on what one means by powder plateau, I don't think those exist either. A lot of shooters will plot velocity vs charge weight, one shot each, and look for a spot where the velocity is flat from one charge to the next, and then call that a node.

In my experience, that does not actually happen. On any given string, you are far more likely than not to see a "flat spot", but it's just random chance. If you try this with 4 or 5 shots per charge, you'll find that the plateau disappears.

But...

I have seen velocity variation change as charge increases. Sometimes the SD shrinks as you approach a certain charge weight, and then starts to grow - sometimes substantially.

But generally, more powder means more energy, which means more velocity. Clearly, something happens to combustion as charge weights increase in small increments, but I don't believe that it's a flattening velocity curve. Many shooters tell me I'm flat out wrong about this, but I've never seen a statistically significant test that showed otherwise.

 

[dcali]

a link to electronic copy of this work was published on AS about 6 months back

I'm normally not a fan of archive.org, as they've got an "ask forgiveness not permission" stance on copyright, and I believe authors deserve to be credited financially for their work. Nut since Vaughn's book is so important and so hard to find (and various attempts at getting it republished have failed), I don't have a problem posting this link:

https://archive.org/details/RifleAccuracyFactsFullV1.0FirstFullScan

 

[mikecr]

OCW seems about finding a forgiving load, and this is what I mean w/resp to a plateau -for hunting capacity cartridges. For underbores (like 6PPC, 30br, etc) competitive pressures get into diminished returns, which provides diminished variance of returns.

Barrel whip is seen with ladder testing. It doesn't follow OCW at all.
If you want both, outside of luck, I'm sure a tuner suites the cause.

I believe in system tuning as well. The way a gun twists, hops, recoils, etc.

Barrel vibrations, as Vaughn tested, pretty much show nothing beneficial for us. Only bad.

 

[miningshawn]

Thanks for the great dope, I didn't see this thread going this far.

Damon, I am building a whole new cartridge. Where I see PT2 giving me a leg up will be determining upper and lower charge weights - AFTER I get a calibration. Since the cartridge is based on .308 I have tons of data available for comparison. I will probably try a strain gauge on one of my .308's and extrapolate data for the new cartridge. Pressure limits should be similar. Of course there will be much fired case inspection, but this will give me a start.

QL just does not seem to be as intuitive. It can predict pressure when given specific values, but I don't have the values yet. I am not writing QL off - more like postponing until I gather enough data. I have taken (and passed...) Thermo, Fluids, Strengths, Dynamics, etc... in core engineering classes and can understand and appreciate the effort of developing QL. I also know what garbage or inaccurate data does to a formula... Just not ready to dive into that pool yet.

I can predict a usable load but do not want to do OCW and visual pressure tests for RL16 all the way through 4831!

Mike, I find it interesting reading up on optimum barrel time. I have to dig a little further but it appears there are some variables that are VERY hard to pin down. I will stick with OCW for a while!

 

[Ned Ludd]

The primary cause of inaccuracy in Quickload outputs I have found over the years is that the predicted responses are linear, whereas in reality they are not.

I initially "calibrate" Quickload to a given rifle using a slightly reduced charge weight, typically about 2%. With a known average velocity for a given charge weight, as well as the additional pertinent inputs (barrel length, bullet OAL, case trim length, case volume, temperature), you can then adjust the powder burn rate factor (Ba) until the predicted velocity exactly matches the measured average velocity. Once this is done, I have found the QL outputs to be quite good as long as the final load (charge weight) doesn't end up too far from the initial calibration charge weight.

The farther away the final load ends up from the initial calibration step, the greater the discrepancy between predicted and actual results seems to be. My interpretation of this behavior is that the real-world responses are only close to the predicted linear responses over a somewhat narrow charge weight range. I address this issue by re-adjusting the charge weight, temperature, and burn rate (Ba) values every time I generate additional data, then saving the new file/date.

In my hands, QL can facilitate and expedite the process of getting you to the right neighborhood, but finding the exact right house requires testing, interpretation of the targets, and regular updating of the QL inputs as you test.

 

[dcali]

I think quickload is very good. I mean, it sucks because they must have some guy that's been trapped in a cave since 1998 writing it, but it does a very good job regadless. The inputs are not that daunting - you can pretty much input case capacity, OAL, bullet dimensions, and barrel length, and it will give you usable results. They'll be off a little, as any analytical engineering software will be, but it's surprisingly good. It is very useful for picking a good powder, and will give you a very good estimate of maximum charge. It will be off a little bit on velocity unless you're lucky, but it's still much better than reloading manuals, where you may not even know the barrel length used. If you really want to tune it to match your tests, there are inputs for the thermodynamic data of the powder that you can manually tweak. I get nervous doing that, and have never had it so far off that I needed to do it, but you can.

It's worth the money for this sort of thing. I would highly recommend getting it *before* messing around with strain gages.

One thing if you happen to be using a Mac - you'll need to either run windows on it, or use an emulator like wine. Wine is not currently compatible with the latest OSX version, in a non-trivial way to fix. There is a commercial version called Crossroad that will do the job, however. But Apple just announced that new models will have Apple chips rather than Intel, so my guess is that will screw it all up again, but hopefully not as bad. In any case, make sure you can actually run it. You will probably need to buy a cheap optical drive to even install it, because (stupid?) reasons.

 

[mikecr]

A while back I sat down with a bunch of 25wssm cases measured, improved the case with RCBS 'Cartridge Designer' to 26wssm Imp. and run what-ifs in QL. Here I set weighting factor for short/fat, tweaked H20 capacities, and using a 26cal test barrel choice I knew to be good (for correct barrel volume). Set the chosen bullet bearing seating just shy of expected donut area, and a starting pressure based off the lands.
I set barrel at 28" to reduce muzzle pressures, and chose coolest powder that filled the case for best velocities at SAAMI max. Having discovered best overall capacity for 26cal, I filled out a reamer print to produce this, with the right throat for the bullet, and made my order for a set.

After the barrels were finished with my reamers, cases fire formed and tested across an Oehler chrono with 20' screen spacing, it actually happened that measured velocities were within a +/-3 FPS of QL estimated.
That screen spacing gets me to +/-2FPS, so,, damn!
This was a bit lucky given variances in powder lots. I'll concede that.
But, H20 capacity measurements showed EXACTLY what Cartridge Designer showed.
I also ran MyMax testing for the pressure point requiring FL sizing -from a single firing of new cases, as measured at weblines. The result was 5Kpsi past SAAMI max (65Kpsi), which I fully expected.
It was a fantastic success of prediction. Totally happy with the outcome.

I doubt there is another way to account for so much.
But if you know another way, I'm all eyes.

 

[Full Chisel]

The farther away the final load ends up from the initial calibration step, the greater the discrepancy between predicted and actual results seems to be. My interpretation of this behavior is that the real-world responses are only close to the predicted linear responses over a somewhat narrow charge weight range. I address this issue by re-adjusting the charge weight, temperature, and burn rate (Ba) values every time I generate additional data, then saving the new file/date.

I hope you guys don't mind me reviving this thread, so let me know if I need to start a new one. BTW greetings and thanks for all the good info.

I have been messing around in QL for for countless hours over the last couple of weeks trying to see if it will match up with some of previous load data. It actually did a pretty good job with velocity once Ba tweaked. It also seems to be indicating that the QL barrel times vs published OBT node times seem to be syncing with my accurate loads, pretty well in fact. I have put in everything as perfect as I can get it, which is to say pretty dang good.

But I see the velocity discrepancy @Ned Ludd mentioned. If I calibrate velocity for a lower charge, the upper charge, if it is 1.5 or so grains higher, will be predicted lower by QL than I actually measure. I have seen this for 5 different loads, with two powder lots for one particular load. Loads are 223, 22-250, two 308's, and 30-30. All showing the same behavior. I have a lot of velocity data from these loads with many data points. I have tried Ba, cart weighting, bullet weight, temp changes (to match actual) and everything Chris Long and others have mentioned, but can't get the charge vs velocity curve to change "slope". Any ideas?

I'll throw this out there, though it is highly unorthodox. I finally tried tweaking the propellant solid density and bingo, the slope change changed and I got the velocity data to sync with some follow-up Ba adjustment. Afterward, I will say that the pressure predictions went crazy and it seems everything I'm shooting is at or near max, LOL - which they're not, confirmed by actual testing. But, I got it to predict the velocities of a new OCW load workup that a buddy was shooting on his 308. But, this seems pretty unorthodoxed and I am hesitant to claim any validity to doing it at this point. Anyone else try this?

Anyway, thanks in advance for your thoughts.

 

[Jager]

Once calibrated with accurate chrono results, I find QuickLoad to be remarkably predictive. But as @Ned Ludd noted, the mathematical modeling that QL does is linear. And the wider a charge ladder is the more disparity one is going to pick up on the opposite end from where the calibration was determined.

You can calibrate QL at a charge weight somewhere in the middle of where your ladder will be, letting the upper and lower parts of the ladder be off a bit.

My primary use of QL, however, is to predict pressure. And since I'm far more interested in what my actual pressures will be as I approach SAAMI max (or whatever maximum I have determined to go to, if it's a wildcat round), I inevitably find myself calibrating QL at the upper end of the ladder. Letting the lower end of the ladder fall where it may.

I don't use QL to try and determine nodes or OBT or accuracy or anything else. But it's great for analyzing potential powders, different bullets, different seating depths, different case capacities, different barrel lengths.... really, anything that hinges on the pressure curve when the round goes off.

 

[Full Chisel]

You can calibrate QL at a charge weight somewhere in the middle of where your ladder will be, letting the upper and lower parts of the ladder be off a bit.

That is what I found to be the compromise for the ladder and OCW tests I analyzed. Interesting program though. Not sure where its going to ultimately fit in my load development, but my original goal was to use it to identify the major and minor target flat spots as either correlating with an OBT node or not. Still not sure if that's gonna do anything for me, but it seems it could mean more overall stability for load. IDK.