Discrepency between Quickload & Observed Data

[Gary L. Griffiths]

I recently purchased Quickload based on comments from several members who use it, and some pressure signs I was getting from what I thought were good loads. (According to Quickload, one of my .223 loads topped 73,000 PSI!)

I recently did some load testing in .308 to see how much velocity degradation there was between my 18-inch barrel and the 24-inch test barrels used by the powder manufacturers. I loaded ten loads each in once-fired PMC brass, using CCI 200 primers and 168-gr Sierra MatchKing bullets. I had to use maximum loads, since that's the only data Alliant publishes. Please note that these are maximum published loads, to be approached with caution. One gave signs of excess pressure in my rifle.

Tonight, I checked the loads in Quickload, then checked the data with my observed results from shooting Monday afternoon.

AR-Comp, max load 42.2 grs. Quickload calculates 2582 fps with max chamber pressure of 59,115 psi. Alliant publishes 2782 fps from 24" bbl. My results were an average of 2635.71 fps., with no signs of excess pressure.

Varget, max load 46 grs. Quickload calculates 2612 fps with max chamber pressure of 62,139 psi. (exceeds maximum allowable pressure). Hodgdon publishes 2731 fps from 24" bbl. My results were an average of 2663.3 fps., with no signs of excess pressure.

BLC(2), max load 47 grs. Quickload calculates 2598 fps with max chamber pressure of 57588 psi. Hodgdon publishes 2754 fps from 24" bbl. My results were an average of 2705.5 fps. Primers were flattened with this load, and three primers were cratered.

Based on my limited experience with this software, I would say that its predicted velocities and pressures are quite a bit off, unless I'm not using it properly.

Advice from experienced users would be much appreciated.

[jwrowland77]

Originally Posted by Gary L. Griffiths

I had to use maximum loads, since that's the only data Alliant publishes.

Really???!!!!!!You're supposed to reduce the load given by 10% and then workup.

Btw, this is directly from Alliant's website on the WARNING page, you know the one you click on to enter the load data.

"REDUCE RIFLE AND HANDGUN CHARGE WEIGHTS BY 10% TO ESTABLISH A STARTING LOAD."

Originally Posted by Gary L. Griffiths

Primers were flattened with this load, and three primers were cratered.

I'm surprised they both weren't overpressure. Sounds like you need to slow down a bit before you hurt yourself.

Did you put all pertinent data into Quickload? Water capacity, etc?

[steve4102]

Did you check the actual case capacity in grains of H20?

QL default is 28.5 for the 223, which IMO is on the small side. My actual capacities are closer to 30gr H20.

Originally Posted by Gary L. Griffiths

I had to use maximum loads, since that's the only data Alliant publishes.

Bad Idea and No it is not the only data published. They also publish this little bit of data.

REDUCE RIFLE AND HANDGUN CHARGE WEIGHTS BY 10% TO ESTABLISH A STARTING LOAD

Found here on their "Warning" page. You might want to read it.

http://www.alliantpowder.com/reloaders/default.aspx

[cryogenic419]

You need to get the H20 capacity for your cases, that helps QL better calculate your loads. The other thing you can do to help zero in on accurate predictions is add your guns to the gun database file, that way you can have one load and switch between guns in the software to see what difference it should make between barrel lengths.

QL is usually pretty accurate as long as you feed it the correct parameters. I've tested my velocities with a chrono and compared that against what QL says to expect and its never far off.

[mehavey]

I'd say your AR-Comp and Varget results were right on (within the differences in individual barrels), while BLC2 was off (reasons TBD)

In the TBD department, adjusting the BLC2 burn rate from default 0.5160 to 0.560to match your velocity predicts a 68,000psi pressure peak. I'd look there first. (BTW, I've always had problems w/ BLC2. Maybe it's just me.)

Anyway, you now know the effective burn rate for your rifle with that powder batch. Proceed from there.

FWIW: I always run a significantly below-max load to establish effective burn rates for the system and go on those.

[Gary L. Griffiths]

Guess I should have mentioned that I had previously worked up all loads from 2 gr under in half-gr increments. No, it isn't prudent to just load up maximum charges and hope for the best!

The reason I chose to compare maximum published loads was because that was the only source of published velocity data. What I was looking for, was the relative decrease in velocity in my 18" barrel from the data published for a 24" test barrel. FWIW, BLC(2) gave 98.24% of published velocity (albeit with over-pressure signs); Varget gave 97.52% of published velocity, and AR-Comp gave 94.74%. None of the loads gave any pressure signs at -0.5 gr from max.

Thanks, cryogenic & mehavey. I'll check the water capacity of the fired cases, and adjust Quickload to that and the observed results from my rifle. That's what I wanted to find out.

[Brian Pfleuger]

Thanks, cryogenic & mehavey. I'll check the water capacity of the fired cases, and adjust Quickload to that and the observed results from my rifle. That's what I wanted to find out.

QuickLoad can be amazingly accurate but it does have a learning curve.

There are a number of variables that need to be adjusted to match your gun. Water Capacity is the most important, by far. I have found that QuickLoad under-estimates it in almost all cartridges by around 3-10%.

One of the next most important ones is Weighting Factor. QuickLoad's defaults for it are sometimes very odd. It's supposed to be a measure of the "Over-bore" of the cartridge but there's no definition given (or agreed upon anywhere that I know of) of exactly what quantifies "Over-Bore". If you go to the top menus and look for cartridge data (sorry, I'm not near QL right now so I can't be specific), there is an option for "Change Cartridge Data in Active File". In there, is a couple of boxes to click for bore/groove diameter and case dimensions. If you carefully enter the case dimensions, QuickLoad will give you a VERY accurate estimate of the case capacity (you should measure to verify) and a "Reasonable Estimate of Weighting Factor" (I think they call it).

Additionally, there are two formulas for figuring "Over-Bore" that I reasonably trust. One is the case capacity divided by the cross sectional bore area in inches. If the result is 1,200 or higher, the cartridge is Over-Bore. The other formula was developed by Bart B and is the powder charge divided by the bore area is mm^2. A ratio of 1:1 is perfect, anything more than about 15% higher is Over-Bore. Weighting Factor is sliding scale, from 0.33-0.75. I set typical bottle-neck cartridges between 0.45 and 0.50 or adjust based on those formulas.

You can also use Expansion Ratio as a measure to set Weighting Factor. As you see from QuickLoad's (annoying vague) explanation, it is a measure of the percentage of the powder charge and gases that follow the bullet down the bore. The higher the expansion ratio, the higher the weighting factor SHOULD be because more of the powder follows the bullet.

The third most important variable is Start Pressure. QuickLoad says to add 7,200psi for typical, jacketed rifle bullets touching the rifling. In reality, this too is a sliding scale, not a Yes or No. The minimum pressure is somewhere in the neighborhood of 0.25" (depends on cartridge, exactly. Might be 0.15 for one, 0.35 for another) off the rifling and anything closer or farther should give a higher value. The easiest way to handle this is to start at the 10,800 (I think, just check the values in the box to verify) max value and subtract 145psi for every 0.005 your bullet is from the rifling.

Get these 3 values reasonably close and QuickLoad should be very, very accurate in most cases.

[Clark]

I have been posting about Quickload on this forum since 2001:
http://thefiringline.com/forums/show...ight=quickload
I handload ~ 65 cartridges. I own 236 reloading dies.
This means I have been using QL for a long time on a lot of cartridges
QL thinks my hot 9mm handloads are over 1,000,000 psi, yet the primer does not pierce. I don't think a small pistol primer can go over ~ 70,000 psi.
QL predictions for velocity of bottleneck cartridges are often the center of a string I later chronograph.
What makes the hot handload predictions off by 1400% and the bottleneck within 1%?
The QL manual says hot loads in straight wall cartridges will be over estimated because the amount of powder blown out the muzzle can't be predicted.
But the 223 is bottleneck. You should be able to get very good predictions. Put the powder in a 308 with bullet off the lands and shoot a string. Compare the the chrono measure velocity to the QL predicted velocity. Change the powder charge in QL until the velocities match. Calculate the percentage change to powder charge. This characterizes your jug of powder with respect to the QL library. Now load some .223 off the lands and calculate the predicted velocity by using the characterization offset. Now shoot the .223 ammo over a chono. Notice how the prediction is in the middle of the measured string?

If you want to jam into the lands, then the start pressure in QL will need to be adjusted upwards.

[Bart B.]

Brian's comments on one of two:

The other formula was developed by Bart B and is the powder charge divided by the bore area is mm^2. A ratio of 1:1 is perfect, anything more than about 15% higher is Over-Bore. Weighting Factor is sliding scale, from 0.33-0.75.

I empiracally developed that formula from barrel life numbers top ranked competitive shooters in high power, benchrest, international free rifle and silhouette shooters. Also from test barrel life at Sierra Bullets testing their stuff for accuracy. It was all based on cartridges whose charge weight numbers in grains equaled the square millimeter numbers for the bore's cross sectional area. They all produced about 3000 rounds of barrel life. For example, .22PPC, 21 grains of powder, 21 square millimeters of bore cross sectional area and the .308 Win, 45 grains of powder, 45 square millimeters of bore cross sectional area in square millimeters with 3000 rounds of accurate barrel life.

The factor was based on the inverse square law for charge weight. A 30 caliber cartridge burning 45 grains of powder at normal peak pressre has twice the barrel life of a 30 caliber rifle burning 1.41 (square root of 2) times as much powder at 63 grains. .30-.338 Win Mags were popular for long range and burned 66 grains of powder getting 1200 to 1300 rounds of accurate barrel life with a bit more powder than 63 grains. Twice as much powder for the bore resulted in 1/4th of 3000 rounds for barrel life; 750 to 800 was all folks got with the 7mm Rem Mag compared to about 3000 with the 7mm-08.

The criteria was based on Sierra Bullets' one for test barrel replacement. When the test groups opened up 50% over what they started with, the barrel was considered worn out for best accuracy. Their .308 Win. test barrels used for bullets 180 grains and lighter opened up from 1/4 MOA to 3/8 MOA after about 3000 rounds and were then replaced. Top ranked competitive shooters used the same standard for the most part.

Note this was for super accurate competition rifles. Normal hunting rifles and their ammo will have twice the numbers; 6000 rounds of barrel life for the .308 Win. Service rifle life based on combat accuracy requirements is three times as much. M14 barrels (as well as 30 caliber Garand ones) were replaced at 9000 to 10,000 rounds.

[Clark]

I have been quoting Bart's barrel wear out formula for many years, always with the caveat, shot out for him [national level competitor ] would be brand new for me [putz].

From 1992
https://groups.google.com/forum/#!ms...8/UF0WINR94kAJ

[Gary L. Griffiths]

This thread is just golden! I've cut and copied Posts #4 - 10 into WordPerfect so I can print them out and study them at length. Thanks, guys, so much for taking the time to educate me on setting up and tweaking QuickLoad!

Clark, I'm moving in the foreseeable future to some property we have on the Toutle river about 25 miles west of Mt. Saint Helens. Would love to pick your brain over an adult beverage or two some time!

[Clark]

Gary,
I drive South to a gun show in Puyallup where I see a rancher who drives up North from Mt St Helens.
He is always buying an old lever Win. I think he sold me this one because it has a carbine butt and a rifle barrel.
I will be one of the 10,000 middle aged men in a plaid shirt.

[Gary L. Griffiths]

I carefully weighed the water capacity of my unfired LC13 brass, and found it to be 30.0 grains, with 0 SD over the three cases I filled and weighed. I loaded up 40 cases, 10 each with Armscor 55-gr FMJBT bullets & CCI-41 primers, 10 each with Winchester 55-gr FMJBT bullets & CCI-41 primers, 10 each with Armscor 55-gr FMJBT Bullets & CCI-400 primers, and 10 each with Winchester 55-gr FMJBT bullets & CCI-400 primers. All had identical loads of 25.0 grains AR-Comp.

I adjusted the case capacity from 28.5 to 30.0 grains. According to (my understanding of) Brian's formula, I divided 30 by 0224X0.224 and came up with 597.9 - well under 1200. Using Bart's formula, I divides 25 by 5.56X5.56 and came up with 0.81. Guessing that these formulas indicate that the standard weighting factor as specified by QuickLoad, of 0.6 was high, I changed it to 0.45 (a SWAG).

QuickLoad predicted a velocity of 2991 fps and pressure of 49726 psi with the standard (0.6) weighting factor, and 3021 fps and 46930 psi with the 0.45 weighting factor.

So, today I repaired to the range with my trusty F1 Chrony, and commenced to fire for effect. The Armscor bullets averaged 3134.7 FPS with CCI-41 primers, and 3155.7 FPS with CCI-400 primers. The Winchester bullets averaged 3067.0 fps with CCI-41 primers, but I began to have trouble with the Chrony giving errors with the first 4 shots with the CCI-400 primers. And then I shot the chrony. It was a quick but violent passing.

ANYWAY, in playing with the actual velocities, it looks like QuickLoad would have been fairly in the ballpark if I hadn't adjusted the case capacity to the actual recorded water weight. I suppose my math on the weighting formula is FUBAR, so would greatly appreciate further elucidation!

FWIW, all loads were fairly consistent (between 16 & 28 SD) and none showed any pressure signs.

Thanks, guys!

[Clark]

I bought another copy of Quickload and put it on my brother's computer. I also bought the computer for him.

This is what I wrote to get him started.

1) Click on the Quickload icon on your desktop
2) Click on "continue".
3) select a cartridge
4) click on the 7th icon on the tool bar. It is the second image that is binoculars over a case.
5) click on "ok"
6) Click on "ok"
7) Click on "ok"
8) Click on "yes"
9) Select a bullet
10) select a powder
11) type in a powder charge
13) type in a barrel length
14) click on "Apply&Calc" in the charge section
15) Wait for 10 seconds for the velocity and pressure to appear

16) Click on the QuickTarget icon on your desktop
17) Click on continue
18) Click on "Receive Data from QuickLOAD"

19) Click on the 16th icon on the Quickload tool bar that says "1 2 3".
20) Enter a maximum pressure of 65,000 psi
21) Click on "Apply&Exit"
22) Find the powder in that list, that you own, that gets the highest velocity
23) Select that powder in the charge section

http://www.youtube.com/watch?v=a3RkvTxW4lE
Kevin Adam
http://www.shootforum.com/forum/

[44 AMP]

While I'm sure its a wonderful tool, I don't use it. Simply because I don't do reloading stuff on the computer.

All I really want to point out is that no computer program, (or paper calculations) can be anything more than a general guideline, unless you input the specific values for all your personal variables, AND do so accurately.

The mind set that "if its in the books, or on the screen, it must be right" is a trap. Certainly it is right, BUT only for those specific components/variables used in the test. What happens in your gun, could be different.

Guidelines, things to be aware of, fine. Taken as absolutes, not so much.

M14 barrels (as well as 30 caliber Garand ones) were replaced at 9000 to 10,000 rounds.

I'd like to address this statement, while its probably correct, I can tell you that in the mid 1970s when I worked in Army shops, we NEVER paid any attention to the round count of rifle barrels. In fact, with regular service rifles, that information simply did not exist. Barrels were replaced when they failed erosion gauge checks (or other failures).

If the Army had the info on round count for rack grade rifles, we never saw it. Now, artillery (including mortars) had logbooks, where round count was kept, and we recorded inspection results (borescope & pullover gauge readings) in them, but ordinary small arms didn't have such logs, as far as I ever knew.

match rifles might have had such, I don't know. The shops I worked in didn't support those rifles.