Questions regarding case capacity and QuickLoad

[Boogaloo]

Here is the front story....

The Rifle: AR15, Satern hand cut 16" match barrel, 1:8 twist, Wylde chamber, Young National Match BCG and the rest of a long list of fancy parts that make up this "special" rifle. It is a nice piece to say the least.

I shot a couple of boxes of Federal XM193 through this rifle after I built it. Did my own personal break in procedure, sighted in the scope and had a great day of shooting... That was a little over a month ago.

I collected all of that brass and saved it as fire-formed to that rifle.

Once I started reloading that brass, and started my load development for that rifle, I purchased QuickLoad and started in on the process.

One of the first things I did was to get an average (maximum) case volume/capacity for those particular fire-formed, once fired cases. That number is 30.9 grains of water , filled as indicated so that the meniscus just protruded over the top of the case mouth.

Here is where the problem/challenge begins:

QuickLoad's default case volume for .223 Remington (SAAMI) is 28.8 grains of water. Conversely, it shows 28.5 grains of water for 5.56x45mm (NATO) cases.

Using that data, and knowing that I have 5.56x45mm NATO cases (Lake City 11 head stamp) I select the 5.56 case from the drop down in QuickLoad and input my maximum case capacity of 30.9 grains of water. I select the bullets I was going to reload (Hornady #2266 55gr SP W/C) and select the powder (Accurate 2230).

Additionally, just prior to starting in on the loading process, I made up a dummy round seated to the top of the cannelure and did a chamber test on my rifle to determine that this particular bullet seated at this particular depth (COAL of 2.185") afforded .048" of bullet jump, and was safely off the lands. I have a home made series of tools I use to make this determination and I am completely comfortable with my methods.

QuickLoad will work up a load ladder based on powder charge number you input, so I selected a starting charge of 26.2 grains of Accurate 2230 since this charge was in the "yellow zone" and more than 15% below max indicated (NATO) chamber pressure. See the attached picture below:

Looking at the data QL provides for this load, one could expect this to be a reasonably safe load, since as indicated, it is at the maximum .223 (SAAMI) chamber pressure of 52K PSI and more than 10K PSI below the NATO max chamber pressure of 62K PSI. So I proceeded with this as my MAX load for the day, and loaded up a ladder of 20 rounds for each, decreasing the charge by .2 grains for each rung of the ladder. At 25.6 grains, QL indicates that load to be 25% BELOW the NATO max chamber pressure of 62K PSI (bottom of the "yellow zone".

Interestingly enough, at 26.2 gr. QL indicates muzzle velocity should be 2931 FPS, and is right about where I thought these Hornady's might start to get me close to an accuracy node, which is what I was going for.

So, with reasonable confidence that I should be in the hunt.... off to the range I went with my CED M2 Chrono and my new rounds. It should be noted that the rounds were loaded in the evening and it was 72*F in my shop when the cartridges were created. At the range yesterday, it was 97*F, so it was considerably warmer... Accruate 2230 temp stability is the reason I mention this... I have no real data to show me that the difference in temperature could have anything to do with my findings, nor do I know how temp unstable Accurate 2230 is.. I am just mentioning it in the spirit of full disclosure, so that you folks have all of the data I had.

The Chrono data indicated that these loads were more than 300 FPS FASTER than QL indicated they should be as seen below..

Here is a pic of a ready to fire cartridge. As you can see, I seat them to the top of the cannelure:

Needless to say, I knew these numbers indicated a potentially serious problem which is why the string is short, and I halted the testing on these particular bullets at that point for safety reasons. I promptly collected the brass from this string and inspected it carefully and the ONLY signs of high(er) pressures were that the primers (CCI #41) were slightly flatter than I like to see them. There were no other obvious signs of dangerous pressure, but I was alarmed that I was seeing velocities far in excess of what QL indicated I should be seeing.

When I got home and downloaded the chrono data, I also went back in to QL to see if I could adjust input(s) to a point that I would see these velocities, from these bullets, using this powder, and the only combinations that pushed the bullets that fast were 28.6 grains of powder (which did NOT happen) or a case (water) capacity of 26.7 grains (waaaaayyyy smaller than I measured).

A case capacity of 26.7 grains of water and the indicated powder charge would have put chamber pressure over 80,000 PSI and would have surely resulted in my gun (and possibly my face) coming apart.

A charge load of 28.6 grains would have pushed chamber pressure to 72,000 PSI and would have probably damaged something seriously as well.

Again, no pressure signs on the cases, no damage to the gun, definitely NOT a chrono malfunction because I also tested different loads with predicted results, and I also compared my chrono against my buddies new magnetic chrono that mounts to the end of the muzzle, and results were within 30-50 FPS using his ammo.

Really wondering what I am up against here because it is definitely un-nerving to say the least. I am really curious to hear what you guys have to say....?

I just can't see pushing a soft point 55 grain bullet to 3200 FPS being remotely accurate, and the 300 FPS difference in QL definitely means that something is amiss in my procedure(s).

Care to help me try and uncover the "mystery" ? The only thing I can come up with is that because this rifle has a Wylde chamber which is a bit tighter than a NATO chamber, I am seeing a pressure spike since the case cannot expand as much as it would in a NATO chamber?

 

[918v]

Different temp

Different lot of powder

Different barrel

Different chamber

300 FPS is within 10%

Reasonable

Based on what you saw, I'd call that load maximum. But please tell me you are not necksizing for your AR. Are you necksizing?

 

[Boogaloo]

No sir I am not necksizing.

My general procedure for once fired brass is:

de-cap and full length re-size
Swage primer pocket
new primer
powder drop
powder check
bullet seat (competition seating die)
taper crimp (very VERY light)

All done on a Dillon 1050

Every single finished cartridge is checked in a cartridge gauge.

 

[918v]

Thank goodness, cuz when you said "fireformed to that rifle" I had visions of the bolt molesting the barrel extension.

I had a Savage 22-250 with a polygonal 1-7" barrel that was 200 FPS slower than QL was advertising. I figured the bore must have been larger than .224" so I called Lothar Walther in hopes of getting the bore/rifling specs to plug into my QL, but instead was treated like a proprietary information thief. Woody at LW told me I shouldn't be using QL to develop my loads. That's how LW customers are treated.

 

[W.E.G.]

Your post is so long-winded that it is somewhat hard to follow.

But let me ask a question.

When you were cooking up your Quickload numbers did you alter the default case capacity, and insert the case capacity you believe to exist in a FIRED CASE?

 

[FROGO207]

I was always under the impression that water volume was measured in a casing that was sized to SAMMI specs.-----not a fired casing out of your rifle, for the volume number. So that was the number they were referencing in QL. I agree if the data was within 10% that is as about accurate as the program would be with multiple variables. There are a lot of variables in the equation to a loaded round and any or all of the above mentioned by 918v could have a sizable impact on your results. That's why all the noise about one working up their load------safety.

 

[MEHavey]

Accurate powders have been known to have seriously wild variations in energy/burn speed between powder lots.
See... http://www.shootersforum.com/handlo...tices/71769-powder-variation-batch-batch.html
for a discussion. Note also that this is one reason that I look not only at QuickLoad, but at the latest manufacturer's website info when working up first-time-use loads.

Case in point: Accurate's current loading for 223Rem in a 24" barrel lists
Powder: 2230
Bullet: 55 HDY SPSX (close enough for gov't work) OAL 2.195"
Min: 21.4gr 2,949
Max: 23.8gr 3,223 54,100 (vice the OP's 26.2gr)

That max alone tells me there is a mismatch between what Helmut tested and what Accurate is now selling -- and I'd and adjust burn rates to match a (lower) starting load's chrono figures.

When I do that using your chrono speeds, I have to increase the burn rate (Ba) from 0.5230 to 0.6180 1/bar. It now matches your speed AND says the pressure was 71,750psi. (Bad, but not fatally bad juju)

Testing at the lower limit of Accurate's recommended 23.8gr of powder, I get a pressure reading of 52,500psi (which is pretty close to Accurate's estimate) and 2,930fps for your 16" barrel

(Note that kicking the barrel length up to 24" then results in 3,201 -- also close to the Accurate prediction).
.
.
.
.
So, chalk it up to learning curve on Accurate powders in particular, and how to use/adjust QuickLoad in general.
From now on with THAT particular lot of 2230, use a Ba of 0.618 and your adult rocket-science chemistry set will
behave as expected.

 

[Boogaloo]

@ W.E.G.

Sorry my detailed post befuddled you.
Yes I input the case volume (that I measured against 9 fired cases) in place of the default (28.5 grains) that QL indicates when you select that case.
Is there another way to do it?

As an exercise, I went through the process of carefully measuring a new (once fired, trimmed and resized) empty case, and input that data into the QL new cartridge UI and the "predicted" case volume was 30.86 grains of water !!! I don't know how much more accurate it get's than that? If you have a secret, I sure would appreciate hearing about it.. That way we all can learn something. Here is a pic:

Pretty freaking amazing that measuring a case with my Mitutoyo calipers and inputting those measurements in to QL's calculator comes up with .04 grains less volume than I measured with water and my scale.

@ FROGO207

The difference between the water volume in a case that was previously fired in my rifle and NOT resized, and one that that was neither fire formed nor resized is .2 grains. When I resized the same lot of cases and did the water volume measurement, I got negligible differences.. I.E. less than .2 grains.

@ MEHarvey

Thanks for that data! On the first test round I shot, I inspected the fired case for pressure signs and other than a slightly flattened primer, I did not think these were fatally dangerous loads. They were exceedingly fast compared to the QL output, and so I proceeded to fire the other 3 rounds to see if I just picked out a bogey from the test rung. The additional (3) rounds and the resulting speeds led me to believe that something was off.
I happen to like my "adult rocket-science chemistry set" !

 

[MEHavey]

There's a pretty "fair" rule of thumb to get actual pressure from predicted pressure (assuming equal barrel lengths): Use the velocity ratios cubed:

QL's initial velocity est: 2,931fps
QL's initial pressure est: 52,270psi

Actual velocity: 3,216fps
Probable actual pressure:

 

[steve4102]

I just can't see pushing a soft point 55 grain bullet to 3200 FPS being remotely accurate, and the 300 FPS difference in QL definitely means that something is amiss in my procedure(s).

Hornady data pushes that bullet to 3300fps in 223. They also push it to 3800fps in other cartridges.

Hodgdon pushes the Sierra SP to almost 3400fps in 223.

Accurate pushes the Hornady SP to 3200fps.

What makes you think this bullet will not be accurate at 3200fps?

 

[W.E.G.]

You need to use the case volume of a properly sized case.

You do NOT use the case volume of a fired case - especially you don't use one that has been fired in a gas-operated semi-auto gun.

 

[kelbro]

That bullet runs accurately at 3300 in my 223AI to 350yds. The wind can mess with it though and I prefer 75gr bullets to keep my groups in check with less than ideal conditions.

 

[steve4102]

You need to use the case volume of a properly sized case.

Quickload says to measure a fired unsized case.

Hey Boogaloo, I think I found your QL problem.

QL uses the Old 2230 powder specs. It has changed. In 2005 it became identical to Ramshot X-Terminator. Call Western powders if you need to verify. You can also go the Accurate and Ramshot's web data and see that indeed 2230 and X-t are identical.

Use Ramshot X-T instead of 2230 as QL 2230 is outdated.

 Cartridge          : 5.56 mm NATO - 5.56 x 45 mm
Bullet             : .224, 55, Hornady SP w/c 2266
Cartridge O.A.L. L6: 2.180 inch or 55.37 mm
Barrel Length      : 16.0 inch or 406.4 mm
Powder             : Ramshot X-Terminator

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   76    21.04   2495     760   31887   9229     87.8    0.999
-18.0   78    21.57   2557     798   34054   9532     89.2    0.972
-16.0   80    22.09   2619     838   36342   9828     90.5    0.946
-14.0   82    22.62   2681     878   38779  10115     91.7    0.917
-12.0   84    23.14   2744     919   41376  10391     92.9    0.889
-10.0   86    23.67   2806     962   44144  10657     93.9    0.863
-08.0   88    24.20   2868    1005   47094  10910     94.9    0.837
-06.0   90    24.72   2930    1049   50241  11149     95.8    0.812
-04.0   91    25.25   2993    1094   53598  11375     96.7    0.789  ! Near Maximum !
-02.0   93    25.77   3055    1139   57181  11584     97.4    0.766  ! Near Maximum !
+00.0   95    26.30   3116    1186   61008  11777     98.1    0.743  ! Near Maximum !
+02.0   97    26.83   3178    1233   65098  11952     98.6    0.722  !DANGEROUS LOAD-DO NOT USE!
+04.0   99    27.35   3239    1281   69473  12109     99.1    0.701  !DANGEROUS LOAD-DO NOT USE!
+06.0  101    27.88   3300    1330   74158  12245     99.5    0.682  !DANGEROUS LOAD-DO NOT USE!
+08.0  103    28.40   3361    1379   79180  12362     99.7    0.662  !DANGEROUS LOAD-DO NOT USE!
+10.0  105    28.93   3421    1429   84569  12456     99.9    0.644  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba     95    26.30   3259    1297   72310  11612    100.0    0.690  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     95    26.30   2925    1045   49987  11371     92.1    0.813

 

[W.E.G.]

Quickload says to measure a fired unsized case.

That would be correct if the case were not an ejected case from a gas-fired semi-auto.

You are going to get significant variations in case capacity from case ejected case from a gas-fired semi-auto, and every one of them will give you a reading which exceeds the actual capacity of the case when compared to a case that actually fits the chamber.

Simple fact:
Cases ejected from a gas-fired semi-auto come out of the gun BIGGER than the the actual chamber dimensions.

 

[steve4102]

Good point

 

[Clark]

In 1987 I designed the power supply for the general aviation computer for the F16. It ran on AC and had to have an efficiency of 80%. To test efficiency I hooked up a Valhalla power meter. That instrument was difficult to operate. A well published engineer in the field at the customer facility [with a voice like HAL the computer in 2001 Space Odyssey] sad to me these words I will never forget:

THE WAY YOU KNOW YOU ARE OPERATING THE INSTRUMENT CORRECTLY IS WHEN IT GIVES YOU THE RIGHT ANSWER.


When I got a copy of Quickload 20 years later, I already had the right attitude.

 

[Boogaloo]

@ MEHavey

Thanks for that "fair" rule graphic.. I love stuff like that. Much appreciated sir.

@steve4102

You are right.. that was a mis-statement on my part. Thanks for clearing that up.

Regarding the 2230 and X-Terminator comparison, I am really disappointed to hear that. I am sitting on 8 lbs of 2230 and I just pulled the trigger on 8lbs of X-Terminator in my most recent order. I also shoot BLC-2, TAC, RL-15 and 335.

@ W.E.G.

As I mentioned in the first couple posts, I did NOT just check one case, nor did I assume the case volume from a fired (in my gun) case held the same volume as a re-sized case. I will mention it again though just to be (completely) clear: The difference in actual volume from a fire formed case and a re-sized case was less than .2 grains of water.

I am inclined to believe that the discrepancies I experienced were more the result of outdated burn rate (Ba) values in QL as opposed to case volume data you are implying I (improperly) entered into QL.

Additionally, the (fired) cases from Saturdays range trip are sitting on my work bench right now. I just got done carefully measuring all 4 of them against a freshly re-sized case, and there are no discernible differences. In fact, the fired cases fit nicely in my cartridge gauge, and although the shoulder(s) need to be bumped back ever so slightly, they fit my Wylde chamber snugly, and fit my NATO chambered AR's as is with no further sizing required if I were so inclined to reload them as is..

They just don't balloon up as much as you are implying, and certainly not enough to cause a significant difference in internal volume. Post #8 shows that QL returns a volume which is nearly identical to my actual measured water volume. I zero the scale with an empty case sitting on the tray, and use a syringe to fill the case with water damn near a drop at a time once it gets up towards the top. I get accurate repeatable results.

Finally, lets just assume that your theory about the case being much larger after it is fired holds water (pun intended), it would have to hold 4.6 grains MORE water once fired, than it does when re-sized, in order for me to see the velocity difference I posted (all things considered). That just doesn't happen. Again, QL shows a case capacity of 28.5 grains of water as it's default volume.

Forgive me for digging in my heels here a little bit, but the numbers don't lie.
I would love to be wrong about the case volume, but I have measured it until I was blue in the face and decided to move on. The average case volume I am seeing is 30.9 grains of water.

@ Clark

Nice story sir! I tend to agree with "HAL" but I am confused about how to interpret the overall message? Are you suggesting that since I measured the case volume by weighing it with water, and then carefully measured the case dimensions and "the instrument" returned the same value, I should conclude that "I am operating the instrument correctly" ?

Thanks to EVERYONE who is participating. I really do appreciate the interaction.

 

[jjjitters]

You can tell quickload a temperature and it will include that in its prediction. Some powders I've noticed had quite a difference between 45F and 80F.It could also be some of the other specs that a person is supposed to fill in when you load your gun file into the software. I put in my actual measured bore and groove dimensions for instance. Several loads I compared were within +/- 100fps. The biggest is probably the TRUE burn rate of your particular lot #.

 

[steve4102]

I am inclined to believe that the discrepancies I experienced were more the result of outdated burn rate (Ba) values in QL as opposed to case volume data you are implying I (improperly) entered into QL.

I would agree.

 

[MEHavey]

...think I found your QL problem.
QL uses the Old 2230 powder specs. It has changed.
In 2005 it became identical to Ramshot X-Terminator.

Accurate strikes again (?)

I've found multiple references to it being (identical to/same thing as) Lovex DO73.2 -- which has a 0.52/bar burn rate,
and now you say it's Ramshot Xterminator w/ a burn rate of 0.656/bar (???!) without even a name change?

 

[steve4102]

Yup, call em and verify.

 

[MEHavey]

Oh I believe you... I'm just aghast at the liability to which they left themselves open.

 

[Clark]

The ways of messing with Quickload to get the right answer:
1) The over all length changes if the bullet gets seated deeper when chambering.
2) If the bullet touches the lands, increase the start pressure.
3) If the bullet is jammed into the lands, increase the start pressure more.
4) The chronograph and Quickload should agree perfectly.
...a) If the chronograph does not agree, I mess with the start pressure.
...b) if the chronograph never agrees with that jug of powder in any cartridge, I alter the powder charge by a Finagle factor.
...c) I have surplus pull down bulk IMR4895 that is so fast that QL predicts perfectly if I call it H322.
5) In revolvers, add the length of the cylinder to the barrel before entering it into QL.

In the end, I want QL to predict chrono data perfectly and I want QL to predict the threshold of long brass life for that case head design, at the same pressure across different cartridges.
If I am all tuned up to do that, load development can be much faster.
When I get to the range, the chono should match the prediction, and in the load work up, the charge that gets any measurable extractor groove growth should be predicted.