Pressure from base loads in Quickload

[nksmfamjp]

I'm loading 300 Sherman, Fed210M, Starline brass, N550 and CEB Maximus 165's.

I'm seeing pressure like flat primers, high velocities and such at a load that Quickload shows 52000 psi. What the heck? Nothing is customized from a powder perspective yet. Why so many pressure signs at a base setting? Literally what say it should be 52000 psi is actually ~70000psi! Velocities were also consistent with max pressure predicted velocities.

I'm going to redo my ladder to end below this charge!

Are you seeing this? Is it the copper bullets maybe? I'm thinking I'll just start lowering my ladder start pressure to a predicted 45000 psi in a 65000psi gun.

….or is this somehow related to the Winchester 70 action?

Btw, never seen anything like this with cup& core bullets and Hodgdon powders with Quickload.

 

[Hawk in WY]

I have been using QuickLoad for a long time. Deviation of predicted velocity to actual is common but not usually by much. I am suddenly seeing both surprisingly high velocities (Ramshot hunter: 150 fps higher) and low (Magpro: 300 fps low). All in 7 SAUM, same rifle, same brass with the same copper bullets. This suggests powder burn rates are suddenly way off. I do believe velocity=pressure.

The starting shot pressure should be 6525 for all copper bullets.

The only thing I can think of is something new is happening with the bullets or the powder. Lot to lot variations of 10% used to be common with powders. That may be more now. I don't know about mono bullets.

Adjusting powder burn rate and/or the shot pressure to match actual to predicted velocity is probably the way forward but which of those two to start with is an unknown.

Let me know how adjusting start pressure works out.

 

[Darkker]

It is actually quite common for QL to be wrong, remember it's guessing.
Here's how the sausage is actually made:

Hartmut appears to get anything he wants from Groupe SNPE, so this predictions are always quite good. It's not perfect with Rhinemetal, or necessarily very good with Thales. And it can be flat dangerous with General Dynamics powder.

QL has had lots of well known errors over the years, which is a large part of why Berger used to push as hard on the OAL as they did. Before they were paying for pressure testing, they used QL for their manuals. QL had a long standing linear pressure assumption that's utterly false, and was pressure tested by Dr. Brownell many decades ago.

So when GD won't give Hartmut the keys to the kingdom, he's resigned to very limited fixed volume bomb calorimeter testing & burn chart estimation.
For those that don't know: burning rate charts and being testing, tells you almost nothing you think it does. Actual burning rates change with volume and pressure, but burning rate charts are based on a constant set of test conditions.... See the problem here?
Also I've never seen QL remotely begin to understand progressive powders.


If anyone is confused by all of that, here's the simple version:

A guy who knows more about powder than you, just not very much more. Sold you a guestimation program, which requires you to guess if he was right. And if he wasn't, he needs you to start changing parameters you don't understand; in the hopes that it will be right with enough tinkering.

If you want to run estimations or approximations, it's a perfectly fine program. But you actually want to know what's happening, you need to be serious and measure it.

 

[cajun]

It's probably a combo of several things. Did you enter case capacity?

 

[MagnumManiac]

QL is not gospel for one. It is a PREDICTION PROGRAM.
I ran QL and my Pressure trace side by side, not once did QL come close to actual pressure or velocity my rifles exhibited. I fiddled with parameters and made changes to burn rates and gave up after not receiving the relevant information. I spent hours trying to make the QL results mirror the Pressure Trace to no avail.

It is a great tool for giving you powder recommendations, but take that info and work up loads the usual way, by shooting until your brass tells you to stop.
I used QL for developing my wildcats based on the 416 Rigby Improved case, and even then, maximums predicted by QL were way off and the only usable info was what powders worked best and gave the best performance. Other than that it was a ballpark guess and took a lot of testing to get it right. Burnt my first 30-416 Rigby Improved 35° barrel out before I even tested every planned bullet for testing, powder issues had me stumped for quite a few years until I happened upon a surplus supply of military grade US869, not the same as the canister powder sold today.

I take QL guesstimates as a very rough guide, but it is excellent for predicting the best powder usage, meaning which powder is the most efficient.

Cheers.

 

[Hawk in WY]

It's probably a combo of several things. Did you enter case capacity?

Yes. ADG brass has a greater case capacity that the QuickLoad default.

 

[Seabeeken]

The starting shot pressure should be 6525 for all copper bullets.

This is not true for hammer bullets. Hammers are significantly lower than even cup and core bullets. QL is known for not keeping powder models up to date and lot variations can be problematic.

 

[Seabeeken]

QL is not gospel for one. It is a PREDICTION PROGRAM.
I ran QL and my Pressure trace side by side, not once did QL come close to actual pressure or velocity my rifles exhibited. I fiddled with parameters and made changes to burn rates and gave up after not receiving the relevant information. I spent hours trying to make the QL results mirror the Pressure Trace to no avail.

It is a great tool for giving you powder recommendations, but take that info and work up loads the usual way, by shooting until your brass tells you to stop.
I used QL for developing my wildcats based on the 416 Rigby Improved case, and even then, maximums predicted by QL were way off and the only usable info was what powders worked best and gave the best performance. Other than that it was a ballpark guess and took a lot of testing to get it right. Burnt my first 30-416 Rigby Improved 35° barrel out before I even tested every planned bullet for testing, powder issues had me stumped for quite a few years until I happened upon a surplus supply of military grade US869, not the same as the canister powder sold today.

I take QL guesstimates as a very rough guide, but it is excellent for predicting the best powder usage, meaning which powder is the most efficient.

Cheers.

^^^^ This
I find grt a bit more user friendly but powder models are getting out of date but very easy to calibrate.

 

[nksmfamjp]

Also I've never seen QL remotely begin to understand progressive powders.

Is N550 progressive?

It's probably a combo of several things. Did you enter case capacity?

Yes.

I ran QL and my Pressure trace side by side, not once did QL come close to actual pressure or velocity my rifles exhibited.

Well, I really need something like QL. I need to know before I pull the trigger that I'm at a start load that isn't a bomb.

It is a great tool for giving you powder recommendations, but take that info and work up loads the usual way, by shooting until your brass tells you to stop.

It is, but it needs to be able to give a start load. I think I'm just starting too high. I was starting at a predicted 52000psi, but probably should start in the 40000psi area.

Yes. ADG brass has a greater case capacity that the QuickLoad default.

Starline in use.

All this said, I think my problem is in the powder properties, but I'm not sure how to change responsibly. I hope GRT updates with something closer.

I've mostly had this issue with Vhitavouri, so I'm kind of thinking that has changed over time or the math is just wrong for the N5 powders.

 

[Veteran]

I'm loading 300 Sherman, Fed210M, Starline brass, N550 and CEB Maximus 165's.

I'm seeing pressure like flat primers, high velocities and such at a load that Quickload shows 52000 psi. What the heck? Nothing is customized from a powder perspective yet. Why so many pressure signs at a base setting? Literally what say it should be 52000 psi is actually ~70000psi! Velocities were also consistent with max pressure predicted velocities.

I'm going to redo my ladder to end below this charge!

Are you seeing this? Is it the copper bullets maybe? I'm thinking I'll just start lowering my ladder start pressure to a predicted 45000 psi in a 65000psi gun.

….or is this somehow related to the Winchester 70 action?

Btw, never seen anything like this with cup& core bullets and Hodgdon powders with Quickload.

1) Did you measure your brass volume by filling with water and weighing? I have found huge differences in velocity and pressure for Hornady brass vs. Lapua for example. Correct brass volume has to be input into QL.

2) How hot was it the day you tested. N550 is not temp stable.
I have seen huge velocity and press
differences for N560 loads developed in 70 F Michigan weather shooting in Tx at 102 F. QL has a temp adjustment input.

3) If N550 is like N560, I call it the chunky monky...... It does not measure worth a flip in a normal powder measure. What powder measure are you using. The only ones I think are valid for many VV powders are the auto weigh types.
A volumetric throw meter is worthless with these chunky powders.

I have had great experience w QL.
It is usually very close and I fine tune it by varying burn rate for each
batch of powder to match actual measured velocity.

There is something rotten in Denmark in the inputs you are using if its telling you 52,000 and you are cratering primers out the gate.

I dont believe its the model or its published burn rates.

Re examine all your inputs, change powders, and bullets and see what results you get. I imagine you will figure it out by trial and error, just dont get hurt. Good thing you started w what is supposed to be low tier load.

 

[Darkker]

Powders are not "stable" nor are they "unstable", it's completely application dependant. This isn't new information, this isn't cutting edge fringe science. This is decade upon decade old, independently verified ballistic knowledge. Published in multiple free places(including Ramshot's website) online, and in several print publications.



nksmfamjp -
I'm not a big Airbus powder fan, so I haven't specifically tested that powder; but here's what I can offer.
Progressive powders are strange, and to an extent appear to also be application dependant.
RL-17 is completely "regular" in the 308. But mildly progressive in the Creedmoor, across the load range. Superformance is extremely progressive in the Creedmoor, but only under a certain operational pressures. It shifts to mildly progressive if you run up pressures.
Almost certain I've said this here before, I've got the Traces proving I can run 50 fps under 140gr max book loads, while cruising at 50,000psi. Anyone still praying to the alter of signs and guestimation, will be cussing the powder because it never increases speed until primers pop.


As for your hope about GRT, I'm afraid that ship has sunk long ago. It's been a hot minute since Gordon died, and he was the only one with the source code info. That why all the crowd sourced pressure testing stopped. No point in any of us sending Traces, to people who can't login to a dead man's program for updates.


If you don't know what real burning curves look like. The really smooth and pretty ones people like posting, aren't real data; or at the very least haven't been calibrated with reference ammo. Charlie Sisk used to have a Schtick where he'd blow the last foot off (iirc)243 barrels with QL estimated loads. Because the estimated curve was smoothed and corrected. When he actually hooked up his PT, you could easily see the Secondary ignitions happening.

 

[Hawk in WY]

This is not addressed to me, but my perspective is as follows:

You said, "I have had great experience w QL.
It is usually very close and I fine tune it by varying burn rate for each
batch of powder to match actual measured velocity."

That has been my experience as well until recently. As stated in the second response to the OP's original post my experience with Magpro tells me the burn rate is way low and Ramshot Hunter way high.

My guess, no data, is QuickLOAD is not keeping up with burn rate changes. Lot to lot variation has always required recalibration but nothing like what I am seeing now.

Your questions are spot on. Yes, I do weight brass volumes, it was hot, but I adjusted temperature, throw weights were within .02 grains.

I believe what I am seeing recently is well beyond the usual lot to lot burn rate variation.

Just my $.02.

 

[tim_w]

If you are just trying to find a starting load for some new wildcatt look for a case with a similar h2o capacity in that caliber and use its starting load. There have been so many cartridges just about every powder volume in caliber is covered or close enough to get a starting charge.

QL is a tool full of formulas. It's populated with data but that data always has to be adjusted to the actual physical items you are using. The actually bullets dimensions the actual case capacity and its outside dimensions . Then at tge very least turn the powder heat energy (forget the actual setting) in powder to adjust the charge to the velocity. No, it's not perfect because it's linear but it will get you close enough to start working up load. Then pay attention to case signs i.e. web and head expansion being the most consistent to judging case stress, primers, base flow etc

For the shooter/ for self reloader I would argue that pressure induced case stress is much more valuable that absolute pressure knowledge. If you are following sane rules of backing off when you see the intial signs and setting that reduced charge as a hard max limit.

 

[benchracer]

QL is NOT a substitute for sound fundamental loading practices, nor does it function as a stand alone reloading manual. NONE of the data generated by QL is valid until you have fired a test charge over a chronograph and reconciled actual data to predicted data.

If you are using QL to determine a starting charge, you are misusing the software. The results you are getting are consistent with using a tool you do not properly understand. The issues you are experiencing are not the result of a problem with the software. The problem is the operator.

If you don't know how to establish a safe starting charge, I suggest you learn how to do that before proceeding any further. Using QL to do that is flirting with disaster.

Once you have that figured out, make sure you have the latest update. QL is known to have issues with its predictions for some of the VV powders. The latest update specifically addresses those known problems. The predictions are more accurate than before, but still require predicted data to be reconciled with actual data.

QL is a GIGO tool. If you are getting garbage results, it is because you have supplied garbage input.