quickload and hodgdon powders

[bilydean]

Ok. I bit the bullet and bought Quickload. Looking to get a bit more speed with my 120gr Barnes TTSX. I wanted to compare what the hodgdon site shows for max load and pressure to compare to what QL says and man, it is WAY off. For example, max load for the 8208XBR is 28.0gr which is a pressure of 50K PSI. I have actually shot that load and don't see any pressure signs, so believe what the Hodgdon site shows. When I set up QL with the same barrel size, bullet, and charge, it predicts a max pressure of 62k PSI. I tried the other Hodgdon and IMR powders and similar result. Pressure in QL shows 20-25% higher. I was hoping to load up some LVR, in this combo, but QL is scaring me off of trying it.

What am I missing for it to be that far off?

Thx. Oh yeah, I am new here on the forum, but been shooting the Grendel and reloading for about 6 years now.

Dean

[Oryx]

There are a lot of variables to to get right...While quick load has been a staple for a very long time, it can be pretty tricky and results can vary from actual by a pretty good amount in some cases. (no pun intended).
Lots of people have switched to GRC (Gordons reloading tool)

[grayfox]

[Oryx]

BTW - Gordon's is free so you might also want to check that out and compare

[daryl]

I've found some actual velocities with my LabRadar to be EXACTLY on - literally to the 1 FPS - with some QL estimates. With others - way, way off. It is a great tool to supplement many other sources - especially when there is little data out there. It is a good way to double-check third-party sources (i.e. forums) to see "does this make sense?". I'm not sure how recommended this is, but I read one place about adjusting the burn rate in QL to match the actual data. I've used this a little and found it to be a useful technique in my case because I use almost exclusively CCI #41 & 34 primers. QL does not have primer selection from what I can tell. So, once you start using it for a particular cartridge, observe what's really happening, and work it back to QL it gives you an idea which combinations are more reliable. I try to keep notes on it. Also, at the bottom of the results it shows +/- 10% variation that could occur with powder batches - it is quite significant.

[Fess]

Grayfox's info is the same that I have heard over the years. Apparently the short-fat case issue has been somewhat reduced. In the early 2000's, quickload would predict that the pressure of some of the safe pressure-barrel tested loads would be over 65,000psi.

Has anyone modeled LVR loads with quickload and then looked at actual results? I ask because LVR's results with 30-30 are well above those found from any other power. The only powder that comes within 150fps is CFE 223, another relatively new powder. It makes me thing that Hodgdon (St. Mark's Powder, actually) is blending more than one powder to broaden the power curve. This is what Hornady stated is done with powders for their Super Performance line.

[kmon]

The only load with QL I have actually worked with in my Grendel is with CFE223 and the pressure was way high and that was with the case volume being corrected for my cases as measured with water fill. QL predicted velocities very well but the pressure data was way high. I was able to almost correct QL to match pressure data that was made available to me by tweaking some parameters getting measured velocities and pressures very close but not exact. I think with the Grendel ramped throat it affects the start pressure some by lowering it. The highest pressures in any cartridge occur when the bullet is being engraved by the rifling and that is spread out more with the compound throat of the true Grendel chamber.

When I matched the velocity of the factory load data with the QL data velocity I considered that to be my stopping point especially with data like that from Hornady that lists pressure. There is a direct coloration velocity to pressure. With the bolt action I am not as worried about the pressure being slightly over 50K as I am loads for the AR.

I do not have pressure test gear like a few do but was able to tweak it for my rifle that I believe was close for my boltaction with velocities spot on and within 4K psi of Hodgdon data which can be the difference between a tight chamber and throat and looser ones. '

Basically QL is a good tool but it is just that a tool. With some more traditional cartridges it has been right along with published data but not with all. I bought QL for some wildcats and old cartridges that data with new components is not available for. With QL data for those I do start off low and work up looking for pressure signs.

i have talked at length about it with a man that has the pressure test equipment and has done a lot of that testing in his work designing cast bullets and uses QL for prediction to start with. As he said it is a good predictor on many cartridges but not all. He also agreed once you reach you velocity you have reached you pressure and is best not to push it. Kinda like the Concord stress fractures that ended the flights of that plane. I do not want stress fractures to give way on my rifles from repeated high pressures.

[bilydean]

Funny. I have even loaded the "safe max" into Gordon's as well and it comes up with a pressure much higher than what Hodgdon shows. I have used that load with no pressure signs on the case or primer. Something is definitely wacked on this. Scratching my head.