Does QuickLoad include Grendel?

[Fess]

I looks like Quickload does a pretty good job despite the complexity internal ballistics. What actually goes on with rifle barrels is ridiculously complicated and a number of methods get enough of the puzzle correct to have some validity. When I got interested in barrel dynamics ten or fifteen years ago, I found Varmint Al's website and immediately got brain overload. Al had the talent to make computer models of at lease eight barrel vibration modes that you can see here: https://www.varmintal.com/amode.htm

I haven't followed the benchrest crowd on sites like AccurateShooter.com for awhile, but a decade or so ago there was big interest in weighted barrel tuners for extreme accuracy. The interest at the time had a great deal to do with the vertical vibration modes and figuring out how to make a barrel self-compensate for small velocity variations. Instead of trying to catch the barrel at the top or bottom of its swing, the idea was to have the bullets leave as the barrel is swinging up. This way, if one bullet is traveling a little bit slower than average, it leaves the barrel when it is pointing up at a steeper angle. The idea was that the steeper angle would compensate for the greater drop of the slower bullet. Interesting stuff.

For nerds like me, the following two pages on barrel vibrations are also interesting (heck, the whole site is interesting). The second one includes actual test data.

https://www.varmintal.com/atune.htm

https://www.varmintal.com/aeste.htm

[RiverRider]

Interesting thread for sure.

In the ten years or more that I've used QL, I'd bet I haven't tapped 10% of the program's potential, but it has so far done what I've expected it to do---which is keep me out of trouble.

I think the case capacity manipulation technique might be a better way to stay out of the weeds, or maybe not. When I was playing with 6.5 G, I was led to believe that reducing Start Pressure to around 500 psi would help get things to line up. That's what I did and it DID seem to help a lot, but I still wonder about how pressures lined up with velocities. My Hornady brass would loosen in the primer pockets after about four firings and whether that was the Hornady brass (which just never impressed me AT ALL) at fault or the actual pressures I was running...flip a coin and tell me, I couldn't argue either way.

What I am trying to point out here is that IF the bullet actually IS in motion before the powder charge begins to make any pressure, then it is very possible and maybe even likely that the bullet is already engraving in the lands. If that is so, then I would think we would have effectively traded some case capacity for higher Start Pressure.

Multiple variables sure can be a can of worms.

I've moved on from the 6.5 G to the 6mm AR and it seems to present some of the same problems when using QL. I'll look into this idea to see if it makes QL work better for 6mm AR.

[centerfire]

That's true. I'm sitting in a hotel room and going from memory but I settled on 37gr of water generically from the original 35.8 (I think, I'll check this weekend when I'm home). For A2520, 37.8 grain gets predicted MV closer to actual MV. PT recorded pressure under 48K for 31gr of A2520 but the system is not known to be very precise from what I understand. Either way, QL predicted my load (107TMK and 31gr of A2520) to be almost 2700fps and 53K to 54K PSI. My actual results were low 2600fps. That is a fairly high discrepancy regardless of individual barrel quirks.

My measured weight of water in grains is 36.5 with Hornady brass. I've been bumping to 37gr generically because it still conservatively over estimates pressure. In some cases, like A2520, I have used more case capacity to get closer to actual MV. I don't think the predicted and actual MV needs to necessarily be perfect, just not 100fps apart.

[Klem]

My measured weight of water in grains is 36.5 with Hornady brass. I've been bumping to 37gr generically because it still conservatively over estimates pressure. In some cases, like A2520, I have used more case capacity to get closer to actual MV. I don't think the predicted and actual MV needs to necessarily be perfect, just not 100fps apart.

Centrefire,

Like I said earlier, I think you've hit the nail on the head here, at least I'm hoping so...It's a really good idea and I am keen to try it. River Rider sums it up neatly also. I think currently QL is pretty good and I am convinced I am better for it than without it. It's just that predicted velocities are sometimes out by up to 50-100fps. Some of that can be put down to the program not being predictive enough and some to environmental causes like 'fast' and 'slow' barrels. But there's also the idea that the bullet has already started down the barrel before the powder is burning meaning 'case' capacity is actually larger than spec.

[centerfire]

Centrefire,

Like I said earlier, I think you've hit the nail on the head here, at least I'm hoping so...It's a really good idea and I am keen to try it. River Rider sums it up neatly also. I think currently QL is pretty good and I am convinced I am better for it than without it. It's just that predicted velocities are sometimes out by up to 50-100fps. Some of that can be put down to the program not being predictive enough and some to environmental causes like 'fast' and 'slow' barrels. But there's also the idea that the bullet has already started down the barrel before the powder is burning meaning 'case' capacity is actually larger than spec.

I've been working up a new 6CM barrel and QL is within 10fps with H4831SC and four different weight bullets. Sometimes QL is spot on. I've been using it for 6.5 PRC powder selection too. I think QL is probably more accurate with larger charge weights. I still don't trust it though.

[nadofr8dog]

QuickLoad runs fine on a Mac with Crossover.

[centerfire]

What if the issue is QL just based their model on the wrong throat geometry?

[JASmith]

QuickLoad runs fine on a Mac with Crossover.

Which OS?

I am hoping your post reflects a change I don't know about.

I got a new Mac last spring and found that QuickLoad no longer worked under Crossover. The issue is that QuickLoad was (is still?) built around the 32 bit architecture and that Mac is pushing (forcing?) the developers to go to 64 bit.

Further, the QL developer intended to not upgrade QL to be compatible for Mac Users.

[acourvil]

I've been working up a new 6CM barrel and QL is within 10fps with H4831SC and four different weight bullets. Sometimes QL is spot on. I've been using it for 6.5 PRC powder selection too. I think QL is probably more accurate with larger charge weights. I still don't trust it though.

Has 6.5 PRC data been added to Quickload? It's not in my current install, but I just ordered the latest update.

My experience is that it has worked well for me for 260 Rem and 6 Creedmoor, not so much for Grendel. But I haven't spent a lot of time trying to tweak parameters.

[centerfire]

Has 6.5 PRC data been added to Quickload? It's not in my current install, but I just ordered the latest update.

My experience is that it has worked well for me for 260 Rem and 6 Creedmoor, not so much for Grendel. But I haven't spent a lot of time trying to tweak parameters.

The newest update has 6.5 PRC.