Quickload---and ambient temperature

[joelkdouglas]

I know there are at least two Quickload users here--Dr Mike and FOTIS. Anybody else?

Do you ever play with the temperature feature? Ever try and get to optimum barrel times? Change the starting pressure for magnum primers?

I believe 1 weekend with Quickload and a mother-in-law (grandma) playing with the kids taught me more about load development, powders, barrel harmonics, bearing surface, etc. than the previous 8 years without Quickload. I cannot recommend it highly enough.

Okay, I'll start slow. If I tell Quickload I want 58.0 grains of Ramshot Hunter at 70 degrees (default), out of a 30-06 with a 24 inch barrel, 69.3 grains case capacity, I have to adjust the burn rate coefficient a bit downward to get the same velocities that I'm seeing out of the chrono. Not too hard to get to 1.22 ms barrel time, and my rifle does appear to like that combination.

Here's where I got to playing around. Try 85 degrees (weather here now), and to get the same barrel time I need 57.7 grains. 40 degrees, around 59 grains. 0 degrees, almost 60 grains.

Adjusted start pressure as such:

((bearing surface) x 1420) + 2860 = start pressure for normal primers; add 600 more psi for magnum primers

Example, a 180 grain SP Partition has a bearing surface around 0.640 inches.

(0.640 x 1420) = 910 + 2860 + 600 = 4370 psi

The grains don't matter, of course, but the resulting barrel velocities do matter. All of these result in a velocity around 2840 fps or so.

Adjusting this way for starting pressure, putting in actual bullet lengths (Partition is 0.08 too long), and adjusting burn factor by no more than 5%, and then adjusting for ambient temperature normally got me dead of for expected velocities, based off old targets. I write the shot velocities on the targets.

So a long question for this:

Does your rifle's "favorite" load change throughout the year based on ambient temperature?

 

[joelkdouglas]

I'll take that as a no.

Well, I'll do a test for all of us then, and post the results.

You probably don't recall that on 31 Mar 12 I got some fantastic results from 180 Nosler PTs above Ramshot Hunter, 4-shot group sizes of 0.753, 0.699, 0.90, 0.564 and a 2-inch fat, ugly load (there's always one, isn't there?). Well, I've been trying to duplicate those results and haven't had much luck. Groups were around 1.2 inches for most other days, nothing spectacular. The Accubonds outshot the Partitions handidly most days. Well, the 0.564 group above was with 59.0 grains Hunter, and I finally gave up and moved back to 58.0 grains instead, and the rifle definitely liked the change. Group sizes shrank to 0.945 inches for a 5-shot group, followed by a group of 1.142 inches.

Then I got to thinking about what would cause the change, and about the only steady variable has been the temperature. Stationed here in Louisiana right now, it's been warming pretty steadily since 31 March. Last weekend was in the mid-80s.

So a load that shot well in March when it was cooler continually got worse as the temperatures warmed up. But I didn't really know why.

Until I got Quickload. I'm not saying it's the know-all, but it is a ballistics model that does happen to fit my current situation. I'm trying to match a 1.228 millisecond barrel time to a 180 Nosler Partition, Ramshot Hunter with a burn rate factor of 0.4431 at 70 degrees, start pressure of 4370 psi, OAL of 3.278 inches. At 70 degrees Quickload says I need 58.0 grains. At 80 degrees, more like 57.7 grains.

For those that got turned off by the math, all I'm doing is adjusting my load down 0.3 grains because it's warmer here than it was, trying to match earlier results. Quickload just happens to be the model I'm using. And yes, all models are wrong, some are useful.

I'm also testing a 155 Lapua Scenar with 55.8 grains Ramshot Big Game, OAL 3.242 inches, at 80 degrees. Quickload predicts 2980 fps with a 1.103 ms barrel time. I have never shot this load before, never shot these bullets, never even shot a 150 or 155 grain bullet out of a 30-06. This test is a true "how good are you, Quickload". I'll keep you updated.

For those interested in this barrel time stuff:

http://www.the-long-family.com/OBT_paper.htm

More:

http://www.shootingsoftware.com/barrel.htm

Scotty, aren't you in the desert/forward? Yeah, you should have plenty of reading time. Or at least when I was stationed with II MEF in MNF-W I had plenty of reading time. But maybe the USMC expected less of me because I was a USAF officer.

Have I ever told you about the time I got my ass chewed by a USMC 2-star? It was awesome. I don't remember anything he said; all I remember was thinking how great it was that very few other USAF officers ever get an opportunity to get an authentic ass chewing from a Marine general.

 

[DrMike]

Joel,

Thanks for the challenge. Yes, I use the barrel time function regularly as I work up loads; it is a major factor in choosing potential loads to examine. I have not coordinated temperature primarily because when I'm working on the rifles for others, I'm focused on a safe load recommendation under any conditions. Consequently, I focus on potentially highest pressure conditions. When working loads for myself, I consider the type of hunting that I do. I am not a distance shooter--most of my shots on game are well under 150 yards and seldom over 250 yards. Consequently, I am not as concerned with temperatures. Also, our hunting season seldom coincides with high temperatures. Much of my load development is performed at temperatures near zero, as that is also the temperatures in which I'll be hunting. I am cognizant of the effect of temperature, but I haven't really taken the time to play with it. Consequently, thanks for posting the fascinating articles. I suppose I'm going to have to do a little serious work and publish it one of these days.

 

[joelkdouglas]

Thanks Dr. Mike.

Working up loads in the temperature you expect to use them would be best. I just wish Louisiana would cool down enough to run the tests!

Seriously, I miss snow. Prior to being here I was stationed in Las Vegas, also no snow. I need another northern tier base tour.

 

[bullet]

Thanks Dr. Mike.

Working up loads in the temperature you expect to use them would be best. I just wish Louisiana would cool down enough to run the tests!

Seriously, I miss snow. Prior to being here I was stationed in Las Vegas, also no snow. I need another northern tier base tour.

hey I live east of Baton Rouge just over the La MS line and it don't hold your breath about to much cool weather from now to spring. I try and get all my major load work done before the middle of May because the late spring and summer are not fun at all to do serious load work and shooting. :mrgreen:

 

[SJB358]

Joel, I am forward right now. I like your testing your doing buddy. It looks very thorough!

As to getting your butt chewed by a 2 star. Well, I am in tears right now... Who was it? I am glad you to experience it, as maybe you took my spot! I have had enough butt chewings as a young Marine for about 20 AF officers!

 

[joelkdouglas]

Joel, I am forward right now. I like your testing your doing buddy. It looks very thorough!

As to getting your butt chewed by a 2 star. Well, I am in tears right now... Who was it? I am glad you to experience it, as maybe you took my spot! I have had enough butt chewings as a young Marine for about 20 AF officers!

I don't remember his name (I have a hard time remembering general's names for some reason), but he was the deputy commander of MNF-W. And he probably could have been a one star, but I remember him being a Maj Gen. Anyway, I was working in the STO at the time with Maj Chris Ieva (USMC), and Ieva told the general's exec that he couldn't get read-in if the general didn't complete his paperwork. Well, the general didn't complete the paperwork (Ieva thought the exec never told him), so didn't get read-in with the other MNF-W leadership. Of course, he took that to be our fault.

Of course, we probably could have gone over to the gen's office to tell him about the paperwork, and didn't. So we probably deserved the butt chewing in part.

 

[SJB358]

What year was it Joel?

 

[joelkdouglas]

Late 2008, showed up just before Thanksgiving, and left in April of 2009. Gens Kelly and Tryon were the CCs (had to look that up in wiki), but I don't remember the deputies. But I think I MEF and II MEF switched out early in 2009. I MEF was "friendlier", but II MEF made better changes to the chow hall.

I think I "lived" in Peleliu, one of the room areas between the HQ building and the chow hall.

I felt especially blessed on one hand and regretful on the other when a SSgt that lived near me told me he was going home to a pregnant wife, and the child wasn't his. Blessed because I have spent 181 days away from home on nuclear alert, but only 131 days away from home deployed. The 181 days is only one day/overnight at a time, much different than the 131 days of never being home. But the Marines have it the toughest, I believe. Some of those Marines had been deployed 7 - 15 months deployed, 5 months or less home, for 6 years. It would be a tough time to spend a 20-year or more career in the USMC.

 

[Oldtrader3]

Joel, I am forward right now. I like your testing your doing buddy. It looks very thorough!

As to getting your butt chewed by a 2 star. Well, I am in tears right now... Who was it? I am glad you to experience it, as maybe you took my spot! I have had enough butt chewings as a young Marine for about 20 AF officers!

Man, I've still got teeth marks from 3 years in the good ole Army infantry, I can't imagine how many teeth marks a career Marine would have?

 

[SJB358]

Late 2008, showed up just before Thanksgiving, and left in April of 2009. Gens Kelly and Tryon were the CCs (had to look that up in wiki), but I don't remember the deputies. But I think I MEF and II MEF switched out early in 2009. I MEF was "friendlier", but II MEF made better changes to the chow hall.

I think I "lived" in Peleliu, one of the room areas between the HQ building and the chow hall.

I felt especially blessed on one hand and regretful on the other when a SSgt that lived near me told me he was going home to a pregnant wife, and the child wasn't his. Blessed because I have spent 181 days away from home on nuclear alert, but only 131 days away from home deployed. The 181 days is only one day/overnight at a time, much different than the 131 days of never being home. But the Marines have it the toughest, I believe. Some of those Marines had been deployed 7 - 15 months deployed, 5 months or less home, for 6 years. It would be a tough time to spend a 20-year or more career in the USMC.

It is the nature of the business Joel, most Marines don't enlist or commission into the Marine Corps for the college money.. The AF and Army have much better benefits. I have seen alot of different drama but overall, it is just the nature of the amount of work to be done and not enough Marines. Most Marines wouldn't have it any other way. If a Marine isn't complaining about something, well, there is probably something wrong..

Charlie, most of my marks have healed, but I never know when the next one could happen!

 

[joelkdouglas]

I have some buddies in the test community, and they've commonly said things like "every test is a success, because you learned something". Then someone says "the missile didn't hit its target" and they say "but we learned something".

I had a very successful test of Quickload's temperature function yesterday. Clear results. Bottom line: Quickload's temperature function is NOT a good predictor of barrel times. It pretty accurately predicted the velocities I saw over the chrono, but the groups were terrible. I had some 1.5 inch 5-shot groups, some 2 inch 5-shot groups, and a 3-inch group!

I also developed one load without the temperature function--58.8 grains H4350, 150 grain AccuBond, CCI BR primer, Lapua brass (neck turned to 0.013 inches), OAL 3.242 inches, 24-inch barrel, case capacity 59.3 grains H2O. I did not use the temp function as Quickload says not to with Hodgdon extreme powders.

Keep in mind, there is no load for H4350 with 150 grain bullets in the Nosler manual. Hodgdon lists the max at 62.0 C.

Also, I had never shot a 150-grain bullet out of any 30-06 prior to loading these. This was a true test of Quickload.

Results were velocities of 2969, 2962, 2976, 2969, 2976, avg 2969, standard dev 7. Group size was 0.764 inches, 5-shot group.

I was impressed with Quickload's prediction ability. This will probably be my deer hunting load this year, as H4350 is a very stable powder, and the case capacity is perfect--when I shake a loaded case there's no sound.

Now, I could have been really lucky with this load, and my rifle just might really like H4350. That's possible. I think there are too many variables in play for it to be probable, but it is possible.

Keep in mind, I only consider this a "not total loss". The rest of the range results were absolutely terrible.