More Chrony reports!! ((WARNING!)) lots of pics.

[Bwild97]

Yes it is! A 1986 Tin Top

[PumpActionJackson]

Yes it is! A 1986 Tin Top

bad ass! i LOVE those things. mine would go ANYWHERE

[sneaky one]

bw-looks more like 11-12'. Try a tape measure, in the interest of odd scientists= all of us guys... Cool old sama ! Those were the orig. side by sides that we see today,- from the motorcycle manufacturers. Comedy.

[Bwild97]

The cable is 18ft in length. I can not move it back any further or the rocking from the shot will pull the tripod over!

[sneaky one]

Nice work, stay focused-many are trusting your data. My-pal can run
some data on the Huge Computer Setup-wayyy, better than quacky quickload data.

[Bwild97]

I got a box of Hornady 6.5 Grendel brass today, so now I can give data with "REAL" 6.5 Gren. Brass. I have CCi 450s and CCi #41s to load with, I should have more data for tomorrow night!

[bwaites]

I've run into the Chrony issue before. We each bought one box of 4 different factory ammo brands. We then sent 5 rounds to 3 other people with chronometers. We then shot the different ammo and came up with averages for the ammo, and then used that baseline to calibrate the differences.

Its not perfect, but it helps with different loads and ammos, and different rifles. We came to the conclusion that most chronometers are a bit optimistic, but not terribly so.

I'm going to try these loads, but I need to get some heavier bullets.

[RangerRick]

I got some CFE over the weekend and loaded up some Scirocco 130's. They worked great in a 20 inch barrel.

Thanks for the jumpstart Bwild. I was able to get 31.5 grains in a Hornady and Lapua case without compressing at mag length.

Those were pre-fired cases, so your new ones may be a little smaller. I posted a report.

I only got 2400 fps in a 20 inch barrel with 31.5 grains, but that's nearly 100 fps faster than I got with anything else.

Generally I get about 100-120 fps less than a 24 inch barrel, so I'm not sure where the difference comes from.

Then again I was getting 2450 fps on the same chrony, same day with factory Hornady 123 AMax loads and Hornady claims 2650 from a 24 inch barrel. So maybe I'm 200 fps off with a 20 inch.

That would be more inline with your numbers.

My altitude was only about 300 feet but that shouldn't make that much difference.

On the other hand I was not getting as much drop at 600 yards as the ballistic tables said I would with my 123 AMax loads, so maybe my chrony is pessimistic.

RR

[Bwild97]

I sure am glad to have someone else working on this with me! I may have to take my Chrony to a local sanctioned range, and daisy chain it with another Chrony(s) to see if mine is optimistic, but then again it is inline with published load velocities.

I'm beginning to see a correlation between the small and large rifle primers, all of my testing/development so far, has been with brass that utilizes large rifle primers. My velocity data seems; for most people, optimistic . I am going to prematurely surmise that the large rifle primer is providing a higher volume of detonation by virtue of its diameter, igniting more powder after detonation than the small primer, i'm not saying that the detonation is "Harder" there's just more of it to go around. I am not a thermodynamics wizard, but I understand enough of it to keep my self out of trouble... (So far).

Rick, If you scroll up to post #36 and click on the Brass Pics link, you can see the brass that was fired from my rifle on 5/7/12, 31.5 grns of CFE223 behind 130gn Norma Gold Target was absolutely horrid. The string started off ok but after the chamber warmed up, that brass was not happy about the pressures it was dealing with. I have all 50 of my Hornady brass loaded up with 8208 and CFE223 with CCi 450s and #41s along with more FF 7.62x39 brass loaded the same, with S&B and Tula 7.62 NATO primers. This will be very interesting data.

I look forward to seeing more of your data as well!!

Bill

[RangerRick]

I sure am glad to have someone else working on this with me! I may have to take my Chrony to a local sanctioned range, and daisy chain it with another Chrony(s) to see if mine is optimistic, but then again it is inline with published load velocities.

I'm beginning to see a correlation between the small and large rifle primers, all of my testing/development so far, has been with brass that utilizes large rifle primers. My velocity data seems; for most people, optimistic . I am going to prematurely surmise that the large rifle primer is providing a higher volume of detonation by virtue of its diameter, igniting more powder after detonation than the small primer, i'm not saying that the detonation is "Harder" there's just more of it to go around. I am not a thermodynamics wizard, but I understand enough of it to keep my self out of trouble... (So far).

Rick, If you scroll up to post #36 and click on the Brass Pics link, you can see the brass that was fired from my rifle on 5/7/12, 31.5 grns of CFE223 behind 130gn Norma Gold Target was absolutely horrid. The string started off ok but after the chamber warmed up, that brass was not happy about the pressures it was dealing with. I have all 50 of my Hornady brass loaded up with 8208 and CFE223 with CCi 450s and #41s along with more FF 7.62x39 brass loaded the same, with S&B and Tula 7.62 NATO primers. This will be very interesting data.

I look forward to seeing more of your data as well!!

Bill

We've been trying to figure out how to calibrate chronys on the other thread. The easiest way I can think of is to get a box of Factory Hornady 123 AMaxes and chrony them. That will be rough, but in he ball park I think.


It looks like everyone is getting higher numbers than me. Bwaites was getting about 40 fps higher with the factory 123 AMax rounds. One range I go to has a big chrony. I'll have to see if it's working and try that one too.

I wasn't seeing the pressure signs with the 130's in the Hornady or Lapua brass. The extra case volume will reduces pressure, but that much? I don't know. Also, if your bullets were on the lands that can cause a pressure spike.

31.5 was my top load so I only had a few of them. I was expecting to top out at 31 grains, so I didn't want to have to pull a lot of bullets. I'll have to load up some more 31's and 31.5's, tread carefully, and get some more data with a larger sample.

The Hornady brass seems a little softer than Lapua. Even the factory loads had some ejector marks on about 20-25% of them. I may need to adjust the gas block down so it doesn't unlock too early.

I was able to load mag length (barely) with the 130s. The Sciroccos have a nearly conical ogive, so they are pretty good at staying off the lands.

Another factor may be barrel length. I have heard guys on here that shot loads in a 16 inch Grendel with no problems that I would not try in my 20. Peak pressure is supposed to be in the first few inches of the barrel, so it shouldn't matter. So I don't know if it's other factors or barrel length.

From what I know already though CFE looks like a winnner. I'm getting 90 fps better than my best 130 grain loads previously.



RR

[Drifter]

It looks like everyone is getting higher numbers than me. Bwaites was getting about 40 fps higher with the factory 123 AMax rounds

Hornady factory loads have apparently changed in the last month or so. They are faster than what I've used in the prior year or so. Not sure if it's a factor in different velocities among different shooters, but wanted to mention it just in case.

The "old" a-max ammo would run ~2510 to 2515 from my 19.5" Satern. New lots runs anywhere from ~2490 to 2590 fps, with vertical groups as a result.

I don't think current a-max factory loads are the benchmark they used to be. There was a thread a week or two ago discussing this topic.

[bwaites]

Hornady factory loads have apparently changed in the last month or so. They are faster than what I've used in the prior year or so. Not sure if it's a factor in different velocities among different shooters, but wanted to mention it just in case.

The "old" a-max ammo would run ~2510 to 2515 from my 19.5" Satern. New lots runs anywhere from ~2490 to 2590 fps, with vertical groups as a result.

I don't think current a-max factory loads are the benchmark they used to be. There was a thread a week or two ago discussing this topic.

Interesting! All mine is from about 15-18 months ago, so that might explain some of the issues.

[Drifter]

Here's a link to the thread discussing new lots of a-max ammo:

http://www.65grendel.com/forum/showthread.php?2728-Factory-ammo-123-gr-A-MAX

[Bwild97]

Data from 5/10/12 24" 6.5 Grendel

Some load comparisons, using (new) Hornady brass W/CFE-223 CCi #41 and 450s

[Bwild97]

5/10/12 continued...




The Brass... Brass Pics

Thought that I would add this pic for the hell of it: