Chrono Results Confusing

[TonyG35]

I don't have a fancy light box setup for my chrono so trying to use other ammo to compare against my re-loads to verify if they will make major.

Using the 1.18OAL .40 180gr from Atlanta Arms and Ammo as a base line I was thinking if my loads are as fast or faster than they should make major PF.

Today the AA&A were in the 1010 FPS range +/- 20FPS.

My re-loads from a STI Edge 5" brl: 4.8-4.9gr TiteGroup, 1.22 OAL, 180gr Montana Gold JHP, Federal Primers. 940 FPS +/- 20FPS

Recoil feels similar to the AA&A.

If I bump up the powder 1/8th of a turn to ~5.0-5.1gr of TG the load feels too hot and starts to flatten out the primers. Chrono's in the 980-1000FPS range.

My normal setup is to put the Chrono under an unbrella ~5ft. off the ground and shoot from ~15ft away. There is no shade where I shoot and it's always sunny.

The question is should I trust these results or can the different types of bullets be causing some strange effects at the Chrono?

Edited August 1, 2010 by TonyG35

[RogerT]

I don't think so, the chrono reacts to the difference in light when the bullet passes the sensor eye, so even if there is a difference between different bullets in light reflection or shape, it's the same difference over the start and stop sensor.

I use a USPSA target (cardboard brown) placed on top of the sky screen pins to shade the sensors, that works fine and is always handy at the range. Wind is of course a problem......

[GrumpyOne]

It's your powder. TG may be too fast for what you are trying to do with a 180. If you were to shorten your OAL to what the AA&A is, with the 4.8-4.9 grains of TG, you'd probably get the flattened primers as well. You need a bit slower powder.

Edited August 1, 2010 by GrumpyOne

[RogerT]

Difference in felt recoil between ammo with the same weight bullet and velocity depends of the powder burn rate used in the loads.

Commercial ammo manufacturers don't always use the same charge weight or even the same powder between production batches, they only check that pressure and velocity is according to specifications. "Top of the line ammo" is of course more consistent between batches, but even there you may feel differencies in recoil.

The same ammo may also feel different in recoil and chrono different depending on ambient temperature, so it is not easy to use bought ammo as a reference, you might have to try different brands until you find something that is consistent.

[G-ManBart]

I think you can trust those results (the umbrella is a good idea BTW), but consider that weather (mostly temp) will cause powders to react differently. Some get faster when it gets warmer and others do the opposite. Have you chrono'd the AA&A and your current load at different temps to compare?

Generally speaking, I'd be extremely surprised if anybody can feel the difference between your two handloads. Take your nominal 940fps load, which can actually be 960fps according to your ES. Compare that with your 980-1000fps load. 20-40fps difference is going to be hard to feel, if at all.

If the primers are just starting to flatten, I wouldn't be terribly concerned. .40 Major with heavy bullets and fast powders is a very high pressure combination....something often overlooked. R,

[GrumpyOne]

I think you can trust those results (the umbrella is a good idea BTW), but consider that weather (mostly temp) will cause powders to react differently. Some get faster when it gets warmer and others do the opposite. Have you chrono'd the AA&A and your current load at different temps to compare?

Generally speaking, I'd be extremely surprised if anybody can feel the difference between your two handloads. Take your nominal 940fps load, which can actually be 960fps according to your ES. Compare that with your 980-1000fps load. 20-40fps difference is going to be hard to feel, if at all.

If the primers are just starting to flatten, I wouldn't be terribly concerned. .40 Major with heavy bullets and fast powders is a very high pressure combination....something often overlooked. R,

Competely agree with Bart. Very high pressure. There are better alternative powders out there to make major with, and not have the issues with the pressure. Just think, one bullet setback as it noses into the chamber and you have a potential KABOOM if it sets back enough (especially since you are already to the point of flattening primers). While flattening a primer isn't all that much of a concern for me either, I KNOW my bullets won't set back when they chamber. I'm not saying TG is unsafe in 40 major (probably far from it), but I'd keep an eye peeled for overt signs...

[TonyG35]

I think you can trust those results (the umbrella is a good idea BTW), but consider that weather (mostly temp) will cause powders to react differently. Some get faster when it gets warmer and others do the opposite. Have you chrono'd the AA&A and your current load at different temps to compare?

Generally speaking, I'd be extremely surprised if anybody can feel the difference between your two handloads. Take your nominal 940fps load, which can actually be 960fps according to your ES. Compare that with your 980-1000fps load. 20-40fps difference is going to be hard to feel, if at all.

If the primers are just starting to flatten, I wouldn't be terribly concerned. .40 Major with heavy bullets and fast powders is a very high pressure combination....something often overlooked. R,

The umbrella actually works great because after your done with the chrono you can use it for shade while your loading mags and even shooting. Haven't had a chance to

do much in different temps yet. With the 4.8-4.9gr the primers are just starting to flatten. At 5-5.1 they are pretty flat.

When you say I can trust the results to you mean absolute results or relative results. I would think that 1000FPS for AA&A is faster than they actually are but maybe not?

If I look at the load data below I found on the forum then I believe my results. The only reason I am doubting them is because I have read that the AA&A just barely makes major.

John Merricks 180gr Mont. Gold 4.7gr Titegroup 1.200” 948 170.6 (66) Para 5” Bbl

Jeffrey Vince-Cruz 180gr Remington FMJ 4.8gr Titegroup 1.200” 948 170.6 (71) STI 6” bull Bbl

Sam Gardali 180gr Mont. Gold 4.9gr Titegroup 1.215” 935 168.3 (53) SVI 5” Bbl

[TonyG35]

I think you can trust those results (the umbrella is a good idea BTW), but consider that weather (mostly temp) will cause powders to react differently. Some get faster when it gets warmer and others do the opposite. Have you chrono'd the AA&A and your current load at different temps to compare?

Generally speaking, I'd be extremely surprised if anybody can feel the difference between your two handloads. Take your nominal 940fps load, which can actually be 960fps according to your ES. Compare that with your 980-1000fps load. 20-40fps difference is going to be hard to feel, if at all.

If the primers are just starting to flatten, I wouldn't be terribly concerned. .40 Major with heavy bullets and fast powders is a very high pressure combination....something often overlooked. R,

Competely agree with Bart. Very high pressure. There are better alternative powders out there to make major with, and not have the issues with the pressure. Just think, one bullet setback as it noses into the chamber and you have a potential KABOOM if it sets back enough (especially since you are already to the point of flattening primers). While flattening a primer isn't all that much of a concern for me either, I KNOW my bullets won't set back when they chamber. I'm not saying TG is unsafe in 40 major (probably far from it), but I'd keep an eye peeled for overt signs...

That is a concern. I guess the reason I started out with TG is because it seems to be a very popular powder for Lim. Major based on what I have read. I might try something else and use the TG for 3-Gun where I can load it to minor.

[G-ManBart]

I think you can trust those results (the umbrella is a good idea BTW), but consider that weather (mostly temp) will cause powders to react differently. Some get faster when it gets warmer and others do the opposite. Have you chrono'd the AA&A and your current load at different temps to compare?

Generally speaking, I'd be extremely surprised if anybody can feel the difference between your two handloads. Take your nominal 940fps load, which can actually be 960fps according to your ES. Compare that with your 980-1000fps load. 20-40fps difference is going to be hard to feel, if at all.

If the primers are just starting to flatten, I wouldn't be terribly concerned. .40 Major with heavy bullets and fast powders is a very high pressure combination....something often overlooked. R,

The umbrella actually works great because after your done with the chrono you can use it for shade while your loading mags and even shooting. Haven't had a chance to

do much in different temps yet. With the 4.8-4.9gr the primers are just starting to flatten. At 5-5.1 they are pretty flat.

When you say I can trust the results to you mean absolute results or relative results. I would think that 1000FPS for AA&A is faster than they actually are but maybe not?

If I look at the load data below I found on the forum then I believe my results. The only reason I am doubting them is because I have read that the AA&A just barely makes major.

John Merricks 180gr Mont. Gold 4.7gr Titegroup 1.200” 948 170.6 (66) Para 5” Bbl

Jeffrey Vince-Cruz 180gr Remington FMJ 4.8gr Titegroup 1.200” 948 170.6 (71) STI 6” bull Bbl

Sam Gardali 180gr Mont. Gold 4.9gr Titegroup 1.215” 935 168.3 (53) SVI 5” Bbl

If you're using shade over the chrono and standing back at 15' like you are, I'd be willing to bet your absolute results are at least reasonable...meaning within the range of error any chrono has.

I have zero experience with the AA&A .40 Major, but I've been very impressed with their 9mm and .38SC. 1000fps seems a little fast, but not that much...probably only 25-50fps over what 90% of us are running and that's within the difference you can see with slightly higher temps.

How many rounds are you running per string? I've settled on at least two 20-shot strings before I believe what I'm seeing, and then I do that on multiple days with different conditions.

Just going off the loads you list, and what I've seen many other folks using your load seems pretty reasonable. Yes, you definitely want to make sure you've got enough bullet pull (neck tension) so setback isn't a concern, but that's not too hard to do. My .40 Major load with N320 slightly flattens primers and I'd bet that most everyone using TG or similar powders is seeing similar flattening. While it's only hiding the symptoms, that's also part of why quite a few folks use SR primers for .40 Major...it's definitely not a low pressure load the way most of us are loading it. R,

[RePete]

Set your chrono at 10 feet (USPSA/IDPA/IPSC distance).

Drop your load to about 4.3gr/TG and then re-chrono.

This is my load in the G35 and STI Trojan and makes major.

[Skydiver]

Set your chrono at 10 feet (USPSA/IDPA/IPSC distance).

Drop your load to about 4.3gr/TG and then re-chrono.

This is my load in the G35 and STI Trojan and makes major.

What is the average temperature for when you tested your rounds? What velocity where you getting?

When you say "makes major", do you mean it just makes it to 165.x PF or do you have a nice buffer above 165? In another thread, the consensus seemed to be 174 was a good target PF for no worries at the chrono stage despite temperature and chrono variances.

(I'm looking for a TG recipe as a backup for my current Universal recipe, so extra data is always useful.)

[TonyG35]

Set your chrono at 10 feet (USPSA/IDPA/IPSC distance).

Drop your load to about 4.3gr/TG and then re-chrono.

This is my load in the G35 and STI Trojan and makes major.

Don't want to turn this into a load data thread but assuming you are using a short OAL close to factory ammo like 1.125.

My gun will not feed short OAL's reliably. 1.22 seems to feed the best so need to use more powder.

I tried 10ft with my chrono and it seemed to be getting velocities in the 850 FPS range at times so decided to back up to 15' and

no longer saw the low readings.

[TonyG35]

I think you can trust those results (the umbrella is a good idea BTW), but consider that weather (mostly temp) will cause powders to react differently. Some get faster when it gets warmer and others do the opposite. Have you chrono'd the AA&A and your current load at different temps to compare?

Generally speaking, I'd be extremely surprised if anybody can feel the difference between your two handloads. Take your nominal 940fps load, which can actually be 960fps according to your ES. Compare that with your 980-1000fps load. 20-40fps difference is going to be hard to feel, if at all.

If the primers are just starting to flatten, I wouldn't be terribly concerned. .40 Major with heavy bullets and fast powders is a very high pressure combination....something often overlooked. R,

The umbrella actually works great because after your done with the chrono you can use it for shade while your loading mags and even shooting. Haven't had a chance to

do much in different temps yet. With the 4.8-4.9gr the primers are just starting to flatten. At 5-5.1 they are pretty flat.

When you say I can trust the results to you mean absolute results or relative results. I would think that 1000FPS for AA&A is faster than they actually are but maybe not?

If I look at the load data below I found on the forum then I believe my results. The only reason I am doubting them is because I have read that the AA&A just barely makes major.

John Merricks 180gr Mont. Gold 4.7gr Titegroup 1.200" 948 170.6 (66) Para 5" Bbl

Jeffrey Vince-Cruz 180gr Remington FMJ 4.8gr Titegroup 1.200" 948 170.6 (71) STI 6" bull Bbl

Sam Gardali 180gr Mont. Gold 4.9gr Titegroup 1.215" 935 168.3 (53) SVI 5" Bbl

If you're using shade over the chrono and standing back at 15' like you are, I'd be willing to bet your absolute results are at least reasonable...meaning within the range of error any chrono has.

I have zero experience with the AA&A .40 Major, but I've been very impressed with their 9mm and .38SC. 1000fps seems a little fast, but not that much...probably only 25-50fps over what 90% of us are running and that's within the difference you can see with slightly higher temps.

How many rounds are you running per string? I've settled on at least two 20-shot strings before I believe what I'm seeing, and then I do that on multiple days with different conditions.

Just going off the loads you list, and what I've seen many other folks using your load seems pretty reasonable. Yes, you definitely want to make sure you've got enough bullet pull (neck tension) so setback isn't a concern, but that's not too hard to do. My .40 Major load with N320 slightly flattens primers and I'd bet that most everyone using TG or similar powders is seeing similar flattening. While it's only hiding the symptoms, that's also part of why quite a few folks use SR primers for .40 Major...it's definitely not a low pressure load the way most of us are loading it. R,

Thank you for all of the feedback. I am feeling a little better about my results now so will start to run more rounds through the chrono. Typically I run 10 rounds but now that I am close will probably run more as you suggested. Might make one more minor adjustment to stay in the 4.9-5.0gr range. Think I also need to make sure I keep the ammo out of the Sun before I chrono it.

[Jaxshooter]

If USPSA/IPSC are chronoing at 10 feet I would use that distance checking my loads for PF.

[RePete]

Set your chrono at 10 feet (USPSA/IDPA/IPSC distance).

Drop your load to about 4.3gr/TG and then re-chrono.

This is my load in the G35 and STI Trojan and makes major.

What is the average temperature for when you tested your rounds? What velocity where you getting?

When you say "makes major", do you mean it just makes it to 165.x PF or do you have a nice buffer above 165? In another thread, the consensus seemed to be 174 was a good target PF for no worries at the chrono stage despite temperature and chrono variances.

(I'm looking for a TG recipe as a backup for my current Universal recipe, so extra data is always useful.)

Set your chrono at 10 feet (USPSA/IDPA/IPSC distance).

Drop your load to about 4.3gr/TG and then re-chrono.

This is my load in the G35 and STI Trojan and makes major.

Don't want to turn this into a load data thread but assuming you are using a short OAL close to factory ammo like 1.125.

My gun will not feed short OAL's reliably. 1.22 seems to feed the best so need to use more powder.

I tried 10ft with my chrono and it seemed to be getting velocities in the 850 FPS range at times so decided to back up to 15' and

no longer saw the low readings.

Correct OAL = 1.125" but 0.002" shorter will be GTG too.

In getting about 950 fps for a PF of 171.

[jmorris]

The unbrella part reminded me of a time I was helping my brother in law with a science project and needed to use the chronograph after dark. The photo below is what I came up with and it worked. I bet the white corrugated plastic roofing stuff from homedepot or lowes would work for many angles during the day as it would seem like just one big cloud.

I have used the load below a lot and 935fps was as slow as it's gone in TX when it was cold as hell but hell never goes below 28 degrees here.

.40 S&W

4.5g TiteGroup

180g Berry's

OAL 1.180

Winchester small pistol

Velocity 935fps

[TonyG35]

Checked with AA&A. Their .40 long averages at 950 out of a G22. Shot it out of my G35 and got ~970 which is exactly what another member stated they saw out of a G35 at a major match.

Based on this I guess my chrono is right on. I didn't think the STI barrel would be faster than the Glock but it looks like it is. Set my loads as close as possible to 4.9gr and getting very

consistent results in the 940's. Guess I will see how close I am at Nationals.

[G-ManBart]

Checked with AA&A. Their .40 long averages at 950 out of a G22. Shot it out of my G35 and got ~970 which is exactly what another member stated they saw out of a G35 at a major match.

Based on this I guess my chrono is right on. I didn't think the STI barrel would be faster than the Glock but it looks like it is. Set my loads as close as possible to 4.9gr and getting very

consistent results in the 940's. Guess I will see how close I am at Nationals.

How did it work out at Nationals? R,

[TonyG35]

Checked with AA&A. Their .40 long averages at 950 out of a G22. Shot it out of my G35 and got ~970 which is exactly what another member stated they saw out of a G35 at a major match.

Based on this I guess my chrono is right on. I didn't think the STI barrel would be faster than the Glock but it looks like it is. Set my loads as close as possible to 4.9gr and getting very

consistent results in the 940's. Guess I will see how close I am at Nationals.

How did it work out at Nationals? R,

That's about the only stage that I did well on at Nationals... Came in a little lower than the results posted above 929, 933, 936 for a PF of 168.5

I also did some averages on my powder measure and it came in closer to 4.8gr of TG. Seems to be a good combination so

going to stick with it.