Less powder = more fps ???

[Ron.B]

Less powder = more fps ???

New to reloading and confused ... I went to the range to test my loads .. I figured I needed 42.5 to 43.3 gr would be my target load for testing and made several bullets at each weight between. Also because this was my first crack at it I made 2 bullets at 42 gr as starters ,,,, my target was 2700 fps for my new load ........ I started with my testing ... The two starters at 42gr. Were around 2750 fps I was worried as these were my light loads and already over my target fps .. I proceeded with the rest, starting at 42.5gr and fps dropped to 2650 and remained there untill 42.8 gr were it just broke 2700 fps then dropped below 2700 all the way to 43.2 gr at 43.3 the fps jumped to 2800 fps .... Obviously I need to do tests around 42gr but am confused as to why with all things equal 42 gr has a faster fps rate than all the way to 43.2 gr .... The only thing I can conclude is it has to do with volume and pressure created ...
So am I out to lunch or can less powder equal more fps

 

[SND]

The most common reason for such results is inaccurate chrono readings, more so if just using a chrony or other cheap unit.

 

[Ron.B]

The most common reason for such results is inaccurate chrono readings, more so if just using a chrony or other cheap unit.

Bran new Caldwell with the infa red lights from cabelas .... First time using but not a cheap unit and seemed to work well chrono'd my 6.5 and my buddies 300 mag. With no issues that I noticed

 

[Andy]

More info please - e.g. powder used, cartridge, bullet weight.

Probably a combination of:

- normal variation of loads; and
- normal variation of chronograph.

 

[GMC403]

Ammo loaded exactly the same will have a variance to it already. A good load will have a very low spread, but 50fps is not unheard of. Couple that with variances from the chrony and that could explain what you're experiencing. How many loads were you shooting to get your data?, 1 or 2?. I try to do a minimum of 3-4 to get a solid average reading.

 

[Papaclaude]

Did you start with a clean barrel? Shouldn't make that big a difference, but it will have a small impact, combined with the factors mentioned above. Also, was your powder weighed or charged by volume? Some powders meter out less consistently than others. I'd try at least 10 of the 42's just to make sure. Also, what type of primer were you using? From the loads you mentioned, I'm guessing you were loading for a 308-class cartridge?

 

[358Rooster]

You can speculate all you want but it doesn't seem like you have much of a control group (you may have but it's not stated in your posts). Unless you have some sort of benchmark control, you can not conclude that any one variable is correct / incorrect.

Do you have previous reliable velocity data from either the 6.5 or the 300 mag? Have you run your Caldwell in tandem with another chronograph to compare direct readings? Until you eliminate some variables (or at least see some sort of trend), you can't really make a call one way or another. Don't hit the panic button just yet.

There are many factors that contribute to wonky chronograph readings including light intensity, light angle, muzzle blast (distance), etc. Figure out what your unit needs to give you reasonably repeatable readings and then you may find some confidence in what it's telling you. Chronograph accuracy is a widely debated topic and for the lower-end units, I believe they can be used effectively to produce decent feedback for load development when set up properly in the right conditions. They'll get you a good ballpark for data to be plugged into a trajectory solution but will rarely get you 'bang on'. You'll have more work to do at distance once you have that baseline.

I have seen loads of the same charge that give velocity spreads of over 100 fps. Doesn't mean a heck of a lot except that you pretty much want to discard that charge weight range from further testing. Also, one or two rounds at any one charge weight will not give you enough data to make any sort of valuable conclusion.

What was the target paper telling you - are you able to correlate each printed result with each velocity reading? This is an important factor in determining what's going on with your loads. You need to do some more work, otherwise you'll be chasing your tail (ask me how I know...).

Rooster

 

[Ron.B]

6.5 creedMoor ... Reloading once fired factory hornady 140 gr ELD match ammo . Reloading with 140 ELD match bullets and h4350 powder ,, using new hornady match grade dies with .288 neck bushing ... Testing consisted of 2 bullets at each weight ... Example 42.0 , 42.5 , 42.6 , 42.7 excedera to 43.3

 

[Ron.B]

delete

 

[Ron.B]

Did you start with a clean barrel? Shouldn't make that big a difference, but it will have a small impact, combined with the factors mentioned above. Also, was your powder weighed or charged by volume? Some powders meter out less consistently than others. I'd try at least 10 of the 42's just to make sure. Also, what type of primer were you using? From the loads you mentioned, I'm guessing you were loading for a 308-class cartridge?

Yes first 2 shots at 42 gr. we're s clean barrel and yes 6.5 creedmoor ... All loads were precisely measured ... primer is federal 210 M

 

[Ron.B]

You can speculate all you want but it doesn't seem like you have much of a control group (you may have but it's not stated in your posts). Unless you have some sort of benchmark control, you can not conclude that any one variable is correct / incorrect.

Do you have previous reliable velocity data from either the 6.5 or the 300 mag? Have you run your Caldwell in tandem with another chronograph to compare direct readings? Until you eliminate some variables (or at least see some sort of trend), you can't really make a call one way or another. Don't hit the panic button just yet.

There are many factors that contribute to wonky chronograph readings including light intensity, light angle, muzzle blast (distance), etc. Figure out what your unit needs to give you reasonably repeatable readings and then you may find some confidence in what it's telling you. Chronograph accuracy is a widely debated topic and for the lower-end units, I believe they can be used effectively to produce decent feedback for load development when set up properly in the right conditions. They'll get you a good ballpark for data to be plugged into a trajectory solution but will rarely get you 'bang on'. You'll have more work to do at distance once you have that baseline.

I have seen loads of the same charge that give velocity spreads of over 100 fps. Doesn't mean a heck of a lot except that you pretty much want to discard that charge weight range from further testing. Also, one or two rounds at any one charge weight will not give you enough data to make any sort of valuable conclusion.

What was the target paper telling you - are you able to correlate each printed result with each velocity reading? This is an important factor in determining what's going on with your loads. You need to do some more work, otherwise you'll be chasing your tail (ask me how I know...).

Rooster

The only control was the 5 factory loads that averaged 2700 fps.... thanks for some great info and ideas ... I see a lot more testing in my future ... To start I was just trying to reproduce the factory ammo with plans to go deeper (chase lands and loads) in the future as I learn more of the art of reloading

 

[Kryogen]

Cold barrel, powder weight variation, bullet weight, neck tension, brass, case volume, chrono error, all this

Regular chronos give different fps reading depending on the the angle of the shot, light, etc...
My lab radar has given me very precise readings, sometimes getting an es of 12 fps for 5 rounds

Most often though, es is around 30 and sd is around 10

Mixed brass volume thrown bulk 223 has an es of 100 fps or so

Chronies always gave me crap results in real world testings so I sold those.
They may test good in a lab with parallel shooting in a vise, but real world not so easy.

 

[358Rooster]

Yep, she's a long ol' road. As with everything shooting, collect data, analyze results, eliminate variables one by one, make adjustments based on findings, repeat, repeat, repeat. There are TONS of factors and few constants.

Just out of curiousity, what sort of velocity spread did you get around that 2700 avg with the factory ammo?

Rooster

 

[Ganderite]

Welcome to shooting and handloading.

I have gone to test ammo many, many times (thousands). I have 3 ring binders of log books for each rifle.

Seldom has a test gone smoothly and given me solid results I can rely upon, so your results are not unusual.

First, learn and use correct nomenclature. Otherwise your posting is confusing. When you wrote "I figured I needed 42.5 to 43.3 gr would be my target load for testing and made several bullets at each weight between" You actually meant you loaded several rounds (not bullets) ...

I don't know much about making bullets, so was going to pass on your posting, until I realised 42 gr was a very light bullet.

When you make ammo for a test, confine yourself to a single variable, like the powder charge. I think you did that.

It sounds like you decided to try to find a load to duplicate factory velocity. To each his own, but this is almost a pointless exercise. If the factory ammo was nice and fast, or very accurate, your results are going to be quite different, unless you happen to have the same powder the factory used. Factory ammo loaded in a new cartridge design is loaded to its full potential. Only a few powders can exploit that potential for high velocity. I doubt 4350 is one of them.

I have started out with a new rifle, new caliber many times. What I do is select a likely good powder. 4350 would be a good candidate for an accuracy load. RL17 would be slightly better. I would load 5 rounds of each powder charge (not just 2), in 0.5 gr increments and shoot them for group. If I was using 4350, I would start at 38 gr. and load up to 42 .5 gr.

As I tested, I would watch for any sign of pressure and would be prepared to bring some of the ammo home, to be pulled.

This first test is to find the powder charge worthy of more testing(and to tell me what the MAX is for my rifle.)

Let's say 41 gr looked promising. I would load 15 rounds of 41 gr and also 0.3 more and less. 10 shots would be fired for accuracy and 5 shots through the Chrony (unless the chrony can be set up to monitor the accuracy shots. if so, only 10 rounds are needed.)

I have found that if I get closer than 15 feet to the Chrony, results get erratic. I usually test at 20 feet. If you were too close, that would explain the random nature of your results.

I load for hunting and I load for target shooting. In both ventures accuracy is the object. Velocity is measured almost for academic reasons. In your case, given the modern design of the cartridge, you can use 2700 as a speed limit. The factory ammo is loaded to high pressure. You would be wise to obey that limit.

And it is possible that with the limited number of powders available to a handloader, you might not be able to match the factory velocity.

Your test started at or over max pressure. Start 3 gr lighter, and work up. And test more than 2 rounds of each powder charge.

 

[Gunneegoogoo]

If you're new at this, read the "understanding pressure" article on the Primal Rights website. I wish it was around when I got into this heavy. I say this for 2 reasons. 1. Overall Safety, and 2. There comes a time when increasing your powder charge results in losing velocity, which is what you're concerned about. I don't think that's your issue here, but it's just food for thought.

GGG

 

[stubblejumper]

Yes first 2 shots at 42 gr. we're s clean barrel

Which often produces a bit more velocity in many barrels. And if you are increasing the powder charge in very small increments, say .1 grain, the accuracy of your scale can be a factor.

 

[Ron.B]

Yep, she's a long ol' road. As with everything shooting, collect data, analyze results, eliminate variables one by one, make adjustments based on findings, repeat, repeat, repeat. There are TONS of factors and few constants.

Just out of curiousity, what sort of velocity spread did you get around that 2700 avg with the factory ammo?

Rooster

Factory 140 ELD match fps was 2753 / 2650 / 2737 / 2676 / 2706 / 2684 fps

 

[Ron.B]

Welcome to shooting and handloading.

I have gone to test ammo many, many times (thousands). I have 3 ring binders of log books for each rifle.

Seldom has a test gone smoothly and given me solid results I can rely upon, so your results are not unusual.

First, learn and use correct nomenclature. Otherwise your posting is confusing. When you wrote "I figured I needed 42.5 to 43.3 gr would be my target load for testing and made several bullets at each weight between" You actually meant you loaded several rounds (not bullets) ...

I don't know much about making bullets, so was going to pass on your posting, until I realised 42 gr was a very light bullet.

When you make ammo for a test, confine yourself to a single variable, like the powder charge. I think you did that.

It sounds like you decided to try to find a load to duplicate factory velocity. To each his own, but this is almost a pointless exercise. If the factory ammo was nice and fast, or very accurate, your results are going to be quite different, unless you happen to have the same powder the factory used. Factory ammo loaded in a new cartridge design is loaded to its full potential. Only a few powders can exploit that potential for high velocity. I doubt 4350 is one of them.

I have started out with a new rifle, new caliber many times. What I do is select a likely good powder. 4350 would be a good candidate for an accuracy load. RL17 would be slightly better. I would load 5 rounds of each powder charge (not just 2), in 0.5 gr increments and shoot them for group. If I was using 4350, I would start at 38 gr. and load up to 42 .5 gr.

As I tested, I would watch for any sign of pressure and would be prepared to bring some of the ammo home, to be pulled.

This first test is to find the powder charge worthy of more testing(and to tell me what the MAX is for my rifle.)

Let's say 41 gr looked promising. I would load 15 rounds of 41 gr and also 0.3 more and less. 10 shots would be fired for accuracy and 5 shots through the Chrony (unless the chrony can be set up to monitor the accuracy shots. if so, only 10 rounds are needed.)

I have found that if I get closer than 15 feet to the Chrony, results get erratic. I usually test at 20 feet. I you were too close, that would explain the random nature of your results.

I load for hunting and I load for target shooting. In both ventures accuracy is the object. Velocity is measured almost for academic reasons. In you case, given the modern design of the cartridge, you an use 2700 as a speed limit. The factory ammo is loaded to high pressure. You would be wise to obey that limit.

And it is possible that with the limited number of powders available to a handloader, you might not be able to match the factory velocity.

Your test started at or over max pressure. Start 3 gr lighter, and work up. And test more than 2 rounds of each powder charge.

Thank you for your reply and ideas ,,, I will be considering them closely.... Chrono was about 10 feet away minimum ...

 

[Ron.B]

If you're new at this, read the "understanding pressure" article on the Primal Rights website. I wish it was around when I got into this heavy. I say this for 2 reasons. 1. Overall Safety, and 2. There comes a time when increasing your powder charge results in losing velocity, which is what you're concerned about. I don't think that's your issue here, but it's just food for thought.

GGG

I had no signs of pressure all the way to 43.3 gr. but your right and I will read the artical ,,, Thank you

 

[cr5]

I would put the chronograph away. In my opinion velocity is useless when doing load development until you find your accuracy node for the bullet being used. I would test each powder charge in the range you've chosen with 0.2-0.3 grains between each load with at least three rounds per charge and waiting 3 minutes between each shot, if your barrel starts getting warm take a break and let it cool longer. You will find one load shoots better than all the rest, primarily watch for verticle spread. Then make 5 of those rounds again plus 5 more with 0.1-0.2 grains more and 0.1-0.2 grains less and do the same test again. Pick the best load then start playing with seating depth and see if improvements can be found.
Once you have your most accurate load run a few over the chronograph and write down your results.

I've seen with many rifles of mine that if you do a wide spread of test rounds you will find an upper and lower accuracy node, I always pick the upper node as my pet load for that bullet/powder combination for that rifle. I don't load for a velocity target but instead the best groups. As was mentioned earlier trying to duplicate a factory load is pointless as we don't usually have access to the same powders the factory uses which will cause different pressures and different barrel harmonics giving different results even at the same muzzle velocity.
I've only been fortunate enough to have the same load shoot exceptionally well in more than one of my rifles of the same caliber once. I have a 300BLK bolt action and a 300BLK semi that both like the same load.