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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/07/2012 at 16:02
Gil P. View Drop Down
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I have read some opposing opinions regarding how "hot" certain brands of primers are and how they affect the pressure of the cartridge.

This link http://www.chuckhawks.com/primers.htm says that Winchester primers are the hottest (and result in the highest pressure) CCI and Federal are in the middle and Remington is the mildest. I have read that Federal primers are the hottest. Which is correct?

I'm asking because im going to change primers in my 308 reloads from WLR to Federal 210 to see if there is any difference in accuracy. Is it safe to simply switch the primers and keep the same powder charge (43.4gr IMR4895)? I suppose I should work up to that load with the Federal primers for safeties sake but if the Federal primers dont produce as high pressure as the WLR I am currently using, it should not be dangerous to switch the primers without working up a load.

Edit: They are Federal 210M primers if that makes a difference.


Edited by Gil P. - July/07/2012 at 16:09
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/07/2012 at 17:09
Alan Robertson View Drop Down
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Howdy Gil P.

There isn't any hard and fast reference listing of primers in order of "brisance", or the heat energy of the primer. The reasons are that each type of priming compound reacts differently with different powders and what is true with one combination of primer/powder won't necessarily be true with another.
Standard priming compounds (not 'lead free' ) come in two formulation types, called basic  (Federal type) and normal (Winchester type). The basic type is more sensitive and easier to light, but are less stable and more 'explosive'. Can't find the reference right now, but seems like I remember that "basic" primers have a shorter and higher pressure curve... don't quote my swiss- cheese memory. I think CCI also uses the "normal" formula, like Win. The amount of priming compound used is obviously also a factor.
Here is as close a reference to relative brisance as I've found: 
http://www.castingstuff.com/primer_testing_reference.htm
 
You didn't say which bullet you are using, so can't determine if your load was just middlin' or near max.

Those Fed 210Match primers should be more consistent, but still less "hot" than the WLRs.

Still, why take a chance? There are enough ways to foul up with hand loading already.

Reducing your loads when changing any component and checking pressure and other results is the way to go.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/07/2012 at 17:18
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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/07/2012 at 18:17
Gil P. View Drop Down
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Thanks for the info and links I will be sure to look at them. I am using 175SMKs and winchester brass.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/10/2012 at 14:22
Gil P. View Drop Down
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Would anyone happen to know anything about the "quality" of different powders? I know its best to shoot what works best in your gun but some powders are more expensive than others. Are you just paying for the brand name or are some powders known to be more consistent? I cant imagine there could be an inconsistency as long as you do your part in preparation of the round.

Ive been using IMR4895 and am thinking of switching to Vihtavouri N150 just to see how a more expensive powder does.
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In some cases a more expensive powder will not perform as well as a cheaper powder.  Like you said, it is all about what your gun likes.  But nothing is at all wrong with trying others, as you may find something that performs better.  Or you may not.  That is half the fun of reloading.
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Originally posted by Gil P. Gil P. wrote:

Would anyone happen to know anything about the "quality" of different powders? I know its best to shoot what works best in your gun but some powders are more expensive than others. Are you just paying for the brand name or are some powders known to be more consistent? I cant imagine there could be an inconsistency as long as you do your part in preparation of the round.

Ive been using IMR4895 and am thinking of switching to Vihtavouri N150 just to see how a more expensive powder does.
I'll just give the jist of what I know, and try to keep it short. Vihtavouri powders are made by the same company that started making them to begin with. I have heard that they are the most consistent from lot to lot, but I have never used their powder, so I can't say first hand (can't get the stuff locally). Most other powders may vary some from lot to lot, and may not be made by the same company from onr lot to the next. A company may contract out powders by formula and performance standards and there may be slight differences from one lot to the next. think of it kind of like this; 2 mothers have tha same exact pecan pie recipe, they both follow the recipe when they make them, but they both taste different when they are done, not bad, just different.
Many powders that I used when I started reloading, are now made by different companies, but the powder has the same name and formula, but like 2 mothers, there is probably a difference in performence. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/10/2012 at 19:04
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Sometimes a powder company has a certain mystique, because their products are more expensive. In reality, importation costs and marketing have driven their higher prices.
Some of our European friends have commented in these threads about how US powders are more expensive 'over there' and as a result, have an extra mystique among some Euro shooters.
Having said that, Vihtavuori does make great powders. VV N105 was an answer to Colt .45 SAA fans' prayers.

Usually, there is one powder that works better than everything else for a particular combination of bullet, case, rifle, etc.  A person can easily end up with a dozen or so powders trying to micro- tune different loads for several handguns and rifles, when far fewer powders would work well, just not at the ultimate best in each instance.

The evolution of powders seems to be moving faster. In the recent past, we have seen many new powders, some of which are true game changers- Alliant Reloder 17 and Trail Boss come to mind.

Better powders just help us get on target and that's the whole point.
 


Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/10/2012 at 19:41
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Sometimes you choose a powder more for other factors. For instance, with one of my rifles I found Reloder 15 was more accurate, but not much more than Varget. Varget worked well in other rifles, has worked more consistently from low to high temperatures and burns cleaner. So I could standardize on one powder, etc. I went with it instead. That same rifle also shot cheapo Speer 165 boattails better than anything (in combination with the RL-15), but I don't like soft points and other bullets had better ballistics and terminal performance.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/10/2012 at 23:43
Gil P. View Drop Down
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What do you consider "low to high temperatures"? I live in an area where the temperature can vary from 100 to 115 degrees during the summer. What about bullet weight? I know some powders are suited for certain weight bullets. Im shooting heavier 308 caliber bullets (175SMKs for now, I do want to try 178 AMAXs though).

I'm glad you found a powder that worked well in more than one of your rifles that certainly simplifies things!
I hear a lot of people like Varget because its not temperature sensitive like you say, but how does temperature difference affect the performance of your powder? I assume it only changes your point of impact; will a certain powder work well at 100 degrees and give poor groups at 70 degrees?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/11/2012 at 10:12
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Originally posted by Gil P. Gil P. wrote:

What do you consider "low to high temperatures"? I live in an area where the temperature can vary from 100 to 115 degrees during the summer. What about bullet weight? I know some powders are suited for certain weight bullets. Im shooting heavier 308 caliber bullets (175SMKs for now, I do want to try 178 AMAXs though).

I'm glad you found a powder that worked well in more than one of your rifles that certainly simplifies things!
I hear a lot of people like Varget because its not temperature sensitive like you say, but how does temperature difference affect the performance of your powder? I assume it only changes your point of impact; will a certain powder work well at 100 degrees and give poor groups at 70 degrees?
I would consider 100* a high temperature. I think a couple of the things you might want to consider when working up a load, is how close you are to the maximum load and what are the tempatures when you worked up your load. If you worked up a load that approached maximum charge weight on a day that was 50*, you would want to look for signs of unsafe pressures if your shooting that same load on a 100* day. If your load falls somewhere close to the middle of the start to maximum load, then your probably ok.
Temperature affects POI because it affects air density. Now wrather it affects group size would depend on the powder. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/11/2012 at 10:21
Gil P. View Drop Down
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Is temperature sensitivity as it applies to powders only affect the pressure that it generates with a temperature swing? And having too high or too low a pressure can be negative for accuracy. So you're saying that a powder like Varget wont generate very different pressure if its fired in a 70 or 100 degree environment? Please correct me if im not understanding.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/11/2012 at 10:34
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i'm not yet a reloader, but with concern to the temperature question... combustion, as a chemical reaction, is a function of:
1. a fuel source
2. oxygen availability
3. an activation energy reaching or exceding the threshold needed by the fuel

different powders have different activation energy requirements, however they're all temperature sensitive to a point.  a powder that needs to reach, 350 degrees is closer to it's activation point in a 100degree environment than in a 50degree environment.  also, these powders in general will burn faster or slower depending on the temperature of the environment.

i beleive that's what beltfed was getting at with the 50/100deg example. 

given these examples, you may want to fire a few rounds in weather comparable to what you're used to when hunting, for just these reasons.
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Originally posted by Gil P. Gil P. wrote:

Is temperature sensitivity as it applies to powders only affect the pressure that it generates with a temperature swing? And having too high or too low a pressure can be negative for accuracy. So you're saying that a powder like Varget wont generate very different pressure if its fired in a 70 or 100 degree environment? Please correct me if im not understanding.
By George I think you've got itExcellent
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/11/2012 at 10:58
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One thing to note.  Just because your velocity goes up when the temp goes up does not necessarily mean that your pressure went up.  Higher temps change the air density so the bullet flies through the air with less resistance, which leads to more velocity.  Using say Varget or RL15 and you create a safe load at 30 that is going 2600.  When the temp gets to 60 you will get 2650, at 90 you will get 2700.  And you may not have any pressure issues.  But becaue of the air density alone you gained 100 fps.  As the temp goes up the air density goes down. 

Creating a super hot load at 30 and then shooting it at 100 may indeed cause pressure issues, and some powders are more susceptible to that than others.   That is why we need to shoot in all temps and test our loads to makes sure things are good. 

As far as accuracy goes, it is possible that those added or lowered velocities could push you out of your accuracy node.  So it is possible you could lose some accuracy. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/11/2012 at 17:24
Gil P. View Drop Down
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Originally posted by BeltFed BeltFed wrote:

Originally posted by Gil P. Gil P. wrote:

Is temperature sensitivity as it applies to powders only affect the pressure that it generates with a temperature swing? And having too high or too low a pressure can be negative for accuracy. So you're saying that a powder like Varget wont generate very different pressure if its fired in a 70 or 100 degree environment? Please correct me if im not understanding.
By George I think you've got itExcellent


Yes! I knew I could do it!
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/11/2012 at 17:26
Gil P. View Drop Down
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Originally posted by supertool73 supertool73 wrote:

One thing to note.  Just because your velocity goes up when the temp goes up does not necessarily mean that your pressure went up.  Higher temps change the air density so the bullet flies through the air with less resistance, which leads to more velocity.  Using say Varget or RL15 and you create a safe load at 30 that is going 2600.  When the temp gets to 60 you will get 2650, at 90 you will get 2700.  And you may not have any pressure issues.  But becaue of the air density alone you gained 100 fps.  As the temp goes up the air density goes down. 

Creating a super hot load at 30 and then shooting it at 100 may indeed cause pressure issues, and some powders are more susceptible to that than others.   That is why we need to shoot in all temps and test our loads to makes sure things are good. 

As far as accuracy goes, it is possible that those added or lowered velocities could push you out of your accuracy node.  So it is possible you could lose some accuracy. 


Thats why its important to test your load in the area you will be hunting to be sure it still works well.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: July/11/2012 at 21:41
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Originally posted by supertool73 supertool73 wrote:

One thing to note.  Just because your velocity goes up when the temp goes up does not necessarily mean that your pressure went up.  Higher temps change the air density so the bullet flies through the air with less resistance, which leads to more velocity.  Using say Varget or RL15 and you create a safe load at 30 that is going 2600.  When the temp gets to 60 you will get 2650, at 90 you will get 2700.  And you may not have any pressure issues.  But because of the air density alone you gained 100 fps.  As the temp goes up the air density goes down. 

Creating a super hot load at 30 and then shooting it at 100 may indeed cause pressure issues, and some powders are more susceptible to that than others.   That is why we need to shoot in all temps and test our loads to makes sure things are good. 

As far as accuracy goes, it is possible that those added or lowered velocities could push you out of your accuracy node.  So it is possible you could lose some accuracy. 


I will go along with most of that but, Air Density has nothing to do with MV.  It will cause you to have less drop for a given range due to less air resistance but only temp effects MV.
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Anyone who has left their ammo sitting in the sun for a few minutes (and was paying attention) has seen what rising temps can do. That's part of the reason why most commercial ammo is not loaded to SAAMI max pressure.


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Temperature resistance is relatively cartridge-specific.  For example, Varget exhibits good temp resistance in the 308 with medium-weight bullets, but its temp-resistance is not as good in the 223.  I would expect its temperature resistance to be poor in the 300 RUM, but I'm not volunteering to do the shooting work to find out. :)
 
So, NO powder is categorically "temperature stable."  They're only temp-resistant, and only in the cartridge-bullet envelope they were designed/developed for.
 
Secondly, performance changes based on temperature are primarily a function of rifle temp.  Ammo temp is a minor factor, but leaving a cartridge chambered for 30 - 60 seconds will bring the powder and brass to rifle temp or close enough, and even the bullet warms (or cools) quite well.
 
Denton Bramwell has a couple of well-instrumented tests on the net which show how temp resistance works, if you're interested.
 
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I forgot to say that, basically, a powder's burn rate is altered slightly as temperatures change.  The temp-resistant powders slightly _increase_ their burn rate when things get cold, to compensate for the fact that more heat is being absorbed by the rifle steel, etc, instead of being used to generate pressure to push the projectile.  Of course, they slightly _decrease_ their burn rate when things get hot.
 
According to Ramshot (see the FAQ on their site), complete temp resistance can only be achieved by double-base stick powders.  Interestingly, none of the Hodgdon stick powders are double-base.  However, temp-resistance (though perhaps not complete?) can also be achieved with additives/coatings.  Clearly, then, this is how Thales (that's who makes Hodgy's 'extreme' stick powders) gets temp resistance.
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Originally posted by MZ5 MZ5 wrote:

Temperature resistance is relatively cartridge-specific.  For example, Varget exhibits good temp resistance in the 308 with medium-weight bullets, but its temp-resistance is not as good in the 223.  I would expect its temperature resistance to be poor in the 300 RUM, but I'm not volunteering to do the shooting work to find out. :)
 
So, NO powder is categorically "temperature stable."  They're only temp-resistant, and only in the cartridge-bullet envelope they were designed/developed for.
 
Secondly, performance changes based on temperature are primarily a function of rifle temp.  Ammo temp is a minor factor, but leaving a cartridge chambered for 30 - 60 seconds will bring the powder and brass to rifle temp or close enough, and even the bullet warms (or cools) quite well.
 
Denton Bramwell has a couple of well-instrumented tests on the net which show how temp resistance works, if you're interested.
 
Thanks for those interesting links, MZ5. I once had them bookmarked before a PC cratered and have since forgotten about the studies.
Bramwell is right about the barrel temp's ability to cause more issues than ambient temps. Ever see an M60 cook off? Air temp just can't get that hot, but ammo temp does make a difference.
The sun came out one July a couple years ago and my mild target load .45acp were then exposed. I noticed it later and loaded a partial magazine... they were really too uncomfortable to handle, so must have been around 130-140F at least. The increase in recoil was quite noticeable- felt like +P.

Bramwell said:
"Going from a powder temperature of 45 F to a powder temperature of 99 F increases pressure by
3797 PSI, or about 70.3 PSI per degree F. There is less than one chance in 1,000 of getting a result
at least this big, just by random chance. This effect is real."

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So on paper at least, a double base powder performs better than a single?
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No, that's not what it means. It just means that no powder is categorically "temperature insensitive" across the board. Ramshot says you can get total temp resistance with a double-base stick, but that doesn't mean they all are; they have to be designed that way. Eurenco does this somewhat for Alliant in Reloder 15, for example. Ramshot also says you can achieve temp resistance with additives/coatings. That's how Thales does it for Hodgy in the 'extreme' line, and how General Dynamics does it in some of the sphericals they make.
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Are there any good books for subjects like these? 
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