Accuracy difference with powder changes

[Nhoro]

Hi all, I started thinking about some powders being more accurate than others. So wenall know that one powder is often more accurate than another and this varies from rifle to rifle. What is good in one rifle may be bad in another. Are there any noticeable trends in accuracy ? I mean, you can have several suitable powders that are around 100 % case fill, you do a ladder in each, find your accuracy node etc but 1 will usually shoot better. Is it the fastest powder or most velocity consistent. Something about a certain powder must make it more consistent and therefore more accurate ?

 

[AckleyHunter]

There are a lot of variables and accuracy for each rifle, projectile, powder, brass, and primer combo needs to be determined empirically.

That being said, varget always seems to be accurate.

 

[uplander01]

If I had to sum up such a discovery I would be pretty limited and better off saying what hasn’t worked for me. Those things are cci 250 magnum primers, RL19 & RL 22 powders. Cci 250’s seem to be harder and need a hard strike and velocity in the same rifle, same charge, compared to f215m, cci much less consistency with velocity. And the RL powders imo leave way more oily type carbon residue in the barrel compared to a varget,h4350,h4831.

 

[AZDAVE]

Your question is VERY open and broad. Without giving the cartridge it is about impossible to answer your question, except for a broad brush kinda statement.

For example a powder that gives very good accuracy in a 308 (Varget) vs a 300 H&H (H4831). if you try varget in the 300 it limits the performance, save the other way around.

 

[johnnybow]

If I had to sum up such a discovery I would be pretty limited and better off saying what hasn’t worked for me. Those things are cci 250 magnum primers, RL19 & RL 22 powders. Cci 250’s seem to be harder and need a hard strike and velocity in the same rifle, same charge, compared to f215m, cci much less consistency with velocity. And the RL powders imo leave way more oily type carbon residue in the barrel compared to a varget,h4350,h4831.

So you notice less accuracy in the cci magnum primers? Or just not going off consistently?

 

[Firebird]

Interesting and I agree, unlimited in its breadth. Interesting because I have never liked varget in anything where I have tried it and I positively love rl 22 in several rifles. So very open to personal experience.
Some seem better suited to specific calibers such as IMR 4350 in the .30-06 or H-4831 in the .270, but still generalizations.

 

[uplander01]

So you notice less accuracy in the cci magnum primers? Or just not going off consistently?

Velocity variance when chrono'd, and yes it affected accuracy, dealt with it in both a 375 and a 416. I also had an instance with a GMA actioned rifle that must have had a weak firing pin spring, probably from being 20+ years old, anyway that rifle wouldn't ignite CCi250's consistently. I changed out the spring for a new one and it wasn't a problem again. BUT, even with the weaker older spring F215 would go off every time. Hence my hypothesis that the CCI require a harder primer strike.

 

[Andrew NOLA]

CCI are definitely harder than federals

 

[BryceM]

There are WAY too many variables here to give a meaningful answer. Some powders are probably better than others in terms of consistency. I've seen huge differences between lots of RL22. I have not had the same problem with H-4831, Varget, or H-4350, at least not to the same degree.

Some powders are more temperature stable than others. Some meter better in a charge thrower, if you're using one of those instead of weighing each load on its own.

More or less, the concept of a "node" is a function of the bullet's velocity. Not every powder can achieve a given velocity at a safe pressure, but within a certain range, it's likely that different powders will give reasonably similar group sizes. To determine this with scientific precision, the necessary statistical sample size will be reached shortly after you've shot the barrel out........

 

[SStomcat]

Back in the days when primers were in short supply I used cci 34 in my 470 with no issues

 

[Ray B]

One aspect about powder selection that "seems" to me would affect repeatability is the amount of blast at the muzzle, particularly with boattail bullets. It seems to me that possibly only a millionth of a second would be involved but one side of the bullet will clear the barrel before the other side. the propulsion of the powder would push out that side and cause a slight tipping of the bullet. This would be a very miniscule amount but it would be greater with a slow burning powder than a faster one- so it would seem to me, that "all other things equal"- slightly better accuracy would be obtained with a faster powder.

 

[Nhoro]

To clarify my thoughts, I was thinking about how you can use one step faster or slower powder in the same cartridge, same bullet. You can possibly even match velocities or be pretty close. And somehow, one powder can be more accurate. You can also see similar powders from Hodgdon and IMR and one performs well in a certain calibre while the other shines for a different calibre. So is there a trend like fastest powder that you can safely use is more accurate or a certain powder is most accurate in a 30-06 across all rifles. Or can you use pretty much any suitable powder and tweak it to be accurate as long as you are willing to sacrifice a bit of velocity. Or is it rifle specific and you just need to try every powder until you find the best for your specific rifle. It seems above that people can get good results from a variety of powders and there is not really a goldilocks powder ?