Primer pressure vs neck tension

[Bmghunter]

There’s been quite a few discussion about neck tension, neck lube, and some discussion on primer weight sorting too and SD
I have no answers but just questions for the experts here.

Do you suppose that there is a good relationship between getting good SD and neck tension/lube has to do with whether a primer by itself causes enough pressure to dislodge the bullet from the case and enter the rifling? Or by how deep it enters?

Suppose a primer does not always dislodge bullet from the case depending on neck tension, neck crimp, and neck lube. So a lighter hold on the bullet from the neck would result is more likely to dislodge bullet with just the primer, and a stronger neck hold results in more unlikely to dislodge. Then wouldn’t it be a good assumption that a middle strength hold on the neck results in inconsistency in dislodging?

Wouldn’t this inconsistency cause the SD to be higher due to different combustion characteristics?

Then all this discussion around SD in relation to neck tension, lube, crimp, primer weights etc really are trying to find a combo that creates a consistent release?

If so, would a consistent strong neck grip that is stronger than the primer alone can dislodge be about as good as one that consistently allows the release? Or would one be preferable to another? Why?

 

[RegionRat]

Hate to answer a question with a question, but....

Have you ever seen a formal study where they intentionally use only primers and test bullet release?
I have not.

It tends to happen by accident where there is no powder, or when powder is so bad it doesn't ignite. Both of those are going to give really different results in terms of pushing a bullet from a neck into the barrel. Even then, I still don't see how that would give any chance of predicting a good SD later on.

Seems like another rabbit hole that leads to swirl and endless conjecture.

When a recipe happens to give a really great pattern for showing great SD in lots of different folk's hands/guns, take it and run.
Give that same "golden recipe" to some klutz with crappy workmanship and a shitty gun, and they will screw it up. YMMV

Merry Christmas and Happy New Year!

 

[Bmghunter]

Maybe this whole discussion is moot and that primer pressure alone always dislodges the bullet?

 

[spife7980]

Maybe this whole discussion is moot and that primer pressure alone always dislodges the bullet?

Except that you can prime an empty case and the bullet stays in the case. Doesn’t always go into the lands.
There is no always, except it always depends.

 

[straightshooter1]

There’s been quite a few discussion about neck tension, neck lube, and some discussion on primer weight sorting too and SD
I have no answers but just questions for the experts here.

Do you suppose that there is a good relationship between getting good SD and neck tension/lube has to do with whether a primer by itself causes enough pressure to dislodge the bullet from the case and enter the rifling? Or by how deep it enters?

Suppose a primer does not always dislodge bullet from the case depending on neck tension, neck crimp, and neck lube. So a lighter hold on the bullet from the neck would result is more likely to dislodge bullet with just the primer, and a stronger neck hold results in more unlikely to dislodge. Then wouldn’t it be a good assumption that a middle strength hold on the neck results in inconsistency in dislodging?

Wouldn’t this inconsistency cause the SD to be higher due to different combustion characteristics?

Then all this discussion around SD in relation to neck tension, lube, crimp, primer weights etc really are trying to find a combo that creates a consistent release?

If so, would a consistent strong neck grip that is stronger than the primer alone can dislodge be about as good as one that consistently allows the release? Or would one be preferable to another? Why?

If the powder is going to ignite, I don't think there's any way isolate what the primer is doing from the ignition of the powder that happening close to the same time, especially where the powder is so close to the initial flash of the primer through the flash hole.

What we do know is that different brands of primers produce a different amount of flash through the flash hole to ignite the powder. How consistent that flash ignites the powder is going to affect SD's. That's where sorting primers and consistent seating depths come in. Like, you sure don't want to mix different primers brands in your batch of reloads.

Remington 7.5's vs Federal 205M's: