What is a muzzle star?

[igolfat8]

I have seen some references made to the star pattern on the muzzle but what is it? How is it formed? How does one read it and gain useful information from it? I only shoot pistols so is this something I should look for or is this only present on rifle muzzle ends? I used the search function and did not find an answer.

[JSnover]

Look for 'lube star.'

[JSnover]

It's the pattern left on your muzzle buy lube being blasted out as the boolit leaves the barrel. It generally means you had enough of the proper recipe to lube the boolit for the entire length of the barrel. There has been some debate...

[Dusty Bannister]

http://www.castpics.net/subsite/Lube/LubeStar.html

Pictures help.....

[igolfat8]

Can I assume that picture is the ideal and of one sees more or a larger star then its over lubed and less star is under lubed?

OT, but is thee any benefit to lubing jacketed or plated boolits too?

[DeanWinchester]

I get a nice greasy star on the crown of my rifle. I rarely clean the bore. It's always sparkling, I just wipe the crown with a rag and put her away. Ben's Red cleans up really easy.

[JSnover]

I haven't studied it that deeply. The stars on mine are larger, FWIW. Lube softens BP fouling. Jacketed/plated bullts are usually (always?) loaded over smokeless, so fouling isn't a problem.

[igolfat8]

Sorry but what is BP fouling?

[375RUGER]

black powder fouling

[45-70 Chevroner]

Sorry but what is BP fouling?
"Black Powder"

[375RUGER]

You will find this helpful- scroll down to post 11
http://castboolits.gunloads.com/showthread.php?104121-Abbreviations-As-Used-on-This-Forum&highlight=abbreviations

[Blammer]

Can I assume that picture is the ideal and of one sees more or a larger star then its over lubed and less star is under lubed?

OT, but is thee any benefit to lubing jacketed or plated boolits too?

a lube star is not necessary, I have a few rifles/handguns that have no lube star but shoot just fine.

do not lube jacketed or plated bullets, not needed, it'd just get messy and there is no where to put the lube on those bullets.

[btroj]

In some cases a big, wet lube star is a bad thing. Many good loads don't develop one at all.

It is something that can be an indicator of what is going on with a load but nothing more than that.

[Chihuahua Floyd]

Igolfat8,
Don't worry about it unless you are shooting Black Powder cartridges. BP needs a soft lube to keep the BP residues soft. Usually required a bullet with larger than normal grooves to hold enough lube.
Smokeless powder does not need a soft lube, the harder wax based lubes or alox based coatings work just fine on cast lead with smokeless powder.
As mentioned above, plated and jacketed bullets do not need lube.
I do both smokeless and BP on occasion, very different.
CF

[igolfat8]

Thanks for the info guys.

[David2011]

Muzzle stars appear when using only jacketed bullets as well. It's just a powder burn and very hard to see on a rounded crown and blued metal. Easiest to see on a bright steel or stainless flat or 11 degree target crown. If symmetrical, everything is good. If uneven, the bore is worn (cleaning rod damage or shot out) or the crown is damaged, but that is normally accompanied by very poor groups. Those symptoms can occur with jacketed or boolits.

David

[Larry Gibson]

Here's a picture of 3 different muzzles (all .308Ws) with lube stars from HV cast bullet loads.

Larry Gibson

93990

[igolfat8]

Does the star form on one shot or after several shots?

[Larry Gibson]

Gradually builds up. How long (many shots) to how much depends on a lot of variables; lube used, amount of lube used, exit psi, velocity, etc.

Larry Gibson