bullet signs

was able to retrieve fired lead slugs. interesting signs on them.

I know a FEW had signs of mold lines, but all were clean and smooth. Fired ones show a lot of melting/flowing.

Strangely I never get signs of melting if I seat the gas check inside the neck, but I get 5" groups if I do that. seat the check inside and use the natural crimp groove gives me golf ball size groups.

fired bases show thebases of the bullets out of round now. gas checks seem to be copper plated aluminum. actually found a few

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Originally Posted by pocketshaver

gas checks seem to be copper plated aluminum

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Not sure I'd want to use those. Wouldn't aluminum gall or melt as it rode out against the steel?

a lot of people on that cast bullet forum swear by aluminum...

I assume its aluminum because the copper seems to have turned to a greyish color I associate with the inside of tin can.

Pocketshaver, I'm not exactly a reloading beginner, but at the moment find the information to be inadequate. How about some basics? What caliber, what rifle, what powder charge... and above all, seating depth?

Your comment that "I never get signs of melting if I seat the gas check inside the neck..." suggests that the velocity is much lower.
Furthermore "...but I get 5" groups if I do that. seat the check inside and use the natural crimp groove gives me golf ball size groups..."

Well I'm not asking these questions just out of idle curiosity, but because I have made a similar observation with jacketed bullets in an original Winchester LAR in 32-40. It has something to do with the depth of seating.

My slightly wobbly theory (and any informed comment will be welcome) is that, quite simply, if the seating depth is too shallow, then the neck opens out to release the bullet before the pressure has built up adequately. Sort of leaking gas too early, rather than banging the bullet into the rifling. The bullet is pushed (relatively) slowly into the rifling, and only then does the pressure really build up.

This could actually result in more gas blow-by than if the bullet was seated deeper and (I know that this is going to sound counter-intuitive) slammed into the rifling with a higher pressure to start off with.

Ok, it's all happening in microseconds, so when I use words like "slower", that is a relative evaluation.

Another thought: the bullet that is - relatively speaking - just flopping out of the neck of a case that is, anyway, sitting on the bottom of the chamber space, is being subjected to a heavily top-sided, i.e. assymetrical force. It is engraved on a slight skew and thus emerges from the muzzle with a tendency to travel in a corkscrew path. BTW: this effect is exacerbated by boattail bullets, especially in milsurps with a long transition cone into the rifling.

In brief: the usually plausible aim to seat the bullet fairly closely to the lands and thus reduce the jump is counter-productive if this means that the cylindrical portion of the bullet within the neck becomes too short, with resulting poor pressure build-up and bullet guidance before the bullet hits the lands.

If you could post some basic facts about your setup, it might be possible to make a more precise analysis.

The neck does not "open up " to release a bullet and that is easily proven in many ways . The powder does not start making it's pressure until the bullet hits the lands and forms a plug to seal . My tight neck bench rest rifles have NO neck clearance at all yet release the bullet every time . The cases reload with no sizing . You can pull a bullet out of a case neck with pliers with no expanding of the case neck . How would the gas act upon the inside of the case neck with the bullet in the case neck block the gas from the brass ? The bullet must be pushed out of the way for the gas to reach the case neck . It takes much more pressure to expand a case neck that it does to move a bullet . A primer alone will push a bullet out of a case neck , without expanding the neck at all . That is why you can get a powder " melt down " were the primer pushed the bullet into the bore but the powder does not ignite , it just melts . With a rifle with a large chamber , long throat , undersized bullet , and a powder that does not light easily , the bore will not seal as the bullet has cleared the case without hitting and sealing the bore . That was the problem with Hornady's 7.7mm Jap ammo . The case neck will expand after the seal is made to what ever size the chamber neck is [ minus brass spring back ] as the case make the rear seal .

"It takes much more pressure to expand a case neck that it does to move a bullet ."

Thanks bob q for the explanation. Discussion helps to clarify woolly thoughts!

I reckon you're correct: to release the bullet it only requires enought pressure to expand the case neck within the elastic range , and not the much higher pressure needed to go beyond the elastic range and cause permanant deformation (which then requires resizing to correct it).

It seems that you have the perfect setup for your bench rest rifle!

10 grains red dot, 170 grain Oregon trail laser cast flat nose gas check.

if I seat the bullet so that the case mouth, .308 Winchester, is in the crimp groove, or AT the bottom edge of the crimp groove and remove the case flare with the lee collet crimp, I can get golf ball size groups all day. But the gas check is INSIDE the case with a good bit of bullet.
These loads really horribly lead barrel. Leave a lead star at the muzzle instead of a LUBE star. and recovered bullets show signs of melting and smearing. And some have base of bullet out of round.

IF I seat the bullet out long, so the gas check is inside the case neck, same powder charge, I get groups in the 5-6 inch but the barrel leading is minimal. Its just powder residue I have to deal with. Think firing 50 rounds of Remington 22lr thunder bolts in a freshly cleaned gun.