Weird sizing / seating issue

[divingin]

My opinion: Too much interference. How is your sizing die set up? .010" smaller than bullet diameter is a lot. It sounds like you've removed the expander from the sizing die and are using the die body alone? That will give the results you're getting. You don't need more than a few thousandths of an inch interference (typically about .002- .005") for everyday shooting (I run more interference with virgin brass and jam the bullet into the lands to minimize case stretch on the initial firing, but that's a special case. 2-3 thou for normal loads.) What does your loaded round measure just below the case mouth?

That said, if you want to run that much interference, chamfering the case mouth is pretty important. It will minimize the inside edge of case mouth from shaving the jacket. A bit of dry lube on the inside of the case mouth wouldn't hurt, either.

Are you sure you're seating deep enough? I've never seen a jacketed rifle bullet swaged down by brass. Can you post a pic of an unseated bullet next to (and lined up with ) a loaded round so we can get an idea of what's actually inside the case? Are your bullets "heeled" with a smaller diameter towards the back?

Lastly, have you removed the sizing die from the 550? If you've already sized on the single stage, the sizing die on the 550 will only be a source of confusing things. And I am also of an opinion (again, this my opinion) that you are not gaining much by sizing separately - you should be able to run your RCBS sizer on the Dillon, can't you? That would streamline the process somewhat.

Just had one more thought: You might be running your seater way too low. If you seat the bullet, but you also massively engage the crimp ring in the seating die, you can swage the bullet down as the neck goes into the crimp ring. You'll end up with loose bullets, as the brass will swage down and spring back a bit, but the lead and copper bullet will just swage down. To test for this, pull the seating stem way up. Measure the neck diamter of a piece of brass, then run it through the seater without a bullet. Check for a change in neck diameter.

To correct it (if it is the problem): Pull the seater stem up. Set the seater body high in the press. Take a sized case, run it into the seater die, and with the ram up all the way, screw the seater down until you feel the crimp ring touch the case mouth. Back the die body off a half turn or more and lock the die. Then adjust your stem for seating depth.

Hopefully you figure it out.

 

[dellet]

The only way to seat a .308” bullet into a .296” hole and have the bullet spin in the case neck, is to have a considerable amount of trouble seating the bullet. I think that shows in the original photo. Could be angles, but the neck looks off center and tweaked. Stretched.

Knowing the bullet would be helpful. Possibly a Lehigh defense. They have a large recess between the base and bearing surface more like a cast bullet with a flat base. Should be loaded the same way, slight bell to the mouth.

With the case neck diameter being small, it’s difficult to start the bullet straight. Moving around trying to seat it maybe what’s going on to open up the neck.

Finally the measurements don’t make sense. .018” neck thickness. .296” inside, .314” outside is a .009” neck wall thickness. Hopefully just a brain fart, because an .018” neck wall thickness won’t chamber.

 

[wedgy]

He is using Hammer bullets that do not have a conventional flat bearing surface like lead bullets.

 

[Dillon Friend]

Try using the 30 M1 carbine powder funnel, #13564, marked "C". Use a separate crimp die as well. You can use a 300 Blackout crimp die for this.

 

[tdogg]

How are you measuring your neck ID, with calipers or pin gauges? Do you have a donut formed at the shoulder junction that is giving you false ID measurements? If you run your sizing die with the expander mandrel, what is the resultant neck ID?

The case on the far right seems to have a flare about it at the mouth, how did that get there? What type of powder drop tube is getting used in the powder measure? Are you using an expanding die?

I'd start over and setup the dies again. Something is obviously setup wrong.

Why are you sizing on the single stage and seating on a progressive?

Cheers,
Toby

 

[GetReal]

So it's official... I AM AN IDIOT.

I guess I'm used to neck bushing dies where I don't have to worry about this but...

It was the neck expanding button. The decapping pin had bent.And I replaced it with the wrong decapping pin unit leaving a 0.296 neck. Put the right one in, got a 0.3045 neck and Im good again.

No one makes a bushing die for 300 HAM'R so Im stuck with neck sizing buttons.

 

[Coyotefurharvester]

^^^^^ back to fun now, the shooting part.

 

[DShortt]

So it's official... I AM AN IDIOT.

I guess I'm used to neck bushing dies where I don't have to worry about this but...

It was the neck expanding button. The decapping pin had bent.And I replaced it with the wrong decapping pin unit leaving a 0.296 neck. Put the right one in, got a 0.3045 neck and Im good again.

No one makes a bushing die for 300 HAM'R so Im stuck with neck sizing buttons.

Well do NOT beat yourself up. Funny thing about life.

Everything goes right and what do you learn.

Nothing.

When things go wrong is where the learning takes place.

Glad you're moving forward.

 

[243winxb]

Thats the bullet design, not shavings.

Glad to hear, problems solved.

Strange bullets-

 

[divingin]

It was the neck expanding button. The decapping pin had bent.And I replaced it with the wrong decapping pin unit leaving a 0.296 neck. Put the right one in, got a 0.3045 neck and Im good again.

No one makes a bushing die for 300 HAM'R so Im stuck with neck sizing buttons.

Yeah; whenever you run into problems with the process, it helps to break things down into as small steps as possible, and investigate where the process is breaking down. Limits where you need to look if you know it's that step that doesn't work right.

I don't know anything about 300 Hamr, but if you want just a neck sizing die (and you don't care about moving the shoulder back) any bushing neck die that's short enough to reach as far down as you want to go should work. For a full length bushing type die (body/shoulder/neck), not so much.

Redding has competition sets sort of like this - a seater, a bushing neck sizing die (doesn't touch the shoulder or body), and a body die (shoulder/body only; doesn't touch the neck.)