]So I have relodaded 2000 plus .223 and 1000 rounds of 45 acp on my new dillon 550. With no problems and they run great through my guns. 308 on the other hand is hit or miss. I am trimming all the cases to the same length and running through the dillon on the same settings. About 2 out of ten rounds will not chamber. But run them through a head space gauge and they seem to be fine. I am at a complete loss. Any tips or ideas?

sounds like either not sizing enough or bullet not seated deep enough. with passing through a headspace gauge I bet the latter

I am at an overall length of 2.750 On a 180 grain bullet

A simple test to see if it has anything to do with seating depth is simply to seat the bullet overly deep in a round that won't chamber and try again.

Since your rounds pass the headspeace gauge, I'm not sure what else too say. Maybe a chamber peculiarity, and you just need to bump the shoulder back an extra .001 or .002?

Are you neck sizing or FL sizing?

I am full length sizing. I was kind of thinking that maybe I am just on the edge of not enough of the neck and need to twist it down some more. But figured if that was the case it would show in the head space gauge. I will try what you said tomorrow.

Fill us in when you can

Also, I just saw your Classified looking for a Lee press. Not to knock on Lee, but every company has some good and some bad products. If you buy a Lee, make sure to buy one made of good cast metal and not a cheap piece of pot metal crap.

If no one has a Lee that suits your needs, I highly recommend a RCBS Rock Chucker, which can usually be found used for a good price.

Also, FWIW, I don't do any sizing on my 550B anymore. I never had any problems with pistol brass on the Dillon, and I never had any insurmountable problems with rifle brass. But I think picking up a single stage like you are trying to do is a good idea for your brass prep, just to keep everything as simple as possible.

Ok thanks for the info. I will keep this updated.

Sound's like it could be a sizing issue to me. What type of rifle is it for and was the brass previously fired in this rifle?

This....^

which case gauge are you using? I just went through this identical issue. I ended up having to screw down my sizing die on my single stage Hornady press and went a step further by milling off 5 thousandths off my shell holder. That made the round sit even deeper in the case gauge. In my case (loading for AR-10) I had to have the base of the bullet below the upper step of the case gauge. If it was just flush with the top step of the case gauge (technically "passing" it would not cycle smoothly on my AR-10. the additional 3-4 thousandths of sizing in my press made all the difference in the world. What type of rifle are you shooting?

I don't know if it has been mentioned above but with a heavy case like .308 I can't imagine re-sizing on a progressive press.

I'd bet money that the case is not getting sized properly. It will most likely be making contact at the shoulder datum point or at the base of the case where the case head area is (about 1/4" up from the rim on the side). Take a dark colored Sharpie, and color up the case in these areas and chamber it a few times. The rub marks will tell you where you need to size more. The sizing on a 550 will work, but you will need to oversize them slightly to make sure all cases get sized to spec. There is a little "slop" in the system, so if you are sizing right on the edge, you will have some that will be too big. Plus, if you are mixing case heads (different brands), this will also cause this issue.

Ok well think I got it figured out. This is for a Sig 716 BTW.

1) Lowered the sizing die down as far as I could. (That was the main fix)

2) Make sure the cheap brass you got from amazon is in fact 308. (Pretty sure its not and its not marked) This got mixed in with my "good brass"

After sorting out the crap amazon stuff and lowering my sizing die. Loaded 30 rounds all cambering very well. Now to send the amazon seller a email.

I'll put my money on the same spot as Chad.

NATO brass is often not marked as .308, or anything else for that matter. It will have a plus sign in a circle to indicate that it's NATO. If that's what you got, it's probably .308 but has been fired in a military rifle or perhaps machine gun (large chambers, lots of expansion).

The only real consideration when using NATA brass is that the walls are a little thicker, meaning the internal volume is slightly less than for commercial brass. That leads to higher pressures so take that into account when loading.