300 BO hard chambering and removal-unfired

[Bzcraig]

Glad I saw this thread! Just fired my 300BO for the first time a couple of weeks ago and had some of the issues discussed here. So I went out a tried to chamber an empty case and sure enough had some difficulty. Ran several through my sizer again and problems went away. Using Lee dies and had to make sure all the 'slop' was removed so die wouldn't stop until it had to and that did the trick. Thanks guys!

[osteodoc08]

I've been using an RCBS Small Base 300 BLK die. I have set it up to where it slightly "cams over" on my Lyman Turret and all has been well.

Ive noticed that my 150gr pull downs have to be seated deeper than the Hodgdon online data suggests. It suggests COAL 2.200 IIRC and I ended up seating mine to COAL 2.075 to work well.

[tim josey]

From the case body or neck? That does sound like a really tight chamber. I turn my necks to insure they are the right size. About 10 sec. each with the drill & hand turning tool. I just used the drum sander on my dremel tool to grind down a 308W die (RCBS SB)so it worked right. I don't care if I remove too much, just set the die where it should be. Get a good medium flat file and go till the nose is loose in the mag (Pmags) You have to lower the rib all the way to the bottom of the mag, else they will jam. Lee die works fine for me.

The case body, from the shoulder down and especially at the base. If the RCBS die does not cure this would lapping the chamber help or would it need to be done with a reamer?
I just did 4 more to make sure, all worked perfectly!

Tim

[popper]

Tim, were these fired from your BO or newly converted range pick up? If from yours and still won't fix it, it's the die. Some one else's chamber may be out of spec so the SB die should work. Goodsteel can tell you about reaming/lapping, I've not done it (he is a good gunsmith, I'm not, I do wish he did AR barrels). If it is the barrel, I'd just send it back with evidence it isn't right. Unless you sent your bolt to PSA for proper HS, you get to do it by setting your die properly. This is where the case gauge helps. Case HS should be so the case just allows the bolt to unlock easy. Too long, the case jams, too short and you get primer push back, stretched cases or FTF. If your HS is different from the case gauge, measure difference with feeler gauge. I'm wondering why you had to re-trim the cases after re-sizing, pushing the shoulder back (reducing HS) won't lengthen the case but will make the neck longer - indicating too short HS. Hope this helps. Oh, the Sheridan gauge if cut to MINIMUM SAAMI specs will insure YOUR ammo fits, doesn't insure it is correct for YOUR chamber. Nothing against it, just a note.

[tim josey]

These cases were fired from my PSA 556 upper which were also a mixture of once fired and some new. As far as re-trimming, when I shortened the Lee sizing die and bumped the shoulder back, the case stuck further out of the Le Wilson HS guage, of course it also went further in the HS guage on the base. I thought the case neck might go to far in the chamber so I trimmed .
I will try some more of the Rem factory 300 BO when I get a chance to unload a few to see if it is my barrel or the guage. Either way the RCBS dies will be here from Midway in the morning.

Tim

[popper]

It won't be the gauge but as you found, chambers/bores run all over the place as does HS. Just general gun making tolerances.

[tim josey]

Got the RCBS small base die set in and resized 5 untouched 556 cut-offs. They worked perfectly! easy chambering and hand removal. Must be a very tight chamber as Popper mentioned.

Now to work on mags and feeding with the NOE 311247's. Anybody use this boolit and could let me know what your COAL is? Mine wiil Probably be different , but want a starting point. Tried doing a search but did not come up with much. I might start a new thread if nothing comes up.

Thanks to all for your help.

Tim

[cs86]

It doesn't look like anyone mentioned this yet so I thought I'd throw in my 2 cents. When I first started with AR blackout I was producing brass out of 5.56 brass also. I read enough to know what head stamps to pick and which to stay away from. After cutting them down, forming/sizing and trimming I would get brass stuck in my chamber. I was following the trim length of the hornady book I have. After some researching and testing I found that the hornady book had a trim length that was too long. Looking at the saami spec of the caliber you should be at 1.368 for the case length and I think people are trimming shorter then that. I'd double check your trim length.

[DocSavage]

I used a file and trim die from Redding 300/221 and standard 300/221 dies to make cases and ammo. Using a Noveske upper my ammo has worked flawlessly. Brass was made from 223 surplus lake city surplus brass.

[GhostHawk]

My question was did you do a chamber cast so you know how much room you have?

Setting your bullets long, or cases a touch longer than they should be could easily be jamming the bullet into the rifling, which would account for hard removal.

I know there is a very good sticky on this forum about this very thing.

And it would explain why the factory loads were fine.

As to sizing, I would slug your barrel, it "should" be .308 but that does not mean yours is.
Then I would cast aiming for 2 thousandths above that. Size only if it is variable or if you need gas checks.

I know my bore is a tight .308, really closer to .3075, so I reamed out a .309 sizing die to .310. Most bullets slip through easy, some are however harder. So in that respect in my opinion sizing is good.

But it is all about fit, size, how long it is in the case, how long the case is.
You can very easily get combinations that in theory should work but with any given rifle might not.

Did you even look at a loaded round inserted and extracted for rifling marks on the bullet??

That to me is your first tip that you are setting them long.

Where did you get your brass? Did you make your own? Did you cut off the old neck/shoulder from .223? Did you cut enough if so?

It ain't rocket science, but that doesn't mean it can't be tricky.