.303 case headscratcher

[Treeman]

Hey Oaf, we both got issues  . I shot some .303 test loads and then went home and collet sized them. By chance I tested one case in rifle and the bolt would not close, how is that possible ?
I set the collet die lower than usual and the bolt closes, but with a bit of a nudge.  How ? They were shot an hour earlier from that rifle ........................
 

[big5ifty]

First check the case length, it may have stretched beyond the max case length.

The collet is perhaps closing firmly on the case neck before the ram is completely at the top, which will happen if the case is stretched. The last bit of movement pushes the neck down, expanding around the neck / shoulder junction.

You can check this with a micrometer, measure the neck / shoulder junction before the collet neck sizer, and after.

If you trim and full length size without the decapping rod, it should push the shoulder back enough so this doesn't happen.

I've encountered a roughly similar problem where the neck sizing is too small on annealed brass, and bullet seating bulges the neck / shoulder junction. Not enough to notice with your eye, but enough not to chamber.

[Treeman]

 and bullet seating bulges the neck / shoulder junction... big5ifty, kinda what I am leaning towards.

[Tripodmvr]

https://leeprecision.com/die-adjustment-help-videos

[Treeman]

https://leeprecision.com/die-adjustment-help-videos

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Do not see a collet die video ?

[Treeman]

Last night I found the opposite of what I thought was happening.  I thought the die was too far down and damaging the shoulders, but turned out I have to drop the die even lower for the case to fit into chamber.
 Still does not  explain how a fired case will not go back into the chamber

[Ds J]

Where does it get stuck - at the mouth, shoulder or web?

Have you coloured the case with permanent marker and ran it through the chamber a few times?

[Treeman]

Yes and yes. None of the usual tell tales. It seems the neck/shoulder junction  has moved to far forward in one firing.
Had to collet size to right against the shoulder, perhaps even touching the shoulder.
Wonder if second firing will fireform fix it ?

[Ds J]

Is it just the one case, or several?

[Treeman]

14 of them. I am baffled.

[big5ifty]

Go back to basics.

Unset all your 303 dies.

Use those 14, remove the decapping rod from the sizing die, and set the die to size the brass to the rifle chamber. NOT how the die manufacturer says. It's an iterative process, size, chamber check, size , chamber check, until the bolt has resistance in the last inch of close.

Yes, the 303 headspaces on the rim, and yes, this method gets it to headspace on the shoulder as well.

My suggestion is to get into the habit of full length sizing every time.

Then use the collet neck sizer to open up the neck. [ instead of using it to only size the neck down ]

Reset and re-configure all the other dies' settings, including crimp if you use it. An incorrect seating die setting that crimps and seats at the same time can also buckle shoulders.

Get into the habit of labelling things. If you put 20 pieces of brass on the table, put a note with where it came from, what was the last thing done, what's the next thing to do. Otherwise you put some brass from a friend's rifle on the table, and then later mix them with a few from yours because you forgot where the ones on the table came from so you assumed it was from yours.

[Tripodmvr]

https://leeprecision.com/die-adjustment-help-videos

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Do not see a collet die video ?

You have informed us that you have stopped drinking. I must now ask what you have been smoking? There are several videos and the collet settings are just before the handguns.

[Treeman]

https://leeprecision.com/die-adjustment-help-videos

]***************************
Do not see a collet die video ?

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You have informed us that you have stopped drinking. I must now ask what you have been smoking? There are several videos and the collet settings are just before the handguns.

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I reopened the page and yes its there, this morning I am life sure it was Breech lock then Neck toggle, there was NO Collet die video. Dunno if page did not download properly or ?? But I knew it was there, thats why you sent link, but it was not there, I looked and looked a few times.

[Treeman]

As for the not drinking, well I reached my desired weight and am holding it month on month. I lost 17 kg.
I have allowed myself to drink but, have found no desire as of yet. I want to be able to have a drink at your wedding or if you offer at a braai, but do not want to be a drinker again.
I have had like 5 beers in 3 months and I am happy with that, even triple that would be acceptable. I usually drink alcohol free now and find it very self pleasing to be able to, but decide not to.

[Ds J]

Start collecting your drinking money ie - put that away what you used to spend on alcohol.