Shorter reloads won't chamber!

[Tony Z]

Maybe a long shot but i have seen this once or twice. Seating die set just a tad too low and for whatever reason collapses the shoulder just enough to prevent it chambering. Usually seen with dies with built in crimp like the early Lee and Hornady dies. No cannelure to close the neck mouth into where the longer cases get pushed back just enough to fuck you over. One chambers, usually the shorter one, the longer one doesn't. Rookie mistake

[DSD]

Maybe a long shot but i have seen this once or twice. Seating die set just a tad too low and for whatever reason collapses the shoulder just enough to prevent it chambering. Usually seen with dies with built in crimp like the early Lee and Hornady dies. No cannelure to close the neck mouth into where the longer cases get pushed back just enough to fuck you over. One chambers, usually the shorter one, the longer one doesn't. Rookie mistake

This is why I wanted to see the case, my bet would be his press cams over past tdc and he set the dies to that.


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[The Raven]

OK guys, now for some grainy photos.

Left round is the one that's failing to chamber (along with the others I tested). The projectile is hitting the rifling. There's multiple marks here because I've had this round in the rifle a few times trying to figure out what's going on.

Right round is a Modified case with the projectile held in place by some cotton thread. This chambers but is longer than my reloads.

Case lengths are the same (within a poofteenth), I should have aligned them to make that clearer in both pics...

2.jpg (133.19 KiB) Viewed 3888 times

[Rabbitz]

Hi Raven,

Have you compared the diameters and concentricity at both angles on the shoulder? It might indicate shoulder being disturbed at seating.

Also if you run one of the jamming cases into a FLS die, is there any/much resistance or shape change?

(I am guessing here)

Rabz

[DSD]

OK guys, now for some grainy photos.

Left round is the one that's failing to chamber (along with the others I tested). The projectile is hitting the rifling. There's multiple marks here because I've had this round in the rifle a few times trying to figure out what's going on.

Right round is a Modified case with the projectile held in place by some cotton thread. This chambers but is longer than my reloads.

Case lengths are the same (within a poofteenth), I should have aligned them to make that clearer in both pics...

2.jpg

1.jpg

Take a picture showing the next 5mm


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[The Raven]

Hi DSD,

As requested a pic showing more of the case. Note this is a different round as I've just pulled the projectile on the one from the first set of pics.

You'll note this one also failed to chamber and shows the projectile is hitting the rifling.

[The Raven]

I've just pulled the first round that wouldn't chamber (one from first pic) with my inertia bullet puller.

Pulled round that wouldn't chamber
Once fired ADI brass, first reload.
Brass chambers fine.
Projectile is correct weight/length so there's no mix up there.

Case Length 2.0105 - within spec
Neck OD 0.3370 - a bit under SAAMIs .3435 but the same as the other loaded rounds.
Shoulder compares fine compared to the modified case. Not sure I could measure that accurately with digital calipers.
Shoulder OD 0.4570 (3 thou more than SAAMI specs)
Web OD 0.4685

Now one of the reloads that chambered and fired without issue
Case Length 2.0115 - stretch?
Neck OD 0.3430 - has been fired
Shoulder compares the same as a non-chambering and modified round.
Shoulder OD 0.4570
Web OD 0.4685

And finally the modified case (a Hornady)
Case Length 2.0110
Neck OD 0.3380
Shoulder compares the same as the first two above.
Shoulder OD 0.4670
Web OD 0.4680

[DSD]

I was expecting a slight bulge just below the shoulder from screwing the die down to far but it appears you do not have that.

I have never had a chambering issue from a projectile seated out to far, they always chamber just require slightly more effort.

Is there anything stuck in the throat or chamber.




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[DSD]

Just had a look at your pics and there is a slight burr at the case mouth where you haven’t chamfered the case, try removing that and reseat projectile and chamber a round


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[The Raven]

Hi Raven,

Have you compared the diameters and concentricity at both angles on the shoulder? It might indicate shoulder being disturbed at seating.

Also if you run one of the jamming cases into a FLS die, is there any/much resistance or shape change?

(I am guessing here)

Rabz

Diameters are OK but concentricity, I can't measure beyond rolling rounds across a bench (looks OK). Yes, I do get your point on the seating.

I'll rerun the pulled round through the FLS die and see if anything changes. Gotta set the press up.

[The Raven]

OK, just to check the brass I've just run it through the FLS die.

Case Length 2.0050
Neck OD 0.3350
Shoulder looks the same.
Shoulder OD 0.4535
Web OD 0.4680

Reseating the same projectile into the FLS brass to the same depth (2.726) it then chambers!!!

[LoneRider]

i know its a bit late,but ive only just thought of it:

Shorter reloads won't chamber!

try viagra ...........

[The Raven]

Just had a look at your pics and there is a slight burr at the case mouth where you haven’t chamfered the case, try removing that and reseat projectile and chamber a round


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Thanks for that. I usually trim and chamfer in the one operation but these didn't need trimming (and therefore missed chamfering/deburring). I'll watch for that in future.

Can you tell me where in the pic the burr shows up? I'm not sure what I missed.

As per my last post, FLS then reseating the same projectile will now chamber. Perhaps it was a burr.

Looking at the offending round the rifling hasn't marked the complete circumference of the projectile (even after multiple attempted chambering). So perhaps the round wasn't as concentric as I thought....(or something in the rifle is not as square as it should be).

[The Raven]

i know its a bit late,but ive only just thought of it:

Shorter reloads won't chamber!

try viagra ...........

How many grains do I need to add to the powder?

[Camel]

Cases should only need de-burring, inside and out, after trimming to length, its not something I have ever done after just sizing. In your first photo the marks on the projectile look nothing like any rifling that I have seen, certainly they wouldn't be that long, I highly doubt it was anything to do with the projectile, just the cases needed sizing.
Do you full length size reload, or just neck ? If its for a hunting rifle, full length sizing is the go, rather have easy chambering than any perceived benefit from just neck sizing, it is a Furfy that neck sizing makes your brass last longer, Ackley proved that point back in the 50's or 60's. I think his experiment was to take two 30-06 cases and load them to max, then full length one and neck the other, until they failed. The neck sized case failed after something like 60 reloads, the full length one didn't fail, even though he sized it nearly 100 times.