Case Body Diameter Out of Spec?

[adamkrog]

I recently had a couple misfires in cold weather while hunting. I got a "click" but nothing more. The primers were not contacted at all and I assume it was because the rifle was not fully in battery when the trigger was pulled. The issue is likely due simply to cold weather and moisture and an operator who wasn't as diligent as he should've been when loading in those conditions. But I wanted to rule out the possibility that my reloads contributed to the problem, so here we go.

I checked the cartridges in my LE Wilson case gauge and everything appears fine there. But then I started measuring with the calipers and found the body diameter is out of spec on almost all my cases. If I'm not mistaken, they should be at .441 or under. I measured some factory loads just to confirm. The Hornady cartridges I have on hand measure .438 on average. Federals measure at .4395. Next I measured spent cases coming from the gun. Same Hornady loads once fired measure anywhere from .4430 to .4465. I'm not sure if that's normal or if my chamber is overly loose. Anyway, after I size them with a Hornady Custom Grade full length die, they all still come out over spec. There is some variation, but they range from about .4415 to .444 with the average around .443.

I'm still pretty new to this reloading stuff, but is this normal? Shouldn't the body be sized to spec coming out of a full length die? Again, they pass the case gauge just fine, so I'm confident the headspace is okay, but the case gauge specifically states that it doesn't measure body diameter. Is this a problem? Or am I obsessing over nothing?

All of the loads in my hunting batch seem to chamber just fine save for one. That round measured .4445, the largest diameter in the batch. This is what got me going in this direction. That cartridge appears to pass the case gauge fine too, and overall length doesn't appear to be the issue, so I don't think it's in the lands either (I've been down that road with 129 interlocks but these 123 SST are much more forgiving on overall length).

Any and all wisdom appreciated. I'm curious to know what other's spent cases are measuring and what they measure after resizing. Thanks.

[dpete]

A sample size of 1 each, both Hornady cases:
Two or three times fired, not resized. at case head .439, midway .437, just below the shoulder .432, inside neck dia .268
Two or three times fired, fl resized. at case head .437, midway .435, just below the shoulder .428, inside neck dia .261

Resized using a Forster fl sizing die.

[Klem]

Adam,

The reason most rifle gauges are reamed wide is to ensure the gauge is indicating longitudinal headspace. Headspace is the space around the case when in battery. It is three dimensional, so not just longitudinal, but also axial. Axial headspace is less likely to be dangerously overgenerous than longitudinal, because manufacturers machine dies to permit only a certain amount of axial squeeze when the die is hard up against the recommended shellholder.

Having a chamber slightly larger than SAAMI is perfectly normal. For a reloader, as long as the case does not split on the first shot and the stretch is within SAAMI limits then bumping them back no more than .003-.004" will give you max case life.

Can you separate the upper and lower. Pull out the BCG and set aside. With the upper vertical and barrel pointing at the ground can you drop one of your reloads in and give it a slight press with your thumb to mimic the force of being slammed into battery. Now reverse the upper and see if it falls back out freely with gravity.

With the BCG removed, can you push the bolt into the carrier and then push the pin to make sure it protrudes freely.

It may be your reloads are too fat. The remedy for this is screwing the die in a bit further. Make sure the new reloads are still within the limits of that rifle gauge.

NB: Lee dies tend to squeeze the case too much and get a bad rap on this forum.

[mtnlvr]

Adam,

The reason most rifle gauges are reamed wide is to ensure the gauge is indicating longitudinal headspace. Headspace is the space around the case when in battery. It is three dimensional, so not just longitudinal, but also axial. Axial headspace is less likely to be dangerously overgenerous than longitudinal, because manufacturers machine dies to permit only a certain amount of axial squeeze when the die is hard up against the recommended shellholder....

Just to clarify, I believe you mean radial headspace is less likely to be overgenerous than longitudinal. Longitudinal and axial are most likely in the same direction, at least in chamber definition.

[montana]

I like these slotted case gauges, because you can visually see any discrepancies with your reloads or factory ammunition.https://sheridanengineering.com/prod...unition-gauge/

Klem is correct on how to check your reloads. First use a factory round you trust to test your chamber. It is a good alternative for a function gauge. If the chamber is good, then try your reloads. The Sheridan engineering case gauge will give you a good visual to any discrepancies with your resized cases..

Always make sure your chamber is thoroughly clean before doing any testing..

[LRRPF52]

I have 4 dummy cartridges I made for 6.5 Grendel with different bullet types (different ogives) loaded to maximum reasonable COL that will fit in the magazine without binding or dragging the meplats (bullet tip) against the inside front of the magazine body wall when stacked fully.

I use those by coloring the ogive with black marker to see if they jam the lands on a new barrel, and if they fall free from the chamber.

[Klem]

Just to clarify, I believe you mean radial headspace is less likely to be overgenerous than longitudinal. Longitudinal and axial are most likely in the same direction, at least in chamber definition.

mtnlve,

I'm pretty comfortable with 'axial'. The axis in this case is of course the barrel. The definition of an axis is "a straight line with respect to which a body or figure is symmetrical." The body in this case is...the case.

If you take cross sections of the case along the axis, your word 'radial', related to the radius of a circle, will also work.

[CoyoteConquest]

Depending how cold it was some oils will freeze up causing firing issues. I always use Rem oil in the winter.
I was coyote hunting a few years ago and had the same issue as you using Lucas gun oil. It worked great in warm weather but froze up in the winter