Case length.

[hunters home]

Just use a hammer type bullet puller to remove the gauge.

 

[DGY]

How did you measure the actual length of the chamber?

https://www.brownells.com/reloading...s/sinclair-chamber-length-gage/?sku=749000811

That might be something to get in the future?!?! No one sells them in Canada?

 

[boxhitch]

.

 

[recce]

That might be something to get in the future?!?! No one sells them in Canada?

X-Reload does but they've been out of the .308 for quite some time.

https://x-reload.com/s-749-000-804.html

 

[bearhunter]

During the Boer War, DWM supplied 7x57 ammo that was actually made by using 7.65x53 cases necked down, so 4mm short, or 5/32". The Boers soon experienced a rash of blow-ups, and the cause was put down to the short necked ammo ( and it was referred to as "kortneck"). The theory was that the short neck was causing excess throat erosion, and the increase in friction was raising pressures and causing the bullets to break up in the barrel. I'm not sure how definitive the proof was, they were in a shooting war after all, with little time or facilities for testing. At any rate, the ammo got a bad reputation.

View attachment 563153

The standard trim-to length in most reloading manuals is 1/10" below max case length. With the experience of the Boers in mind, I prefer to err on the side of caution and not trim below that.

There were extenuating circumstances behind the blow-ups and failures of those cartridges, mostly attributed extremely deep throats of the rifles they were being used in, combined with harsh field use,

There was a lot of speculation about the reasons behind the catastrophic failures, and many reports were generated. Take your pick.

Neck lengths of the period were notoriously long, to hold the base of the bullet or help to align it with the axis of the bore as it "jumped" to engage the leade. The long necks also allowed for better control of neck tension, and split necks were not uncommon. There was some discussion that many of the cartridges may have been "reloaded" as the Boers encouraged their fighters to police their brass and turn them in, so they coule be reloaded. I read an article that these reloads were issued for field use.

Very likely, if those cartridges had been relegated to "range practice" purposes only, where the cartridges haven't been subjected to the rigors of the field under harsh conditions.

When the 6.5x55 chambered M38-96, and Agb42 rifles first started to appear in Canada in the mid seventies, ammunition was next to impossible to find, so some of us used 308 Win cases, with the case necks partially sized down to create a sort of false shoulder for fire forming.

I made up several hundred such cases for my personal use, in several rifles, and never had one failure. Yes, I know the base diameter is smaller, but that didn't make much difference in these rifles.

I later managed to get my hands on several hundred fired IVI 7.62x51 "blank" cases, which have extended necks, for feeding into chambers.

It was a no brainer to cut the petals off the necks to the length needed and use these cases instead.

OP, some shooters have concerns about short necks for all sorts of reasons, most of which have nothing to do with safety.

The job of the neck is to hold the cartridge with consistent tension, until it leaves the case mouth, hopefully aligned with the axis of the bore. Ideally, if the throats are long, close enough to the leade so it's engaging before it leaves the neck. This should guarantee proper alignment.