Case length too short?
- Thread starter Ragtop
- Start date
windborne11
Regular
- Location
- SW Ontario
You need enough neck to hold the bullet. So at least 1/8 inch neck length. Reality is your case will not shrink that much. You would have to trim it that short.
As others have said, don't worry about it too short. Too long could be dangerous.
As others have said, don't worry about it too short. Too long could be dangerous.
I’ve had that with Hornady Brass, I don’t think it ever grew
Maybe my chamber was on the loose? Side.
Allowing the brass to expand sideways instead of in length?
More likely not growing because of your reloading equipment and technique. Neck sizing and lube inside the neck, for example.
General rule of thumb for safe neck length is ONE DIAMETER. This comes in handy when creating a wildcat such as one of the Ackley Improved designs. Mr Ackley used this rule of thumb. To short can be dangerous under some conditions, such as milspec chambers
Back in the days of the Boer War, the Boers asked their combatants to pick up and return empty cartridge cases for reloading. They used several different cartridge configurations but mostly 7.65x53, 7x57 and 303 British (captured). As the war progressed, they found they were desperately short of 7x57 rounds. The 7x57 was a relatively new round at the time so the Belgians reformed the similar 7.65x53 cases on hand to 7x57.
Prior to the outbreak of the ABW, the OVS and Transvaal imported some 45k German made Mauser rifles and carbines of Spanish Pattern in calibre 7mm. Sources indicate that the main arsenal at Pretoria held about 17 million rounds of appropriate ammunition for the Mausers; together with considerable stocks of .45" MH, .303" and 8mm Guedes.
All, however, was not well regarding the 7mm Mauser rounds themselves. Complaints were made about "certain Mauser cartridges causing Mausers to burst" and that "men put the cause down to certain cartridges - and refused to take them". The rounds in question were described as having "short" cases.
(citation can be supplied). It certainly was not a Camp Rumour.
Observing the conflict from the Boer side was the US Military attache; who reported that special "short neck" Mauser ammunition was made for the Boers and that ruptured cartridge cases were common, bullets broke up frequently but all of this was "fairly overcome" by lubricating the bullets. Correct specification 7mm Mauser rounds had a cartridge case length of c.57mm; wheras the "short" cases measured 53mm.
What had gone wrong? Why had non-specification rounds been supplied? A clue seemed to be provided by the offending "short neck" rounds having the letters "F y A" included in their headstamp; the letters indicating "Rifles and Machine Guns" and this marking may have been appropriate for Mauser ammunition supplied to Belgium, Spain and Turkey in another calibre. That other calibre was 7.65mm and the cartridge case of that round was dimensionally similar to the 7mm Mauser round; save for it's length (53mm) and calibre.
It does seem highly probable that one or more ammunition makers contracted to make 7mm Mauser ammunition for the Boers had converted Mauser rounds in one calibre to another; perhaps during the production process and before the rounds had been finally assembled. No proof exists for any of this - just a shrewd guess. Not all Boer Mauser 7mm ammunition was of the offending sub type; the "short neck" rounds today are reasonably scarce here in OZ.
The Boer authorities got around the Mauser ammunition problem as best they could. Some were resized and reloaded by their Dynamite Factory, rounds were greased and the Dynamite Factory even used "red copper" as a bullet jacket material. It all came to nothing and Pretoria fell on 05061900.
The attached pics show examples of the two types of 7mm Mauser ammunition; as well as appropriate headstamps (base markings). I have had to take a few short cuts in presenting this litle contribution; if any forum member needs to know more, I would be happy to supply sources and citations.
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windborne11
Regular
- Location
- SW Ontario
Appreciate your history lesson. Perhaps you could explain to us how a short neck would cause pressure problems? .30 wolfpup?
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windborne11
Regular
- Location
- SW Ontario
Circa 1900 era wartime. Could have been anything that would fit in the chamber and fire?? I imagine there were some pretty extreme circumstances with ammo availability. That other calibre was 7.65mm and the cartridge case of that round was dimensionally similar to the 7mm Mauser round; save for it's length (53mm) and calibre.
I think that explains the gun blowup reason. The short case ammo had a 7.65 bullet, for a 7mm bore rifle. The short neck size was the simple way of identifying the 7.65 mm cartridge.
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I’ve had that with Hornady Brass, I don’t think it ever grew
Maybe my chamber was on the loose? Side.
Allowing the brass to expand sideways instead of in lenght?
Weird. I've had the exact same "problem" with Hornady. It arrived short, and never grew. I just seated the bullet further out of the neck.
I've seen pics of the "kort nek" cartridges compared to properly manufactured cases of the proper dimension. It's possible that the bullets were out of the necks before entering the leade, which may have caused canting.
As for my own personal experience, there was a time in the early seventies when finding quantities of 6.5x55 Swede cases was next to impossible. I experimented with all sorts of cases, including necking down and resizing 7x57/8x57 cases, which were almost as difficult to find with boxer primers and shortening them. It worked well but I had issues with the cases. Nothing catastrophic but case life was short.
The cartridge case conversion I settled on was necking down IVI 7.62x51 cases and fireforming them to the 6.5x55 chambers in my M96 rifles. The necks were very short but seemingly adequate. The best cases were made from IVI 7.62x51 BLANKS. With care, I could get neck lengths that were within a couple of thou of suggested minimum spec. Those cases actually had a very good lifespan. I might even have a couple around or at least one in my box that contains several dozen one off rounds for comparison. I never had any sort of failure with the 7.62x51 cases but I also did tests to make sure the bullets were well into the leade before they left the neck mouth
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.223 cases are still within SAAMI specs at a minimum of 1.730". 1.750" is the typical trim length found in reloading manuals.
In general, trim lengths give you some leeway, so that if your cases end up a bit short, they will still be within spec.
In general, trim lengths give you some leeway, so that if your cases end up a bit short, they will still be within spec.
