Reloading Info for 174 gr Bullet |
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The Armourer
Senior Member Joined: June 23 2019 Location: Y Felinhelli Status: Offline Points: 1246 |
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It is interesting that 'we' consider headspace to be so important - is this solely because we are reloading, or is it because non-military cases are 'made to a price' and are very thin walled and thin rimmed ?
The UK Military considered that the LE was safe to shoot Military specification cartridges and authorisation was given to keep them 'in service' with a headspace of up to 0.080" (80 thou) |
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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I for one do not worry about headspace The Armourer. You have a rimmed cartridge and it can only move x amount backwards upon firing. My question to britrifles was to learn how he is getting up to 50 reloads with the same brass and I can only get a max of 7 reloads before my cases start separating. I have just made an assumption that it is due to the generous chamber area designed into the Enfield and the repeated stretch of brass in that generous chamber area leads to case separations after so few reloading sessions.
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The Armourer
Senior Member Joined: June 23 2019 Location: Y Felinhelli Status: Offline Points: 1246 |
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I understand that - I am up to about 10-12 reloads (a few maybe more) using PPU. Headspace is "within spec" but not especially tight. I was simply showing that having an excessive headspace with thin walled and thin rimmed cases is likely to reduce the number of reloads due to taking the web area of the case beyond its elastic limit. The only separation I have ever had was with S&B cases on the 2nd reload (third firing) and I know of some that have had them split on the 1st reload. They are 'rubbish'. 'Good' headspace and 'good cases' makes for 'good reloads'. |
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Tight headspace + thick rims = many reloads. That’s what has worked for me.
Minimize the clearance between bolt face and rear face of case head.
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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I should have also added “thick case webs”, as this is also likely a factor, although strain (deflection) is the failure mode. Additional thickness only helps so much, the case web will still strain the same amount until it is stopped by the bolt head.
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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It is interesting to note here that. I can actually get more reloading sessions out of the 7.62mm Lake City brass if I dedicate that brass to my No4Mk2 with the 2A1 barrel as opposed to my M700P. I full length resize the 308 brass after every firing and the brand new Remington will end up with a case separation (without fail)🙃 after the third reload whereas the No4Mk2 will not see any case failure until the 7th or at the most,the 8th reload.
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philtno
Senior Member Joined: May 04 2019 Location: Blenheim, NZ Status: Offline Points: 261 |
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The very first set of cases I used were PPU (my very box of rounds I bought more than a year ago). I may have reloaded them around 20 times now with no case issues. Same for the HXP which I may have reloaded even more times for some of them, only one partial case head separation and maybe 3 to 4 split shoulder over a batch of 150 cases batch. I only full length-size them when the bolt becomes hard to close. Other than that, I only neck size them either with the Lee Loader (takes time but it's fun ) either with the hand press and the neck sizing die... I use light to medium loads.
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Honkytonk
Senior Member Joined: December 30 2017 Location: Brandon Mb Status: Offline Points: 4770 |
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I also has switched to PPU brass exclusively. I've probably reloaded each brass 5x so far with no issues. I think maybe when I was stupid and "felt the need for speed" and pushed the upper limits of max powder specs, that was when I experienced failures after two or three reloads.
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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A simple calculation shows the axial (longitudinal) stresses in the .303 cartridge case just in front of the case head will be approx 120,000 per sq inch (at a nominal 40,000 psi chamber pressure). That far exceeds the yield strength of cartridge brass, by as much as 10x, depending on the temper of the brass. This is why headspace is important, if it is excessive, the cartridge will rupture, that is a mathematical certainty. Do you need to worry if it is at the maximum of 0.074? No, but you will get lost life from your brass.
The bolt head prevents the brass from failing in overload in the axial direction while the chamber prevents it from failing in radial (hoop) overload. Axial overload causes circumferential cracks (i.e. case web cracking leading to a head separation) and hoop overload causes lengthwise cracking (i.e split necks or along the case body). Chambers that are large radially would cause lengthwise cracks, not circumferential cracks. Unless the head clearance (space between bolt head and back of cartridge) is very small, the case will plastically deform under the pressure of firing the cartridge. The strain causes the cross section just in front of the solid head to neck down as the brass continues to elongate under the load, and the effect is cumulative with each firing, especially so if you FL size. The only way to slow this process down is to minimize the head clearance (reduce headspace, increase rim thickness or reduce load pressures). The case rims of my 1943 Defence Industries Mk 7 service cartridges measures 0.063 to 0.064. The headspace on my No. 4 rifles is just slightly larger, about 0.065. This gives only 0.001 to 0.002 head clearance. I believe this is why my DI 1943 brass lasts for 50 reloads. Final head separations invariably occur after I have FL sized. The Long Branch No. 4 Mk 1/2 I just refinished has the headspace set to 0.064. The bolt just fully closes with no fore/aft movement when locked on the GO gage. I fitted a No. 3 bolt head to get this headspace measurement. Photo below shows the typical region of case web necking (thinning) from axial tensile overload. Canadian DI 1943 Mk 7 service cartridge rim thickness, right at maximum, 0.064 inches. |
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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My headspace is as it would have been directly out of the factory door. I cannot locate any Mk7 cases and as such,I have to use the cases I currently have that have an average rim thickness of 0.0625". I have no fore or aft bolt movement with a GO gauge installed. The LB barrel is the one I found still wrapped in wax. The rifle itself shoots superbly and all of my reloads are charged with the minimum weights listed for my powder of choice. The headspace for my Savage No4MkI* is as it should be as well with the aforementioned nonexistent fore or aft bolt movement as well. My issue is not with headspacing.
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Stumpkiller
Senior Member Joined: April 03 2020 Location: Port Crane, NY Status: Offline Points: 254 |
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Major G. Nonte, Jr. in his excellent "Modern Handloading" described it as "Chamber Slop". Not so much a headspace issue as a generous chamber bored out to allow a cruddy, sandy, iced up cartridge to chamber. But must of us, as individual shooters, do not have a well funded war department to supply us free cartridges for single use; or anything with a suitable hunting bullet. So we church-mouse poor reloaders seek to squeeze out as many reloads as possible. Worse, some of us are in draconian oppressive government controlled isolation from resupply (like New York State for example) and loaded cartridges or reloadable brass can be precious indeed. Actually - new brass is readily available - for a price. Primers, bullets and powder may be a bit "iffy" as some retailers will not ship to any part of NYS because of the damn "SAFE Act" that, supposedly, only prevents citiots ("city- idiots") from buying components in the five boroughs around New York City. 10% of the surface area of NY (where 95% of the population clusters) makes the other 90% suffer. |
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Charlie P.
Life is not about how fast you run, or how high you climb, but how well you bounce. |
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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I will agree with the chamber slop. I will not agree when I am questioned in regards to my headspacing. I reload to exacting standards and have never loaded to any maximum charge weights. I have resolved to chalk this up as luck of the draw and I have a very large supply of sh*tty brass...
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Goosic, I’m not questioning you or your rifles. I apologize if it came out that way.
I made an attempt to explain why headspace is important, particularly if you reload. Your issue does likely come down to commercial brass, it’s already thin in the web area when new. You asked me what my secret was for long case life, I gave the best answer I could based on my experience. That’s all.
I check headspace on a LE rifle I purchase, bolt heads can get swapped out. The one I just got was about at the field limit with a # 1 bolt head and I doubt it was issued that way after the FTR which included a barrel change. Either headspace increased with use or a previous owner changed out the bolt head (wanting a #3 head perhaps). I’m having trouble understanding how radial expansion Into the chamber causes a circumferential crack, anyone have a theory on that? If you have PPU brass, let’s track how many reloads we get in our .303 rifles, this will eliminate the brass as a variable. In my LB Mk 1/3, I have about 5 to 7 reloads, that’s just an estimate, but I’ll track this from now on. In my Mk 1/2, just one reload, so I’ll be able to accurately track it. |
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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No worries britrifles.
My brass of choice currently is this so called Canadian Mfg stuff. Unfortunately for me,I have 1000 rounds of it. I have been loading 100 rounds at a time. After 5-7 reloads,I typically will find 20-25 separated cases. I segregate each batch and tally how many reloads that batch has gone through. Still cannot get past the seventh reload without a case failure...
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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"Major G. Nonte, Jr. in his excellent "Modern Handloading" described it
as "Chamber Slop". Not so much a headspace issue as a generous chamber
bored out to allow a cruddy, sandy, iced up cartridge to chamber." Thank you, I've been looking for the correct term for that for a long time. For the rimed .303 headspace stops immediately in front of the rim's front face, but I never heard that term before.
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Goosic, next time I fire some DI 43 Mk 7z ammo, I’ll send you the cases to try. I’m very interested in finding out exactly why I seem to get so many reloads and others do not. I have run some too long, even a few more reloads after the white line of death appears. PPU does seem to be closer to military specification, so perhaps it will last longer. I’d also suggest sectioning a case and measure the thickness of the case body. My Mk 7 cases all crack 0.32 inches from the back of the head where the web thickness measures about 0.032 in. I need to confirm this thickness on an unfired case.
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