cartridge length
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cartridge length
This question is not limited to pistol cartridges. The Lee manual lists a COL for each recipe. Is this meant to be a minimum overal cartridge length, or a maximum? It doesn't say. Things like this contribute to the utter confusion out there about this subject. Any thoughts on this?
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Re: cartridge length
Generally speaking the listed COL is the one that that load combination was tested at. Altering COL particularly reducing can cause dramatic changes in pressure. A tenth of an inch doesn't sound like much but depending on the load it can make a big and potentially unpleasant difference. Speaking just for 4 lever guns I find the listed length generally is the one that feeds the best. With some of the other guns I've found I need to adjust the COL to the gun and bullet, interesting enough longer. If I have to go shorter I reduce the load by at least 10% and work back up, YMMV.
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Re: cartridge length
My Lee 2nd Edition book as well as all my other manuals label the column for length "MIN OAL".
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Re: cartridge length
C.O.L is minimum in all my manuals. Unfortunately it is somewhat bullet shape specific. It is the seating depth that is important for keeping pressures in check and more similar from round to round, especially in small cases like the 9mm. In the Lee manual, with some exceptions, the bullet used is not shown. Lee gets all their data from the powder companies so just go to their reloading page and you can cross reference the load and see what bullet was used. Check with the bullet or mold maker and you may be able to ascertain the length of the bullet. There is also a forum that had a listing taken from the database used in a popular reloading, computer application. This gives you something to compare against if you are using a shorter or longer bullet.
The two other factors that are important with respect to C.O.L or sometimes, controversially, referred to as O.A.L are:
- the relative chamber length variation from firearm to firearm even of identical make and model. A longer C.O.L. may jam the bullet into the rifling and this can cause a serious rise in peak pressure or prevent a semi from fully returning to lock position. I have two 6.5x55 Swedish rifles with different chamber lengths, one is a full military rifle and the other a later modification to a target rifle. I mixed up my dummy cartridges that I use to adjust the seating die for the specific bullet in the correct rifle. My next trip to the range and I was getting really high FPS in one rifle up to over 300 FPS than previous notes indicated for that load. When I discovered that the bullets were jammed into the rifling I checked my cartridges and the error was noted and my ass properly self kicked.
- too long or short a C.O.L. can lead to magazine and feeding problems. I never considered this a safety issue until I was experimenting with using pistol bullets in a 35 Remington pump action. While racking another round the round underneath slipped up behind the closed breech block. The next rack of the action jammed the back of the breech bolt into the hidden round crushing the neck of the cartridge and pushing the bullet into the case. If the primer had hit the right way it could have been a messy and embarrassing moment.
The two other factors that are important with respect to C.O.L or sometimes, controversially, referred to as O.A.L are:
- the relative chamber length variation from firearm to firearm even of identical make and model. A longer C.O.L. may jam the bullet into the rifling and this can cause a serious rise in peak pressure or prevent a semi from fully returning to lock position. I have two 6.5x55 Swedish rifles with different chamber lengths, one is a full military rifle and the other a later modification to a target rifle. I mixed up my dummy cartridges that I use to adjust the seating die for the specific bullet in the correct rifle. My next trip to the range and I was getting really high FPS in one rifle up to over 300 FPS than previous notes indicated for that load. When I discovered that the bullets were jammed into the rifling I checked my cartridges and the error was noted and my ass properly self kicked.
- too long or short a C.O.L. can lead to magazine and feeding problems. I never considered this a safety issue until I was experimenting with using pistol bullets in a 35 Remington pump action. While racking another round the round underneath slipped up behind the closed breech block. The next rack of the action jammed the back of the breech bolt into the hidden round crushing the neck of the cartridge and pushing the bullet into the case. If the primer had hit the right way it could have been a messy and embarrassing moment.
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Re: cartridge length
I've reached a point where I start at magazine length for those that have magazine length restrictions , maximum feed lengths for slide , lever etc rifles and in the cannalure for everything else .
I guess the 45 ACP is the exception to the above because those are run in revolvers with Colts or longer cylinders .
I guess the 45 ACP is the exception to the above because those are run in revolvers with Colts or longer cylinders .
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Re: cartridge length
Hogdon's data specifies a COL for 38 spl, using an XTP jacketed bullet, as 1.455. But the FP/xtp are somewhat shorter. If you crimp at the cannelure, you'll get a round which measures 1.452 or so. This is below the minimum COL. Seating at 1.455 will result in an ugly crimp, with too much of the cannelure exposed. I'm wondering if the .003 makes any difference....
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Re: cartridge length
Powder and chamber matter too...I know what I'd do but you'll have to decide.
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Re: cartridge length
Depending on the powder and chamber I would load them 0.003" short. Getting advice like this on the internet isn't all that great of an idea though. I'm sure someone knows the pressure difference if you can tell us what powder and charge you're using and what the firearm is.
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I've always been crazy but it's kept me from goin' insane.
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