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A few articles coming on the general topic of reloading but a few individual sections for discussion like this one on Trimming Cases to Length.
So, the basics for those that don't know a Cartridge Case has a SAAMI specified maximum case length that is safe to fit and fire in a firearm. If the case is too long then the case neck will be forced into the "Free Bore" of the Rifle Barrel and most likely be squeezed around the actual bullet in the case. If this is fired it can create an extremely high pressure build up in the chamber and possibly damage to the firearm. So, every Factory Calibre has a specified SAAMI Case Maximum Length but not all Calibres are of Factory Standards and commonly called "Wildcat Calibres". These Custom Chambers will be cut by a Gunsmith using a Reamer and that particular Reamer has a Print of Specifications with it and one is the Case Maximum Length suggested.
All of these maximum measurements are just that, maximum and should never be allowed to grow past that dimension. The suggested Length to Trim the cases to is called "Trim To Length" and is quoted in most all Reloading Manuals but is normally 0.010" less than maximum.
No, you do not need to trim cases every time they are reloaded but you should keep an eye on the case length and trim when it starts to approach maximum length. Some like to keep all their cases uniform and may trim to a specific length every reload or perhaps every two or three reloads. For precision shooting the case neck length has a factor involved with the amount of neck tension is applied to a bullet and if they are uneven then so is the neck tension and possibly accuracy as well.
For the basic reloader who wants to trim cases. Well, Lee Precision make a pretty basic but very usable range of Case Trimmers consisting of a Cutter & Lock Stud in one Kit and the Calibre Specific Case Length Gauge & Shell Holder. The downfall of these is that all are set to cut at minimum case trim length and are not adjustable unless one modifies the Gauge Length. The downfall is they are only available for most Factory Calibres but not all. For example there is not one made for the popular .204Ruger Cartridge Case (last time I looked) as the story was it would need the whole tooling line to be altered.
There is a work around by modifying a 22/250 Case Trimmer Gauge and hence why one is pictured....never did bother making one. That story later in this Topic.
Here are the Lee Precision Case Trimmer parts.......
The latter photo's are of the .22 Hornet set which I used to use.
There are a number of ways to drive these and some wear off very quickly. You can hold the Lock Stud and rotate the Cutter, you can put the Lock Stud in a Handle and rotate any one you like, you can use what Lee make called a Zip Trim (like pulling the starter cord on the lawnmower) or you can use a Cordless Drill.
Okay, no .204Ruger Trimmer so way back in those times I had to look around at what was available so I could trim my .204Ruger Cases. There are a number of adjustable Case Trimmers that use different Pilots for specific calibres....next stumbling block is that few if any made one for the .204Ruger or .20 Calibre in general .... never had a .17 Remington so that might have been the same story... Wonder how the .17 Hornet is going to go. Maybe the pressure will be on for manufacturers to come to the party.....anyway, I don't care as I found something way better.
Enter the L. E. Wilson Case Trimmer ..... and it not only trims cartridge cases. Bullet meplats too....
The basic version....
The fancier Stainless Steel Micrometer version .....
They use a Case Holder to keep the case parallel to the cutter centre and can be reversed if you want to square the case head. Also can be used to trim Bullet Meplats ......
Then comes Bullet Pointing but that's maybe in another Topic .....
Hope someone gets something useful out of all this ........
So, the basics for those that don't know a Cartridge Case has a SAAMI specified maximum case length that is safe to fit and fire in a firearm. If the case is too long then the case neck will be forced into the "Free Bore" of the Rifle Barrel and most likely be squeezed around the actual bullet in the case. If this is fired it can create an extremely high pressure build up in the chamber and possibly damage to the firearm. So, every Factory Calibre has a specified SAAMI Case Maximum Length but not all Calibres are of Factory Standards and commonly called "Wildcat Calibres". These Custom Chambers will be cut by a Gunsmith using a Reamer and that particular Reamer has a Print of Specifications with it and one is the Case Maximum Length suggested.
All of these maximum measurements are just that, maximum and should never be allowed to grow past that dimension. The suggested Length to Trim the cases to is called "Trim To Length" and is quoted in most all Reloading Manuals but is normally 0.010" less than maximum.
No, you do not need to trim cases every time they are reloaded but you should keep an eye on the case length and trim when it starts to approach maximum length. Some like to keep all their cases uniform and may trim to a specific length every reload or perhaps every two or three reloads. For precision shooting the case neck length has a factor involved with the amount of neck tension is applied to a bullet and if they are uneven then so is the neck tension and possibly accuracy as well.
For the basic reloader who wants to trim cases. Well, Lee Precision make a pretty basic but very usable range of Case Trimmers consisting of a Cutter & Lock Stud in one Kit and the Calibre Specific Case Length Gauge & Shell Holder. The downfall of these is that all are set to cut at minimum case trim length and are not adjustable unless one modifies the Gauge Length. The downfall is they are only available for most Factory Calibres but not all. For example there is not one made for the popular .204Ruger Cartridge Case (last time I looked) as the story was it would need the whole tooling line to be altered.
There is a work around by modifying a 22/250 Case Trimmer Gauge and hence why one is pictured....never did bother making one. That story later in this Topic.
Here are the Lee Precision Case Trimmer parts.......
The latter photo's are of the .22 Hornet set which I used to use.
There are a number of ways to drive these and some wear off very quickly. You can hold the Lock Stud and rotate the Cutter, you can put the Lock Stud in a Handle and rotate any one you like, you can use what Lee make called a Zip Trim (like pulling the starter cord on the lawnmower) or you can use a Cordless Drill.
Okay, no .204Ruger Trimmer so way back in those times I had to look around at what was available so I could trim my .204Ruger Cases. There are a number of adjustable Case Trimmers that use different Pilots for specific calibres....next stumbling block is that few if any made one for the .204Ruger or .20 Calibre in general .... never had a .17 Remington so that might have been the same story... Wonder how the .17 Hornet is going to go. Maybe the pressure will be on for manufacturers to come to the party.....anyway, I don't care as I found something way better.
Enter the L. E. Wilson Case Trimmer ..... and it not only trims cartridge cases. Bullet meplats too....
The basic version....
The fancier Stainless Steel Micrometer version .....
They use a Case Holder to keep the case parallel to the cutter centre and can be reversed if you want to square the case head. Also can be used to trim Bullet Meplats ......
Then comes Bullet Pointing but that's maybe in another Topic .....
Hope someone gets something useful out of all this ........
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