Hi gentlemen and ladies,I'm just about to start reloading .243 AI. I'm using lapua brass, fireformed from .243 win. the thing is on the .243 ai guide on this site the case length should be around 2.045. My cases are measuring 2.022, is this normal, is it safe and will it have an effect on accuracy...I'm new to reloading much help needed,thanks gents.
fire formed .243 ack imp
- Thread starter 237law
- Start date
That should be fine. Case stretch will depend somewhat on your fireforming loads and brass makeup. I recently used winchester and remington brass with various loads and powders to fireform a 270 AI. All cases were not the same length after fireforming. It also depends on your specific chambering, although that should be fairly close to other 243 AI'S.
Chris
Chris
thanks guys,the twit rate is 1/10, as for the chamber length I have no idea. The barrel is a stainless shilen, rem700 action,the rifle was originally built for benchrest but the owner got caught eligally shooting a roe deer on the way home from a match.I will be using it for fox and deer management.
would it be a good idea to to get the bore measured as I dont have a clue on seating depth either.I would like to take the advise of my freind as he has been loading for over 30 years,but what he has told me to do sounds a bit iffy,he has told me to seat a bullet way over length in an emty case,gently chamber the case and bullet,remove and measure your seating depth from there. has anyone heard of this before?
thanks Jerry
would it be a good idea to to get the bore measured as I dont have a clue on seating depth either.I would like to take the advise of my freind as he has been loading for over 30 years,but what he has told me to do sounds a bit iffy,he has told me to seat a bullet way over length in an emty case,gently chamber the case and bullet,remove and measure your seating depth from there. has anyone heard of this before?
thanks Jerry
Preacher
Gold $$ Contributor
Measuring bullet seating depth by using a case that will allow the bullet to be pressed into the case when it touches the rifling is as good a way as any, just be careful you don't allow it to move into the case while it's being measured.
Also measure off the ogive, not the total length, as they are almost never the same...
Also measure off the ogive, not the total length, as they are almost never the same...
As far as determining chamber length, Sinclair International sells a neat little device for determining your true chamber length. I would highly suggest you call Sinclair @ 1-800-717-8211 and tell them you want the chamber length gauge for 6mm. It is a piece of leaded steel that won't harm your bore and comes with instructions. You'll need a set of dial calipers to take this measurement but you'll know exactly when you need to trim or not. If you get on Sinclair's web site, you'll find a decent description of how this works.
Chino69
Chino69
ChuckMiller
Silver $$ Contributor
Your short case is typical of a fireformed Ackley case, it will shorten in the fireforming process. I doubt it will ever reach the minumum trim to length as most don't. That's one of the advantages of an improved case design, very little stretch because of the straight sides and sharp shoulder.
Your buddies advice is good. Load a case long and chamber softly, chances are the bolt won't close. Continue to seat the same case deeper until you can close the bolt. Take a new case and seat to your new depth and then check closely for rifling marks at the ogive of the bullet. Seat either way + or - to suit. Some like them in the lands others like a little jump. Measure the finished case to the ogive as bullet lengths vary too much and you now have the measurement to the lands. As for the neck length I've never seen a chamber that wasn't at least 20-30 thou longer than the max saami trim length. I also don't know a gunsmith that would chamber a rifle to saami max trim length unless specificaly ordered to, big liability after that gun changes hands a couple of times and a unexperienced reloader gets it. With an ackley case I would estimate your about 50 thou short of the actual neck length. Oh yea, listen to your buddy.......
.
Your buddies advice is good. Load a case long and chamber softly, chances are the bolt won't close. Continue to seat the same case deeper until you can close the bolt. Take a new case and seat to your new depth and then check closely for rifling marks at the ogive of the bullet. Seat either way + or - to suit. Some like them in the lands others like a little jump. Measure the finished case to the ogive as bullet lengths vary too much and you now have the measurement to the lands. As for the neck length I've never seen a chamber that wasn't at least 20-30 thou longer than the max saami trim length. I also don't know a gunsmith that would chamber a rifle to saami max trim length unless specificaly ordered to, big liability after that gun changes hands a couple of times and a unexperienced reloader gets it. With an ackley case I would estimate your about 50 thou short of the actual neck length. Oh yea, listen to your buddy.......
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