Originally Posted By: varmit_masterI only have a Lee hand trimmer and I cut a little off well a hair to much. I got a few brass trim to 1.830 . Most is 1.900 I bought some once fired 22 250AI brass and they are 1.870 I have around 80 after I full length size them with my Redding dies. I was reading on a custom barrel maker he trim his to 1.802. What is to short this is my first AI rifle and if I can't get it shooting right. I am going to sell it my friends around me don't have a AI rifles only ya do. I was going to have my 243 and 280 but it I can't get this shooting right I will leave them alone. I need help bad I don't want to go so short and blow my gun and self up please help. I am ordering a Lyman unvercial 9 pilot trimmer with carbine cutter head to trim my brass right. Help me guys.
You're focusing on the wrong things.
1) With these cartridges, don't use someone else's fireformed brass, period. Get rid of them and form your own with new brass, to your chamber. It's real easy.
2) Get a Sinclair chamber length plug and see how long your chamber really is. Unless yours is a particularly short custom chamber with an abnormally short neck, you'll find there's no need to trim cases. And with this cartridge there never should be. New brass necksize only to make them nice and round, no need for full length sizing. And fireforming, there should be some felt resistance on the bolt handle when chambering a round.
3) Just leave the brass full length and form it and it'll come out at whatever length it is. Don't trim and yes you can go too short. But no it won't blow the gun up. If this "custom barrel maker" you mention really does trim to 1.802" the guy's way off base. Unless he has a reamer with really weird spec's, that's entirely too short - stupid too short - gotta be a misprint.