No load data for Lapua, plenty for Winchester, Remington and federal

[Mike D Texas]

Mike, when I have a custom barrel chambered, the gunsmith always has to cut off 1" on the muzzle because the barrel maker laps the barrel from the muzzle end. So, I have the gunsmith run the reamer into that 1" section up to the depth of the shoulder only. This little tool used to be called a neck checker, if the round goes into the neck checker, then there is enough clearance on the neck. This "neck checker" can also be used to measure the shoulder length(some would call this headspace length) using a dial caliper. When the barrel is brand new, the neck checker can also be used to measure the seating depth on a brand new barrel.

Over on accurate shooter dot com in the gunsmithing section, there is a nice discussion on reamer design, relating to the dimension on the web that gives people fits, "clickers" on the bolt lift.

Mike, CIP spec reamers are larger in dimensions than SAAMI As a rule of thumb. Lapua brass will not work well at all in SAAMI spec chambers in 223, 22/250 & AI, all cases based off of 243 that I have found. I had major headaches with Lapua, RWS, Hertenberger, and Norma brass, until I got my reamers/brass/dies figured out.

Reamer makers have a +/- of .0005 on tolerance of neck dia, web dia, etc. I have found that JGS and Manson are very reliable regarding what you get vs. what you ordered.

My smith does exactly the same thing when reaming a new barrel. And I agree about Manson, I have no experience with JGS.

 

[MtnOak]

With the barrel chamber comments above have me wondering if I should contact the barrel maker that's building me a 260 Remington, I'm planning on shooting Lapua brass in it also, I wouldn't think the chamber specs would be any different than standard would they??

 

[Mike Matteson]

X2!!!

My reamer is base off of Sierra Reloading manual. I used the 280AI chambering for the 6mm case. I had speck out. .013" and end up at .0125". Nothing wrong with that. So it's off 1/2 ths. I don't figure that's any deal. So what I have is 6mm/280AI chambering. So when I set this up at the neck area. figures are ..243 OD &.026 for neck thickness for a total of 0.269 OD for the case neck area. i figured that the reamer people would set up the additional clearance to ream the neck. If I do something next time I will speck that out.
The smith had the barrel made 2" longer to start with and cut off about 2" at the muzzle. So my barrels end up at about 30" long. So I think I have that covered. Twist rate is 7-1. I probable should have turn that up to 6.5 rate.
The other is I have been reading about some case not fitting in other rifles. I would think that brass manufactures would want to conform to SAAMI standards as far as building the O.D. of the case. I am set up with a Gen-3 for case length trimmer, and a 21st Century cutter for neck neck thickness. I have a Bench-Source Machine for annealing, and figure I can get that to work for me. I am going to set that up with hoses and a Propane tank not little bottles.
Where some of this came about was. The smith wanted 5 case sized down from 7mm to 6mm. So I cut my case to length first thing. Then cut my neck to thickness. Using Redding bushing dies, it take 4 steps to reduce the necks to .241 ID. That give me .002 for neck tension. I will shoot 100 round in 100 cases to fireform and brake-in of the barrel. will anneal those cases, FL size them. I find out at that time if I need to use a different bushing because of spring-back. I will also set the primer pocket depth if needs and clean the flash-holes before first firing. After that I will anneal again and after each time I use that case or cases. After first firing I will volume weight the cases to see where they are at. I will FL size them each time and bump them back .001 or .002. I have or will have a high end priming tool to seat the primers, and a bullet seat too. Concentric is the name of the game. Hopefully I got it, and my SD?ES are very low. I have learned a lot here, and that's a GREAT THING! I have put to gather a 37 page doc on reloading steps, and cut the long reading out. So I need to check something. I can get too it.

 

[Mike Matteson]

With the barrel chamber comments above have me wondering if I should contact the barrel maker that's building me a 260 Remington, I'm planning on shooting Lapua brass in it also, I wouldn't think the chamber specs would be any different than standard would they??

You would think not, but with all the reading I been doing, there something going on. It maybe people don't understand or not sizing correctly. I can see manufactures building a case that different dimensions from SAAMI exterior case dimensions. I can see that a smith or others reamers aren't correct or warren. I can see that different people at the same plant would do it a little different. That the reason fireforming and transferring a case from one rifle to another, from the same plant may not work. The big question is "What is fireforming" and what does it mean. I understand it, but there seem to be other that don't.

 

[Gmac]

Lots of new chambers are being cut and I have to imagine that in some instances with popular calibers the same reamers are cutting numerous chambers. As the reamers dull the quality of chambers can vary in quality and size. In turn brass, will also need to fit the specific chamber.

With the rise in popularity of everything in the gun world, more guns are also being chambered with varying skill, equipment and can cause issues. additionally, with the rise in popularity of custom guns and wildcatting, more and more people are also tweaking reamers to their desired specs.... Some of these reamers can end up in the hands of the unsuspecting.

So many variables for little things to cause potential issues. There's also a lot of education that needs to take place still with the growing populace of shooters/reloaders.