Reloading 280 AI

[Kurtdnelson]

Thanks to all of you for your time and help.
I will check out the suggestions first thing tomorrow.
BTW, I called Kimber to discuss and they basically told me they could not help me because I'm reloading and they won't assume any responsibility for my results. That's also a new one for me

 

[xsn10s]

???
Does that matter? Never had an issue with using an RCBS or Redding shell holder in conjunction with an RCBS, Redding, Wilson, Hornady, Forster, or Whidden die set.

I have had dies not size enough when using shellholders of a different manufacturer. When that happens the shoulders did get bumped alittle but not the body. So this caused the body to "swell" which caused hard bolt close. For me the die was bottomed out so I went to the same manufacturer and was able to bump the shoulders more and got the bolt to close easily. Didn't happen for all my dies or rifles, but I have seen this happen in more than one rifle. YMMV.

 

[xsn10s]

You can easily see where the brass is contacting hard for hard bolt close by taking a sharpy and blacking the brass and bullet. Hard contact will scrape off the sharpy.

 

[xsn10s]

I doubt that this is an issue caused by "over sizing". That would just swag the brass to smaller dimensions. Which would make it easier to chamber. So my idea is that the body swelled out due to bumping the shoulder, but not sizing the body. IMO that would be under sizing the brass. The other issue could be the brass being too long. But IMO the brass would have to be pretty long to cause hard bolt close and I've never had that happen. Not to say it can't, but I put my bet on my idea.

 

[xsn10s]

You state cases are at max length. Trim them .010" to minimum length. Then try again.

I'd trim down the brass too. I don't think it will help the hard bolt close but you never know. I do know that brass that is too long can be cause to crimp the bullet during bolt close which can increase pressure. It can also cause accuracy issues. I hate trimming brass, but to load brass that needs trimming has proved to be a waste of time and effort.

 

[L.Sherm]

Chamber just a full length sized case no bullet and that will eliminate if it's a bullet issue. Next measure a fired case at the .200 line and shoulder, you should be .002 smaller with a FL sized case. Buy some comparator it's really the only way to setup your dies properly.

 

[6MM06AI]

One way to find out is to pull the bullet and see if the brass will chamber, or use xsn10s method and check it with a sharpy

 

[xsn10s]

Usually works best without the ejector and extractor removed. But you can do it with them in too. Just more accurate especially with ejector removed. I think that is an old Ken Waters trick I learned before the comparators or "precision mics" were around.

 

[mpayne]

LSHERM has it right make sure a resized case will fit, take a once shot brass and set your Die to where it just chambers with no resistance. Some say to do this with the firing pin out so you can feel when it just shuts, but I've had good luck with out removing the pin. this is how I set up my full length die for my guns, I do not share my ammo because its probably not going to fit another gun!

 

[misterc01]

I use an RCBS precision mic to check my headspace, and size -001-.002 under. Then I run each case, and then later, loaded round thru an Ammo checker. BTW - I use BOTH a Hornady and Sinclair comparator, so I have two seating depth references.

 

[Chuck32571]

I've had some new unloaded Hornady brass that I try out in my chamber prior to loading. After running them through a FL sizer to round the mouth I insert them into the chamber and see how easy the bolt will close. Any that are stiff and hard to close the bolt on are then run through the FL sizer again but this time I use the Redding competition shell holder set for that caliber that sets the shoulder back in increments with each holder in the set until the bolt closes with ease.

 

[Tiny Tim]

Had a similar issue several years ago. Thought I was full length sizing but was only neck sizing. After a while, the cases wouldn't chamber or were difficult to close the bolt on. Got a Hornady head space comparator and found I was not setting the shoulder back. Try running your full length sizing die past where it touches the shell holder so it "cams over" abit at the end of the sizing stroke. Then see if this resized empty case will chamber.

 

[nicholasjohn]

You can easily see where the brass is contacting hard for hard bolt close by taking a sharpy and blacking the brass and bullet. Hard contact will scrape off the sharpy.

Good call, Sir. I was going to suggest this to see if the case body is too big around. It may be, just below the shoulder. If the shoulder is too far forward, it may or may not rub off the blacking, because the shoulder is pretty steep at 40 degrees. The case mouth may also be too long, and if it has black sharpy on it, his should get rubbed off when it gets pinched into the end of the chamber neck. If the bullets are seated too long, they should push in deeper as the bolt cams shut, and they should also end up stuck in the throat. Since this is not occurring, I wouldn't think that is the issue. So, in my mind, it's a case that is either too long at the shoulder, too big around in the body, or too long at the end of the neck. The sharpy trick ought to tell the tale, if it's any of these problems.

 

[William Persons]

I have both a .280 ai and .260 ai. The .280 ai actually sizes just fine, but the .260 ai did not. After talking to the smith that did my barrel and another for a second opinion...these smith's and others are seeing issues with redding die's (and probably other manufacturer's) with ackley sizing die's. I'm not saying this is everyone's problem, but I had to cut my redding shell holder down in my lathe to bump back head spacing with a 1/4 turn camover on the die. I didn't try trimming down the die, because they're supposed to be made of hardened steel. My smith offered to precision grind down the die which I may do at some point so I can use it in my forsters. I believe redding also makes shell plate holder kits in various sizes that would also accomplish the same thing. I tried having guys tell me it was bad gunsmith work or they used the wrong .260 die, but that doesn't appear to be the case. Good luck.
Buck