280AI won't chamber

[longbowelk]

I am working on getting my 280AI off the ground you might say. I've been fireforming Hornady 280 brass and doing a 2nd firing with midrange AI loads. Prior to my last session I was prepping the 1st fired rounds that yielded me the headspace of 2.116 to 2.118. I resized and primed them and prior to powder and bullet I checked each one to make sure they would chamber. All passed that test. Next I put the powder and 162 gr Hornady SPBT bullet in just off the lands about .020. Now comes the problem. All the rounds were successfully shot and yielded a final headspacing of 2.117 to 2.1175 except one. See picture below showing the loaded round that would not chamber next to a successfully 2nd fired casing. When measured with the Hornady headspace tool it still shows to be 2.116 where it started. I am not sure but it looks like a false shoulder may be showing. Also, the shoulder looks messed up . Is it possible that when I rammed the bullet in the brass, the die possibly caused the false shoulder or the sort of flattening of the shoulder? I am using the Redding 280AI dies along with the .014 Redding competition shell holder.

 

[Patton243]

Make sure the outside of the case is well chamfered. I use a drill tool even to chamfur the outside. Especially if you're using a softer brass. (like Hornady) I had this same problem with a 280 AI after the 3rd firing or so with Nosler brass. Bullet wouldn't chamber in gun after FL resizing etc. Once it was chamfered outside after every reloading never had an issue after. Your case could be different, of course.

 

[yobuck]

Could also be that your case shoulder needs a bit of bumping back.
Check into a set of competition shell holders from somebody like Sinclair and follow the directions.
You could also call there and talk with a tech about your situation, and his opinion on using the different shell holder.

 

[DHBWA]

Neck "looks" long on the one that wouldn't chamber and also looks like the case mouth may have contacted the die during seating.....

 

[longbowelk]

Neck "looks" long on the one that wouldn't chamber and also looks like the case mouth may have contacted the die during seating.....

I plan on pulling the bullet tonight and check the length and also may run the deburr tool around and see if it will chamber. When I put the bullets into the casings I did a dozen that came out fine. This is the only one that appears to be messed up by the seating die.

 

[Brianc74]

Appears you are pushing the shoulder back to far. If you do not have the Sammi chamber and are using Sammi dies, then that's the problem. Ask the person whom did the chamber work and what reamer did they use. What are the reamer specs. There are lots of reamers with different detentions. The newest is a sammi and goes well with nosler 280AI brass.

Brian

 

[DocDoc]

Measuring tools are needed to set the shoulder bump about .002 in. You can blacken the case, neck and shoulder of the offending case, try to load it and see where contact is occurring. It is so much easier to diagnose when you have micrometer, caliper, and bump gauges.

 

[26Reload]

Yep...definitely looks long in the neck.....
Shoulder looks a lot like a weatherby.....be kinda cool..your own 280 weatherby ai

 

[lancetkenyon]

Here is my guess...
Too much neck tension. Or, seating stem hitting the case mouth due to die not being set up quite right. Causing the bullet or stem to actually push down the shoulder, causing a very slight bulge in the body just below the shoulder. Meaning it won't chamber.

Pull the bullet, run it back through a FL die to resize body, trim case neck, back seating die out 1/4 turn, reload, shoot to fire form again.

 

[Unoboats]

I am working on getting my 280AI off the ground you might say. I've been fireforming Hornady 280 brass and doing a 2nd firing with midrange AI loads. Prior to my last session I was prepping the 1st fired rounds that yielded me the headspace of 2.116 to 2.118. I resized and primed them and prior to powder and bullet I checked each one to make sure they would chamber. All passed that test. Next I put the powder and 162 gr Hornady SPBT bullet in just off the lands about .020. Now comes the problem. All the rounds were successfully shot and yielded a final headspacing of 2.117 to 2.1175 except one. See picture below showing the loaded round that would not chamber next to a successfully 2nd fired casing. When measured with the Hornady headspace tool it still shows to be 2.116 where it started. I am not sure but it looks like a false shoulder may be showing. Also, the shoulder looks messed up . Is it possible that when I rammed the bullet in the brass, the die possibly caused the false shoulder or the sort of flattening of the shoulder? I am using the Redding 280AI dies along with the .014 Redding competition shell holder.

I have gone thru this in the past few weeks and the neck did not properly get sized by the die. Almost like you did not complete the throw of the press on that one

 

[Bob Wright]

Here is my guess...
Too much neck tension. Or, seating stem hitting the case mouth due to die not being set up quite right. Causing the bullet or stem to actually push down the shoulder, causing a very slight bulge in the body just below the shoulder. Meaning it won't chamber.

Pull the bullet, run it back through a FL die to resize body, trim case neck, back seating die out 1/4 turn, reload, shoot to fire form again.

Yeah, I crashed my 22-250 Redding comp seater die due to me not setting it up correctly. It hit the end of the case mouth if I remember correctly. Been a while.
Grab that manual...

 

[VLD Pilot]

Check trim specs (Saami OAL) and trim them cases to spec. That one looks awfully long in that pic. Probably why it's not chambering.

 

[CTK]

Possibly seating die screwed too far down causing rim of shoulder to expand. Been there, done that. And the neck looks too long. Would measure.

 

[DHBWA]

I assume he has the ability to set up the dies using whatever is giving him the headspace measurement.
He'll get it!