280 AI : Any Down Side To Fire Forming With All Copper Bullets?

[PA Plumber]

That's probably the best use of the GMX as they are woefully unreliable and inconsistent on game.

I'm happy with my Hornady and Redding dies.

Good to know.
As soon as my die set shows up, I'll start putting them together.
Thanks

 

[PA Plumber]

Had some trouble getting scope rings, but they are now on their way from Optics Planet. LGS tried but couldn't get them.
Same for the die set, but ordered it online and it showed up a couple days ago.
Have the brass annealed, resized, and in the media now.
Hope to get three shells ready to go today.
I have oodles of H4350 so settled on: 52 grains of H4350 with 139 GMX bullet.
Planning to try to figure out where .050 off of lands is and start there. Would prefer it not touch since it's a monolithic bullet.

 

[Mark37082]

Keep us posted. I have a couple of lbs of H4350 and several pounds of IMR4831 that I'm squirreling away for a 280ai build in process. Still looking for RL23 and 26 to come back in stock. 338Dude was kind enough to offer to trade some 26 for Retumbo awhile back. Life just got in the way of me making the trip to trade. My assumption is the 280ai will work on powders I have used for 7RM.

 

[Roughrice]

Keep us posted. I have a couple of lbs of H4350 and several pounds of IMR4831 that I'm squirreling away for a 280ai build in process. Still looking for RL23 and 26 to come back in stock. 338Dude was kind enough to offer to trade some 26 for Retumbo awhile back. Life just got in the way of me making the trip to trade. My assumption is the 280ai will work on powders I have used for 7RM.

IMR 4831 works fine with 160's. Mine drags along @ 2960 in a 24" barrel under dime.
Could possibly get more speed with other powders but 3000 fps is my threshold with standard bullets.

H 4350 behind140's is fast.
Would also work great behind light coppers.

 

[lancetkenyon]

Had some trouble getting scope rings, but they are now on their way from Optics Planet. LGS tried but couldn't get them.
Same for the die set, but ordered it online and it showed up a couple days ago.
Have the brass annealed, resized, and in the media now.
Hope to get three shells ready to go today.
I have oodles of H4350 so settled on: 52 grains of H4350 with 139 GMX bullet.
Planning to try to figure out where .050 off of lands is and start there. Would prefer it not touch since it's a monolithic bullet.

View attachment 346206

I would still jam the lands. Especially since you just mentioned you resized the brass. Unless it was neck sizing only. Keep that head tight against the bolt face so the firingbpin doesn'tpush it forward before the primer pops, and get that initial pressure to blow the case out. That case blowing out os going to take a lot of the initial pressure off the load anyway. It takes a lot of energy to blow it out.

 

[PA Plumber]

I would still jam the lands. Especially since you just mentioned you resized the brass. Unless it was neck sizing only. Keep that head tight against the bolt face so the firingbpin doesn'tpush it forward before the primer pops, and get that initial pressure to blow the case out. That case blowing out os going to take a lot of the initial pressure off the load anyway. It takes a lot of energy to blow it out.

The brass was resized using the 280 AI FL die.
When loading a newly resized empty, the bolt doesn't close the same as it does on an empty chamber. I can feel it pushing against the brass just a little.
I'll look at it some more before taking it to the range. From what I understand (which isn't much), a factory 280 shell should be able to safely fire out of this AI with good results. I won't load anymore until I review what's been done.

Something I discovered...using the 280 AI FL die to resize seems to work fine. Using the 280 AI bullet seating die is another matter entirely!
The die pushes on the shoulder of the standard 280 brass before the bullet is seated to spec. Hopefully it's due to the fact the standard shell has not yet had the shoulder changed. I just unscrewed the AI die back a couple of turns to allow clearance. Likely I could use my standard 280 die to seat, but hate to change it, since it's set up for another load I put together.

 

[Slick8]

My fire forming to an Ackley Improved chamber is usually not "light". I load for middle of the road charge weight of the parent case, bullet at the lands. So look at .280Rem loads, and go right in the middle for whatever powder you plan to use. I like a bit on the fast burn side to give that initial "pop" for a quick expansion of brass rather than a slow burning powder.

Hammer meet nail.

 

[lancetkenyon]

The brass was resized using the 280 AI FL die.
When loading a newly resized empty, the bolt doesn't close the same as it does on an empty chamber. I can feel it pushing against the brass just a little.
I'll look at it some more before taking it to the range. From what I understand (which isn't much), a factory 280 shell should be able to safely fire out of this AI with good results. I won't load anymore until I review what's been done.

Something I discovered...using the 280 AI FL die to resize seems to work fine. Using the 280 AI bullet seating die is another matter entirely!
The die pushes on the shoulder of the standard 280 brass before the bullet is seated to spec. Hopefully it's due to the fact the standard shell has not yet had the shoulder changed. I just unscrewed the AI die back a couple of turns to allow clearance. Likely I could use my standard 280 die to seat, but hate to change it, since it's set up for another load I put together.

The "crush fit" you were feeling with .280 Rem brass was a good thing. That also holds the case head to the bolt face. Since you just eliminated that, you should definitely jam the lands now.
My current .260AI has that same feeling with virgin .260 Rem brass, but once fired chambers very smoothly, even without running them through the FL die.

 

[PA Plumber]

Just looked at my dies again.
It seems the case mouth is hitting the seating die. I am well under the max case length listed in my reloading book.
My standard 280 seating die will let the case go into the die much further than the AI seating die will.
I have a call in to RCBS to see what they say. This could easily be user error, but would sure like to know what I'm doing wrong.

Heard back from RCBS while typing this...
The 280 AI die set is not machined deeply enough for the included instructions to be accurate. I was advised to just turn the die out a little further. I had already done that, it's good to go.

 

[PA Plumber]

The "crush fit" you were feeling with .280 Rem brass was a good thing. That also holds the case head to the bolt face. Since you just eliminated that, you should definitely jam the lands now.
My current .260AI has that same feeling with virgin .260 Rem brass, but once fired chambers very smoothly, even without running them through the FL die.

Okay, I'll try to make the adjustment on the bullet seating depth.
Is 52 Grains of H4350 adequate? I'll be pulling bullets to simple enough to change the powder charge.
Thanks.

 

[lancetkenyon]

Hornady book shows 51.1gr to 57.1gr H4350 with the 139 GMX in a .280AI.
42.9 to 52.7gr H4350 with the 139 GMX for the .280Rem.

52.0 is close to the top end for .280Rem case.

If I was loading FF rounds, I would load 3 rounds of each: 48.0, 48.5, 49.0, 49.5, 50.0, 50.5, 51.0, and go see what shoots best and gives sharp shoulders. Then load that recipe uonfor the rest and go have fun with it while forming brass.

 

[PA Plumber]

Hornady book shows 51.1gr to 57.1gr H4350 with the 139 GMX in a .280AI.
42.9 to 52.7gr H4350 with the 139 GMX for the .280Rem.

52.0 is close to the top end for .280Rem case.

If I was loading FF rounds, I would load 3 rounds of each: 48.0, 48.5, 49.0, 49.5, 50.0, 50.5, 51.0, and go see what shoots best and gives sharp shoulders. Then load that recipe uonfor the rest and go have fun with it while forming brass.

Thanks.

 

[PA Plumber]

Hammer meet nail.

I get it.
The all copper part of the equation is what concerns me.
Maybe I missed it, I didn't see anything looking around where folks were using all copper bullets for fire forming.
My own experience with monos has been, more distance off the lands helped with accuracy and pressure.
It's hard for me to let that go.

 

[Roughrice]

I get it.
The all copper part of the equation is what concerns me.
Maybe I missed it, I didn't see anything looking around where folks were using all copper bullets for fire forming.
My own experience with monos has been, more distance off the lands helped with accuracy and pressure.
It's hard for me to let that go.

If you do like lancetkenyon mentioned...you should be safe.
I usually go 10-15% off of max with faster powder, light to midweight bullets (I mentioned earlier about going 20% under max because you will use copper) and touch lands (slight bolt feel) and had nice forming.