swithing from 260 to 260ai

[bsekf]

Foxx, back to your original question. Just use a 260 case as a go gauge, add 2 pieces of Scotch tape to make it a no-go. You are fireforming a wildcat, who cares if it is a .001 different from everybody else's. As I recall, the 260 has a short neck, have you considered making it longer? Just bump the shoulder back a little, keeping in mind that a stock 260 will not longer chamber. Being able to substitute the parent cartridge for the AI version is one of the "Ackley" beauties.

[calib]

Hey, foxx how is that 260 ai shooting? I get my barrel friday and should have it married up to my action this weekend, should have my stock in the next couple weeks i am hoping.

I am planning to try the 123 scenar as well as some 142 customs i have from precision ballistics. Not sure of powder yet. Probabky rl17, h4350, maybe some 4831 and see what happens.

[foxx]

So far all I have shot is the Hornady 140 match with 44.6g H4350. Had .25 to .333 groups at 100yds. Love it. Still working on 140 Amax, but I have heard H4350 is good with them, too.

[scope eye]

RL 17 and RL 19 also work great in your application.

Dean

[foxx]

RL 17 and RL 19 also work great in your application.

Dean

RL19? I had good luck with it in my 25-06, but it was so temp sensitive! At 20* I was getting 15 shot groups that were better than 1/2, the same loads at 80* were all over the place. That's when I decided to go with Hornady extreme powders whenever I can. I know they are still affected by temp, but not as bad as RL19. I suppose if you're shooting target with known temps you can adjust for that, though.

[foxx]

Hey, Calib, if you need gauges for that ai, let me know. I might be able to round some up for ya! ;)

LOL

[foxx]

Calib, you'll probably need new brass for it. The chamber was so tight I could not chamber 1x fired 260 Lapua in it.

[calib]

I may need to use the gauge, glad it worked for ya. You should be able to full length size the lapua brass and be good.

I just ordered a box of 260 lapua brass

[foxx]

I thought I'd be able to use the Lapua after FL'ing, but I couldn't. Had me frustrated for awhile.

Fred and others said to try new brass. That did the trick.

I still have a 260 for hunting, though, so they did not go to waste.

[calib]

Gotcha, did you measure them to see where they were different?

[n4ue]

Probably too late for this, but recently I pulled several Axis bbls. One was really, really stubborn. Just a light pass with my small (hand sized) propane torch, broke loose the thread locker Savage had all over the threads. NO, I didn't get it hot enough to change the Rockwell of the bbl..... Just heated the splined nut.

ron

[foxx]

Gotcha, did you measure them to see where they were different?

The base of the AI 1x-2x fired is .4695 to .470. The 260 1-3x fired is .4705 to .4710 hard to say, though, because I can't get the same spot each time. It's in the base though, because they will almost chamber, but not quite. If they do, you gotta beat on the bolt to open it.

[Hotolds442]

Blacken that brass and chamber it, I'd be surprised if it wasn't bottoming out on the shoulder.

[foxx]

If it was the shoulder, wouldn't FL Sizing to 260 have fixed that?

[calib]

Must have been hot loads

[foxx]

I don't know, but they still load, chamber and fire fine in the 260.

And the 260AI does well with reloads that came from virgin brass 260. They were all Lapua. Others have said they had the same experience. I gave up figuring why.

[Hotolds442]

Not if your dies can't bump the shoulder back.
same problem you had with the used brass....

[foxx]

No, I only had a problem when going from 1-2x fired 260 Lapua brass to 260AI. It would not chamber in the 260AI barrel.

When I used Virgin 260 Lapua brass it would chamber in the AI barrel and it fire formed perfectly. Have reloaded it a few times since. No problems.

When using 260 Lapua brass in my 260 barrel, I have never had any chambering problems. Have reloaded 3-4x without issue.

[bootsmcguire]

foxx, perhaps what is going on is that your 260AI FL-die and your 260 FL-die are made differently and pushing the shoulders back different amounts hence why it works one way and not the other. Perhaps try sizing your brass through both your 260 and then 260AI FL-dies before trying it in your 260AI barrel, it may be the answer. Obviously after you fireform it to the 260AI chamber you will only need to use the 260AI die, I only say that in the interest of keeping clear for other readers/noobs.

Just a thought as dies being of different dimension is possible and an often occurrence.

[Hotolds442]

And what happens when you FL size that brass that chambers perfectly in your 260, and insert it into the AI? What I'm saying is the 260 brass is more than the .004 longer and you can't bump the neck back far enough to allow it to chamber in the AI. I could be wrong, but I'd bet your dies full length size the 260 brass somewhere near the upper end of the SAAMI spec (loose chamber), and your chamber in the AI is somewhere nearer the lower end (tight chamber), because the datum line of the neck is out a bit further than a no-go gauge would be. Not really a problem as long as you don't get your brass mixed up, and you're still able to chamber factory 260 rounds in the AI. I've had this problem before, and machining .0015 off of the shellholder solved it and I was able to use all of my brass in my AI. I could touch the neck, but I couldn't move it with the regular shellholder. Once all of the brass was resized to a tighter spec, I was able to switch back to a regular shellholder and all of my brass was usable in the AI.

ETA: Boots has a good idea that's worth a try.