260 chamber help!

[Sixfivesavage]

Alright, I've read so much about this the last few weeks, and I'm sure the answer is right in front of me but I can't see it. I'm trying to make a dummy round for my smith to chamber with but have no idea what coal I should make it to leave a little room in the aics mag. I'm using the 142 smk to set it up from. I understand that if I go long in the alpha mag I may run into feeding issues with the action. I know it would be easy if clearance had a tac match reamer but I don't think he does. So...what do you guys say for my oal to give him?

 

[thrusty]

SAAMI spec OAL maybe and just ask them to make the jump to the lands whatever you want....that way you still have room to chase the lands in your mag.

AICS mags I've used would allow up to 2.86"...but I ran into 50% failure rate feeding...dropped my .308's COL back to 2.84" and have had zero issues since.

 

[Sixfivesavage]

So I'm guessing load one at 2.80 maybe and tell him I want a .02 jump from there?

 

[Supersubes]

Like mentioned above. Essentially saami spec with a little more freebore. My reamer is .090 freebore and i can use 142's in a AICS mag and 140VLD's in an AW mag. If the gunsmith has a throating reamer, he can run it out to whatever you like.


Edited: Forgot a couple things. If you plan on using lapua brass, the neck may need to be larger. My 6.5's are .295 neck and wont fit Lapua. Remington .260 and necked 7-08 brass come out to .290-.291 loaded round neck diameter. Gunsmiths will usualy tell you what they use as far as specs, make some calls. I started ordering my own reamers from PTG. Dave Kiff can tell you what you need off the top of his head. You can also send him your dummy to make a reamer from. I'm not a gunsmith, but the reamer isnt very expensive so I just started buying them for each caliber as i had a new rifle built or a new caliber chambered.

 

[Sixfivesavage]

Yea, the .090 freebore is what I keep seeing, and the neck diameter as well. I guess I just needed to see it another way. I told him what freebore I wanted, but he wants a loaded round to go off of and I'm just wondering what coal to load it to be able to chase the lands a bit in an aics mag.

 

[Supersubes]

My first .260 went several thousand rounds before the throat moved, and then it was only .030 approx. I never hammered the barrel very hard, pretty much all slow fire, and I almost never cleaned it. Make up a dummy that gives you some space in the magazine, say .030-.050 and be done with it.

 

[Sixfivesavage]

My first .260 went several thousand rounds before the throat moved, and then it was only .030 approx. I never hammered the barrel very hard, pretty much all slow fire, and I almost never cleaned it. Make up a dummy that gives you some space in the magazine, say .030-.050 and be done with it.

Thank you! That's what I was looking for.