Thread: Kimber Hunter .280 Ackley Improved

Bought one of these brand new a couple of months ago, but have not hand a chance to shoot it just yet. Really like the look and how light it is and how it balances

Have a couple of quick questions:

1. What us the recommended torque settings for the action screws?
2. How do they shoot out of the box...any requirement to be bedded?
3. I assume it is ok to shoot factory .280 Remington loads? I know there has been some talk about a .14 thou headspace difference between the SAAMI version of the 280 AI and the traditional .280 Remington AI.

Cheers,

Michael.

I have used factory 280 in my 280ai for bush loads no problems at all. Also gives you fired formed brass for reloading.
A light weight 280ai with out brake or suppressor kicks like a 3 legged ninja, well at least mine does. Make sure your scope has good eye relief and keep a grip on that fore end.

Hey mate I would just shoot it with a few types of ammo to see how it goes before a bedding job.

I tourqe all my guns to 40 in-lbs.

Nice guns those kimbers.

Good luck.

Here ya go

@Sideshow, you may remember what I posted about Foster's torque settings last time round?

They do not take into account the material the bottom metal is made from.

Believe me, if you torque up a pillar and/or epoxy bedded Tikka or Howa to Foster's settings, you'll wreck the bottom metal in one go. I know. I found out the hard way.

So not knowing what a Kimber build is like have never even held one, just bear in mind what the bottom metal is made from.

Sorry @Flyblown I missed that post.
But good point. If I found that the bottom metal was that weak I'd pillar bed the rifle!
Then torque away

It's only tikka owners that need worry

Looks like the Kimber hunter is pillar bedded in a polymer stock.
https://www.americanrifleman.org/art...-rifle-review/

Ah but you see @Sideshow the polymer or alloy material over time gradually compresses and flows up into the gap between the action screw and the pillar. Makes it a pain in the rear end to remove the screws and if it gets brittle it will snap and you're left with too big a hole for the screw. Mine didn't get that bad but I've seen it happen on another pillar bedded Tikka. The fault isn't the torque so much as the cheap-ass materials used for the bottom "metal".

I found sticking to 40in-lb with epoxy bedded rifles with pillars is fine. I only use 50in-lb on my chassis based rifles.

Another consideration is that if you torque up some of these lighter actions too much, even with bedding, e.g. T3, they will twist ever so slightly and even as much as not being able to turn the bolt. I have a T3 Laminate stock here with a proper epoxy bedding job plus pillars and no way will the action take 60in-lb. I tried!

And the DPT chassis on the same action at 60in-lbs produces the same results, but is fine at 50...

Are well if you stick to the old wood and blue with a nice bedding job a a couple of pillars you don't get these troubles.

Good points though from Flyblown to watch out for! It seems what he has found dose have merit.

I snapped an action screw in a Remington tactical model once trying to tourqe up to 60 inlbs.

Hence now it’s 40 for everything, never had a problem and they all shoot.

Originally Posted by 6.5mm-mag

3. .... I know there has been some talk about a .14 thou headspace difference between the SAAMI version of the 280 AI and the traditional .280 Remington AI.

As a user of rifles chambered in original .280 Ackley Improved, I haven't found the definitive or entirely trustworthy answer to this question. It could be that the cases are more similar in length than this figure appears to indicate and that the difference is only or partly in the reference line from where the length measurements are taken - or then again maybe not. In view of this uncertainty - and bad experiences with loose head-spaced cases in the past - I have not used SAAMI 280AI cases and opted to continue to fireform from .280Rem cases on which my chambers have been set up as 4-thou crush fits.

I have seen @Carlsen Highway shoot a sub 1" group with a classic 30-06 of some sort without the actions screws done up. I guess torque settings vary. Anyone ever shot groups while progressively tightening the action screws?

Originally Posted by Puffin

As a user of rifles chambered in original .280 Ackley Improved, I haven't found the definitive or entirely trustworthy answer to this question. It could be that the cases are more similar in length than this figure appears to indicate and that the difference is only or partly in the reference line from where the length measurements are taken - or then again maybe not. In view of this uncertainty - and bad experiences with loose head-spaced cases in the past - I have not used SAAMI 280AI cases and opted to continue to fireform from .280Rem cases on which my chambers have been set up as 4-thou crush fits.

As a user of the 280ai for some years when this issue popped up I went down the rabbit hole trying to find the mystical .014 in its physical form. After gauging more than a couple of chambers I have not been able to find it. I happily use nosler SAAMI brass in my old traditional chamber. The fired cases come out of the chamber with the exactly the same head space as new .
These guys put up a very good demonstration
https://gunsmithtalk.wordpress.com/2...eadspace-test/
They give a good explanation but there are those so invested in the opposing side of the discussion they cant/wont accept it and few engaged in the comments section to challenge them.

Nosler get blamed for perverting the spec but this is what they have to say.
https://faq.nosler.com/index.php?act...=39&artlang=en

As you pointed out the problem seems to be in the drawings and the relevant datums used to measure headspace. If you look at the SAAMI reamer drawing the headspace dimension ( base to neck/shoulder junction)
used to compare the traditional vs SAAMI ,has an * after it. This is indicates the datum is ignoring the radius of the neck shoulder junction and uses a point at which the neck and shoulder lines intersect. The reamer prints Iv found for the traditional aren't SAAMI and don't use this point.

Originally Posted by Tussock

Anyone ever shot groups while progressively tightening the action screws?

Only with a 22LR, trying out the idea of tuning accuracy with screw tension which I read about on an American rimfire forum. IIRC I did find some apparent improvements, but wasn't (I'm still not) a consistent enough shooter to be sure it was the tension tuning rather than just me shooting better or worse groups with tension somewhere in an ok range.

PS are you the old forum Tussock returned from the wilderness? If so welcome back.