270ai or 270 gibbs for a kimber 84L?

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cdn shooter

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Just bought a another Kimber, this ones a montana in 270 win. Thinking about having it cut to 270ai or 270 gibbs right away...or maybe after hunting season seeing how there's sure to be a delay.

I like the idea of trying to get close to wsm speeds out of the much lighter 84L...think this is doable? Looking at loading forums it sounds like it might get into the 3300fps range with 130s.

Other customs I've had done are always in standard chamberings so I dont know much about having reamers made. Will this be common enough that I just have to look for a smith that has the reamer or am I better off just ordering one?

And last, which improved is the better design? The ai or the gibbs?

The goal here is an ultra light, flat shooting, 3-9x40 leupold duplex, hold on hair to 300, no muss no fuss mountain rifle.
 
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IMO if it ain't broke don't fix it.The .270 win is on hair out to 300 yards any day of the week sighted in 2-3" high at 100 yards, Harold
 
But the extra volocity can't hurt.

Been looking for dies...not much out there.

Edit: midway usa shows 270ai dies. Reasonable price if they ship here
 
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Midway won't ship to Canada. I agree with leave it alone. Or sell it and buy one in .280 A.I.

Personally, I think these A.I. conversions are a good way to trash the resale value of a good rifle, with very little gain.
 
Expect no more than 100 fps from either "improved" cartridge over the standard 270. This would be cool, but you have to be sure it's worth the significant extra cost.
 
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.270 meets your criteria already... you would be just throwing your money out the window on the upfront cost and again in resale value... my vote is leave it "as is."
 
9.3mauser said:
Midway won't ship to Canada. I agree with leave it alone. Or sell it and buy one in .280 A.I.

Personally, I think these A.I. conversions are a good way to trash the resale value of a good rifle, with very little gain.
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Finding a Montana in 280ai is pretty tough. Actually I don't ever remember seeing one for sale anywhere. The mountain ascent in 280ai seem very desirable, they disappear quick off the EE so I don't think the "improved" status hurts these rifles when talking resale.

I'd have to look but I think a standard 270 matches the 280ai ballistically and an improved version would have the edge, short range anyway.
 
Andy said:
Expect no more than 100 fps from either "improved" cartridge over the standard 270. This would be cool, but you have to be sure it's worth the significant extra cost.
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100fps wouldn't be worth the effort thats for sure. I was hoping the interwebs might be right with the 200fps gain that some claim
 
Well, I am the odd man out here. Twenty years ago I had a Ruger No 1 in 270 Winchester rechambered to 270 Gibbs by Ron Propp in Lethbridge. It easily went past 3300 fps with 130 gr Partitions and 3000 fps with 150s.

Had I not also owned a 270 Wby, a Bevan King built repeater on a VZ24 Mauser that got close to 200 fps more than the Gibbs, the Gibbs would not be hunting in Atlin, BC today.

The only reservation about the Gibbs chamber in your Kimber is getting that long straight body with its very short neck to feed properly. It will be a bit of a challenge, however Rocky Gibbs managed to do it in many rifles, most of them bolt actions.

Ted
 
my Remington 700 .270 shot those Vor-tx 130gr ammo to -10 low at 300m, that's on the Fur.

without the full power load and minus 150-200fps my Back line hold was 300m (-15) and air out backline for 350m... with the full power factory, my new backline hold was 350m and airing the backline was 400m... longest shot 370m (youtube)

with a higher POI at 100m, that 300m drop would be less and with reloads going full tilt and a 120gr TTSX / ACP its guna go 400 no troubles 'eh'

WL
 
I bought off the EE, they go fast so if you find one at a decent price snap it up. I have one in .308 that I might sell after seeing what the .270 will do.
 
Why not? said:
Well, I am the odd man out here. Twenty years ago I had a Ruger No 1 in 270 Winchester rechambered to 270 Gibbs by Ron Propp in Lethbridge. It easily went past 3300 fps with 130 gr Partitions and 3000 fps with 150s.

Had I not also owned a 270 Wby, a Bevan King built repeater on a VZ24 Mauser that got close to 200 fps more than the Gibbs, the Gibbs would not be hunting in Atlin, BC today.

The only reservation about the Gibbs chamber in your Kimber is getting that long straight body with its very short neck to feed properly. It will be a bit of a challenge, however Rocky Gibbs managed to do it in many rifles, most of them bolt actions.

Ted
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The feedramp might have to be trimmed down a bit. Not sure but the 84L might be ready to go...because so many are made as 280ai.

Interested in what you did for dies, and fireforming?
 
cdn shooter said:
The mountain ascent in 280ai seem very desirable, they disappear quick off the EE so I don't think the "improved" status hurts these rifles when talking resale.
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I disagree. The .280AI has almost acheived "standard" status.... A .280AI is viewed as a desireable mountain/flat country chambering... a .270AI or .270 Gibbs, not so much... you would definitely either take a hit on the value or have it up for sale for an extended period of time... I am not surmising here, I have been there so many times personally that I now have to give myself an internal "talking to" before I jump too fast on something interesting... sometimes it even works.
 
SuperCub said:
Sell it to me. Don't let bubba have hiis way with it.


....... or 7mm mag.
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Going from the 84L to the 8400 in 7mag is about 1lb,3oz increase. Not at all the direction I want to take things.

You really think this is a Bubba move? Seems like a strong opinion from the majority here....has me second guessing this.
 
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