Two part question on building a rifle

[MuleyFever]

Backstory: I have a Kimber 280ai. I love the cartridge and want to stick with it. The mag length is lacking though. So, after picking up reloading I have found the best rounds are those that are too long for my mag. Now the wheels are spinning.

I have a Winchester M70 in 270 that was handed down to me. I could build a new 280ai off the action. What are the limitations on building off the Winchester action. You do not see many people building off of them so I am assuming there are draw backs. Given those limitations, can I build a light weight rifle, 6.5# or less, off that action without spending over $2500?

Second. Originally I considered a Tikka in 7mm-08 and having it re-chambered. If I went this route are there options for an extended mag with an aftermarket stock?

 

[DoubleBroomedMountainRifles]

In all seriousness you have to ask yourself this ONE question before headed down this “heavy for caliber” bullet selection that is honestly a fad that will eventually run its course in the rifle building world.

How far are you going to shoot at game with this set up? If it is under 700 yds with most modern rounds including the 280 AI......your heavy for caliber bullets is really not worth chasing this/going down this rabbit hole (this cartridge in particular anything above 162 gr is what I consider heavy for caliber)

A 140-160 gr traditional bullet weight selection (Accubonds, ELDX, TTSX, LRX, Interbonds) will do EVERYTHING you need out to 700 yds without the heavier recoil of “heavy for caliber” bullets or the magazine box issues you are considering changing to.

100 to 200rnds of quality ammo in traditional weights used for behind the rifle practice from 300-700 yds will go 10x more for actual your performance on game (making successful kill shots) during hunting situations than changing up for the “in thing”.

You have a great set up currently. No way would I change.

For what it’s worth if going down this path The Winchester will give you a touch longer mag box length over the Kimber as will the Tikka.
The limitations on a Win 70 are the weight issues. It will be tough getting them to a 6.5lb rifle no matter what you do with the lightest aftermarket stocks etc. The Winchester is a solid rifle even the push feed rifles built after 1964 through early 90’s are solid rifles. With perhaps the most reliable trigger assembly designed. Again tough getting it to 6.5lbs.

I have your same current set up and I am shooting a 145gr LRX or the 150gr ELDX pushed to just under max pressure in my rifle and I regularly shoot to 900 yds on steel. I would never consider anything over 600 yds in the field at game. I have no issues with mag box length etc with this setup. My recoil is not bad as well with these lighter bullet weights.

Good luck

 

[handwerk]

I have had many semi customs built on model 70 actions, mostly pre 64's. In fact in a couple days I'll receive my latest, a 280AI/with mcm edge stock. The bare rifle will come in at around 6 3/4 lbs with Williams BM. So if you went the ADL route I think you'd be right at 6.5.
If you already have the action buying a barrel/having it chambered will be around $650 and another $600-$700 for a custom LWT synthetic stock.
The pre 64 and classic model 70 actions are my favorite to use.

 

[MuleyFever]

In all seriousness you have to ask yourself this ONE question before headed down this “heavy for caliber” bullet selection that is honestly a fad that will eventually run its course in the rifle building world.

How far are you going to shoot at game with this set up? If it is under 700 yds with most modern rounds including the 280 AI......your heavy for caliber bullets is really not worth chasing this/going down this rabbit hole (this cartridge in particular anything above 162 gr is what I consider heavy for caliber)

A 140-160 gr traditional bullet weight selection (Accubonds, ELDX, TTSX, LRX, Interbonds) will do EVERYTHING you need out to 700 yds without the heavier recoil of “heavy for caliber” bullets or the magazine box issues you are considering changing to.

100 to 200rnds of quality ammo in traditional weights used for behind the rifle practice from 300-700 yds will go 10x more for actual your performance on game (making successful kill shots) during hunting situations than changing up for the “in thing”.

You have a great set up currently. No way would I change.

For what it’s worth if going down this path The Winchester will give you a touch longer mag box length over the Kimber as will the Tikka.
The limitations on a Win 70 are the weight issues. It will be tough getting them to a 6.5lb rifle no matter what you do with the lightest aftermarket stocks etc. The Winchester is a solid rifle even the push feed rifles built after 1964 through early 90’s are solid rifles. With perhaps the most reliable trigger assembly designed. Again tough getting it to 6.5lbs.

I have your same current set up and I am shooting a 145gr LRX or the 150gr ELDX pushed to just under max pressure in my rifle and I regularly shoot to 900 yds on steel. I would never consider anything over 600 yds in the field at game. I have no issues with mag box length etc with this setup. My recoil is not bad as well with these lighter bullet weights.

Good luck

This reply is probably what I needed to hear. I'm not a long range shooter and certainly not with a Kimber. I'm probably over thinking my bullet needs.

 

[16Bore]

I’m assuming you looked at the “gains” you’d achieve from shooting the heavier bullets?

99 times out of 100 the ballistical skullphuqq leaves me scratching my head and wondering what the hell I was thinking.

Math has a way sorting through the bullshit.

 

[MT257]

If you use the handed down rifle you will have that much more in your budget. I think you’d be able to build your rifle for $2500 or less with a new barrel trigger and stock to stay under that budget number. I haven’t looked but I’m guessing the bolt face would be the same for the 270 and 280 ai.

 

[Ndbowhunter]

Hornady makes a 162gr elf-x factory fodder load

if that doesn’t work I’d see if 150 eld-x like to be jumped from mag box length. .575 at 2950 should do some good things.

or run 162gr eld-m

between those two bullets you should find something that works and save the 2500$ for something else.

 

[Ram94]

I’m assuming you looked at the “gains” you’d achieve from shooting the heavier bullets?

99 times out of 100 the ballistical skullphuqq leaves me scratching my head and wondering what the hell I was thinking.

Math has a way sorting through the bullshit.

16Bore, are you saying that there aren’t benefits to shooting a heavier bullet? I’m not sure I follow 100% as I can think of a few but maybe I’m misreading your post.


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[Ram94]

I’m mostly curious because I’m in the heavy for caliber (160gr for a 7mm08) boat right now and if there’s a conclusion that I haven’t come to yet, maybe you can help fast track me there...but so far, it seems to be the answer minus the added recoil.


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[MarcherLord]

What is the goal? Distance/game/bullet intended. I'd be happy with the Kimber as is but a Tikka 7mm-08 with extended mag would get check some boxes.

 

[6mm Remington]

I think if you did build a 280AI on a Model 70 action you would be very happy. As stated getting it below 6.5# would be tough. It's a great cartridge and action to build on . I built the exact same rifle using a Model 70 Classic Sporter in 270 that I found.
1. Shilen match grade stainless barrel 1-9 twist 24" long
2. John Norrell Arms moly resin coating on barrel and action. (It's holding up well.)
3. Factory trigger fine tuned to 2.5# by my gunsmith.
4. Factory walnut stock pillar and glass bedded.

It turned out fantastic. I love that rifle and it sure shoots good also. I was using 140 gr. Partitions at first but now I'm shooting 140 gr. Accubonds. That is what I used on my grizzly bear last fall! One shot at 158 yards and he was dead almost instantly with a shot through the lungs tight behind the shoulder.

As alluded to I don't think there is anything wrong with your Kimber though. If you do the build you could always save one for one of your kids when they started hunting or do hunt currently! I'm just trying to help you out!

!https://www.rokslide.com/forums/threads/alaska-grizzly-bear-hunt-2019.156410/#post-1481185

 

[6mm Remington]

Right at 9 1/4 pounds with scope & sling.

 

[Low_Sky]

16Bore, are you saying that there aren’t benefits to shooting a heavier bullet? I’m not sure I follow 100% as I can think of a few but maybe I’m misreading your post.


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Heavy for caliber bullets get pushed slower than lighter pills. If the "standard" bullet weights are adequate for the game, you aren't gaining anything with the heavy bullet (speaking of trajectory) until it outruns the lighter bullet at long ranges. At the ranges most people shoot game, a lighter, faster, flatter shooting bullet is the better bet without the hassles associated with the heavy pills.

A day spent playing around with the JBM Ballistic calculator is enlightening.

 

[carter33]

Heavier for caliber higher BC bullets are pushed less by wind which in my opinion is the advantage. With modern day ballistic solutions if you do your part with the input the output will be spot on for drop. Wind is more of an art form in being able to read it.The high BC heavy bullets are little more forgiving in that regard.

While I agree at most hunting shot distances the advantage gained by the higher BC higher weight bullet won’t almost, if ever, be the difference between a good or bad shot people are always pushing for that little edge that may help. Don’t think that is a bad thing.

 

[DoubleBroomedMountainRifles]

Heavy for caliber bullets get pushed slower than lighter pills. If the "standard" bullet weights are adequate for the game, you aren't gaining anything with the heavy bullet (speaking of trajectory) until it outruns the lighter bullet at long ranges. At the ranges most people shoot game, a lighter, faster, flatter shooting bullet is the better bet without the hassles associated with the heavy pills.

A day spent playing around with the JBM Ballistic calculator is enlightening.

I’m with you. Most just read heavy for caliber and that is what the gotta have until I break out the numbers!! Under 700 yds and light fast beats slow and heavy almost everytime. With less recoil as well.

 

[Ram94]

I get that line of thinking. I also still think that bullet drop is less important than energy and velocity down range. Sure, the heavy bullet will drop quicker than the light bullet but the heavy bullet will carry its velocity and energy further out and hit harder. Dial for the drop. Carter also mentioned the wind bucking advantage of the heavy. Staying under 350 yards, sure the light bullets still have plenty of punch but it dies off very quickly past that.


I also think the heavy, high BC bullets perform better at close range being pushed at non-magnum speeds as compare to not being able to use them for anything within 300 yards or the bullet explodes on impact when using that same 162 gr in a 7RM vs a 7mm-08.

It is great that there are so many options to work with and pick what suits a person best though


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[wind gypsy]

It depends on what numbers matter to you. Flat shooting is important if you are more likely to be in situations where it is difficult to get accurate ranges or are a MPBR guy. Wind drift is more important if you are likely to get accurate ranges and aren’t a MPBR guy.

Unless you’re going to fill an arc all of this is probably just mental masturbation. I only shoot 1-3 big game animals a year with a rifle but I have yet to kill one that I wouldn’t have had the same result using any of my other hunting rifles.