I have a model 70 short action donor. I am leaning heavily on the .284 Winchester. With a 26 inch tube i think it can do anything the 280 remington will and can get close to 30/06 ballistics which i am pretty familiar with.

My question is regarding overall length. There are some fabulous bullets on the heavy end with some incredible ballistic coefficents. In order to push these bullets a faster speeds one will probably have to seat them out a ways in order to get as much powder capacity as possible. My question is how far out should one go? What can i possibly get out of the 2.8 inch max length? Can i get 2900+ from 150-160 grain bullets?

Without switching to a magnum bolt, the 284 looks like a front runner to me. Other possibles would be 308 winchester and 6.5-284, but barrels burn out a little faster when one starts necking down. Any suggestions?

my little winchester classic compact model 70 in .308 is a wonderful little gun, with its 20 inch barrel (19 inches sticking out of the action and about an inch inside the action). It was made for the light carry and is just right for that task.

I don't know why one would want to put a 26 inch tube on it and gain 200 feet per second but lose that compactness. I doubt very much if any animal ever shot properly would know the difference between a 165 grain nosler 30 caliber nosler at 2600 fps mv and a 150 grain 7mm at 2900 fps mv. If you want the long barrel, get the long action as well and go with the 7mm Rem Mag.

You'll find that the 24" bbl will probably give you all that you want. The 22" bbl was standard for most rifles, except for the BLR lever gun which was 20". Its a great all-around cartridge that will work through short actions...and, many a gunsmith could make your magazine just sufficiently longer to seat the bullets out where you want. Good Luck on this project and keep us informed.

257R,

your M70sa should have 3.080"(78mm?) magbox, perfect for .284win
Why winchester never brought out a run of .284win rifles on that short action Ill never know,they surely would have had more than a few takers and a great revival oportunity for that cartridge.
It would be super in a stock like this:
HillCountryM70stock I dont think it could get much better for m70-284fans.

Load up a 154interbond@2900 and your ready for just about anything the 284 win is good for near or far.
Outside of that,if you dont need that much power or desire so much weight, you could go a shorter trimmer barreled 7x57 with a lighter McmillanEdge, that would make a very nice easy carry rig.
Leupold 2.5-8x leupold DD bases&Superlow rings smooches beautifully into the action.
Im not against longer barrels but I like 23-25" for a 7x57,284win varying the length&dia. to siute the balance of the rig depending which stock one chooses.
cant really go wrong with a #1-24"for 7x57 or .284win.

My personal 284 has a long throat and longer OAL cartridge length (3.100) but was done on a 1909 Argentine. I shoot the 160 Barnes and luv it. You could possibly lengthen the M70 if necessary.

My donor gun is a Winchester 70 XTR featherweight...previously a poor shooting 257 Roberts. I took it apart, and the magazine seems to be 2.85 inches max. Also the bolt stop is a limiting factor. Do i need to go anything bast 2.8 OAL to get maximum performance out of say 150gr+ bullets? I know barnes bullets are superior bullets, but are long for their weight, the 162 AMAX is also a very long bullet. Thanks for all the advice...

I think your Winchester has a block in the rear of the magazine box. Check to see if it does and let me know. It is a simple matter to lengthen the box by shortening that block. I just did a 257 roberts custom for a client that wanted to load 117 grainers a little longer than normal. It is a simple matter to grind a bit from the bolt stop.

I have a Sako L579 in .284 with a 2.8' oal magazine. 2.8' absolutely sucks for a .284. I wish I had it chambered in 7-08. So, if you chamber for the .284 i highly recommend you make sure you can lengthen the oal, or you will not be satisfied.

This reminds me that I need to see if my Sako can be lengthened.