6.5x284 questions

[model 12 toby]

What is the longest overall length of a loaded round and what is the difference between a 6.5x284 Norma and a 6.5x284 Winchester?

 

[284driver]

The over all length is dependent on several things. Are you feeding from a magazine? What length is it? How much freebore does your chamber have that's an important factor to be able to answer your question. The 6.5x284 Winchester designated the 284 Winchester being the parent case.
6.5x284 Norma is simply a standardized version of the wildcat.

 

[Laurie]

6.5x284 Norma is simply a standardized version of the wildcat.

Close, but not 100% so. To be listed in SAAMI or the European CIP cartridge list, (the latter applying here as it was Norma a Swedish company which registered the cartridge), many things are mandatory including rifling twist rate, maximum cartridge overall length, chamber throat (freebore) specifications, different bullet weight loadings and their MAPs / velocities from a 'standard length barrel' listed solely for that cartridge ........... etc, etc.

As a wildcat, the 6.5-284 can be any COAL you fancy as skyavv8r correctly says, the chamber can have any freebore that suits your purpose, and rifling twist rate / barrel length etc likewise. When people say '6.5-284 Norma', it means a particular cartridge specification built around 120 and 140gn bullets and with a maximum COAL of 82.00mm (3.228-inches), the barrel throated to suit.

At that COAL, a long action is nearly mandatory - certainly for a repeating, magazine-fed rifle. The original .284 Winchester that provides the 'parent case' was specifically designed to be used in short actions and so had a maximum COAL of 2.800-inches. This pretty well ruined a potentially superb ballistic performer by limiting its usable bullet length and weight, anything much over 140gn in the original 7mm form seated too deep. The case was so useful though, it formed the basis for lots of wildcats and non-standard versions of the original 7mm cal model, principally its use in long-action rifles, chambers throated to suit 160gn and heavier bullets - now discovered by target shooters and often misleadingly referred to as the 'straight 284'.

Of all the many wildcats based on the case, the 6.5mm version was probably the most successful before Norma adopted the concept. As noted, it could have any set of specifications you fancied, but it was correctly called 6.5-284 Winchester back when it was only available as a wildcat. Since an 'official, regularised' (Norma) version appeared, any loading data that refers to it as 'Winchester' means it's a non-CIP form, as opposed to the 'official' Norma form. As many bullet companies did the work in working up loads for their products pre-Norma, they continue to print it under the 6.5-284 Winchester' name, and if they've redone it afterwards might provide two sets of data, the latter listed as 6.5-284 Norma', or maybe only use that form's data alone now.

In theory, the 'Winchester' version name could be applied to any wildcat form, but all the handloading manuals I've seen that use this title list short COALs, at or much closer to 2.800-inch than Norma's 3.2. Assuming that the listed loads don't exceed the Norma Version's maximum pressures (410MPa / 59,450 psi using the Piezo electronic strain gauge system) their data are therefore likely to use lower powder charges than those applicable to the official Norma version as short-throated chambers = deep-seated bullets = higher pressure in any given case + powder charge + bullet combination.

So, if you see any loads data for '6.5-284 Winchester', the first thing to look for is the listed COAL. If it's around the 2.8-2.9-inches mark, it's likely the charges listed are safe, usable, but will not develop full pressures in a 'Norma-chambered' barrel. I'm talking here about powder / bullet company data - the usual caveats apply to 'unofficial, private' data which may or may not be safe depending upon the source.

 

[model 12 toby]

Thanks guys. I just may have to get a long action. Damn it.

 

[284driver]

If you want a repeater and heavy bullets, probably a good idea. I have a 284 on a long action.

 

[JCinCalif]

I built mine on a long action. I'm shooting Berger 140gr VLD's. The LA gives me plenty of room to seat them out where they need to be in my gun. Also, it feeds very well from the magazine.

A great caliber. I use mine to chase Antleope around.

 

[mlj56]

I have ben reading info about 6.5 284 Norma for some time. Finally having my gunsmith acquiring the components for a rifle. So far I have ordered a Defiance Rebel XM action with their XM bottom metal (can handle cartridges up to 3.2 OAL), #5 contour Krieger stainless fluted barrel with 1 in 8 twist (planning on 26 inches), McMillan stock. I have a chamber print of Dave Kiff's no turn reamer - but probably will go with a .299 neck. Dummy cartridges using Lapua brass and Berger as well as Nosler 140 grain accubonds mike out at .294 neck diameter. Plan to use for long range hunting for coyote, wolf, antelope (out to 500 yards). I would also like to wring it out to as far as 1000 yards. Up till now all of my shooting from 500-1000 yards has been with a Shiloh 1874 in 45-2.6. Curious if anyone here has taken Clint Smith's (Thunder Ranch) mid-long range rifle course in Oregon? Also, what kind of scope are people using for long range paper punching? - Mike