View Full Version : 7 by 51

Doug Casner
04-20-2011, 11:15 AM
Got a question. Would my old .284 be a 7x51 in mm? Was the .284 made on the .308 case? I dont have a way of measuring mm. Thanks Doug

04-20-2011, 11:44 AM
Not enough information to give any kind of answer. What is your old .284, make, model, approximate age, etc.

Roger T
04-20-2011, 11:46 AM
The 284 case has the same rim .473 dia (rebated) as the 308 but the case itself is completely different, base dia is a nominal .501 vs .470 for the 308

Doug Casner
04-20-2011, 12:00 PM
My .284 is a 88 pre 64. I guess what I was wondering if you could neck down a 308 to 284 and fireform it in a 284 chamber then have a .284 win. The 284 may have a different size head and extractor groove I know its a bigger case body. Would a 308 blow out that big? Just curious. Doug

Roger T
04-20-2011, 12:08 PM
NO ...Don't even THINK about it....ALL sorts of BAD things will happen

Doug Casner
04-20-2011, 01:04 PM
Thanks guys, I didnt know how much brass would expand without splitting. Ive heard of it being done 308 to 243 but that might have been bull. It was from a guy that was too tight to buy brass and found some 7.62 and necked it to 243. That was probably bull. Doug

04-20-2011, 01:32 PM
Hey Doug,

Making 243W brass from 7.62mm is very common since they are basically the exact same case, only the neck diameter is different. The first wildcats leading up to the 243W were made from arsenal brass and later from the new 308W brass.

Don't try to make 284 Winchester brass from any other case. You can still find new 284 brass.

BTW, for those who may not know this, the wildcat HBR cartridge, 30 Fat Albert, was based on a shortened 284W case. Some shooters made their brass from 308W. It requires an expansion of .030" above the solid head but no one ever reported blown cases, AFAIK. I had one for a while. Not recommended for girly-men.


Charles E
04-20-2011, 07:33 PM
Don't try to make 284 Winchester brass from any other case. You can still find new 284 brass.

Well, you can sort of make it from 7.5x55 Swiss brass. Problem is the head is .492 with RWS and .4905 with Norma -- you get an alinwa type fit. You can maybe make it from the 9.3x64 Brenneke case, might be a touch too fat.

All this from when Bill Shehane and Dave Tooley were trying to get a good 6/284 for Bill. They went with the Swiss case, then wound up getting a new reamer anyway.

So it's kinda like Ray said -- anything else is harder to get than the .284.


Oh, and the 7.5x55 does not have a rebated rim, so if your bolt recess is deep, another problem even if you turn the rims.

jackie schmidt
04-20-2011, 09:51 PM
This is some sort of joke, right?.......jackie

04-21-2011, 09:52 AM
All this weirdness and no one has has tried Reloader 17 in 8 x 57 Mauser ? ;)

Joe Maisto
04-21-2011, 08:02 PM

Leave it alone! You already have my favorite meat gun, as I've had three of them, one in a Mod. 100 carbine, 2 in an 88.
Nothing faster in the woods ( for me) to get on an animal. It simply fits me as no other hunting rifle has. Often times I have intentionaly closed my eyes, shouldered the rifle, opened them, and I'm looking right down the peep sights.
And...they are worth a bunch of money ! But it kicks like a mule on the bench.
For what it's worth, all bullets do not work well because they need to be seated so deep for the magazine. My favorite was Speer. They retained their dia. over a longer distance than some others. So did the Norma bullets of yesteryear.

Doug Casner
04-22-2011, 11:27 AM
Joe, Im not gonna try to make any cases for it. I was just curious. It sounds like its a varmit all its own with that rebated rim deal. Where does it headspace? My dad got it new when I was a kid. Its not goin anywhere. He said something about the mag. being short you had to seat the bullets deeper than you wanted to. He killed some deer with it. I ve never shot anything with it . Its got an old Lyman 4x on it. Neat ole setup. Thanks for the replies. Doug