Home Forums Hunting & Shooting Custom Rifles & Wildcats 7MM Mashburn Super ????????

I ran a couple of long-throat 7RM's that I hunted and shot with till the barrels wore out.They were set up so that the 160 Partition was seated with its' base was even with the base of the neck.This longer than 30/06 length,but easily doable in a Rem 700 action,or M70 with some modifications.

While still not quite the equal of the Mashburn,this set up ran 160's at about 3125-3140 with 7828;140's did 3300 or a bit under.I never had a problem of any kind.If you do it this way rather than with the 175,and the free bore is cut properly,accuracy will not suffer with lighter bullets.One of these rifles weighed 7.5 pounds;it was a favorite and would make composite groups with the 160 Partition,140 Partition,and 140 BBC you could cover with dimes and nickels.Barrels have all been Krieger 9 twist.

That said, I suspect the Mashburn will get a guy "there" easily,along with the Dakota, which is about the same thing.Both have more capacity than either the Remington or the Weatherby. Agree with Doc that the Mashburn is what the Remington shoulda been.....I mean, they had Pages data for a 22" Mashburn several years before the Remington mag was inroduced.

While I honor Bob Hagel and also Warren Page I would rather not have to fire form belted brass if there was a 7mm factory round thats similar.

I do like the 7mm bore for long range hunting however I am selling my 7mm WSM M70 as its just clunky.

Since I have other 'magnums' I am going to look at the Kimber 84L when it comes out. Since the advent of the laser rangefinders perhaps I don't need an extreme overbore magnum?

Its the rifle more than the cartridge to me.

Sorry about being slow, I am off line after noon CST. Wolfe Publishing has a BIG book of Handloader reprint articles available. It covers a LOT of cartridges. Go to their web site or call them and find it. Bob Hagel has an very thorough article re. Mashburn history/loading in it. Retumbo and RL-25 powders weren't available when Hagel did his article and I believe they are really execelent in this application. I use RL-25. As a reference, I use a current Hornady manual and 7 Roy data for loading inspiration.

As Bob says the Mashburn & Dakohata are about equal. Serious horse power is a right sized package

I suspect not many 'smiths have Mashburn reamers on hand anymore. I called JGS and they gave me a list of people that had bought that reamer and I rented it from a fellow in Oregon. You might call Dave Kiff at Pacific Tool or maybe Fred Zieglen for reamer rental/sources.

The easiest way to make brass is to use a RCBS form die set and start with .300 Win. Mag. I prefer Federal but anyones will do. The original parent case was .300 H&H.

Hmm.....I just happen to have a reamer sitting about 3 feet away from me at the puter...

Nothing like owning your own reamer.

Dober

Oh cripes......... That is information I did not need................. I got a Rimrock stock for a Classic action....and a Krieger #2 9 twist in the safe......oohh, man!

Bob, the brass is easy to make and if you travel and have lost your ammo, you can use 7 Rem.. DO IT!

True story. I was out at the local range one day and there were some 20 somethings out there shooting also. I asked what the gun was and the fellow said that he had inherited it from his Gpaw. It was a 7 mm Mag. He commented that the fired brass looked a little funny. I examined the said brass. He was shooting 7 Rem in a 50's 60's custom Mashburn. Groups weren't bad and I didn't have the heart to explain to the kid. He was happy and wouldn't have understood what I was talking about anyway.

Doc, that's a riot! I never woulda thunk it!

.............175 Partition at 3050....mmmmmm....sounds like an "anything" load to me......

Doc/Dober: Do you need a H&H length action for the Mashburn?

Just say the word and it's coming your way Bob.

Dober

Yes. I have mine on a Rem 700 but any H&H length action would do. Trying to put the 7 Rem in a 30-06 length action for conversion and ammo sales is what big green tried to do and that is how they go into trouble. The option to get Mashburn performance out of an 06 action would be to shorten the body/neck down the .375 Ruger to get the same useable case capacity and have a long neck.

There is no need for an STW/RUM capacity. You get WAY over the hump on the diminishing returns curve.

hmmmmm.

What's involved with using an M70 in 7RM (i.e. standard mag)?

I understand that the M 70 used a full length action and blocked the mag. box back to '06 length. If that is so, then remove the block or aquire a new mag box. You are looking at a COL of 3.565" +/- to get full performance.

If you long load a 7 Rem. you will get within about 50 fps. with a Rem but with less bullet flexibility.

To rechamber a 7 Rm you will need to turn off 1 thread and then run in the reamer. That's all the chamber takes. Magazine length is the other issue.

Consult an expert gunsmith on M 70's for best advice.

Thanks!

Does anybody make dies as a standard production item or is this a special order deal?

RCBS lists the set. Look on their chart and e-mail them as to availability.

I found some dies online. Forming dies for $165...A big 7 sounds fun and for a few reasons the RemMag is not as attractive. I wonder if dies for a 7mm-300 WinMag would be cheaper.

I am wondering, if the neck on the 300 Win is sometimes criticized for being too short, wouldn't it be even shorter if necked down?

One-caliber is often quoted as being the rule of thumb for necks and the .300 WM doesn't quite meet this. With that said I have owned several and never had trouble with bullets moving in the case with the bullet weights I use.

I supect a 7mm-300 would be fine in regards to neck legnth.

It is fine as is it is on the 300 winnie

Dober

I had a reamer made for the 7mm-300 Win and the neck was a little on the short side. It was very easy to load for. I have pushed the shoulder back on virgin 300 Win cases with no need for a form die. I believe the Mashburn had a 30 degree shoulder. If I was creating a "cat" from scratch I would keep the 25 degree shoulder of the Win and have a neck about .300". The capacity would be a little more than the Mashburn. Remember that Page built his last few rifles in 7 Rem Mag. The difference is not too much. It will move the 160's at 3050-3075 fps quite predicably. Pretty darn close and you can actually get over-the-counter ammo at Walmart. Sorry. I know it is common.

My recollection is that Page's Old Betsy was on a std length FN which had a 3.375" box. Hagel used an FN with the 3.58" box. Does anybody know?