- Oct 30, 2004
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7mm Mashburn Super Magnum
- Thread starter SJB358
- Start date
- Oct 30, 2004
- 24,275
- 2,988
- Oct 30, 2004
- 24,275
- 2,988
93 grains of Retumbo was the load I gave to Jim for that 7mm RUM rifle
- Nov 4, 2004
- 25,162
- 8,416
FOTIS":2915xwh6 said:
This.
JD338
That should be a fun one Scotty. I'm going to do a modern version of a old school caliber here soon, 6.5x68 Imp, with a 35 degree shoulder and a lot less taper. It should put me between 300wm and 8mm Rem. mag for capacity with the best brass there is (RWS) and a sharp shoulder so little to no trimming. I'll probably end up doing the 7mm version as well unless Berger finally introduces their 195gr before I get to it. Then I might be inclined to do a 7-338 Norma Imp.
- Oct 30, 2004
- 24,275
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So you just reamed out the winnie 7mm rem mag?
- Thread starter
- #27
Yeah, the Mashurn has no taper to the case, so it takes out what little taper there is to a 300 Win Mag. Seems to be pretty straight forward Fotis. A few I've been corresponding with have just ran the reamer in Model 700's and gone hunting with excellent results. Model 70's require and H&H box, follower and shortened bolt stop (about 50.00).
I wasn't sure if I believed everything I'd read till I loaded a few. The 7mm Rem Mags are pretty cramped with shorter throating and mag boxes. Some have gone the way of lengthening throats and mags and done pretty well, I would rather just try it like this with extra case space and see how well the 7 MSM combo works. Seems like it should be similar to a Dakota in case size which feels like a good place to be.
I wasn't sure if I believed everything I'd read till I loaded a few. The 7mm Rem Mags are pretty cramped with shorter throating and mag boxes. Some have gone the way of lengthening throats and mags and done pretty well, I would rather just try it like this with extra case space and see how well the 7 MSM combo works. Seems like it should be similar to a Dakota in case size which feels like a good place to be.
longrangehunter
Handloader
- Jun 19, 2011
- 1,479
- 7
Sounds a lot like what Dave Tooley did many years ago with the same case, I had what he called the 7mm Boo Boo, which was the 8x68S necked down and slightly blown out, hell of a shooter.IdahoCTD":117e1iv0 said:
I had planed on doing what Scotty is working on now, the 7mm Mashburn Super, but when I found a great deal on a used rifle built by Dave I snapped that up instead.
I remember reading about the Mashburn magnum in bob Hagel's book, Game Loads and Practical Ballistics for the American Hunter decades ago and still have the book, great reading stuff but a little out dated.
- Thread starter
- #29
longrangehunter
Handloader
- Jun 19, 2011
- 1,479
- 7
Tell me about it Scotty. I think I've read that book so many times I could recite it word for word back in the day. Great stories, and very useful information for anyone on the subject.SJB358":ubvi3qf9 said:
Dude, you're always coming up with my all time favorite classic cartridges. First the Newton and now the Mashburn... man, you have the coolest classics of all time!
longrangehunter":1tr790et said:
Case wise it's a lot like what Dave and several others have done but what I really want is a hot rod 6.5mm not a bench gun in 7mm or .30cal like most of the others did. Rich Keyser (he lives in Nampa) did a 257 Banshee probably close to 25 years ago and did a write up on it in Precision Shooting magazine. It was based on a blown out 6.5x68 Schuler case as well. I'd only do a 7mm because I'd have bushing dies that could be used for it and 2 7-300wm's that I could rechamber to it with very little work. I shoot my 6.5 and .30 caliber guns a lot more than my 7's for some reason and I like playing with hot rods more than anything anymore. I just built another 30-338 Norma Imp. yesterday to put a X-caliber brand barrel through it's paces against my Bartlein. It's one of the straightest button rifled barrels I've ever seen but we will see if it shoots. I just got the parts to build a 6.5SAUM for a buddy on Friday. When I can find a Bartlein light Palma barrel I'll build a 6.5SAUM for myself in a short light(ish)(well light for me) package. The only thing I've built recently that isn't a hot rod is a 6.5x47L and I have all the parts to do a 6x47L. I'm just not sure how much I'll shoot them when I have a couple 6.5-300's and .243AI's to shoot. I even have a 6WSM if I want to shoot 105's at 3600fps.
longrangehunter
Handloader
- Jun 19, 2011
- 1,479
- 7
The 7mm Boo Boo I had was in a hunting rifle that I came across while looking for a Mashburn Magnum. I got rid of it simply because the barrel was too thin in my opinion and I wasn't super hip to the work involved forming brass. Although cheaper way back then, the RWS is heavy stiff stuff, it isn't so cheap today, and having only one retailer doesn't help either.
gerry
Ammo Smith
- Mar 1, 2007
- 6,849
- 1,633
Cool round Scotty, like some of you I read about the Mashburn in Hagel's writings as a young guy and was intrigued. With those long 175 gr Partition's he got exceptional penetration on big moose and also took one of the most beautiful caribou I have ever seen with a 160 gr PT.
As a side note I find the 6.5mm Saum very interesting, I do wonder if the data was pressure tested how much lower the reported speeds would be.
As a side note I find the 6.5mm Saum very interesting, I do wonder if the data was pressure tested how much lower the reported speeds would be.
George Gardner at GAP has pressure tested the 6.5saum. It is basically a .264wm because it runs at higher pressure. The brass is tough and many people are getting 10+ reloads on cases. The down side is most reamers require neck turning and doughnuts in the neck do happen and are a PITA. There is a bunch of info on Snipers Hide. I probably wouldn't build one but mt buddy is trading me most of the work for the reamer. If I own the reamer I have to build one :mrgreen: .
- Thread starter
- #35
gerry":l75nhdrb said:
Yup, I've read the same stuff Gerry. I haven't really decided which bullet to start with to be totally honest. A 160 at 3200 seems really good to me. 300 yard zero, 7-9" low at 400 and 18-24" low at 500. That's pretty good stuff in the high country if you ask me. I have a huge pile of red tipped 160 ABs so they might get the nod. Not sure there is a bad choice in the mix. I really liked what I saw from the 150 Swift too. It's got good BC and it should be able to be launched pretty hard. I like the bullet a bunch as well.
- Thread starter
- #36
longrangehunter":1i9e83jo said:
I guess that is one of the reasons the Mashburn appeals to me so much, 300 Win Mag cases are fairly easy to get and don't require much forming to make the MSM. I've got some data for a forming load so we shall see. Most of the guys say the fire forming load is very accurate as well.
truck driver
Ammo Smith
- Mar 11, 2013
- 7,303
- 845
Since the 264wm is a necked down 300wm wouldn't it be easier to neck them up and have less chance on getting a doughnut effect?
- Thread starter
- #38
truck driver":3ggv3ipk said:
The 300 Win Mag is 2.650 so it's a larger case than the 2.5" 264 case. A 264 case necked up to 7mm is the 7mm Rem Magnum.
I haven't seen or heard of any problems with donuts, but I'll let you all know if something happens along the line.
You might have to turn the necks since it uses part of the shoulder to form the neck Scotty.
The 300wm is actually 2.62". The 6.5x68 is 2.679 but just about all of the additional length is in the neck. The length to the neck/shoulder junction is almost the same as the 300wm.
The 300wm is actually 2.62". The 6.5x68 is 2.679 but just about all of the additional length is in the neck. The length to the neck/shoulder junction is almost the same as the 300wm.
- Thread starter
- #40
