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

Keith,were you running 26" barrels with the STW?

25 1/2, 26, and 27's.

Thanks!

Keith;

For a 26" barrel what sort of velocities are you running with a 160 gr. or 175 gr. bullet?

I worked up a load with H1000 with the 162g SST when I first got the 27" barrel chambered, 3350 was the accuracy node; never shot the 175's.

I have a minimum SAAMI Match chamber, neck dia .002 over loaded dia, .2845 throat, zero freebore, 1 1/2* leade angle.

Winchester brass is the only brass that is tough.

Normally I shoot the 140g Nosler Combined Technology bullet at 3650 out of the 25 1/2" barrel using IMR 7828 with 215's, bullet seated to just barely touch the lands.

My brother's pac Nor three groove 27" barrel is so fast, I won't even quote the velocities using the 140g C/T bullet. Deer never take a step when hit with these speeds, in otherwords, all we have ever had were bang flops in 50+ deer killed.

Keith-if you don't mind how much 7828 are you pushing that 140 with?

Thx

Dober

Mark, there is a huge difference in loads between a 140g Barnes Tripple shock, the 140g Nosler Ballistic tip, and the 140g Nosler/Win Combined Tech bullet.

The C/T bullet does not build pressures anywhere near as fast as other 140's and I have been able to push it faster with out pressure issues.

Large sloppy factory chambers change the ballistics on this cartridge tremendously vs a Min spec chamber with +.0005 over bullet dia throat and minimal freebore.

For your rifle, you will just have to work up a load, stopping when you see pressure issues...you are a very experienced reloader.

I use Win brass since I can no longer get PMC 300 Weatherby brass to make these cases out of.

I also had excellent accuracy and velocity fireforming Rem 300 Weatherby brass with the 140's, but had to throw the brass away after fireforming due to enlarged primer pockets. If I knew how much bigger the Win Mag primer was, I would have kept the Rem brass for another couple of firings.

No problemo, for the most part I only run 7828 in my Mashburn and dats why I was curious.

Thx
Dober

Very cool writings on the old Mashburn. I have a few of Bob Hagels books out here. I have read them from cover to cover a few times over the last 15-16 years.

I have a 7WSM and 7 Rem Mag. As much as I would love to have another 7mm, the 7WSM and 7 Rem Mag will do mid 2900's with the 175 PT's and about 3100 with 160 AB's. I know the Mashburn really has a big benefit with the longer neck, but with the Model 70 7WSM, I can actually load the bullets for it out to around 3.00" so it gives me a little room to run. I haven't messed with the 7 Rem Mag in a long time, but I have a ton of 175 PT's, so I think when I get back home, I am going to bolt on the new B&C Medalist and see what it does.

Thanks for the reading, it was great.

Beretz: With guidance from Dober and Docbill on here,plus reading about everything Hagel and Page said about the cartridge,I built a 7 Mashburn Super about 2 years ago now.

I have been very happy with it,and have found the case easy to work with and a slight tick up from the smaller 7's when it comes to the heavy 7mm bullets many seem to like today.

There is no practical reason to have a Mashburn today, and put up with the inconvenience of the wildcat,especially since the gains over common factory stuff like the Remington,Weatherby,or WSM are only in the 100-150 fps range.

OTOH, if you want something a bit different that really works with heavy bullets,have an interest in cartridge history and development,like wildcats, and are bored to tears with "common" 7 mags,the Mashburn is a fun project that delivers the goods.And after you have one, those "other" 7 mags may well cease to have a reason for hanging around....they won't be needed.

After all, this is, or should be about fun and games anyway.

I'm gonna have to have a Mashburn, just cause Bob had one!

I'm going to use 160 Partitions in my Mashburn this year in honor of Bob.

I had one built last year, mainly due to Bob's never ending praise of the cartridge. Not my first wildcat but one of the easiest I've had to work with. As I told him in our frequent conversations, while I'm satisfied overall with the rifle, I suspect mine has a somewhat slow barrel. I've used Hornady, Norma, Remington and WW brass and none will allow me to get 3200fps with 160gr bullets and have any sort of case life. 3200 or more and primer pockets cease to hold primers after 3 shots at most, and my chamber has quite a lot longer throat than his. Given my experience with just my own rifle, I'm not so sure there is anything to gain over a 7mm Wby.

Way over book max load, bug hole accuracy on top end pressures.

I have a reamer that I bought when Bob helped me build my Mashburn and can supply a dummy round seated to Bobs specs.
If anyone is interested, you pay shipping both ways and if your smith screws up it needs to be replaced. I also reserve the right to refuse.
I do miss hearing Bobs opinions.

Amen to that Les. I cannot wait to get the new MSM out and shooting. Bob had a huge part in my current one (who am I kidding, I just copied his! )

Also, that is very cool of you to lend the reamer out. That is the spirit with keeping the old Mashburn alive and kicking.

"Sho, got that right."

John, what powders were you using with the 160s. A buddy of mine who shot side by side with me had a KS 7 Rem Mag that was rechambered and couldn't do much more than about 3150 without drama in his with anything. He tried Retumbo, H1000, H4831.. His gun, rechambered with another reamer just wouldn't do it. 24" barrel, same as mine. We never really "figured" it out. Bob, myself and another fella ran almost the exact same loads of H1000 (75.5) in Winchester and Hornady cases and got right at 3200 day in and day out. I couldn't wear out my Hornady cases.

Mine was a rechambered mid 90's Model 70 7mm Rem and it was set up to make a 160 AB touch the rifling at 3.605".. Same reamer I used for the new one I just put together.

And I will never say the Wby isn't GREAT, cause it really is, but it gets it speed with the freebore, the MSM doesn't have it. I am also not saying freebore is bad at all, I just prefer not to have it if possible.

I have been using RL-25 in my Mashburn for years. 76 gr gets me 3275 with good brass (Federal match .300 Win) life and Hornady 162 Interlocks. I think that this a little too high pressure so am backing down to 74-75 on my next load session. I would try RL-26 if I was going to work up a new powder and will when I use up the 3 lbs. I have on hand.

I once considered a Mashburn. But, my 7 Wby meets all of my needs. I honestly dont see how it could be improved or superseded.