Home Forums Hunting & Shooting Custom Rifles & Wildcats The 7mm Mizzum

The way Rcamuglia runs his .264 WM, he's nipping at the heels of the 26 Nos and with less case capacity. He's using RL-33 instead of 869 or 872 like I use in my 26. I'm burning a good bit more powder for only marginal gains over his top loads. I know, I know, case capacity rules but there are limits on how much one can squeeze out of a round. Some accuse him of running excessive pressure, but he seems to know what he's doing. I've pushed the 26 to pressure signs without that much gain in performance.

It seems to me, as overbore capacity increases, efficiency drops and reloading for top performance in some of those mega rounds can become a challenge. Data I've seen from even bigger 6.5's isn't as impressive as case capacity would indicate. The new 6.5 Wby edges the 26 Nos by a little, burning more powder and using freebore. The 6.5 RUM and STW are more examples of diminishing returns, IMO.

I know 7 mm's with similar case capacities aren't as overbore as 6.5's and probably not as finicky.

I noted all that to say, the 28 Nosler premium in performance over the 7 mm Mizzum comes at a price some may be unwilling to pay. I can't argue with that...

DF

DF: Rick knows what he's doing....Dave 7mm,too.

Both are experienced hand loaders and match shooters and whistled through case forming,finding pressure, and "nodes" at distance so fast it made my head spin. They both demonstrated how easy it can be. As I recall both were mostly "done"in 2-3 range sessions. These boys don't screw around.

Rick taught me something when he bumped into a case problem which he solved quickly. Done.

I never recommend the round because it's a wildcat;most people are turned off by making cases. Understood. They are far better off with a factory offering.There are plenty of good high capacity 7mm's out there, the Nosler among them. No need to wildcat a Mashburn.

But if you do, it'll perform well against any of them.

Thanks Bob.

My main point, bigger isn't automatically better, or more of these mammoth, overbore rounds would have caught on, which they haven't.

Efficiency, at least to me, is a big deal. Diminishing returns are just that, diminishing returns...

Balance is a big deal, at least for me.

I think the 26 Nosler is on the edge and for sure the new 6.5/300 Wby. I find myself working more with my 6.5-284 and 6.5 Creedmoor. I still like the 26, just have other projects ongoing that do what I need them to do. I don't have to burn 90 gr. of powder every time I shoot something...

My 6.5 stories are off the 7 mm topic, used as examples of what I'm seeing.

DF

Tested a 28 Nosler a couple months ago. Didn't have time to test a zillion powders and bullets, but did test a few, and the best load was 160 at just under 3350 fps, using published data with Norma 217. That's from a 26" barrel.

There were zero "pressure signs" but I am sure the load could have been pushed some more without encountering any, since SAAMI maximum pressure is 65,000 PSI and pressure signs don't usually start showing up until around 70,000.

That's moving the 160 grain bullet right along.

That would be a sweet rifle. I need to resist.

Thanks JB

That's fast!!

Granted, it is fast.

What do you reckon Nosler's "flat out, lights out" Herd Bull MPBR is advertised at?

Don't know how Nosler measures PBR,but probably so close to the 26 Nosler you'd be hard pressed to tell the difference.

I just ran the quick and dirty numbers through a ballistics calculated, with the 160 AB at 3350. From a 300 yard zero the drop at 400 yards is 7.8"; 13.5 at 450,and 20.6 at 500. That's "flat" for a BG rifle and bullet.

In comparison I ran the numbers for the Mashburn with the same bullet at 3200 ( I would call 3250 as top end). From a 300 yard zero the Mashburn drops 8.6 at 400; 14.9 at 450,and 22.8 at 500.

We can play with vital area numbers and come to our own conclusions. The differences exist but are not great.

Keep in mind the Nosler numbers are from a 26" barrel and the Mashburn a 24".

I bet if we fed the Mashburn a 162 Amax there would be no difference at all....but we won't go there. Just a thought.

Ever run the numbers using the 150 gr Nosler LRAB Bob ?

No RD I never have.

To be honest I was thinking that 28 Nosler would match up well with the real heavy 7mm bullets,say nothing less than the 160's 162's...the 175-180's...maybe even the 195 Berger if you're inclined that way.

The case has the capacity to really drive those heavy bullets and I think that's where the advantage is.

Anyway that's how I'd go today. I shoot the 162 Amax a lot in the Mashburn but have yet to use anything less than 160 in that case.

Makes sense. Reason I asked was because the 150 gr LRAB has a higher BC than the 160 gr AB. The 168 gr LRAB's BC is off the charts. I'll bet that you can drive them faster due to the shorter bearing surface on the LRAB's.

RD: That case has enough capacity to drive any 7mm bullet fast!

And the heavies will outpace the lighter stuff at distance. It's a long range cartridge. Might as well take advantage of all that capacity.

My own half-assed rule is that if a cartridge will drive bullets substantially over 3200 fps, I figure I will reach for the next size up. But that's just me.

Lately,if I want to know if a magnum capacity 7mm shoots well, the 162 Amax is the first bullet I grab to try. I have never killed anything with them, but to 600 yards(as far as I can shoot here regularly), it out paces everything else that I have tried.

Which isn't everything mind you...

But that's the beauty of those LRAB in that you can run either the 150 or 168 LRAB and still have super high BC's and drive em fast too. I'm a deer hunter so I wouldn't need to use a heavier bullet than either one of those. Might be a little less recoil too using the lighter slugs. One of the loads on Noslers Load Data site calls for 78 or 79 grs of IMR-7828ssc that will drive those 150's at over 3300 fps whereas a lot of the other loads that get top velocities are using 90+ grs of powder. More muzzle blast, throat wear and barrel wear I'd imagine pushing 90+ grs of powder every time you launch a slug down the tube. The standard 160 gr Accubond has a BC of .531. The 168 gr LRAB has a BC of .652 which I believe is higher than the (162) AMAX's. If I were chasing down Elk, I rather be using an Accubond over an AMAX.

If the BC values of those LRAB's were accurate, they'd be a much better alternative than they actually are...

RD: Sure! I see what you're saying.


Nice thing about it is you can run any good 7mm bullet in it.

Tag

Put my 7mm Mashburn Super Magnum (AKA 7 Mashengruber :D) together on an A-Bolt LA. Bartlein light Palma 9 twist 5R. Just bedded it into the factory stock whilst I wait for my McMillan A3-5 to show up. Leupold Mark 4 8.5-25 LR/ERT that was hanging around, EGR 20 MOA rail and TPS rings




195 Bergers

Nice! Are those 300 WM necked down in the photo?

Yes. Run them through the 7mm Mashburn sizing die (I used a Redding Type S FL Bushing Sizer)

Next, either load bullets like BobinNH does to fire form, or use the Cream of Wheat method like I did to save barrel wear. After the COW method, my shoulders were still .004" short of fully formed.

Went into development at that point. I would definitely turn the necks after they are fully formed into the shoulder like you see there to eliminate any chance of a donut forming....

For some reason, the necks on those appear longer than the 300 WM ? Trick photography ? My eyesight outta whack ?