SHERMAN MEGA LINE

Hopefully this is in line with forum rules (sorry about earlier; I simply NEVER do social media or post online, so I am a bit clueless about protocol).

If any of you are in the Central Texas area and want to chamber a barrel, I will make whichever reamers I have available (under proper supervision, so they don't get ruined). Sounds like, within reason, Bamban (Nez) will help you ream in his shop. I will, as well, but I suspect he is more experienced with chambering. I dislike renting reamers or borrowing someone else's since I want to be self-sufficient. So, I will be purchasing the reamer/go gage and resizing die for whichever cartridge(s) I end up going with. It will probably be the 7-Mega, but there are other cartridges that interest me as well.
 
Need some help on selecting two cartridges.

Rich has been generous with his time and has agreed to provide some more detailed information regarding his designs, so I don't want to bother him further. However, while I am waiting on data, I would like to seek your opinions on what Sherman cartridges to pursue. Hopefully, this will kick off a significant discussion. I am genuinely seeking input and not 'humble bragging' with the post.

Here is the storyline so far...

I am building 5 bolt action rifles, with the support and instruction of a well-known marksman and gunsmith. I am fortunate to be in that stage of my life where I have enough disposable income and time to pursue my hobbies. This is not an idle, theoretical debate - I AM building all 5 rifles; the only question is what they will be...

Rifle 1: This one is essentially complete. It is a Bat-M (long) action (single-shot) in a Cerus F-Class walnut stock and a Bartlein Heavy Varmint SS 29" barrel chambered in 6-Dasher. Although I am not, personally, currently able to shoot at the level, this rifle is CAPABLE of holding its own in international F-Open competitions. I can easily chamber another barrel (perhaps 300 WSM or 7 SAUM) for the rifle.

Rifle 2: I have all of the components, but I have not yet barreled or bedded the action. It is a Tuebor titanium (short) action (custom, single-shot) in an X-Ring cherry stock and a Bartlein Heavy Varmint SS 31" barrel to be chambered in .308 Winchester. This will be a competitive F/TR rifle in local, national, and international competitions. Again, I am personally not currently able to shoot at this level, but the rifle is CAPABLE of holding its own. This is pretty much dedicated to F-Class F/TR competition with the Berger 200.20x bullets.

Rifle 3: This one is not really up for debate, since I have invested a lot of money in components and reloading equipment/gear. It will be a Kelbly Prometheus (long) action in a Woox Furiosa chassis (Hawkins DBM with Win Mag magazine) and a Bartlein Carbon 29" barrel to be chambered in 300 Win Mag. The idea is to have a medium-weight rifle capable of hunting anything in North America and a 'fun' plinker for long-distance shooting. I already own everything, including lots of Peterson brass and good bullets' for this rifle.

Rifle 4: This is one where I need help. I want a high-end, lighter-weight hunting rifle that I can use in the Western US and Canada to hunt large game, primarily Elk and Moose. I also want it to be fun for long distance target shooting. It will be a Kelbly Nanook lightweight (long) action in a beautiful (relatively light) Cerus GT-Hybrid Maple stock (Badger DBM with appropriate magazine, up to CIP) and a carbon-wrapped (either Bartlein or Proof) 26" barrel. I am torn between the Sherman 7mm-Max or the 280 Sherman (based off the 280 AI cartridge). It is a long action, so the question of what magazine will work is paramount. My personal aesthetic preference is for the 280 Sherman (I like long and sleek more than short and fat) but my teacher is a SAUM guy (so the 7mm-Max is his preference). What do you think about the 7mm-Max versus the 280 Sherman vs just a straight-up 280 AI?

Rifle 5: I also need help here, although I am a bit more focused. I want the 'ultimate' flat-shooting rifle for long-distance hunting and ELR target shooting. It will be a Kelbly Prometheus (long) action in a Woox Exactus chassis (Hawkins DBM with long-action or CIP magazine) and a Bartlein SS Sendero/Remington Varmint 29" barrel. I am torn between the 7mm-Mega (based on the 300 WSM cartridge) or the 28 Sherman Magnum (based on the 300 PRC cartridge). The chassis and action are long (not up for debate) and my personal aesthetic preference is for the 28 Sherman Magnum but, again, my teacher is a fan of short and fat cartridges (so the 7mm-Mega is his preference). What do you think about the 7mm-Mega versus the 28 Sherman Magnum?

I don't want three cartridges that basically mimic each other (eg. 7mm-Mega, 300 Win Mag, 28/30 Sherman Magnum). Since the 300 Win Mag is a given, I want a non-magnum cartridge and a magnum cartridge. That is how I ended up with the choices above: 7mm-Max vs 280 Sherman and 7mm-Mega vs 28 Sherman Magnum. I am fine with any permutation, although aesthetically I prefer the longer cartridges. The action lengths are set and I cannot change them - we will have long actions. I am a little worried about the short, fat cartridges for feeding in DBMs (again, not negotiable, since that is what I have). If you suggest a short, fat cartridge then, please, also suggest the magazine that will feed them in a DBM stock/chassis.

I apologize for the long post, but I hope this is an interesting question. To be clear, I WILL be making this choice in the next week and ordering accordingly, so it is not a theoretical question.

Regards,
brittf
 
So it took me a 5 long years to put together a 7 max. It's not a full blown custom like yours but I can say as soon as I pulled the trigger I was in love. It feeds with out issue from a tikka factory long action mag. Mine are loaded long.
The max is a blast to shoot and the decrease in recoil for me was a plus, I have other heavy recoiling calibers so it's nice to have a rifle with the performance that it does with out the recoil.
I didn't get the crono out when I was breaking in the barrel but I'm expecting 2850-2900 with n570 which I have a surplus of with 180-190 grain bullets.
 
So it took me a 5 long years to put together a 7 max. It's not a full blown custom like yours but I can say as soon as I pulled the trigger I was in love. It feeds with out issue from a tikka factory long action mag. Mine are loaded long.
The max is a blast to shoot and the decrease in recoil for me was a plus, I have other heavy recoiling calibers so it's nice to have a rifle with the performance that it does with out the recoil.
I didn't get the crono out when I was breaking in the barrel but I'm expecting 2850-2900 with n570 which I have a surplus of with 180-190 grain bullets.
I'm at 2900 with a max load and the 175 eld-x using VV N565, out of a 20" 7.5 twist barrel. What is your barrel length?
 
Any reason to not consider a 338? The BC's really increase, especially with solids. Since the actions you chose do not offer lapua boltface, and you want to mag feed, the RUM case is out. But the PRC improved and the Mega are both considerations. I'd probably go PRC improved, since you have a true long action, and do rifle 4 in 338 and rifle 5 in 7mm.
 
So it took me a 5 long years to put together a 7 max. It's not a full blown custom like yours but I can say as soon as I pulled the trigger I was in love. It feeds with out issue from a tikka factory long action mag. Mine are loaded long.
The max is a blast to shoot and the decrease in recoil for me was a plus, I have other heavy recoiling calibers so it's nice to have a rifle with the performance that it does with out the recoil.
I didn't get the crono out when I was breaking in the barrel but I'm expecting 2850-2900 with n570 which I have a surplus of with 180-190 grain bullets.
I suspect my ignorance will show with this post, but I am not familiar with the Tikka stuff. I am familiar with Remington 700 clones and Badger/Hawkins DBM bottom metal using either AICS, Accurate, or MDT metal magazines. Will the Tikka stuff work with my M5 inlet, Badger DBM bottom metal, and a Remington 700 clone?

My fear in taking on the 7mm-Max (or any SAUM or WSM variant) is the 'internet-driven worry' that they do not feed well in long actions.

MDT makes a purpose-built SHORT action magazine for SAUM/WSM that limits COAL to 2.955" but my stocks and actions are LONG and I want a longer COAL anyway. Defiance has developed the mid-length 'XM' action but, again, that is not in the cards since my stocks and actions are long.

So, back to the question of how to successfully feed 7mm-Max, 7mm-Mega, or any SAUM or WSM variants successfully in an M5 long-action DBM magazine?

I get worried because when I spoke at length with MDT I got the answer "we don't make a long-action magazine that works for the WSM or SAUM cartridges, but check with Accurate Mag because I think their 300 RUM will work." Then, when I talk with Accurate Mag, I am told that I should use their SSSF long-action .308 magazine which, by the way, isn't out yet. Then I call Hawkins and they say use a 300 Win Mag magazine and bend over the feed lips a bit. Then, after spending a long time on the phone with the man who started and runs Badger Ordinance, I was flat out told that SAUM and WSM cartridges are a problem with Badger M5 bottom metal and AICS magazines. When I brought up Accurate Mag and ADT, he said he only recommends AICS magazines (from a build quality perspective) and has no comment on other magazines. AICS does not have a solution for SAUM or WSM cartridges. These are four different, conflicting answers and all a bit messy.

One purpose-built system is Hawkins Hunter DBM that fits in an M5 inlet. They have a long-action version and 'promise' that later this year they are releasing a spacer for their Hunter-specific magazines that will reliably feed SAUM and WSM based cartridges. However, these are relatively flush-fit PROPRIETARY DBM and magazines from Hawkins (so, no other source) and can only hold 3 rounds IF AND WHEN the spacer is released.

So, another wordy post :) I can't help myself, since I am a professor and tend to be on the 'annoyingly precise' side of things.

Can anybody help me out with my basic question?

Thank you in advance for your time.
 
Any reason to not consider a 338? The BC's really increase, especially with solids. Since the actions you chose do not offer lapua boltface, and you want to mag feed, the RUM case is out. But the PRC improved and the Mega are both considerations. I'd probably go PRC improved, since you have a true long action, and do rifle 4 in 338 and rifle 5 in 7mm.
That is an interesting question. It WOULD differentiate my cartridges better if I had one 7mm (SAUM-based 7 Max, WSM-based 7 Mega, 06-based 280 Sherman), one .308 caliber (300 Win Mag), and one .338 caliber (WSM-based 338 Mega, 06-based 338 Sherman, or PRC-based 33 Sherman Magnum). The bolt face is not a problem, since I can still change that (my Kelbly's are in queue and due in late March or early April).

I am open that that idea. Comments?
 
MDT makes a 3.56" COAL magazine that I use in my Vision chassis for my Tikka in 6.5 Max. These magazines are like butter with the Max (saum imp).

I asked about bolt face because the larger cartridges that still fit in a long action magazine (norma improved / lapua improved) use the 588, and those are not listed as options on the kelblys you've selected. The RUM has that capacity in a normal magnum boltface, but you'd be running 4.2" with the big stuff in an Edge, so definitely no mag feeding.

Back to selection, you should use the pdf on Rich's site to figure relative velocities for his cartridges and run ballistics on the cases and projectiles that interest you. I generally compare 500,1000,1500, and see where each goes trans-sonic, for the case and projectile I'm considering. Don't forget about the Badlands solids... and don't forget about barrel twists - you can thread the needle to shoot both solids and the heavy cup and core.
 
MDT makes a 3.56" COAL magazine that I use in my Vision chassis for my Tikka in 6.5 Max. These magazines are like butter with the Max (saum imp).

I asked about bolt face because the larger cartridges that still fit in a long action magazine (norma improved / lapua improved) use the 588, and those are not listed as options on the kelblys you've selected. The RUM has that capacity in a normal magnum boltface, but you'd be running 4.2" with the big stuff in an Edge, so definitely no mag feeding.

Back to selection, you should use the pdf on Rich's site to figure relative velocities for his cartridges and run ballistics on the cases and projectiles that interest you. I generally compare 500,1000,1500, and see where each goes trans-sonic, for the case and projectile I'm considering. Don't forget about the Badlands solids... and don't forget about barrel twists - you can thread the needle to shoot both solids and the heavy cup and core.
Which MDT magazine? The only two I see for 300 WSM/6.5 PRC are for either the XM (mid-length) or the short action. When I talked to the service rep, she said they don't have any long-action magazines that are explicitly for the 300 WSM/SAUM. I believe you, I just want to check it out in detail before I order my reamer and brass and dies.

The Kelbly's Prometheus long action comes in .308, .532, and 338LM bolt faces. It is easy to overlook, but if you go to 'Products' then 'Actions' then 'Steel Actions' then 'Prometheus' you will see the bolt faces for long actions listed on the right hand side.

Not much reloading info for the 338 Mega or the 33 Sherman Magnum.
 
MDT, just select the 3.56 option - perfect for Max/Mega:
https://mdttac.com/300wm-mdt-metal-aics-magazine/

Great on the Prometheus - I see it now, I glossed over it because it says "338" lol

So, really, you just need to decide what ballistics are worth to you... Barrel and brass life plus powder per charge vs how much better wind and/or energy at given distances. For rifle 5, you said ultimate flat shooting... 7 lapua Improved? Or is 338 Mega with Badlands 285's good enough...

My purposes are practical, i.e., to ethically put an animal down, repeatably and controllably, from a cold bore. So all of my decisions are based on that. I don't own a 6mm simply because the ballistics are inferior to 25 and up, and for my purposes, the reduced recoil or component wear doesn't outweigh the performance deficit.

So, for my purposes, and from my research and personal anecdotal data, it seems like the 6.5 Max is indeed a max for that caliber, at least with today's projectiles. I expect the 7 Mega to be very close as well. By max for caliber, I mean the point at which the benefits from more capacity diminish to negligible (for my purposes) while component wear goes exponential.

I really like the 338 Mega from the limited data thus far. I'm thinking about 338 Mega barrels for both of my 6.5 Max rifles - one a short light hunter, and the other a longer, heavier chassis rifle. The efficiency looks great from a powder/velocity standpoint, and the ability to use a shorter barrel is also a plus. But, it won't do what a PRC Imp would do, and certainly wouldn't hold a candle to an Edge or Norma Imp or Lapua Imp. Decisions!

*Edit - the projectile BC's available per caliber help to put velocity in perspective - my go to load for my 308 is a 208 eld-m @ 2640. Look at the velocities required of a 6.5 with a 156 to match that. Now look at the 156 with a Max case, @ 3160. What velocity is required of different 7mm or 30 cal projectiles to have equivalent wind at 500,1000,1500... And which cartridges/projectiles get you over 2K yards supersonic... You start building a nice matrix and decision tree. Then factor in energy, and it becomes pretty easy to see where you want to be for each rifle/purpose.
 
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