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Campfire Outfitter
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Campfire Outfitter
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Hodgdon max load is 59 gr H4350 with 140 gr 2,927 fps 50,000 CUP, but I find the threshold of extractor groove growth to be at 72 gr. I find 70 gr 3.34" Nosler Ballistic tip moly has plenty of safety margin for all my rifles over all my hunting temperature ranges to ensure long brass life over many years. It varies between rifles, but typically 3400 fps over the chrono.
So your "safety margin" load is 11 grains of powder and over 400 fps above book? I am beginning to see how you went through nine rifles.
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Joined: Jan 2007
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Campfire 'Bwana
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Campfire 'Bwana
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A lot depends on how hot you are willing to load. To take Keith's load as an example to compare, I load 70 gr of RL22 with a 150 BT and 150 NPT for a velocity of about 3125. I know I can go higher,likely up to just under 3200 but what for? Accuracy is excellent to 600 yards, and the load will knock the socks off any NA big game. No 270 is going to safely give you 3100-3200 fps with a 150 gr bullet. Many will not do that well with a 130 from a 22" barrel. here's my own velocity thresholds with the 7 RM, YMMV: 140-3200-3250 (yes I have killed game running them clear over 3300). 150- 3150 160- 3000-3100.(Mostly they settle in at 3050 or so). 175- 2900-2950 None of this is anemic When i see these velocities I STOP. You won't find a 270 or 280 that will duplicate them. If you argue with me I will ignore you. Good luck I wish you all the best. I have seen the 7 Rem Mags that give 3200 fps with 160's,and 3400 fps with 140. Those velocities are the province of bigger jugged 7mm's like the Mashburn and Dakota, LRM, etc. I would be very uncomfortable seeing those velocities from a 7 RM. You may not blow yourself up but you are teetering on the edge IMHO. YMMV.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Jan 2007
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Campfire 'Bwana
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Campfire 'Bwana
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Here 's a picture sent by Rick Camuglia. Rick runs a Mashburn with 195's to 1500+ yards. On the left is a 7 Rem mag, in the middle a 7mm Mashburn Super, and on the right a 300 Win Mag. We can easily see the 7 Mashburn and 300 Win Mag are longer. Th mash burn has the longer neck.Hader to see but it also has less taper. It does not look that much bigger but a charge of 75 gr of H1000 does not even come to the base of the neck! Water capacity is 90 gr. How'd that happen? Smarter guys than us worked htis out in the 1950's,and optimized the cartridge to give OVER 3000 fps....with a 22" barrel....with a 175 gr bullet. The most modern 7mm magnums don't really beat those performance levels by all that much. To wildcat the 7RM where you gonna go? Blow it out? it'a already pretty straight. Blow the shoulder forward? That makes the neck shorter than it is which is already a drawback.Compromises bullet seating. Simply put the 7RM does not have enough case to work with if you want the next step up in velocity.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Feb 2009
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Campfire Tracker
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OP
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I am a fairly careful handloader and the 7mm Mag makes me nervous. My last 7mag an early SS barrel Remington that was really clean wouldn't hit 2800 before ejector marks and cratered primers with 175 NPTs and a few feet per second better with 160s. That was with Retumbo.
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Campfire Tracker
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OP
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I played with two Sakos also and they weren't much better, though they were accurate with 160s at 2800-2850.
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Joined: Jan 2007
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Campfire 'Bwana
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Campfire 'Bwana
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I am a fairly careful handloader and the 7mm Mag makes me nervous. My last 7mag an early SS barrel Remington that was really clean wouldn't hit 2800 before ejector marks and cratered primers with 175 NPTs and a few feet per second better with 160s. That was with Retumbo. With those results I don't blame you for being shaky on it. That's pretty freaky but goes to show what can happen to a cartridge when the barrels/chambers, etc et vary so much. Of course you gotta watch RETUMBO.....that shidt WILL jump around on you lot to lot,and gets touchy at top end. We used it in the Mashburn where it recorded some very high velocity but we did not trust it. That's why we use H1000 today.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Jan 2007
Posts: 35,900
Campfire 'Bwana
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Campfire 'Bwana
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Recent 7 Rem Mag play time has involved these rifles: M70 Classic action, Brux #2 9 twist,std that and box. Bansner stock. M70 Classic action, Brux #2 9 twist, std throat.RBorden RR stock, 6X SS MQ Interesting thing is that both these cut rifle barrels will show markedly different max charges than my custom 7 Rem Mag which uses a Douglas barrel, despite throats being more or less standard for all three.
Last edited by BobinNH; 05/15/16.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Campfire Tracker
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Bob you ever play with a 7-300? Seems a lot easier to neck the 300 Winny straight down instead of forming cases for the Mashburn.
I probably hit more elk with a pickup than you have with a rifle. I have yet to see anyone claim Leupold has never had to fix an optic. I know I have sent a few back. 2 MK 6s, a VX-6, and 3 VX-111s.
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Joined: Jan 2007
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Campfire 'Bwana
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Campfire 'Bwana
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Bob you ever play with a 7-300? Seems a lot easier to neck the 300 Winny straight down instead of forming cases for the Mashburn. Bellydeep I have formed cases for it but never chambered a rifle. One buddy of mine on here has/had a reamer. For all practical purposes, that's the 7mm Practical developed by Nathan Foster of NZ, but really it's been around a long time. I like the Mashburn better due to the longer neck, A short neck has been a criticism of the 300 Win Mag, too. But ballistically the Practical and the Mashburn do the same things.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Aug 2005
Posts: 11,364 Likes: 1
Campfire Outfitter
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Put on an 8.5 twist, throat it for 180 scenars and burn H1000. Live long and prosper.
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Campfire Outfitter
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Campfire Outfitter
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My 7mmRemMag reamers are SAAMI dimension reamers, but I load hunting ammo at 3.34" like a 300WM or 30-06. The SAAMI OAL for 7mmRM is 3.29" and I ignore that.
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. -Ernest Hemingway The man who makes no mistakes does not usually make anything.-- Edward John Phelps
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7mm RM on the left, 7mm Hart on the Right. No significant difference in performance.
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Joined: Jan 2007
Posts: 35,900
Campfire 'Bwana
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Campfire 'Bwana
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7mm RM on the left, 7mm Hart on the Right. No significant difference in performance. That's interesting! I guess no one could come to grips that Art Mashburn figured out the belted 7mm long before the 7 RM showed up. They still haven't made anything any better on a belted case.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Jul 2010
Posts: 1,758 Likes: 24
Campfire Regular
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Campfire Regular
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Posts: 1,758 Likes: 24 |
7mm RM on the left, 7mm Hart on the Right. No significant difference in performance. Wow! That looks almost exactly like a short necked Mashburn!
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Joined: Jan 2007
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Campfire 'Bwana
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Campfire 'Bwana
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Only shorter through the body, too.Circus freak. That guy wasted his time and money. He should have listened more carefully to Art, Warren, and Hagel. If you're gonna do anything to make a 7RM easier to work with I'd roll like Rick did and throat one long on a 700 or M70. BTDT.
Last edited by BobinNH; 05/16/16.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Jul 2010
Posts: 1,758 Likes: 24
Campfire Regular
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Bob, are your above 7mag classics using the longer box?
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Joined: Mar 2006
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Campfire Outfitter
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Campfire Outfitter
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Joined: Jan 2007
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Campfire 'Bwana
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Bob, are your above 7mag classics using the longer box? pathfinder they could be H&H length as you know. But both were put together after the Mashburn build,so I had pretty much made up my mind the Mashburn was simply better,and take the 7 RM for what it is. So I left he boxes and throats 30/06 length. Actually both those rifles have been recently sold. I did not see any sense having them around when I have the Mashburn. I am down to one 7RM.
The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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Joined: Dec 2007
Posts: 16,182 Likes: 10
Campfire Ranger
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Campfire Ranger
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you ever play with a 7-300? Seems a lot easier to neck the 300 Winny straight down instead of forming cases for the Mashburn. It is......no FFing....no custom dies..... 7 Mag w/162 vs 7x300 w/183SMK.....
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Campfire 'Bwana
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Campfire 'Bwana
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The 280 Remington is overbore.
The 7 Rem Mag is over bore.
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