I have decided to build another long range rig that will shoot the 190-210 grain bullets at over 3100FPS. I have a 338 Lapua, 6.5-284, 300SAUM but I want a flat shooting 1 mile cartridge. Right now I am leaning toward the 300RUM since I have about 1000 208AMax and 190 Berger Bullets. I am not a 300WM fan but I have considered a 7MM version of a Win Mag. I would like to stay with something I don't have to fire form.
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New Build 300 RUM or 7MM of some kind?
- Thread starter Tazman
- Start date
Well I think you are thinking like I think, I love the 300 and 338RUMs. Easy to load and easy to load down if you want 300Win speed. They say they are hard on barrels but you don't have to load balls out. Most of my friends that have 300Win are always trying to push for more speed, hell on brass. The 300RUM can be loaded to be easy on brass and that's a good thing. Can't go wrong, I shoot one, my son and wife also have 300RUMs.
Been researching the 7/300WM for a while myself for the same reason. No fireforming required, just run the 300WM case through a collet neck sizing die set up for 7mm.
If you want long range bullets to fit a magazines, you might consider the 300-338 RUM. This is sort of like the 338 edge going the other way, necking down 338RUM brass to 30. This shortens things slightly for mag length. Just run in the 300RUM reamer short and trim the bottom of the dies slightly. You loose a little case capacity, but that's not a big deal because there really isn't any powder available that can use it. You either top the case off with surplus 50BMG powder or you leave room with something like retumbo that will still get higher velocity.
...just an idea. Good luck with the build!
This would work if/when 300 WM brass becomes commercially available again. Not sure of the barrel life, but it should get you to a mile and then some. Is there a slight increase in powder capacity over the 7mm RM with the necked down 300 case?
Sadly, sadly true.
The 7mm RM has 84 grains of case capacity, the 300WM has 89 grains of case capacity. The 7/300WM is seriously overbore requiring slow burning powders and long barrels to see full benefit.
^^^^This!!!
The 300 norma with a 240grn bullet. WILD! Kinda wish i would have done the 300 vs the 338NM now after looking into it more.
xdeano
+1 on what they said, got a 300 norma in the works now. I had a couple 300 RUMs and they were great but got 4 reloads on brass before I had to chuck it. My biggest problem (my pet peeve) was I wanted 3-5 rounds in the mag. Tried wyatts extended box magazine and tried AICS 338 lapua with the ribs milled out. the AICS worked decent but under recoil the bullet slammed into the front of the mag and deformed the bullets nose. With the 300 Norma you can run a 5 round AICS mag they will feed flawless and Norma brass is better. We do quite a bit of hiking in during hunting season and the last thing I need 5-10 miles in is my shit not running and I want a 5 round mag and be able to load the bullet out so Im not taking up my case capacity. I sold my RUMs and built a 7 mag, love it. Its a little heavy for hiking in so I will sell it and maybe do another.
Just my thoughts,
Casey
I am looking at the 300 Norma to see what speed I can get with the 190 or 210 bullets. I still have time to make changes but time will run out soon. 30-378 was also an option but I want to stick with a standard round on this build. It seems brass is hard to find for any of them right now. Need to get about 3200 + FPS out of a 26 inch barrel. I will admit this is a little out of the normal build for me but I want something a little better than the 300WM. I looked at several 7MM options but I have a great deal of 30 cal bullets.
7mm WSM or SAUM will get you to a mile with much less recoil. 300 norma mag has always intrigued me and the ballistics are great too.
I have a 300SAUM that is 1-12 twist. It shoots the 208 Amax at 2900FPS with 60 Grains of R17. My wife has declared it her rifle which frees me up to build this. The only issue is she wants to have it re-coated to pink and 2 shades of sniper grey to make it hers.
300 Norma +1000
The RUM is by design more flinchy, very long case with very slow burning powder, by design to get the ultimate fps out of it it needs it's absurd amount of freebore, to act as a pressure chamber. And the window of suitable powder charge before pressure spikes is normally very small.
If you want a 7 mm overachiever the 7 LRM would be perfect.
The RUM is by design more flinchy, very long case with very slow burning powder, by design to get the ultimate fps out of it it needs it's absurd amount of freebore, to act as a pressure chamber. And the window of suitable powder charge before pressure spikes is normally very small.
If you want a 7 mm overachiever the 7 LRM would be perfect.
I believe 308Nate on here is doing a 7 version of the 338 Norma Mag case. He calls it the 7mm Dakota if i remember correctly.
xdeano
xdeano
Better quality brass, better mag length fit, better bullet/powder column relationship.
What are you considering for an action and magazine setup?
What are you considering for an action and magazine setup?
Merideth Rifles will be building it. Stiller action and Wyatts extended box mag if I do the RUM. I haven't talked with him about the 300 Norma Mag yet. I assume it will still be a Stiller action.
If you use the extended box mag on the RUM I was hoping to be able to load the round longer so it doesn't loose as much case capacity.
If you use the extended box mag on the RUM I was hoping to be able to load the round longer so it doesn't loose as much case capacity.
Norma makes brass for the 300 RUM now, that was one of my two complaints about the RUM was I was going thru brass quickly getting about 3-4 loads out of em. I was pushing it pretty hard though. The norma brass may fair a lot better though.
Casey
Casey
I talked with Tooter yesterday and I think I will just build the RUM with a long throat and extended mag to be able to load them long. I can also load them down to 300WM level if recoil becomes an issue. I am going to do a spiral fluted M40 style barrel on this one and I hope to have a fun all around rifle with long range capability.
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