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I need to know what donor to buy for a 7 lrm. The 7 lrm parent case is a 375 ruger. What cartridges have the same bolt face that I could build off of. Could I just buy a long action and change the whole bolt? I have a few 30-06 action that I could purchase to build from would that work?:frusty: What if I built a 28 nosler? What donor same bolt face and firing pin questions.
Buy a Magnum Long Action such as the 300 Win Mag , and sell the barrel. Then have a 7LRM chambered up acquire some go and no go-gauges, and go to town. Or you can by a 30-06/270 etc.. but you would need replace it with a magnum bolt head and then would have to adjust the firing pin protrusion due to differences in lug size.
Just an FYI, here is list of cartridges that have the same rim diameter as the 375 Ruger -------257 Weatherby, 264 Win Mag, 270 weatherby Mag, 7mm Rem Mag, 7mm Weatherby Mag, 7 STW, 7mm Rem Ultra Mag, 300 H & H, 300 Win Mag, 300 Weatherby Mag, 300 RUM, 303 Brit, 8mm Rem Mag, 338 Win Mag, 340 Weatherby Mag, 338 RUM, 375 H & H, 375 Weatherby,375 RUM, 416 Rem Mag, 458 Win Mag, and the 458 Lot.
I think GunWerks actually sells fully formed brass so you might want to check with them since I think that would be easier. They created the 7 LRM by necking down the 375 Ruger AND moving the shoulder back creating a longer neck. But you would want build off the .375 Ruger since it is the parent case.
Any belted magnum donor rile will work. I've run a few different 375 Ruger based rounds on Savage and a standard belted mag action and magazine work beautifully. The 30-06 would work too if you changed the bolt head and magazine.
You may want to just go with the 28 Nosler. LRM brass can be hard to get and forming it from 375 Ruger brass can be a pain. The 375 Ruger case is so thick that necking it down and pushing the shoulder back is actually a fair bit of work. The 28 Nosler will give better ballistics (despite what any LRM shooters will tell you) and have brass available, but possibly not readily available.
Andrew
I ended up with a never fired 7mm mag. I only paid 320 so I feel like its a good deal. Yorketransport, can you give me a bit more info on the advantages of the 28 nosler. It looks to me that the 28 nosler will cost a fortune in brass. Ballastically it looks like the lrm is only 50 fps slower. However I have no expereince with either cartridge and would appreciate input. The stock I have on order is the EH-1 from manners for the donor action I picked up. I havent ordered my barrrel yet because I am unsure of the shank size, The gun is still in transit. Contouring is whats causing me the most stress. I am trying to keep the gun around 9.5 scoped so not to heavy of a barrel. the stock weighs 28 ounces. Apache gunworks says lightest I can go is a heavy magnum. So looking for a contour between a heavy mag and a varmint. Appreciate any advice.
The brass for the LRM can be hard to find. If you're not worried about having factory brass or ammo try looking at the 7mm/375 Ruger. Necking the Ruger case down isn't too hard, trying to move the shoulder back is a little tougher. I've necked it down as far as 25 caliber (haven't actually done anything with it though) and it takes a couple of steps, some annealing, and then neck turning. You can go down to 7mm in 4 steps. The 7/375 will duplicate the Nosler or possibly beat it and it will beat the LRM. The downside is the case forming. The 28 Nosler would probably be the easiest route if factory brass or ammo was a concern.
I think the heavy mag contour would be perfect for what you're building. It will heat up pretty fast, but should make a beautiful hunting gun!
Andrew