7LRM clean up

pig ranch deadeye

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Will a 7LRM reamer "clean up" the chamber of a 7mm Rem Mag? It would be nice to be able to do that without having to set the barrel back or re thread it. Anybody know?
 

jd5521

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I would think you would have to set back because of the belted mag in the 7rm but I’m no gunsmith.
 

jd5521

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Ok, please tell me why. I understand that the practical thing to do is just stay with the 7mm Rem Mag. But can you point to other reasons?
Availability, make and cost of brass. Gunwerks is the only one that offer this brass which is made by Hornady and it’s very expensive.
 

WeiserBucks

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Ok, please tell me why. I understand that the practical thing to do is just stay with the 7mm Rem Mag. But can you point to other reasons?
Because there's only one source for brass and the brass is garbage. I've been down the 7 LRM path and I'm speaking from experience. It's not worth dealing with the brass . I'd do a 7-300 WM or throw the barrel off a cliff, where all the LRM brass belongs.
 

Rick Richard

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Because there's only one source for brass and the brass is garbage. I've been down the 7 LRM path and I'm speaking from experience. It's not worth dealing with the brass . I'd do a 7-300 WM or throw the barrel off a cliff, where all the LRM brass belongs.
Been there and done that too with the 7LRM.
 

P7M13

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I'd have to look at my reamer prints - I think you'd be in for a set-back of at least one turn.
If your 7mm is a 1:8, it'd be worth it. If you're 1:9 - 1:10, maybe not.
Availability, make and cost of brass. Gunwerks is the only one that offer this brass which is made by Hornady and it’s very expensive.
Supposedly ADG is now producing brass in 7LRM for GW.
I make my own from Hornady 375 Ruger stock, and it works better (lasts longer) than the Hornady 7LRM brass from Gunwerks. I ruined a bunch of cases figuring out how, but it still comes out much cheaper than the stuff from GW.
I have their brass too.
 

WeiserBucks

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Several years ago I posted a thread titled "School me on the 7 LRM" , or something like that. Every knowledge member here told me to steer clear, but I did it anyway. Very expensive education ensued.

If you search the forum perhaps you can find the thread. Bottom line is that the LRM doesn't offer anything that the other 7's don't, and plenty of drawbacks.
 

Privi457

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If you believe you need more performance than a 7mm RM can give (with a proper length bbl), the 7mm RUM is powerful enuf for anything, will fit in your action and can be loaded down to any level your shoulder likes.

Can't imagine what you wish to do that a 7mm RM cannot.
 

P7M13

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You say 7mm Mashburn, but are you really thinking about the 7mm Practical (see link in the name)? Also consider the 7 STW, for which you can easily find brass and loaded ammo.
None of those should require a setback. Anything else probably will. You might want to consider setback anyway to eliminate any throat erosion you have from your 7 mag. If you give yourself a longer lede, you can run higher pressures too.
You might also want to look at the 7mm Shehane, a wildcat by the legendary Bill Shehane.
----
I remember going through all the research when I was going to switch my 300 RUM. Settled on the LRM. I already had a 7 Rem Mag, but had the "wildcat bug" and all my spent 300 RUM brass was going into my 338 Edge. The first thing I did was sort out brass availability. I had already read complaints about their brass on the web, so looked into making my own. Found it was not hard, just laborious. Then I set about building the rifle. I bided my time and got everything but the barrel on sale for $1,200. Valuing the donor rifle at $500, $1,700 all in.
McGowen 26" 1:8 | MDT Tac21 Chassis | Luth AR MBA1 stock (already had) | Timney trigger | AICS 3.715" Magazine | MB&M 4 port brake. My only regret is picking too heavy of a profile, 13# with glass. However, when I shoot with buddies, it's the one they want me to bring. They get a kick out of exploding coke cans at 500 yards.
I'm on my 4th loading of brass, which puts me at ~450 rounds so far. Some of the GW brass started splitting necks after 2 loadings. I haven't had any loose primers yet. I have no clue why the brass I've made by converting Hornady 375 Ruger brass performs better than the Hornady made GW brass. It just does.
I haven't scoped my throat because it still shoots sub-MOA, though it might be good to have a baseline picture.

In hindsight, would I do it again? Heck yes! The things I learned doing this are priceless. Besides, it's my hobby, and I'm not looking for a return on my investment. If I had put that money into Bitcoin instead, I'd be sitting on several million dollars. 🙄

Some info for you:
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Several years ago I posted a thread titled "School me on the 7 LRM" , or something like that. Every knowledge member here told me to steer clear, but I did it anyway. Very expensive education ensued.
I heard all the nay-saying too, like "why would you want to spend money to build what can be done better with a 7 Mag?" To that, I can confirm the 7 Mag cannot do it better, and because I wanted to build another rifle.
I was struck by your comment above and took the time to look up your thread, https://www.longrangehunting.com/threads/school-me-on-the-7-lrm.198690/ -- it seems your last post excerpt below doesn't bear that same info. I don't believe in bashing a cartridge. The Hornady made GW brass sucks, I'll give you that. I find the cartridge a winner.
H1000 was the clear winner, 73 grains produced velocities of 3072 , 3079 and 3072 . Very minor pressure signs and about a 1/2" group. I'll concentrate on fine tuning this load in the future.
 
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