7mm RM Performance Potential

KT-PNW

FNG
Joined
Nov 20, 2022
Messages
57
Location
Washington State
Hello there,

I have a bit invested in my 7mag, from Redding bushing dies and Peterson brass to a backstock of bullets and powder. The rifle was passed down to me, I have no idea on the round count of my rifle and cannot get it to group at long range to save my life. I spent time messing with different variables, 1 at a time. Groups tightened up and it'll stack them at 100 yards but seems to lose consistency further out.

I haven't given up entirely just yet and committed to swapping my barrel, but if I did, would it be worth it to go same caliber with a twist rate of 1-8 or 1-8.5? Or does the 7mag have no chance to achieve relatable performance to the 7prc?

Or do I just toss it in the back of the safe and buy something new? It's a mkv 5 weatherby accumark and I always don't love packing it up and down mountains, but it is comfortable to shoot.

What do you guys think?
 

JRS3

Lil-Rokslider
Joined
Sep 24, 2022
Messages
179
I shoot 180gr VLD-Hs from a 7mm RM and a 7mm PRC. The RM has a 26” barrel and the PRC has a 22”. Both are clocked at 2,950 FPS.

I have always been a fan of a 7mm RM and own two. One is a factory 700 with 24” tube, minus McMillan stock and Timney Trigger, and it is very accurate. The other is a custom built on a Ti Pierce action with 26” Proof CF. Both have been very good to me.

I have the one 22” 7mm PRC and like it, as it’s setup with a TBAC UL 7.

All have done everything I could want them to and are already contemplating a 20-18” barreled for an even handier setup.
 

TaperPin

WKR
Joined
Jul 12, 2023
Messages
3,527
Hello there,

I have a bit invested in my 7mag, from Redding bushing dies and Peterson brass to a backstock of bullets and powder. The rifle was passed down to me, I have no idea on the round count of my rifle and cannot get it to group at long range to save my life. I spent time messing with different variables, 1 at a time. Groups tightened up and it'll stack them at 100 yards but seems to lose consistency further out.

I haven't given up entirely just yet and committed to swapping my barrel, but if I did, would it be worth it to go same caliber with a twist rate of 1-8 or 1-8.5? Or does the 7mag have no chance to achieve relatable performance to the 7prc?

Or do I just toss it in the back of the safe and buy something new? It's a mkv 5 weatherby accumark and I always don't love packing it up and down mountains, but it is comfortable to shoot.

What do you guys think?
I love the 7 mag, or rather, I love an accurate one. Folks make a lot of excuses at the range - “that shot was pulled,” “trigger didn’t break quite right,” “the target is a little hard to see,” “this 4.5x14x scope needs more magnification,” “this little breeze is really opening up the group,” “recoil makes my tummy feel funny,” etc, and all those excuses go out the door with my best 7 mag. Any shooting buddy can shoot this gun for the first time with a fixed 6x and simple black square as an aiming point and put 5 shots into the smallest group they’ve ever shot at any range they want to try - a nice evenly distributed 3/4” group at 200 yards is typical. The typical first time reaction is to break out laughing at how small the group is. The reloads are simple Nosler bullets in cheap Federal cases FL sized in ordinary RCBS dies. Most experienced shooters actually shoot better than their factory rifle shows - having guys test drive this rifle has sold a number of 7 mag barrels and 6x scopes because it’s so easy.

If you were a shooting buddy and having issues with inconsistency, without a doubt the best advice is to stop wasting time, tears and cash on a factory barrel and send it off for a top name custom barrel. Barrels often shoot better or worse at distance and it sounds like you’ve proved that to yourself and rather than good at long range the barrel is lacking. I’d bet lunch no matter how many loads are tried you’ll eventually replace it, or should.

The cost of a top custom 7 mag barrel is only about $1/shot. Use that limited barrel life plinking or hunting, but beware of high volume shooting or you’ll go through a barrel every year.
 
OP
K

KT-PNW

FNG
Joined
Nov 20, 2022
Messages
57
Location
Washington State
I love the 7 mag, or rather, I love an accurate one. Folks make a lot of excuses at the range - “that shot was pulled,” “trigger didn’t break quite right,” “the target is a little hard to see,” “this 4.5x14x scope needs more magnification,” “this little breeze is really opening up the group,” “recoil makes my tummy feel funny,” etc, and all those excuses go out the door with my best 7 mag. Any shooting buddy can shoot this gun for the first time with a fixed 6x and simple black square as an aiming point and put 5 shots into the smallest group they’ve ever shot at any range they want to try - a nice evenly distributed 3/4” group at 200 yards is typical. The typical first time reaction is to break out laughing at how small the group is. The reloads are simple Nosler bullets in cheap Federal cases FL sized in ordinary RCBS dies. Most experienced shooters actually shoot better than their factory rifle shows - having guys test drive this rifle has sold a number of 7 mag barrels and 6x scopes because it’s so easy.

If you were a shooting buddy and having issues with inconsistency, without a doubt the best advice is to stop wasting time, tears and cash on a factory barrel and send it off for a top name custom barrel. Barrels often shoot better or worse at distance and it sounds like you’ve proved that to yourself and rather than good at long range the barrel is lacking. I’d bet lunch no matter how many loads are tried you’ll eventually replace it, or should.

The cost of a top custom 7 mag barrel is only about $1/shot. Use that limited barrel life plinking or hunting, but beware of high volume shooting or you’ll go through a barrel every year.
I suppose one thing that gave me hope and made me chase better accuracy is that by just controlling a few variables (this gun is sensitive to brass for some reason) my accuracy at 100 went from complete trash and flyers averaging varying groups well over 2moa to sub 1/2” groups and it pisses me off that it won’t group well at distance!
 

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Formidilosus

Super Moderator
Shoot2HuntU
Joined
Oct 22, 2014
Messages
10,378
I suppose one thing that gave me hope and made me chase better accuracy is that by just controlling a few variables (this gun is sensitive to brass for some reason) my accuracy at 100 went from complete trash and flyers averaging varying groups well over 2moa to sub 1/2” groups and it pisses me off that it won’t group well at distance!


No. Guns don’t magically “fall apart” in groups at distance. You have a random, or a couple random 1/2” groups at 100 yards- this not the true cone of the gun; or- you are doing something to negatively effect groups at longer ranges.

Take your 1/2” load and shoot 20 shots at the exact same target (a 20 shot group) letting the barrel cool whenever you want. It will not be a 1/2” group, and will probably be 3+ inches.
 
OP
K

KT-PNW

FNG
Joined
Nov 20, 2022
Messages
57
Location
Washington State
No. Guns don’t magically “fall apart” in groups at distance. You have a random, or a couple random 1/2” groups at 100 yards- this not the true cone of the gun; or- you are doing something to negatively effect groups at longer ranges.

Take your 1/2” load and shoot 20 shots at the exact same target (a 20 shot group) letting the barrel cool whenever you want. It will not be a 1/2” group, and will probably be 3+ inches.
I’ll do this next time I go out and follow up with results. It’s very possible it’s me, I shoot other rifles I own very well at distance so shooting this specific one poorly would be a head scratcher.
 

Formidilosus

Super Moderator
Shoot2HuntU
Joined
Oct 22, 2014
Messages
10,378
I’ll do this next time I go out and follow up with results. It’s very possible it’s me, I shoot other rifles I own very well at distance so shooting this specific one poorly would be a head scratcher.

I would like to see what you come up with. Odds are it just small sample size variation.
 
OP
K

KT-PNW

FNG
Joined
Nov 20, 2022
Messages
57
Location
Washington State
I'm planning on loading and shooting this weekend (weather permitting). If I go, I will post what I come up with. I've looked down the reloading wormhole and am curious if anyone has a recommendation for this particular situation. I have Redding type S elite dies with a few options for bushings or basic Hornady custom grade dies.

Last load was 60.6gr of IMR 4831 loaded into new peterson brass w/ fed match 215's, using 162 eldx's. I'm not sure the distance to the lands but they're as long as I can make them and still fit in the gun.

Additional readily available components are:
-2x fired federal brass or 1x fired peterson brass
-150gr ttsx, 150gr nosler ballistic tips, 160gr partitions, 150 or 175 gr sierra match hpbt's, or 168 gr vld hunting
-H4831, H1000, RL 19 or 22, Accurate Magpro
-Remington, CCI and Fed Champion Large Rifle Magnum Primers

Again, this is being shot out of an unknown round count, 26" weatherby mkv accumark (manufactured between 1995 and 2002) with a radial brake. Optics are a 5.5-22x50 NXS, that was mounted and leveled by someone who shoots competitively.

I will chrono it when I shoot to have a big sample of velocity with ES and SD. I greatly appreciate any input or advise.
 

grizz19

Lil-Rokslider
Joined
Dec 13, 2018
Messages
290
Location
California
If you have the components and want to leave it a 7RM you really aren’t losing much. Maybe a little speed with heavy’s. If you rebarrel I’d do 1:8, it will give you more bullets choices. A 7RM case will actually hold more grains of water vs 7prc if it is throated for a 180gr bullet. 7RM kill very well. Most of my family, friends and I have shot them for years with great results. That being said a couple of us have moved to the 7PRC in order to shoot the heavier, higher BC bullets a tad faster. But if that is not a concern then run with it.
 

LaHunter

WKR
Joined
Mar 9, 2013
Messages
1,422
Location
N.E. LA
2850 fps with the 162 grain eldx bullets is fairly 'slow' for a 7 rem mag. You should be able to easily get over 3,000 fps with that bullet from a 26" barrel. Some rifles may not shoot great with a 'light' load.

As far as putting a new barrel on it, since you are already set up for loading for the 7 rem mag, I would stay with this cartridge if it were me. If you want to shoot the 180 eldm bullets, just get an 8 twist barrel. If you want to stay with the 162s, a 9 twist is good.
 
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