7RM Load Development Results – Advice Moving Forward

[Husky user]

I am one of the lucky ones that have enough RL26 to last my hunting life.
I settled on 67.4gr with good accuracy,hit pressure at 67.7 (mid day at 70 F)
The chart I used said 67.5 was max 67.4 flattens the primer a bit,but I have seen worse!
No heavy bolt lift.
This is in a Husqvarna 8000.

 

[Husky user]

I forgot to mention this is with Federal Terminal Ascent 155gr.
I was lucky enough to purchase 100 on Gun Broker couple years ago
These are running in the 3050 fps range!

 

[AussieWriter]

I'd run the 69gn load and count the case reloads. If they last more than 5, I'd leave it. If they don't, change the powder. Even H 4350 runs higher velocities than what you are getting.
Running 7x57 loads in a 7mm Magnum is...........

 

[jfield]

Looking for some advice. I'm not new to reloading but I don't have as much knowledge and experience as many on here do. I had a new carry hunting rifle built chambered in 7RM. Bartlein #3 24" 1:8. I recently started load development for 160 Accubonds pushed by H1000. After a couple OCW tests I have 2 good accuracy nodes… a lower one at 65.3 grains (2,869 fps) and an upper one at 69.0 grains (3,015 fps). At 69.0 the primers start showing the slightest sign of flattening but not much. In the photo, the 69.0 case is on the right and the 65.3 case is on the left. I don't notice any other signs of pressure… although I had the bolt cerekoted and its brand new so still not worn in silky smooth yet and I'm not sure I would notice a little sticky bolt lift?? It certainly shows no signs of noticeable heavy lift.

I have not gone beyond 69.0. Both loads are sub MOA with the 65.3 load having a slight advantage at a solid 1/2 MOA. I was really hoping to find a good node in the 67.5 to 68.5 range like I have with previous 7RM's but it's not there with this one. Looking for advice on what load to move forward with. My goal is to focus on a specific load and that's the one for this rifle. It will be used 80% for hunting and 20% for occasionally banging steel, rarely over 800yds. The rifle should easily outlast me. I'm not sure how "hot" the 69.0 load is, but barrel life, case life, and rifle wear and tear is a consideration. At the same time, I feel I'm sacrificing a lot of the advantages of the 7RM to move forward with an under 2,900 fps load.

Anyway, please talk me through this and what load to move forward with and not look back. Thanks!!

7rem Mag load (.465")
160 Accubond
Peterson Brass
Federal 215M
70.3 gr. H1000
3190 fps
.050 jump
SD 7
ES 11
26" barrel

 

[Buckys]

Can't develope a load, especially near max on virgin brass. Get one or, preferably two firings on the cases then try again.

Too much energy is used fire forming your virgin brass. A max load on virgin brass will likely be over max on fully formed brass.

Your barrel will likely "speed up" if you're under 100 rounds.

Use this time to fire form and do seating depth testing.

I suppose you could so long as you'd only use that recipe with virgin brass.

As others have made clear, your results will vary significantly with 1x, 2x, etc. fired brass.

 

[bballard]

My goto 7mm Remington Magnum load:

Norma brass
160 Nosler Accubond
63 grains RL 22
CCI 250 primer
Velocity is running around 3007 fps from a 24 inch Cooper model 92 backcountry.
Not sure what I will go to if I run out of RL22. I have 7 or 8 rifles in this caliber and they all shoot this load very well. Usually 1 moa or less at 100.

 

[Shane Lindsey]

Shoot the 65.3 load for the first firings on the brass. Then play with it if you want.

Put the two velocities in a calculator and see if there is really that much difference at distance (prolly not worth chasing if you have a 1/2 MOA load that repeats).

 

[jfield]

7rem Mag load (.465")
160 Accubond
Peterson Brass
Federal 215M
70.3 gr. H1000
3190 fps
.050 jump
SD 7
ES 11
26" barrel

Forgot to mention this was the 3rd firing of that Peterson brass and dropped the elk where it stood.

 

[Full Curl]

Your over thinking this. You have a sub MOA load safely at 3000+fps pushing 160gn bullet is a legit 7RM round, run a seating depth test if you want to shrink its group size even more but your already good to go.
Watch for pressure signs though as the new barrel speeds up....

I like the 69.0 load just fine. I just want to make sure on the "safely" part... and take it a step further and make sure I'm not being overly hard on the rifle and/or cases as far as extra wear. But I am guilty as charged for over thinking things at times!

 

[Full Curl]

I just broke in a 7rm with new Norma Brass. I was running monos with RL26 and got a noticeable gain on the second firing. I also topped out at the first firings first signs of pressure. You may want to play with some of your once fired before you get too set on either of your current options.

Do you remember how much fps gain you got with the second firing?

That's interesting that your pressure sign charge of the first firing matched that of the second firing. I never really tested that before.

 

[Full Curl]

On virgin brass you're developing a load for, you're wasting a lot of effort and material chasing a max load. Once you go to a 1x or greater firing, you'll be in trouble.
Part of the pressure is being used to fireform new brass.
It took me 3 firings and some annealing to fully form the brass I used. Then I had to rework that load to get back into the 2920 fps node where the 180 Bergers like to run.
If you have plenty of brass 1x fired, start back with them and measure headspace first. I bet they have .005 variation across all of them.
This chambering will grow brass about .020 after first firing with a lot of variation. You're not even close to getting this brass settled down for reloading.

Ha. That's what I'm trying to minimize... wasting time and components and that crazy rabbit hole I want to stay far away from! I started with 100 brand new Norma cases and have not even fired all of them yet. I now always start a new rifle with new brass, I've had too many headspace issues in the past using cases that were fired in a different rifle. I'm assuming you were chasing the absolute best of the best accurate load with the process you used. I don't necessarily want or need a max load, it's just that a near max load 69.0 showed me one of the 2 best accuracy nodes with new brass. If it was more of a mid-load charge, I would be fine with that. 65.3 just seems less than even mid-load for a 7RM. I don't need 1/4 MOA, my goal with this hunting rifle would be sub-MOA and I have that with both the 65.3 and 69.0 charges with new brass. After reading all these replies I would like to know what accuracy I get from a 1x or 2x fired case with the same charges?? If I can avoid having to fire cases 3x times just to fireform for a sub-MOA load, I would be happy with that. Thanks for the info.

 

[Full Curl]

Can't develope a load, especially near max on virgin brass. Get one or, preferably two firings on the cases then try again.

Too much energy is used fire forming your virgin brass. A max load on virgin brass will likely be over max on fully formed brass.

Your barrel will likely "speed up" if you're under 100 rounds.

Use this time to fire form and do seating depth testing.

Great info. Thank you. I guess I never realized there would be so much difference between new and fireformed cases as far as load testing for accuracy. And when I say accuracy, I mean for a sub-MOA hunting rifle and not a comp rifle.

 

[Full Curl]

Loading for the 7MM Remington Magnum

For me, when developing a round for hunting, my goal is under one-half inch. Over the years, I have managed to reach that goal with each of the six rifles chambered in 7MM Rem Mag that I have listed here.

www.mossyoak.com

here is an article on loading for the 7mm Rem Mag that may give you some different options to look at. Some of these loads are very mild but they might give you some ideas if you are looking for accuracy.

Great article. Thank you. What that article covers... as far as how many different powder and bullet combinations were tried for each rifle is exactly what I want to avoid... to me, that is the rabbit hole. I can see it for trying to find a 1/4 load, but I'm perfectly happy with a sub-MOA load and do not have that many bullets and powders on hand to even try or the desire to buy that many. If I knew the author I would be better off just paying him or assisting him to test the rifle. It would be fun to try that many, but I just don't have the time or the means to go down that road.

 

[Full Curl]

Are you committed to the 160 gr Accubond bullet?

Yes. I have 400+ of them and really like how they perform on game.