7RM Load Development Results – Advice Moving Forward

Buckys said:
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.
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This definitely gives me something else to think about now... even with other rifles. I wonder how much results can vary?? It makes me want to back away from max even more just to maximize the number of times I can use a case. Sticking to only virgin brass would get expensive fast! I just don't have a ton of extra time for the bench and range and good enough is good enough usually for a hunting rifle IMO. Going down that rabbit hole just takes more and more effort and components and I never know where to stop! :)
 
Full Curl said:
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.
Click to expand...
The natural case stretch is your variable of concern for reloading. Measure the headspace and see how much these vary. You should expect the hottest load on virgin brass will be over pressure on 1x or more fired brass.
With your Norma brass:
If you anneal the shoulders properly you could accelerate the fire forming on the next reload using 1x fired brass.
You have to look at headspacing to see how much variation you have now vs the next reload.
Probably why the 7 PRC is becoming the cartridge of choice (over the 7RM) using the Alex Wheeler reamer during chambering on new barrels.
 
As far as pressure goes, it likely won't change much after the first fire forming compared to subsequent firings. There is alot going on in that first firing and some cases are worse offenders than others.

If you're happy with <MOA, fire form while seating depth testing, do a ladder or OCW and see where your at.
 
Full Curl said:
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.
Click to expand...
I got my best accuracy on my 3td firing and also my best velocity. Shows slight flatening of the primers, but no bolt lift problems.
 
Bob Wright said:
The natural case stretch is your variable of concern for reloading. Measure the headspace and see how much these vary. You should expect the hottest load on virgin brass will be over pressure on 1x or more fired brass.
With your Norma brass:
If you anneal the shoulders properly you could accelerate the fire forming on the next reload using 1x fired brass.
You have to look at headspacing to see how much variation you have now vs the next reload.
Probably why the 7 PRC is becoming the cartridge of choice (over the 7RM) using the Alex Wheeler reamer during chambering on new barrels.
Click to expand...
I'll take some measurements of a few of my 1x fired cases and see how much they expanded. I do know the chamber on this particular rifle is pretty tight. How much will an accuracy node achieved with new brass change using that same brass fired 2x+ times? Is it typically pretty close to the same charge weigh or can it be significantly off??
 
Tiny Tim said:
As far as pressure goes, it likely won't change much after the first fire forming compared to subsequent firings. There is alot going on in that first firing and some cases are worse offenders than others.

If you're happy with <MOA, fire form while seating depth testing, do a ladder or OCW and see where your at.
Click to expand...
I'm assuming the lighter the load the more times required to fully fireform the case? I've always had pretty decent results with new brass in most of my customs which is probably more due to the rifle than the cases.

I'm now left pondering what is the most efficient process to develop an accurate load in a new rifle without going down the seemingly bottomless rabbit hole of time and components ever pushing towards a <=1/4 MOA load...?? Even if I had a vast variety of components on hand for every one of my 10+ calibers, I simply don't have the bench or range time to test that much. Over the years I've learned to call good enough, good enough and most times sub-MOA accuracy is my goal... 1/2-MOA to 1-MOA works fine for me in my hunting rifles. I guess it's a constant balance between efficiency and performance.
 
All my belted mags have required to drop the load if finding max pressures with virgin cases.

If the higher load is your preferred, found on virgin cases, drop .5 gr and see how it does. Probably be close to the same velocity you found on virgin cases.

Don't be surprised if pockets go fast. I had a 300 WM that I did this with and the loads were much "hotter" on subsequent firings. Pockets lasted about three firings with slight ejector print.
 
Shane Lindsey said:
All my belted mags have required to drop the load if finding max pressures with virgin cases.

If the higher load is your preferred, found on virgin cases, drop .5 gr and see how it does. Probably be close to the same velocity you found on virgin cases.

Don't be surprised if pockets go fast. I had a 300 WM that I did this with and the loads were much "hotter" on subsequent firings. Pockets lasted about three firings with slight ejector print.
Click to expand...
Thank you. 3x case life pushes me back towards the rabbit hole with more components needed more often but I can definitely see it happening. 0.5gr gives me a good reference, thank you.
 
If strictly a hunting rifle (what's the fun in that) that may be all you ever need. If shooting it often, I would drop down to the lower node to preserve components. But like I said in a previous post look at the two different velocities and see what they really differ at the max range of the bullet.

I have a 338 cal shooting a 213gr bullet at 2677 FPS and 2860 FPS. Both are accurate.

2677= 575 yards art 1800 FPS
2860= 650 yards at 1820 FPS

Difference is really negligible. Would I take the shot with the 2677 at 650 yards...YUPP!!!
 
Full Curl said:
I'm assuming the lighter the load the more times required to fully fireform the case? I've always had pretty decent results with new brass in most of my customs which is probably more due to the rifle than the cases.

I'm now left pondering what is the most efficient process to develop an accurate load in a new rifle without going down the seemingly bottomless rabbit hole of time and components ever pushing towards a <=1/4 MOA load...?? Even if I had a vast variety of components on hand for every one of my 10+ calibers, I simply don't have the bench or range time to test that much. Over the years I've learned to call good enough, good enough and most times sub-MOA accuracy is my goal... 1/2-MOA to 1-MOA works fine for me in my hunting rifles. I guess it's a constant balance between efficiency and performance.
Click to expand...
The previous component shortage changed the way I do load development. With a new round find out what the preferred powder(s) are. No sense trying to reinvent the wheel. Run a one shot ladder off some book data. When I get to the target velocity without pressure signs I'm done. If they show up early I'll stop. Then I load to mag length or 20 off. Then I go shoot some groups. Sometimes I will play with seating depth going shorter if results are not acceptable which is usually .5-.75 moa. That is more than sufficient for me and is not worth the components burned up to get smaller.
 

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