So...earlier this evening, I was at a friend's workshop, reloading some 7mm RM brass with Barnes 150s. I could swear I read his reloading manual twice before acting, and that it called for 60gr of H4350. But...upon getting home, I looked in my Barnes manual and it calls for 53 grain with a max of 58. Awcrud.

So...my question is: what do I do now? I'm new to reloading, and this is my first error of this kind. Do I:

- cross my fingers and blast away
- try to remove the bullets and re-do the load
- toss the batch into the trash and take up needlepoint

Any input is appreciated...thanks.

quote:

Originally posted by mzimmers:

- toss the batch into the trash and take up needlepoint

Any input is appreciated...thanks.

While funny, not required.
Invest in a bullet puller.
Keep the powder seperate and start over.
In the future keep the book open in front of you!
When you get this behind you, don't forget it!

Reloading is relaxing BUT don't get complacent, and you'll have fun.

Thanks for the information. I'm going to be really interested in what that book says when I go back there tomorrow AM. Is it possible that two reloading books could differ by that amount? Is there an online source of "recipes" that I could look at?

H-4350 From 53.0 grains to 62.0 grains
CCI-200 Primer

I have noticed the Barnes book to be conservative on alot of their loads. Something different about their X bullets vs conventional ones? Their data seems to say so.

Any other bullet I'd say shoot'em. All of my manuals say 60-62gr max.

But you said Barnes. If this is an X bullet, I'd pull'em.

ZM

You can find an inertial hammer pretty easily and the bullets will probably come out no problem unless you've put on a serious crimp. Might save you some time rather than waiting for a bullet puller die and bushing. You'll lose a little powder but not much.

Hey mzimmers

Load data can vary quite a bit. Barnes data does tend to be conservative.

Try this. Load up some more starting at 57.5 gr with the same powder, then 58 gr, 58.5 gr, 59 gr and 59.5 gr. You can load just 3 at each level. Start shooting at the 57.5 gr load and keep going up while looking for pressure signs. If you hit any pressure signs before the 60 gr load, then you can pull them. My guess is that those loads will be fine and you might even be able to load a little higher.

Besides that, you may be able to find an accuracy node because you will be performing an OCW test.

http://home.earthlink.net/%7Edannewberry/dannewberrysop...ightloaddevelopment/

mzimmers

I have to say pull them...

It MAY BE that the loads are OK. However, there is just too much risk involved to shoot them without working up to that level.

At the VERY LEAST, put these rounds aside carefully marked so that you will not stumble into them unawares, and work up loads on another batch of brass to what feels like a good max load when you shoot them. If the reasonable charge is over the loads of concern ... the loads you have put aside are OK to shoot. If not they have to be pulled down.

Invest in a collet type bullet puller that fits into the reloading press. Eventually you would have needed one anyway. Then take apart the loads of concern. You can reuse the bullets for practice.

NEVER take a change on loads that may be too hot!

I'm with ricciardelli and Woods.

Load up a test batch in .3 to .5 gr steps and watch for pressure signs.

My book shows you to be 2 gr under max. That's about where I would start testing if I were starting from scratch.

quote:

Originally posted by mstarling:
It MAY BE that the loads are OK. However, there is just too much risk involved to shoot them without working up to that level.

At the VERY LEAST, put these rounds aside carefully marked so that you will not stumble into them unawares, and work up loads on another batch of brass to what feels like a good max load when you shoot them. If the reasonable charge is over the loads of concern ... the loads you have put aside are OK to shoot. If not they have to be pulled down.

Invest in a collet type bullet puller that fits into the reloading press. Eventually you would have needed one anyway. Then take apart the loads of concern. You can reuse the bullets for practice.

NEVER take a change on loads that may be too hot!

This makes sense to me...

OK, everyone, here's an update:

First, thanks to everyone who replied. While I didn't follow everyone's advice (how could I?) I did give all responses due regard. I don't want anyone to think I was discounting their input. That said, after speaking with some other people on the subject, I decided to try firing a few of the "hot" loads. While nothing spectacular occured, the primers were a bit flattened and accuracy just plain reeked, so I quit early. I purchased a bullet puller and emptied out the remaining cartridges, then loaded 5 each at 56.0, 56.5, 57.0, 57.5 and 58.0 grains of H4350. After lunch, I took another trip to the range and tried these loads out. Here are the results.

56.0 grains



OK...so the grouping wasn't too swift. The mean velocity was 2656 fps.

56.5 grains



AARGH...what is happening here? The left-right spread is just plain unacceptable. Oh, I also dialed the scope down 2" before this shoot. Mean velocity was 2684 fps.

57.0 grains



At this point, I'm starting to really wonder just WTF is going on. Mean velocity was 2718 fps.

57.5 grains



Ahh...now this is a little more like it! The man at the gun shop who sold me the puller, with whom I've spoken before and who's impressed me as reasonably knowledgeable in reloading matters, said that magnums tend to do better toward the higher end of the powder spectrum. This certainly seemed to corroborate that. Mean velocity was 2732 fps.

58.0 grains



This was a bit of a buzzkill. You might notice only four bullet holes. I shot five; I can only surmise that the fifth (which was really the second) flew over the target altogether. This rogue shot notwithstanding, this was my second best grouping, but clearly nowhere near as good as with the 57.5. Mean velocity was 2746 fps.

Other notes: I didn't fire a fouling shot, so the first grouping may have been somewhat victimized by barrel heating. I didn't space my shots out as much as the gun store guy suggested (he said three shots per 20-minute session, and I just didn't have that kind of time), but I did let the barrel rest a minute or two between shots. Weather was warm but not hot, humidity middling, wind negligible. Oh: and this was at 100 yards, not 50 as the printing on the target might suggest.

Anyway, it looks like 57.5 grains is the ideal load for this rifle and bullet combination. I welcome any feedback. Thanks again to everyone who helped me with this.

Well, crud...my pictures didn't align the way I wanted them to. Can anyone tell me how to edit a post in this forum?

You should have an edit button on your post. It's a little tablet with a pencil eraser on it.

My first thought is, man that's slow. A 7 mag with 150 gr bullet ought to be shooting in excess of 3000 fps minimum. That H4350 powder is not getting it done for you or you need to keep going up. My Nosler #5 reloading manual shows 2 powders that produce over 3200 fps with 150 gr bullets. They list the most accurate as IMR4831 at 65 gr. I have always had excellent accuracy from IMR4831, I would try that powder and start at 64 gr.

Barnes bullets always shoot best just below max and you are not there yet. Your accuracy is suffering because you are pushing that bullet too slow.

ALSO, ALL YOUR VELOCITIES ARE LOWER THAN ANY OF THE VELOCITIES LISTED FOR THE MINUMUM LOADS. YOU ARE BELOW MINIMUM SPEEDS AND THAT CAN LEAD TO EXCESSIVE PRESSURE.

JMHO

My Barnes manual shows staring load with 150 gr X as 59.5 gr H4350 and a max of 64.5 gr H4350
For 2743fs to 2974 fs.

Lyle

????? this is a 7MM Rem Mag is it not.????

quote:

Originally posted by woods:
My first thought is, man that's slow. A 7 mag with 150 gr bullet ought to be shooting in excess of 3000 fps minimum. That H4350 powder is not getting it done for you or you need to keep going up. My Nosler #5 reloading manual shows 2 powders that produce over 3200 fps with 150 gr bullets. They list the most accurate as IMR4831 at 65 gr. I have always had excellent accuracy from IMR4831, I would try that powder and start at 64 gr.

According to the Barnes Manual, this bullet, this powder, and a load of 58 grains should give 2882 fps. Admittedly I fell more than a bit short of this, but...where would I place the blame? H4350 is a "recommended powder" for this bullet, according to Barnes.

quote:

Barnes bullets always shoot best just below max and you are not there yet. Your accuracy is suffering because you are pushing that bullet too slow.

Well, this morning, my accuracy seemed to be suffering because I was trying to push it too fast (with the 60 grains). This afternoon I got a 1" group with the 57.5...not bad for a hunting rifle. I'm not convinced that going higher is the answer, especially given the performance I got with 58 grains.

quote:

ALSO, ALL YOUR VELOCITIES ARE LOWER THAN ANY OF THE VELOCITIES LISTED FOR THE MINUMUM LOADS. YOU ARE BELOW MINIMUM SPEEDS AND THAT CAN LEAD TO EXCESSIVE PRESSURE.

JMHO

I'm not sure what you mean by "minimum speeds" -- according to the Barnes manual the expected speed with a minimal load is 2634 fps. I'm well ahead of that.

I do agree that trying H4831SC might be a good experiment, though I'm wondering how much more accuracy I can really expect.

Yes, this is a 7mm Remington Magnum rifle (a Sako AV).

2 bullets for 7mm mag 175gr and a friend swears by 160gr 7mm mag as the best all around bullet weight .

Sorry mzimmers

I am not getting on your case. I realize the Barnes data is as you say. There are also 2 other powders listed as *Recommended powders, RL19 and IMR7828. Both of those powders give velocities over 3000 fps at the max load. You are operating in the high 2600's to low 2700's.

I have a book "One Book / One Caliber" ( www.loadbooks.com )that lists multiple load data from sources such as Barnes, Swift, Vihtavuori, Winchester, Accurate, etc.

Swift lists 62 gr H4350 as max with 2976 fps
Swift also lists 65.5 gr RL19 as max (and the lowest standard deviation) for 3016 fps
Accurate lists 66 gr 3100 for 3003 fps
Hodgdon lists 57 gr H4350 as max for 2859 fps (the slowest velocity for all their recommended powders)
Hodgdon also list 68 gr of H1000 for 2936 fps
Speer doesn't have a 150 gr bullet so lets look at a 160 bullet which should be slower
Speer lists 61 gr H4350 for their 160 gr bullet for a velocity of 2904 (please note: a faster velocity for a heavier bullet than the Barnes reloading data)
Speer lists 67 gr RL19 for their 145 grain bullet and the velocity is 3153 fps. 5 grains aint that much difference
Sierra lists 62 gr IMR 4350 (which is a faster powder) for their 150 gr bullet for a velocity of 3100 fps
Sierra list 62.8 gr RL19 for a velocity of 3100 fps
Nosler lists 65 gr IMR4831 for their 150 gr bullets for a velocity of 3240 fps and is shown as the "most accurate powder tested"
Nosler lists 63 gr IMR4350 for a velocity of 3248 fps

The point I am trying to make is that Barnes is the most conservative of all of them. Personally, I use Steve's pages and the Nosler book, it is the best and has never led me astray (yet) but I use both as a source of reference only and make my own decisions.

Also, the load density on that 57.5 gr load will be somewhere around the 74% range. One of the criteria I use for picking a powder is I want a load that is around 90% to slightly compressed. Gives me better accuracy.

quote:

Well, this morning, my accuracy seemed to be suffering because I was trying to push it too fast (with the 60 grains).

I don't think so and how could you know that is the reason. What was the velocity?

I consistantly load 2 different 7 mags with the 160 gr Barnes bullets and push them 3050 fps with RL22. To me, you are driving 35 mph on the freeway.

Woods:

No worries about getting on my case...this is an excellent discussion. But let me make sure I understand you: you think I should go back to H4831 and *begin* at 64 grains? I'll do it.

Chrono readings from the 62-grain loads were a little over 2800 fps, BTW, and the patterns were far and away worse than any I show above. FWIW...

Nope, IMR4831 which is much faster than H4831 in my experience.

IMR4831 is an excellent powder for many calibers. Works well with 270 win 140 gr bullets, 300 win mag 168 gr bullets, and fairly well with 30-06 165 gr bullets. I have never been able to get satisfaction from H4831, it is pretty slow, up there with RL22, IMO.

RL19 would also be a very good choice. That powder is slice bread with the 338 win mag and also works well in the 30-06 in the 165 to 180 gr bullets.

You don't have to do things my way but typically I start looking for a load 1.5 gr below max and go up to .5 gr above max on the first loading with a new gun. Never had to stop shooting before I hit the high load yet. Look for sticky bolt lift or extractor groove shiny spots and at the first sign go back down .5 gr.

So, 'twer me, I would start with 5 loads (3 or 4 loadings each, 5 is unnecessary when looking for a load) of IMR4831 starting at 62.5 and ascending to 64.5. If you are still not getting 3100 fps and are not getting any pressure signs (I'll get flamed for this) keep going slowly up in .3 gr increments.

Or, start with RL19 at about 64.5 grains.

Hard to believe there would be much difference between the 4831 recipes; they're really close to each other on the powder burn speed lists. But who knows.

OK...I'll pick up a pound of IMR4831 tomorrow and will report back with the results.

Woods is giving you good info.

My books show 2850, 3000 and 3250 fps as the most accurate speeds for a 150 gr 7mm Rem Mag boat.

If your powder can't get it done it's time to switch powder.

Powders that have "the same burn rate" often have different dynamic pressure curves when burned in a chamber with a moving bullet.

OK, guys...here's the rundown on todays fun and games:

The day got off to an inauspicious start. On my first round fired, the scope rings lost their grip and the scope came off, hitting me in the forehead and (more importantly) throwing off the scope calibration. Between loads, we dialed the scope back in somewhat.

62.5 grains of IMR4831

Mean velocity of 2852; extreme spread of 1 3/8" not counting the first round that caused the scope to jump ship.

63.0 grains of IMR4831

Mean velocity of 2891; extreme spread so bad I didn't even bother to measure it.

63.5 grains of IMR4831

Mean velocity of 2912; extreme spread 2 3/4".

64.0 grains of IMR4831

Mean velocity of 2947; extreme spread 2 1/8".

64.5 grains of IMR4831

Mean velocity of 3008*; extreme spread 2".

* velocity only calculated on the first three rounds; the chronograph inexplicably quit recording after that.

So...needless to say, I'm less than thrilled with the results so far. I think the explanation for the mediocre showing can be reduced to the following choices:

1. the rifle sucks.
2. the bullets suck.
3. the powder sucks.
4. the chronograph sucks.
5. I suck.

The rifle is a Sako AV. I bought it used, but it's sure in good condition. Scratch possibility #1.

The bullets are Barnes Triple-Shock 150 grains. While not everyone's cup of tea, I think it's safe to scratch possibility #2.

The loads are indeed hot, but I wasn't getting decent groupings with lower loads and slower powder (except for that one nice group at 57.5 grains of H4350). Plus I don't exactly think all of you got together and decided to lie to me about your successes with these loads. Scratch possibiility #3.

The chronograph is an Oehler Research 35P fresh from the factory. Most definitely scratch possibliity #4.

So...what to conclude? Either I'm a basket case, or perhaps my standards are too high. In any event, today was a little discouraging. Any further suggestions before I head for that needlepoint course?

Oh, one other data point: I didn't clean my rifle after yesterday's shooting, so by the end of testing today, it had over 50 rounds through it. I suppose it's possible that some amount of copper fouling may have impaired the later results.

Oh well, suppose we could have hoped for a quick solution. They do happen about half the time.

Were there any pressure signs?
How are you determining seating depth?
You are loading the new Triple Shock bullets and not the old X bullet, aren't you?
What type of brass and primers are you using?
Have you checked all the action screws to make sure they are tight?
How about the scope and base/ring screws?

In the 7 mags I load for I shoot 160 gr bullets, in one the 160 Accubond and the other the 160 gr Barnes Triple Shocks. For those I use RL22 but I have tried up to 64 gr IMR4831 with the 160 gr bullets for 3025 fps. That is one grain over book max.

Your search begins. I had a 338 win mag Sako Finnbear that I could not get to shoot. A friend talked me out of it and since then I have found a load after trying several. That happens to be 72 gr IMR4831 with a 225 gr TSX. The point is that it took a lot of work.

Hey, I just noticed that the max load for a 150 gr bullet with IMR4831 in the Nosler #5 manual is 65 grains. So my opinion is that you need to keep going up at least a couple more loads at 65 and 65.5 gr IMR4831.

Also work on the small things like bullet seating, cleaning, different primer, etc.

If you feel more comfortable shooting at the slower speeds, then by all means do it. It just seems shooting a 7 mag at 2700 fps is not what you buy one for. It is supposed to be a fast, flat shooting cartridge and it's not happening at that speed.

quote:

Originally posted by woods:
Were there any pressure signs?

No...the cases looked good. The primers were pretty flat, but my technical advisor didn't seem concerned about that.

quote:

How are you determining seating depth?

Determining? I set them to just a hair under the stated maximum. I think max cartridge length is 3.29 and we're at 3.25. I could be off on the actual numbers, but we're about a millimeter below maximum.

quote:

You are loading the new Triple Shock bullets and not the old X bullet, aren't you?

Yep.

quote:

What type of brass and primers are you using?

Estate brass and Federal primers.

quote:

Have you checked all the action screws to make sure they are tight?

No...I'll look into that tomorrow.

quote:

How about the scope and base/ring screws?

Heh...obviously not, at least not until after the first shot today. I think they're good now.

quote:

Hey, I just noticed that the max load for a 150 gr bullet with IMR4831 in the Nosler #5 manual is 65 grains. So my opinion is that you need to keep going up at least a couple more loads at 65 and 65.5 gr IMR4831.

OK...I suppose I could try this.

quote:

Also work on the small things like bullet seating, cleaning, different primer, etc.

By cleaning I assume you mean rifle cleaning. The cases are spotless before I load. I just got 400 primers today; how important is it really to try a different one?

Thanks for all the assistance with this.

I haven't loaded for the 7mm rem mag but I've never loaded anything that didn't beat 2" @ 100yds.

You mentioned that the scope came off during the test.

I would get a good set of rings and a different scope and try again.

quote:

Determining? I set them to just a hair under the stated maximum. I think max cartridge length is 3.29 and we're at 3.25. I could be off on the actual numbers, but we're about a millimeter below maximum.

The listed COAL in the manuals is a standard maximum length for the bullet manufacturer to insure that cartridge will fit in every 7 mag ever produced. Your gun has a certain distance between the bolt face when closed and the start of the lands in the barrel where the bullet first contacts. For example, I load my 300 win mag to 3.585" with the 200 gr Accubond even though the book COAL is 3.340". I can do this because I have measured the "distance to the lands" and it was 3.605" from which I subtracted .02". In other words I can say that I am shooting the 200 gr Accubond and seating the bullets .02" off the lands and everybody understands.

https://forums.accuratereloading.com/eve/forums/a/tpc/f/.../527104854#527104854
https://forums.accuratereloading.com/eve/forums/a/tpc/f/.../168102794#168102794

quote:

By cleaning I assume you mean rifle cleaning. The cases are spotless before I load. I just got 400 primers today; how important is it really to try a different one?

Thanks for all the assistance with this.

Yes, cleaning the rifle. I use the foams, it is amazing how much better they clean the bores but a little messy until you learn to control the foam.

https://forums.accuratereloading.com/eve/forums/a/tpc/f/645100744/m/981105205


Federal primers are what I use, for your load either a 210M or 215M would work. One will be a little more accurate than the other and the magnum primer should give you a little more velocity, but not much.

How are you sizing the brass? Are you neck sizing only, Partial Full Length Resizing or Full Length Resizing (how do you set your sizing die) and with what brand of dies? Are you crimping? Are you cleaning the inside of the neck out after sizing, getting all the lube out?

My son-in-law never got good accuracy from Barnes bullets. Just to let you know.

In my 7mm RM, I use H1000 and those cheap Remington 150 pointed soft points. It's less than MOA at 100 or 200 yards and runs about 2900 fps.

I killed a deer at 185 yards with that load which was 68 grain (max Load) for which I slowly worked up to. But my rifle is a Ruger #1, which from what I have heard, is a strong action.

Alway start low and work up.

Hey Bill

Good suggestion. I haven't got into different bullets with him yet but I was going to recommend 150 Nosler Partitions if needed. I have a pre-64 model 264 win mag that doesn't like the TSX but it loves the 125 gr Partitions. That bullet is always a performer in the field but usually not the best accuracy. The Nosler Accubonds have generally been second in line behind the TSX for accuracy, in my experience.

OK, guys, here's the plan: today I made up a few rounds with powder (IMR4831) loads of 62.5 (my best from yesterday), 64.8, 65.1 and 65.4 grains. I was going to go in increments of .2 grains, but the scale only claims accuracy to .1 grain, so I decided on the .3 spread.

The rifle has been cleaned, and the action is tight on the barrel. I haven't decided whether to go back to my original rings, but whichever pair I go with, I'll make sure they're well secured.

I'll go up to the range Tuesday AM (can't go tomorrow) and use the 62.5s to get the scope re-adjusted, and to try to repeat the tight grouping I got yesterday. I think I'm going to shoot these close up, becausee of the scope -- either 25 or 50 yards. Hopefully, after these, I can set the scope to something predictable and I'll move the target back to 100 yards.

If I find something that beats the 62.5 for accuracy, I'll jump on it and consider it a done deal. If I can't, I'll either fall back to the 62.5 and live with the sub-3000 velocity, or think about a different bullet. Does this sound like a good plan?

Hi, all -

Today I returned to the range with my 150 grain XBT bullets in a few different loads. Here are the results. Note that the groupings were at a *50* yard target, unlike the 100 yard targets from prior tests.

62.5 grains: 1/2" grouping, 2837 mean fps *
64.8 grains: 1 1/2" grouping, 2956 mean fps
65.1 grains: 1 1/8" grouping, 2982 mean fps
65.4 grains: 7/8" grouping, 2993 mean fps

* first of this shot was on a cold barrel. Excluding this first shot, mean fps was 2854.

These figures, along with the earlier data, seem to corroborate Swamp_fox's assertation that the highest accuracy for this cartridge is at 2850 and 3000 fps (and 3250 fps, but I just don't think that's gonna happen with this rifle).

So, the choice appears to be:

- 62.5 grains for ~2850 fps and excellent accuracy, or
- 65.4 grains for ~3000 fps and very good accuracy

Doesn't seem like I can lose either way. Thanks for all the help, guys. I welcome any closing remarks on this.

quote:

Originally posted by mzimmers:

Today I returned to the range with my 150 grain XBT bullets

Hey mzimmers, you are calling the bullets XBT's. My question, do the bullets have cannelure ( 3 or 4 of them ) on the bullet? Does the box say Triple Shock or just X bullets?

IMO, stick with the higher velocity and get what you bought the 7 mag for, flat shooting hard hitting. Work on the small things like distance from lands, neck sizing, runout, etc. and the groups will get tighter.

Yeah, you're right -- these are Triple-shocks, not XBTs. The bullets do have cannelures on them (I think three in the 150s).

I think that the "small things" you refer to are beyond my level of accomplishment right now. Do we have a resource in this forum that explains them in more detail?

I referenced a couple of threads in my post above on distance-from-lands and there are a couple more going on now.

What type of dies are you using. Are they RCBS full length dies (most common) or something else? How are you setting your sizing die, in other words how far in are you threading it? Most reloading problems and solutions are a result of how dies are set and what kind of dies you use.

Just keep following the threads on this forum and you will learn a lot quickly. Just remember to take everything said (even by me ) as information for you to think about and make up your own mind.

quote:

Originally posted by woods:
What type of dies are you using. Are they RCBS full length dies (most common) or something else? How are you setting your sizing die, in other words how far in are you threading it? Most reloading problems and solutions are a result of how dies are set and what kind of dies you use.

Yes, they're RCBS. I have both a full-length die and a neck sizer for this caliber. I imagine that the cases are pretty well fire-formed to my chamber by now. My COAL is about .04" below maximum, but I haven't done the lands test you refer to (maybe that's next).

mzimmers

when you finish your box of 150 TSX's

http://longrangehunting.com/ubbthreads/showflat.php?Cat...age=0&gonew=1#UNREAD

cheaper too

Thanks for the link, woods...you've been very helpful. How big a deal do you think it really is whose primers I use, bearing in mind that I'll be happy with a consistent 1" group?

Mzimmers/woods:
Sounds like you two guys were meant for each other. Re: Problem, problem solver. Good deal, that's the way things are supposed to work.

Missed the start of this as I've been on other things. Just found it and read the whole thread, now it's time to add my nickles worth to confuse the hell out of you. Hope not!

I've got a Sako Finnbear, new in '72, has maybe 4-500 thru it. Very few other than 175's as I got if for elk and that's a time when heavy bullets are needed most. First few yrs I used one of Hornady's 150s for antelope and a buck muley. But, this rifle's too nice to beat it up and most times it's left in camp in the case as a back up. Unless I'm walking and haven't been doing much of that due to knee's and back problems. Driving around I carry an old beat 1917 Enfield .300WinM, 200gr Sierra's now.

But: my experience with two Sakos. They are as fine a rifle as ever made, or the older one's are. My mounts are Sako's too, got them with the guns. Excellent set up the way they clamp onto the machined on action bases.

Expect since that scope came off, you've taken the stock off, and the scope, mounts, rings all apart and cleaned them up. Put them back on tight, then glued the screws in place with either Loctite, or clear nail polish. That's the first thing you need to do with a new, or newly acquired used gun. Make sure you've got a sound setup before trying to make it shoot and run into problems as you did with this one.

Next, get that bore polished out clean as it can be. (I recommend Blue Wonder Gun Cleaner as it'll take everything out real easy: ten strokes with a bronze brush, ten minute break and ten more strokes, then patch it clean and OIL that bore soon as it's patched so it don't flash rust as it'll be bare metal with all the oils, copper & lead fouling cleaned out to the steel). Then Slug the bore with a piece of soft lead from the chamber end, just keep pushing it thru and get a micrometer, or find someone that does and mic that slug. Compare that with your bullet sizes. Should be compatibly close. Inspect the muzzle real well to make sure there's no burrs, or damage to it.

Pay close attention to these things. When the bore is as clean as it can get. Study the light patterns while looking thru it. Make sure all the reflections are straight without any wavyness to the edge's of them.
When pushing that slug thru, pay attention to how it feels. Does it slide smoothly, or does it grab hold in tight spots, then get loose and move easy in other spots.

Reason I say this. My .222Mag, Vixen from when it was new had loose spots in the bore where a bullet/slug would float free without any contact at all. When I got the guns, was a short timer about to be shipped home for discharge from the Army/Germany. Too late to do anything about it, and after all the red tape hassles decided to just take it and go. It shot very tight groups thru 6000 rounds. Barrel still looks good as far as the rifling goes. But, the loose spots never changed. My gunsmith was concerned it had been plugged up when fired and buldged, but, it was like that before the first shot.
As I imported these two guns to the USA myself, of course Stoeger refused to even reply to my letters for assistance. When the accuracy went to hell, I just replaced it with another brand barrel and it's shooting one hole groups now as long as I want to keep shooting at the same spot.
This gun's stock was tight against the barrel. When the accuracy went to hell (+6"/100yds!!), one of the things my gunsmith said to try was free floating it. That helped for about 500 shots, then lost it again and gave up on it.

Can't say on the 7mmag Finnbear whether it's free floating, or not. Shoots fine, so leaving it alone. Barrel is smooth without the hollows too. So far I've shot three times at game and made one shot kills every time with it. Can't beat that no matter what, right?

After years of believing a 7mmag was magic, I got to studying the loading tables and discovered it's not much better than an 06. And much less so when it comes to bullet selection. Before jumping my ass on that, study those tables side by side.

Something I've never done and doubt ever will is use those high dollar bullets. Seems I've read where the Barnes copper bullets are mostly slower shooters in general. I have never read their books, nor used their products so don't know that for fact.

Another thing I haven't seen here yet. Get at least three loading books for comparison. Never load anything from JUST ONE book. Not even that same bullet makers book. Everyone makes typo's and mistakes sometimes, hell, even I do, rare, but, have.

Thing I've found with almost every loading book is you get one from a bullet, or powder maker and all the loads will be solely for their brands and won't include anyone else's brand of powder or bullet. Therefore, I preach getting equipment makers loading books. Of course you'll run into the same problem there too, of nothing being loaded on other brands of equipment. But, at least the components don't matter there.

I recommend: Lyman, & Lee, to start with. Then Hornady, Sierra, Speer and others as you desire. Read each book at least twice from cover to cover and study the ballistics tables for the bullets and range's you intend to shoot. At every loading, study all three book's tables for mistakes and how they match up. Each one is derived from them shooting thru their own chambers. So they can't match 100% to each other, or your guns. Every gun is an individual, same as people and animals. When you find a big difference in loads for the same powders bullets between books. Study things til you figure out why.

Have you been trimming your cases? IF not, I'd bet they're getting stretched out by now and need to be trimmed back to proper length. For ease of use and cost. Get the Lee pins/gage sets. Get two for when you break the threaded end off so you'll still have a means to finish trimming that batch til they get a replacement sent. I put the pin & cutter in a small drill press and have made up a 4" handle from steel to hold case's with. Works great and at times I've been able to trim (one step) over 400 cases per hour. The whole cost per cal runs about $6, other than extra's and the drill press. You can't trim that many, or match the price with any of those hand cranked trimmers various outfits make and charge over a hundred bucks for, plus then you'll have to fidget around with those tiny ten dollar pins.

Anytime you can't get the accuracy you want. Go bullet shopping. Get as many different makes of the same wt as you can afford. Sierra will send samples of theirs. Most others won't, but, many of the guys on here would send ten, or so to test. That's after you've settled on a load. Only change one item at a time and then work with it until you find what meets your goal. Swapping bullets, powders, primers and cases, plus different seating depths all at the same time will drive anyone nuts. So find what you want with one, then change only one of the settings, or components and start over until you get it worked out. Doing this with those $2 bullets like you're doing will break a man's bank account. OR it will mine.

Anytime the stock, or scope comes off. First session: start at 25yds to get it lined up. Then move to 100yds and make final adjustments according to the game and distance you intend to shoot. For out here in CO in the wide open plains a 300yd zero is not out of line a bit. But, many places like back east, and down south you guys have never seen 300yds even on many of the highways. I know, I've been there. haha!

Hope this helps some, wish you well.

George