Help rookie with reloading and shooting data

Joined
Jan 10, 2026
Messages
35
Hey guys!

Brand new reloader here. I just worked up my first set of test loads for my .308, and I'm having a hard time making sense of how they shot and could use some wisdom! I worked these up mostly to learn about the process and get experience.

Here's the data on the loads:

Bullet:
Hornady 308 150gr FMJ-BT #3037
BC: .398 (G1)
SD: .226

Powder:
Vihtavuori N150. Their tests with this bullet were from 44.0 gr - 48.0 gr. I tested the following, 5 rounds of each:
46.0gr
46.5gr
47.0gr
47.5gr
48.0gr

Brass: All matching Winchester, once fired. No crimp.

Primer: Magtech Large Rifle.

All bullets were backed off the lands by 0.005."

Shooting was done at 100yrds, and from a vice. Loads were shot out of a 20" barrel with a 1/10 twist.
Here is how they shot:


46.0gr loads:
#1: 2712 FPS
#2: 2708 FPS
#3: ERR
#4: 2738 FPS
#5: 2706 FPS
Avg: 2716 FPS
Min/Max difference: 32 FPS

20260605_111105.jpg

46.5gr loads:
#1: 2686 FPS
#2: 2755 FPS
#3: ERR
#4: 2718 FPS
#5: 2742 FPS
Avg: 2725 FPS
Min/Max difference: 69 FPS

20260605_111109.jpg

47.0gr loads:
#1: 2780 FPS
#2: 2789 FPS
#3: 2755 FPS
#4: 2794 FPS
#5: 2761 FPS
Avg: 2776 FPS
Min/Max difference: 39FPS

20260605_111112.jpg

47.5gr loads:
#1: 2813 FPS
#2: 2831 FPS
#3: 2835 FPS
#4: 2816 FPS
#5: ERR
Avg: 2824 FPS
Min/Max difference: 22FPS

20260605_111115.jpg

48.0gr loads:
#1: ERR
#2: 2841 FPS
#3: 2839 FPS
#4: 2841 FPS
#5: 2831 FPS
Avg: 2838 FPS
Min/Max difference: 10FPS

20260605_111118.jpg


For comparison (and to make sure I wasn't the problem), here is a 5 shot group I shot right after these with Factory Hornady Black 168gr.
20260605_112806.jpg


It looks like the 46.5 and 48.0 shot the best groups, and the 48.0 had the tightest FPS. But no group looks good compared to factory.

My question is where do I go from here? Should I try the same loads with a crimp so they have even neck tension? Go down in powder charge? I know that the projectile isn't the greatest, but should my groups be this bad? I'm here to learn!
 
You could try tuning the seating depth specifically further from the lands.

But if it were me I'd try a new bullet. FMJ 150ish 308 bullets in my experience can turn good rifles into shotguns. Try a sierra match bullet.

I'd also mention that unless you've gotten good accuracy out of other guns the user error possibilities are endless. Not to mention possible issues with your rifle, scope mount, etc.
 
You could try tuning the seating depth specifically further from the lands.

But if it were me I'd try a new bullet. FMJ 150ish 308 bullets in my experience can turn good rifles into shotguns. Try a sierra match bullet.

I'd also mention that unless you've gotten good accuracy out of other guns the user error possibilities are endless. Not to mention possible issues with your rifle, scope mount, etc.
I'm inclined to agree with all of this. 150gr factory loads have looked about similar to these reloads. 168-180gr have shot moa groups from this rifle though.

I bought these bullets mostly for target practice and working through the reloading process. It's a bummer if the rifle hates em

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I'm inclined to agree with all of this. 150gr factory loads have looked about similar to these reloads. 168-180gr have shot moa groups from this rifle though.

I bought these bullets mostly for target practice and working through the reloading process. It's a bummer if the rifle hates em

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You won't be the first to think 150 gr FMJ would make a great practice round.

You won't be the last to get terrible accuracy with them.

Mine are being used up plinking out of a .300 aac.
 
Is the shot on the top of the large diamond from the group of factory ammo? If so it's at the same size as your best test groups
 
Read this. IMO those are kind of not Great bullets. Try an ELDX, or Sierra 150 game kings if you want to stay at 150 grains.

 
Is the shot on the top of the large diamond from the group of factory ammo? If so it's at the same size as your best test groups
No sir, it should be the bottom picture of my post. Had tight group of 4 and a flyer for shot #2 that I knew I pulled as soon as I felt recoil.

Here's the picture of the factory ammo again. Hornady Black 168gr.20260605_112806.jpg

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Read this. IMO those are kind of not Great bullets. Try an ELDX, or Sierra 150 game kings if you want to stay at 150 grains.

Dang, I was worried about that. I'm not married to the 150gr by any means. Thought that it might make a good bullet to get some reloading experience on. But if it's not shooting well then I guess I was wrong on that

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Dang, I was worried about that. I'm not married to the 150gr by any means. Thought that it might make a good bullet to get some reloading experience on. But if it's not shooting well then I guess I was wrong on that

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I tried the 150 fmj’s in my 30-06, and also 165 gr hdy interlocks. My gun didn’t like either but it does fine with 178 eldx, 165 SGK, 165 nosler accubond. My son’s .308 also likes the 178 eldx. I think long skinny bullets are great if your barrel has enough twist to stabilize them, and if you don’t mind the recoil.

Main thing I was driving at… try some different bullets.
 
Try a premium bullet

Don’t be discouraged, some bullets just do not shoot well in some rifles.

Clean the gun till you get pretty much a white patch. Shoot 5 shots, then start o er with groups.


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I do most of my initial load development with Sierra Gamekings. If I can't get a rifle to shoot well with GKs, I don't think it will shoot well with anything.

What do you mean by using a vise? Can you show us a pic?
 
155 Scenar would be on my list. And I'd get an actually rifle rest and rear bag to shoot with.
 
I do most of my initial load development with Sierra Gamekings. If I can't get a rifle to shoot well with GKs, I don't think it will shoot well with anything.

What do you mean by using a vise? Can you show us a pic?
My apologies! Wrong terminology! Idk why I've always called them a "vice." It was a lead sled. I shot from a lead sled. super sorry for the confusion.

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Seems like the consensus is to try a different bullet. Am I hopeless to try for any better groups with this one for target practice? I have 275 left I don't expect .25 moa. But it would be cool to at least get 1.5 for target practice.

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First of all, get rid of the lead sled. Contrary to popular belief they don't do a dang thing to increase accuracy. In fact, they hurt it as it is much harder to get consistent with your hold and follow-through. Plus, they play merry hell with your mounting screws (action and scope).

Second, I disagree with this statement whole-heartedly.
New bullet, new powder, or new barrel. You pick.

There is no subtle thing that will fix a terrible group in my opinion.

In my experience, seating depth can take a 3" group to a >1" group. I am not saying that it will always happen that way, but there are bullets out there that are very depth sensitive.
Also, you didn't state what velocity you were getting from the Hornady ammo. I would say that if that ammo shoots good in your gun, then get some 168 grain bullets and try to replicate that load, rather than come up with a brand new load using different bullets. There are some relatively inexpensive 168 grain bullets out there.
 
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