Is this load worth tuning?

[IdahoSpud]

Is this load worth tuning or is something wrong and I should scrap it and change components? I was finally able to get some good SDs and ESs but the groups are HORRIBLE. Rifle shoots sub MOA with factory rounds.

The last 3 five shot groups were reading ES of 21 or less with SDs in the single digits.

300 Winchester Magnum. Using brand new Peterson long brass. Neck tension set with a mandrel, cases chamfered and deburred before loading. Bullet seated to mag length with .001 tolerance.

 

[Krob95]

tune your seating depth. Start by going back 3 thou to whatever you want the shortest to be. Usually I start from 10k off and back off to 40k off.

 

[IdahoSpud]

tune your seating depth. Start by going back 3 thou to whatever you want the shortest to be. Usually I start from 10k off and back off to 40k off.

I’m loaded to max mag length so I can seat it deeper .003 each time. But before I do that, is it even possible to tune groups this large into good ones? They are massive. I just want to make sure I’m not going to waste more time and components.

 

[Krob95]

I’d say yes it is possible to tune it in to something smaller. If you want you can do 5 thou deeper each time. 3 thou is just my go to.

 

[Krob95]

It’s not wasting time or components if you’re moving towards a goal which in this case is getting the groups smaller. If it was easy, everyone would do it lol

 

[redx]

i say start over. Do a decent ladder test and go from there. BTW what load are you using? Plus is it a hunting profile barrel or a heavy barrel?

76 looks ok, is the flyer the 1st shot for that charge?

 

[culater]

Tell what rifle you have and twist rate ect.

 

[IdahoSpud]

Bergara HMR 1:10

I have tried 220s, 215‘s, and now these 200s. All Bergers. H1000 powder. They have all looks like this. I guess I should’ve added I can’t really start over. It took me six damn months just to get 400 rounds worth of components.

I don’t understand what’s going on. I know the rifle shoots. I got a solid load on my .223 with crappier tools and components.

I’m not sure what shot the flier was on 76. There were no pressure signs at 78 grains with 3200 FPS. Should I keep going up….?

 

[redx]

try starting at 74.5 and working your way up to 76. seems like everything past 76 was opening up.
I had a feeling it was a Bergara when I looked at the 2,2,1 group the flyer was probably the last shot. What velocity was the factory loads that you liked? you might try to load to that velocity.

 

[tnc]

If you’ve tried all those different bullets at mag length and got bad groups with all of them, seat it deeper. Do 10,20,30,40,50 thou off and you’ll see one noticeably better. Then tweak it .003 in either direction

 

[IdahoSpud]

try starting at 74.5 and working your way up to 76. seems like everything past 76 was opening up.
I had a feeling it was a Bergara when I looked at the 2,2,1 group the flyer was probably the last shot. What velocity was the factory loads that you liked? you might try to load to that velocity.

No idea what velocities. Since I’m using a bayo I didn’t want to hang it and alter the groups.

I guess it depends, but wouldn’t less than 3000fps on a 200grn projectile be pretty lame? 68 was right there at 3000.

 

[918v]

I’m loaded to max mag length so I can seat it deeper .003 each time. But before I do that, is it even possible to tune groups this large into good ones? They are massive. I just want to make sure I’m not going to waste more time and components.

Yes. A 300WM will go from a quarter inch to what you see fairly quick when using new brass. Once you have fireformed 1x brass it gets better.

I would pick 77 grains and start seating the bullet deeper in .005” increments. Do 3 shot groups.

 

[IdahoSpud]

Yes. A 300WM will go from a quarter inch to what you see fairly quick when using new brass. Once you have fireformed 1x brass it gets better.

I would pick 77 grains and start seating the bullet deeper in .005” increments. Do 3 shot groups.

I don't have any other components so as long as It's possible it will tighten up to 0.5" messing with seating depth I'll continue on. Just wanted to make sure I wasn't pissing away components on something that wasn't possible.

 

[redx]

Yes. A 300WM will go from a quarter inch to what you see fairly quick when using new brass. Once you have fireformed 1x brass it gets better.

I would pick 77 grains and start seating the bullet deeper in .005” increments. Do 3 shot groups.

why 77 over 76? 76 is the tighter group. Its clear that the groups open up the higher the load that's why I suggested 74.5 and working up.
I do suggest 3 shot groups as well. In my experience Bergara 300 win mags dont like 5 shot groups.

 

[n0glock]

I know this is probably the wrong way to do it but I start my length on new bullets by using a comparator on ammo I know shoots well and start there, I am usually in the ball park of what shoots well with the new bullet.

 

[bluejay75]

The bottom side of the charge range might be worth trying and reshoot 76. Imagine shooting a one hole group to find out it’s not so great in fireformed brass. You’re in a good spot at the moment. So getting your set of fire formed brass will increase your confidence when you’re done.

 

[918v]

why 77 over 76? 76 is the tighter group. Its clear that the groups open up the higher the load that's why I suggested 74.5 and working up.
I do suggest 3 shot groups as well. In my experience Bergara 300 win mags dont like 5 shot groups.

Because you can’t tell when groups are that big, and H1000 is a bit too slow burning for 200gr bullets so the higher charge will make more pressure and help lower the ES/SD.

 

[IdahoSpud]

Because you can’t tell when groups are that big, and H1000 is a bit too slow burning for 200gr bullets so the higher charge will make more pressure and help lower the ES/SD.

I figured because it was where my best ES and SD were. Using Eric Cortinas method that is the only thing that should be important when selecting a powder charge?

Focus on a low ES and then tune with seating depth for group sizes. From what I’ve read a lot of guys won’t even shoot a paper when selecting a powder charge and will just shoot into a berm and check ES and SD.

this is why I started with five shot groups. Once I move to seating depth adjustments I will go back to three shot groups

 

[918v]

You can always fine tune the charge up and down but find the coal first because your groups are too big right now.

Also, just because you got best ES at charge A with coal B doesn’t mean it will stay low at coal C.

 

[GONE BAD]

I’m loaded to max mag length so I can seat it deeper .003 each time. But before I do that, is it even possible to tune groups this large into good ones? They are massive. I just want to make sure I’m not going to waste more time and components.

OP, I have been in the same boat as you.
Factory 300WM.
I started a thread awhile back asking about pressure signs and flat primers.
I got quite a bit of useful info from members here on the Hide.
Now after 180 rounds of priceless ammo I'm just starting to see a glimpse of light.

The rifle shot excellent for me and my abilities with factory ammo (1/2" groups) didn't matter if it was clean cold bore or 20 rounds.
They were just not made for what I wanted for shooting long distance, 150gn spire point.

I started load development with the same bullet as you and COAL at magazine length, which still left me with a long long jump!
Now after 160 rounds I was able to get 500 ELDX and started over. Powder supplies were getting low and then I was able to get 8lbs of 7828ssc.

Now fast forward I've lowered my powder charge to mim book and started to look for a velocity that more aligned with book speeds. In my case 2850 fps.

The next thing I did was get my cases fire formed and sized to within .002.
Then I loaded two different COAL's.
One was 3.420, 10 rounds.
The other was 3.485, 10 rounds.
Same everything except COAL.

Here's what I found out; 3.420" shot better than the 3.485". Also the velocity was different as was SD's .
3.420 = 2830 w/SD 4.5
3.485 = 2860 w/SD 8.2

My last outing i upped the charge wt. 1gn and kept the COAL at 3.420 and shot a clean cold bore group less than 1moa.
I haven't checked velocity yet but hoping I'll be at 2900fps. The I'm going to keep adjusting COAL more towards the 3.340"
at probably .010 at a time.

I really can't say any of this is the norm and others will chime in but for a hunting rifle it seems if you don't run a long magazine that you can get to the lands then your choices are limited.

Hope some of this makes sense?
Chasing speed can be challenging.
Pick a speed that is exceptable and adjust COAL more closely to 'saami'.

 

[IdahoSpud]

Damn. I appreciate you typing all that out. I sure hope it doesn't take that much screwing with just to get a 1 MOA rifle. I'm going to mess with seating depth. I'll do a handful of loads pushing the bullet back in and if it doesn't work I guess I'll seat longer than mag length.