300 Win Mag / H1000 / 200 Accubonds test

[TackDriver284]

I may need some advice, but can think what the issue may be. " Case Volume" but not sure, hope you guys can advise.

Nosler book minimum 74 and max is 78 grains
Lapua brass ( current ) H20 is 92.29 gr and Norma brass is 95.20 ( recently used ) / started using Lapua last year and been using Norma and never had high speed or pressure issues if following Nosler manual powder recommendations
300 Win Mag using H1000, CCI 250, 200 grain Accubonds, COAL 3.515" Lapua brass, 3 round groups in .4 increments:

Fouler : 76.6 grains / 3,005 fps
77.0 grains / 3041, 3075, 3068 fps
77.4 grains / 3052, 3018, 3061 fps
77.8 grains / 3096, 3025, stopped shooting
78.2 grains N/A

Speed is incredibly fast with the slow H1000 powder, ES is all over the map and I measured to the kernel using the FX-120i and expected 2900-2950 fps and grouping was not good, best is 1.25" to 1.5" @ 100. Max is 78 grains and speed should be around 2851 fps as shown in the manual and I was pushing 3,043 fps with 77.4 grains. Here is a couple of charts from QL to see what pressure I'm at. First pic is QL tweaked to use 77.4 grains with the Lapua H20 volume. The Norma brass that I used to use has a larger case volume, unlike the current Lapua brass which is 92.29 compared to 95.20. Would the case volume be the issue why its pushing too fast?
OAL is .010" off the lands, but if seating deeper, then pressure will rise as well

I may want to retry H1000 with lower charges from 74 to 76 grains which is low to mid recommendations in the Nosler manual and seat the bullets deeper to .050" off the lands since my COAL is 3.515" and the manual says max 3.340" or dump the H1000 and go back to RL 22 or RL 25 and do a ladder?

 

[desertcj]

I’ll preface that I don’t load or shoot 300 win mag. Closest I do is 7mm rem mag, 180gr Eld-m, H1000 at 73gr if I remember correctly and I use CCI BR2 primers loaded to 3.475”.
I see that you’re also loading quite long which can produce a difference between book velocities and book charge weights. I get 3000fps with a 180gr bullet, try finding that in any published 7mm REM Mag load data! I do think that your new brass with less capacity could be an issue but are you seeing any pressure signs? You might try a different primer and see if that doesn’t tighten up the ES?

 

[JD338]

I'd stick with H1000. You are almost there.
It could be that you have a fast barrel .
Changing the primer could also help with the ES.
I have found that some of my accuracy loads have ES of 30-40+ fps. Go figure.

JD338

 

[TackDriver284]

I’ll preface that I don’t load or shoot 300 win mag. Closest I do is 7mm rem mag, 180gr Eld-m, H1000 at 73gr if I remember correctly and I use CCI BR2 primers loaded to 3.475”.
I see that you’re also loading quite long which can produce a difference between book velocities and book charge weights. I get 3000fps with a 180gr bullet, try finding that in any published 7mm REM Mag load data! I do think that your new brass with less capacity could be an issue but are you seeing any pressure signs? You might try a different primer and see if that doesn’t tighten up the ES?

No pressure at all, primers don't look too flat, no ejector marks either, just the speed is quite fast which made me stop. CCIBR2 is standard primers, will that be enough to light all that slow powder? I have some Fed 215's and WLRM primers as well.
By the way, its once fired Lapua brass.

 

[JD338]

My rule of thumb is for 60.0+ gr charge weights, I use magnum primers only.
My go to is Federal GM215M match grade primers but I read somewhere that Winchester WLRM primers are hotter than Federal.
I'd stick with what you have.

 

[IdahoCTD]

Smaller case capacity will pressure out sooner and have lower velocity. I had the same problem with RWS brass. It will take the pressure but it never shot well. My guess is your in the same boat. I know the 200gr AB have a longer bearing surface than the 215 Bergers we shoot and we shoot around 2960fps with 215's and H-1000. I think if you drop into the 2900's your accuracy will come around.

 

[wvbuckbuster]

I might have missed it but as you were checking speed, ES, SD, did you shoot for groups? As Jim stated some of my best loads-groups do not have a small ES or SD. If you get the accuracy you want with the velocity, then don't worry about it. It is what it is. Dan.

 

[desertcj]

No pressure at all, primers don't look too flat, no ejector marks either, just the speed is quite fast which made me stop. CCIBR2 is standard primers, will that be enough to light all that slow powder? I have some Fed 215's and WLRM primers as well.
By the way, its once fired Lapua brass.

I was told that BR2’s are almost a magnum primer? Regardless, I’m not necessarily suggesting that you try them as much as I was just stating the components that I use in a somewhat similar application.

 

[SJB358]

Smaller case capacity will pressure out sooner and have lower velocity. I had the same problem with RWS brass. It will take the pressure but it never shot well. My guess is your in the same boat. I know the 200gr AB have a longer bearing surface than the 215 Bergers we shoot and we shoot around 2960fps with 215's and H-1000. I think if you drop into the 2900's your accuracy will come around.

I agree with Nathan here. Drop back a bit and see what you get.

 

[TackDriver284]

Ok, I'll retest it at lower charges and use Federal 215's and see what it shows on paper.

 

[RL338]

Not sure how old your 250 primers are , the ones I bought last year showed awful ES in 2 cartridges.
Yes the Lapua brass would show a little extra velocity with its lower internal capacity , but shouldn’t be that much.
One would next question the chronograph’s accuracy.
Running the numbers provided in the first post , I would believe 75grs is where you may find what you’re looking for.

 

[SJB358]

If your 300 is straight and true you aren't likely to get traditional pressure signs till you're quite a bit about 65K. Good straight guns hide alot of stuff we have read that is a true pressure sign until you're locking bolts up.

Look for 2900-3000 with H1000 or if you dare, try a little H4350 and see what the paper tells ya. That 200 AB is an animal in my opinion in 300 magnums. It has accounted for alot of elk meat for our group.

 

[Teknys]

Oh how I wish my Sako could stabilize that 200AB! Great Elk bullet !

 

[flyingagg]

If your 300 is straight and true you aren't likely to get traditional pressure signs till you're quite a bit about 65K. Good straight guns hide alot of stuff we have read that is a true pressure sign until you're locking bolts up.

Look for 2900-3000 with H1000 or if you dare, try a little H4350 and see what the paper tells ya. That 200 AB is an animal in my opinion in 300 magnums. It has accounted for alot of elk meat for our group.

I load that in my 300WBY, two rifles, 200 AB or 200 PT, RL 22, same load. Took them to Africa, had great success. I need to try in in my M70 300WM and 300WBY

 

[jimbires]

is your old norma brass still usable ? if it is I'd try loading a couple of these powder charges in that brass and see what you get . it looks like 3.0 grains of water capacity changes the pressure about 5000 to 6000 PSI . this doesn't sound like enough to give you the problems you're seeing , unless your loads in the Norma brass were right up against over pressure , but didn't show .

the 200 grain AccuBond has a long bearing surface , this will make pressure easier than a shorter bullet .


I'd like you to measure a loaded neck diameter in the old Norma brass , and also measure a loaded neck diameter with the new Lapua brass . I'm wondering if maybe the necks are thicker causing problems . a quick check is to try to put a bullet in a fired case and see if it falls through , or lightly pushes through the neck . if your cases do this you have enough neck clearance . this quick test is NOT 100% the final word . my custom chambers will not allow a bullet to go through . they are no turn chambers , but tight enough that when the brass neck springs back it's to tight for the bullet to easily go through .

you can also try the old norma load in the new lapua brass and see what happens .

test your scale ; did your powder pan weigh what it usually does ? I use the same scale , it's always been correct . I keep three bullets in a bag that I weigh before every loading session . a 55 grain , a 85 grain , and a 180 grain . I have the exact weights of these wrote down on paper , that I keep in the bag . I think if it weighs three bullets and the powder pan correctly the scale is good to go .


let us know what you find . I'll keep thinking .

 

[TackDriver284]

@jimbires

I had a similar high velocity issue with the ELD X 200 grain / RL 26 as well with the same rifle, wrote this post last year before my 2 nilgai cow hunts.
I'll redo the H20 on the old Normas and the current Lapuas, I'll get back with what i find.

Edited: Checked the H20 capacity on the Lapua and Norma,,,Average from 3 cases,,,Lapua H20 is 92.11 and Norma is 94.96,,,,its almost a 3 grain difference and measured the thickness of the neck with a micrometer, its about .001 -.0015 difference between the Lapua and Norma with Lapua being the thickest with a little variation from case to case with the old Norma which was fired about 6-7 times, and as for dropping a .308 bullet in a fired case, it slides right in the Norma brass fired neck, but the Lapua neck is pretty tight when trying to slide the bullet in, just need to push it in and it seems it may also restrict the bullet from being released upon firing. Possible neck turn the brass a half thousand on each side to make it a little thinner?
I am sure the scale is spot on, used weights to check before using it. I usually let it warm up for 15 mins before using.

Need some advice

I tested the 300 Win Mag this morning, 200 ELD-X and RL26. This is my first time using Rl26 and I did not find any data on the 200 grain bullet, so I used the minimum and max loads for the 210 grain bullet. Lapua brass, fired 1X and CCI250 primers. .002" neck tension 210 grain bullet in Nosler...

forum.nosler.com

 

[TackDriver284]

Not sure how old your 250 primers are , the ones I bought last year showed awful ES in 2 cartridges.
Yes the Lapua brass would show a little extra velocity with its lower internal capacity , but shouldn’t be that much.
One would next question the chronograph’s accuracy.
Running the numbers provided in the first post , I would believe 75grs is where you may find what you’re looking for.

I was leaning to do it again from 74-75 grains,,,,don't get me started on buying the Garmin.

 

[IdahoCTD]

If the bullet is tight on a fired Lapua case that means the clearance was tight to the chamber and the spring back was enough to create a tight neck. When I loaded the Lapua brass I had I turned the necks quite a bit. Too little neck clearance will cause pressure and erratic accuracy as well. My 300wm reamer has a .338 neck for Winchester brass at .335" for a loaded round. The loaded Lapua rounds were .004-.005" over the Winchester. I think Sammi is .342 for neck diameter. Under .003" clearance is asking for issues.

 

[TackDriver284]

If the bullet is tight on a fired Lapua case that means the clearance was tight to the chamber and the spring back was enough to create a tight neck. When I loaded the Lapua brass I had I turned the necks quite a bit. Too little neck clearance will cause pressure and erratic accuracy as well. My 300wm reamer has a .338 neck for Winchester brass at .335" for a loaded round. The loaded Lapua rounds were .004-.005" over the Winchester. I think Sammi is .342 for neck diameter. Under .003" clearance is asking for issues.

I still have some new Norma brass on my shelf, I may just try those instead of the Lapua. If that does fix the high pressure issues, then I'll turn the necks down some on the Lapua brass

 

[jimbires]

sounds like you found a potential problem . keep us in the loop on how things go , I'm interested in the outcome .