I’m new to Lapua brass and I started my 308 load developememt from book min and worked up to book max. Rifle/loads specs:
CA 308 win 20” carbon barrel 1-10 twist Lapua Brass CCI BR 2 primers H4895 powder (bought newa few months ago) Scenar 155 Seated to 2.800
Hodgdon website says 43-46 grains with a velocity range of 2730-2870 for 154 Sierra HPBT at 2.775. Because the Scenar is about .020” longer than the 155 Sierra, I loaded the Scenar to 2.800 OAL
44.5,45 and 45.5 all shot into a small hole at 112 yards.
Remember those velocities are with only a 20” barrel and suppressor, when the book velocities are at 24”.... I thought I should be 75-100 FPS slower than book.
I measured my case capacity of water in several pieces of Lapua brass after being shot in my gun and it measured approx 44.5 grains. I had someone input all this data with 44.5 grain of H4895 into QL and it says I’m at 65,800 psi when sammi max spec is 62,000 psi. At that PSI and grin of powder, QL says I should be at 2816 FPS, so I’m about 40 FPS faster than what QL says I should be . One can only image the pressure that 46 grains was!
But I got no obvious signs of pressure! No ejector marks, no large cratering of the primer, no abnormal bolt lift. Brass head stamp picture attached.
Is this normal with Lapua brass? If so how does one know where pressure is/should be?
That prime on 46 looks flat to me, not easy to tell with the small picture, and BR2's are hard primers, they don't flatten easily.
Keep in mind, it's not uncommon for many of the classic pressure signs to not show up until around 70K PSI.
Thanks for your input, and good to know about the 70k pressure signs.. sorry for the small pic, it won’t let me upload any bigger picture files. Here’s a close up of the 46 grains brass. This is the first time this Lapua brass has been shot
That primer looks fine to me. Probably one of the reasons they say be cautious and know that you wont always see classic pressure signs. One reason to keep an eye on velocities. Ive also been messing with a new to me 308w using the same brand of brass and BR2 primers. Using a few different powders all at close to max book charge weights. No obvious pressure signs either. Even though im running some compressed loads.
Originally Posted by raybass
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style.
Originally Posted by Pharmseller
You want to see an animal drop right now? Shoot him in the ear hole.
I’m new to Lapua brass and I started my 308 load developememt from book min and worked up to book max. Rifle/loads specs:
CA 308 win 20” carbon barrel 1-10 twist Lapua Brass CCI BR 2 primers H4895 powder (bought newa few months ago) Scenar 155 Seated to 2.800
Hodgdon website says 43-46 grains with a velocity range of 2730-2870 for 154 Sierra HPBT at 2.775. Because the Scenar is about .020” longer than the 155 Sierra, I loaded the Scenar to 2.800 OAL
44.5,45 and 45.5 all shot into a small hole at 112 yards.
JMO.. I do believe the Lapua brass has less case capacity than the Winchester brass referenced on the Hodgdon reloading page. Hence, higher pressure with same components. With a 20" barrel following Hodgdon loads I'd say you should be looking for 2770 fps + or - a bit.
I use Hodgdon data with a 308 22" barrel 1:10. I called it good at 44.5gn H-4895 at 2840 fps.
when I used Lapua brass with Nosler’s published load data for my 7mm-08 I hit high pressure below I hit their max load. All components were the same as Nosler’s load data except that I was using Lapua brass.
Is this brand new, unfired brass? Often enough new brass doesn't show pressure as readily as fired brass.
Also, what chrono are you using?
Yea brand new never fired brass. I was not aware that brand new brass didn’t show signs as much as fired brass. I’ll reload some and try the test again. Any idea what the reasoning is why new brass doesn’t show pressure as easily?
Using Caldwell precision chronograph approx 6-8’ from muzzle
when I used Lapua brass with Nosler’s published load data for my 7mm-08 I hit high pressure below I hit their max load. All components were the same as Nosler’s load data except that I was using Lapua brass.
When you say hit pressure, what signs of pressure did you see?
Is this brand new, unfired brass? Often enough new brass doesn't show pressure as readily as fired brass.
Also, what chrono are you using?
Yea brand new never fired brass. I was not aware that brand new brass didn’t show signs as much as fired brass. I’ll reload some and try the test again. Any idea what the reasoning is why new brass doesn’t show pressure as easily?
Using Caldwell precision chronograph approx 6-8’ from muzzle
New brass has never been squished up against the chamber walls under pressure, so on the first firing the expansion of the brass absorbs some of the energy that would otherwise be transmitted to other indicators.
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
You cannot over estimate the unimportance of nearly everything. John Maxwell
It's important to remember that higher velocity than the data projects is a pressure sign, even if the brass doesn't show it.
The way I see it though, is that the bolt actions will take far more pressure safely than the brass will, so if the brass is showing no indications of being pushed outside of its functional window, the load is likely safe, even if it is above SAAMI specs for pressure. But we each take personal responsibility for our loading and shooting practices. Were I looking at what you have here in my own rifle, I'd further test 45 grains for accuracy and low SD/ES of velocity, and run with it if all was good.
While research on this topic I came across a person weighing the water capacity by first weighting the brass, then weighting brass and water and subtracting the two. Originally I was doing it by filling the case and then trying to get all the water out of the case and weighting that water (let’s call this the old method).
Old weighting process results: Case #1: 54.9 grains of water Case #2: 54.9 grains of water Case #3: 54.8 grains of water Case #4: 54.9 grains of water
New weighting process: Case #1: 55.6 grains of water Case#2: 55.7 grains of water Case #3: 55.6 grains of water Case#4: 55.8 grains of water
Difference in case capacity between old method and new method Case #1: + .7 grains = + 1.3% Case #2:+ .8 grains = +1.5% Case #3: + .8 grains = +1.5% Case #4: +.9 grains = +1.6%
So this is telling me my case volume is a bit higher than when I had someone run QL data for me at 54.5 grains of water (was being conservative with the info I gave to the person).
So that would somewhat explain why I’m not seeing pressure signs on my Lapua brass BUT when I rerun these number the velocity will decrease and be even further off what my chronograph says. Currently quick load is underestimating my velocity by approx 40 FPS, with this higher case volume it could then be under estimating my velocity by 60+ FPS?
Seems as tho this added more questions instead of clarifying LOL
Are you using new brass both times? If not after being blown out it can and usually will give different case capacities. Now as far as velocity per charge, that could also be a function of a tight chamber and shorter throat. Case in point I have 3 rifles with match chambers and throats, at .5 to .75 grains under I average about 10-20 FPS velocity over what max charge is supposed to give.
Are you using new brass both times? If not after being blown out it can and usually will give different case capacities. Now as far as velocity per charge, that could also be a function of a tight chamber and shorter throat. Case in point I have 3 rifles with match chambers and throats, at .5 to .75 grains under I average about 10-20 FPS velocity over what max charge is supposed to give.
The case capacity of H20 was weighted on new Lapaua brass after only firing one time in my chamber
Is that 10-20 FPS faster in the same length barrel as published data (24-26”) or do you have a 20” barrel as well?
Now, lets use your new H20 volume and compare the predictions for the Sierra and Sencar:
First the Sencar:
Code
Cartridge : .308 Win. (SAAMI)
Bullet : .308, 155, Lapua Scenar GB491 7073
Useable Case Capaci: 46.753 grain H2O = 3.036 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Hodgdon H4895
Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.111% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-11.1 93 40.00 2510 2168 44772 8471 95.1 1.127
-10.0 94 40.50 2540 2221 46417 8579 95.5 1.108
-08.9 95 41.00 2571 2275 48123 8684 96.0 1.090
-07.8 96 41.50 2601 2329 49893 8786 96.4 1.072
-06.7 97 42.00 2632 2384 51729 8884 96.8 1.054
-05.6 99 42.50 2663 2440 53634 8979 97.2 1.037 ! Near Maximum !
-04.4 100 43.00 2693 2496 55612 9070 97.6 1.020 ! Near Maximum !
-03.3 101 43.50 2723 2553 57665 9157 97.9 1.004 ! Near Maximum !
-02.2 102 44.00 2754 2610 59797 9241 98.2 0.988 ! Near Maximum !
-01.1 103 44.50 2784 2668 62011 9320 98.5 0.972 !DANGEROUS LOAD-DO NOT USE!
+00.0 104 45.00 2814 2726 64313 9396 98.7 0.957 !DANGEROUS LOAD-DO NOT USE!
+01.1 106 45.50 2845 2785 66705 9467 99.0 0.941 !DANGEROUS LOAD-DO NOT USE!
+02.2 107 46.00 2875 2844 69192 9534 99.2 0.926 !DANGEROUS LOAD-DO NOT USE!
+03.3 108 46.50 2905 2904 71779 9596 99.4 0.912 !DANGEROUS LOAD-DO NOT USE!
+04.4 109 47.00 2935 2965 74472 9654 99.5 0.898 !DANGEROUS LOAD-DO NOT USE!
+05.6 110 47.50 2965 3026 77274 9707 99.7 0.884 !DANGEROUS LOAD-DO NOT USE!
Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
And now the Sierra:
Code
Cartridge : .308 Win. (SAAMI)
Bullet : .308, 155, Sierra HPBT MK 2155
Useable Case Capaci: 50.040 grain H2O = 3.249 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Hodgdon H4895
Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.064% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-10.6 91 42.00 2552 2241 45463 9021 95.9 1.116
-09.6 92 42.50 2581 2293 47028 9127 96.3 1.099
-08.5 93 43.00 2610 2345 48646 9230 96.7 1.082
-07.4 94 43.50 2639 2397 50319 9330 97.1 1.065
-06.4 95 44.00 2668 2451 52050 9427 97.4 1.048
-05.3 96 44.50 2697 2504 53841 9520 97.7 1.032 ! Near Maximum !
-04.3 98 45.00 2727 2559 55694 9610 98.0 1.017 ! Near Maximum !
-03.2 99 45.50 2755 2613 57611 9696 98.3 1.001 ! Near Maximum !
-02.1 100 46.00 2784 2668 59596 9778 98.6 0.986 ! Near Maximum !
-01.1 101 46.50 2813 2724 61652 9856 98.8 0.971 !DANGEROUS LOAD-DO NOT USE!
+00.0 102 47.00 2842 2780 63780 9931 99.1 0.956 !DANGEROUS LOAD-DO NOT USE!
+01.1 103 47.50 2871 2836 65985 10001 99.3 0.942 !DANGEROUS LOAD-DO NOT USE!
+02.1 104 48.00 2899 2893 68270 10068 99.4 0.928 !DANGEROUS LOAD-DO NOT USE!
+03.2 105 48.50 2928 2951 70638 10130 99.6 0.914 !DANGEROUS LOAD-DO NOT USE!
+04.3 106 49.00 2956 3008 73093 10187 99.7 0.901 !DANGEROUS LOAD-DO NOT USE!
+05.3 107 49.50 2985 3066 75640 10241 99.8 0.888 !DANGEROUS LOAD-DO NOT USE!
Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba 102 47.00 2881 2857 67291 9879 99.7 0.9
You'll notice the predicted max safe velocities are effectively the same, but the powder charges are 2 gains different. Bullet weight is only one variable, length of bearing surface matters a well.
Last edited by antelope_sniper; 02/13/21.
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
You cannot over estimate the unimportance of nearly everything. John Maxwell
Quick load just arrived in the mail! I’ll run a bunch of data tonight and report back with more info
It's a lot of fun! You'll learn a lot.
It works well with bottle necked cartridges, but be very careful with straight walled cartridges. It doesn't handle them as well. You can still get some useful starting points, but be sure to use lower starting loads for straight walled cartridges.
You didn't use logic or reason to get into this opinion, I cannot use logic or reason to get you out of it.
You cannot over estimate the unimportance of nearly everything. John Maxwell
I’m new to Lapua brass and I started my 308 load developememt from book min and worked up to book max. Rifle/loads specs:
CA 308 win 20” carbon barrel 1-10 twist Lapua Brass CCI BR 2 primers H4895 powder (bought newa few months ago) Scenar 155 Seated to 2.800
Hodgdon website says 43-46 grains with a velocity range of 2730-2870 for 154 Sierra HPBT at 2.775. Because the Scenar is about .020” longer than the 155 Sierra, I loaded the Scenar to 2.800 OAL
44.5,45 and 45.5 all shot into a small hole at 112 yards.
Remember those velocities are with only a 20” barrel and suppressor, when the book velocities are at 24”.... I thought I should be 75-100 FPS slower than book.
I measured my case capacity of water in several pieces of Lapua brass after being shot in my gun and it measured approx 44.5 grains. I had someone input all this data with 44.5 grain of H4895 into QL and it says I’m at 65,800 psi when sammi max spec is 62,000 psi. At that PSI and grin of powder, QL says I should be at 2816 FPS, so I’m about 40 FPS faster than what QL says I should be . One can only image the pressure that 46 grains was!
But I got no obvious signs of pressure! No ejector marks, no large cratering of the primer, no abnormal bolt lift. Brass head stamp picture attached.
Is this normal with Lapua brass? If so how does one know where pressure is/should be?
How many rounds of each charge weight did you chronograph to get your initial results?
Okie John
Last edited by okie john; 02/13/21.
Originally Posted by Brad
If Montana had a standing army, a 270 Win with Federal Blue Box 130's would be the standard issue.
