So I took from some info on here and set up a ladder test using My .308 AIAX 20" barrel that shoots mil M118LR at 2650 consistently.
Load is as follows:
Hornady 208gr AMAX
Aliant PP2000MR powder
Once Fired LC 04 Brass that has been slightly resized to just fit the chamber on my rifle
I loaded from 42 grains to 46 grains in .5 grain increments with a target OGIVE overall length of 2.222" and overall of 2.960" (Magazine ID is 2.974 in the AX magazines and for reliability I found I needed at least 0.024"). Each load was hand weighed and is within .1 gr of target weight.
I loaded two rounds of each weight and also measured the OGIVE for each round before firing.
#1 - 42gr 2.218" - 2359 fps
#2 - 42gr 2.218" - 2322 fps
#3 - 42.5gr 2.222" - 2374 fps
#4 - 42.5gr 2.215" - 2407 fps
#5 - 43gr 2.222" - 2434 fps
#6 - 43gr 2.222" - 2458 fps
#7 - 43.5gr 2.222" - 2523 fps
*#15 - 43.5gr 2.219" - 2489 fps
#8 - 44gr 2.221" - 2504 fps
#9 - 44gr 2.220" - 2497 fps
#10 - 44.5gr 2.222" - 2538 fps
*#16 - 44.5gr 2.222" - 2538 fps
#11 - 45gr - 2.222" - 2547 fps
#12 - 45gr - 2.222" - 2550 fps
#13 - 45.5gr 2.218" - 2547 fps
#14 - 45.5gr - 2.221" - 2590 fps
#17 - 46gr - 2.220" - 2603 fps
#18 - 46gr - 2.220" - 2621 fps
So I found that 3 rounds had some resistance when chambering so I believe I need to resize further since I would run the case into the die a little at a time and chamber check it and stopped when the cases began to chamber without resistance, maybe they are a little tight so I have some once fired brass from this gun I will use next time. The once fired brass from this test was fired through a Sako TRG NOT this rifle which would explain the chamber size difference.
Now every round from 42 grains to 46 grains had the same level of resistance on extraction! Pretty tough in fact, enough to require a hard bump from my hand to unlock the action. This caused me to focus on the case heads for pressure signs.
Here are photos of the spent brass. FIRST PICTURE top right is 42 grains to the top left which is 43 grains, remember 2 cases for each weight, then second row right is 43 again and the left one is 44 grains. SECOND PICTURE is overlapping so disregard the top row, second row right is 44.5 and left is 45.5, Third row right is 45.5 and finishes at 46. The last case is a standard M118LR round with 175 smk @ 2650 fps and notice the cratering of the primer.
Another note is the 42 grain cases although were tough to open the action the primers had zero flow back like normal M118LR which is why I continued the ladder test and disregarded that method of testing pressure signs.
What really gets confusing is that some of these rounds have extractor marks even at 43.5 grains and not seen again until 45/46 grains. Below is a picture of two identical rounds, 45 grains, Ogive measured @ 2.222 and one was 2547 and the other 2550 fps.... Any guess why one would shows these signs and the other not?
The last picture shows M118LR on the left and 46 #1, 46 #2, 45.5 #1 and 45.5 #2 cases, notice all have the same amount of primer flow.
My end goal here is not to blow something up but to produce good velocities that are CONSISTENT in the 2450 fps to 2650 fps range (wherever the accuracy and pressure is safe!) Velocity is not as important as accuracy for what I am doing, fighting the wind with good barrel life.
Also the target below was at 300 yards and each round is marked with number and powder charge. 45.5 and 45 grains produced a group of three rounds touching at 300 yards!
I will run the ladder test again at 400 yards and fire only 1 round of each weight with 0.2 grain increments from 44 grains to 46 grains. Also loading once fired brass from this rifle to hopefully eliminate the heavy bolt lift problem unless it truly is from pressure.
Please offer suggestions, advice, or warnings. I am new to reloading and just trying to work this one up.
Load is as follows:
Hornady 208gr AMAX
Aliant PP2000MR powder
Once Fired LC 04 Brass that has been slightly resized to just fit the chamber on my rifle
I loaded from 42 grains to 46 grains in .5 grain increments with a target OGIVE overall length of 2.222" and overall of 2.960" (Magazine ID is 2.974 in the AX magazines and for reliability I found I needed at least 0.024"). Each load was hand weighed and is within .1 gr of target weight.
I loaded two rounds of each weight and also measured the OGIVE for each round before firing.
#1 - 42gr 2.218" - 2359 fps
#2 - 42gr 2.218" - 2322 fps
#3 - 42.5gr 2.222" - 2374 fps
#4 - 42.5gr 2.215" - 2407 fps
#5 - 43gr 2.222" - 2434 fps
#6 - 43gr 2.222" - 2458 fps
#7 - 43.5gr 2.222" - 2523 fps
*#15 - 43.5gr 2.219" - 2489 fps
#8 - 44gr 2.221" - 2504 fps
#9 - 44gr 2.220" - 2497 fps
#10 - 44.5gr 2.222" - 2538 fps
*#16 - 44.5gr 2.222" - 2538 fps
#11 - 45gr - 2.222" - 2547 fps
#12 - 45gr - 2.222" - 2550 fps
#13 - 45.5gr 2.218" - 2547 fps
#14 - 45.5gr - 2.221" - 2590 fps
#17 - 46gr - 2.220" - 2603 fps
#18 - 46gr - 2.220" - 2621 fps
So I found that 3 rounds had some resistance when chambering so I believe I need to resize further since I would run the case into the die a little at a time and chamber check it and stopped when the cases began to chamber without resistance, maybe they are a little tight so I have some once fired brass from this gun I will use next time. The once fired brass from this test was fired through a Sako TRG NOT this rifle which would explain the chamber size difference.
Now every round from 42 grains to 46 grains had the same level of resistance on extraction! Pretty tough in fact, enough to require a hard bump from my hand to unlock the action. This caused me to focus on the case heads for pressure signs.
Here are photos of the spent brass. FIRST PICTURE top right is 42 grains to the top left which is 43 grains, remember 2 cases for each weight, then second row right is 43 again and the left one is 44 grains. SECOND PICTURE is overlapping so disregard the top row, second row right is 44.5 and left is 45.5, Third row right is 45.5 and finishes at 46. The last case is a standard M118LR round with 175 smk @ 2650 fps and notice the cratering of the primer.
Another note is the 42 grain cases although were tough to open the action the primers had zero flow back like normal M118LR which is why I continued the ladder test and disregarded that method of testing pressure signs.
What really gets confusing is that some of these rounds have extractor marks even at 43.5 grains and not seen again until 45/46 grains. Below is a picture of two identical rounds, 45 grains, Ogive measured @ 2.222 and one was 2547 and the other 2550 fps.... Any guess why one would shows these signs and the other not?
The last picture shows M118LR on the left and 46 #1, 46 #2, 45.5 #1 and 45.5 #2 cases, notice all have the same amount of primer flow.
My end goal here is not to blow something up but to produce good velocities that are CONSISTENT in the 2450 fps to 2650 fps range (wherever the accuracy and pressure is safe!) Velocity is not as important as accuracy for what I am doing, fighting the wind with good barrel life.
Also the target below was at 300 yards and each round is marked with number and powder charge. 45.5 and 45 grains produced a group of three rounds touching at 300 yards!
I will run the ladder test again at 400 yards and fire only 1 round of each weight with 0.2 grain increments from 44 grains to 46 grains. Also loading once fired brass from this rifle to hopefully eliminate the heavy bolt lift problem unless it truly is from pressure.
Please offer suggestions, advice, or warnings. I am new to reloading and just trying to work this one up.
