You can look here: [post=145586]Howa .308 Range Report[/post] for a range report and some follow-up notes and comments about vstart a new thread devoted just to reloading that rifle.
As noted in the link above, this rifle has a 'small' chamber. I think it is only short, not also small in diameter. The average case capacity of cases that fit easily into the chamber is 53.75 grains of H2O. I used two bullets for the preliminary range session:- Hornady 125-grain FP/HP #2020, and
- Speer 130-grain HP #2005
I intend to continue with both of those bullets, but I am going to add at least two more, the Hornady 86-grain "Mauser" #3100, and the Hornady 110-grain Spire Point #3010. The 86-grainer has a horrible ballistic coefficient (BC) of only .130, so it doesn't retain even 1000 ft-lbs of energy much past 90 yd even when launched at over 3300 f/s. The 110 is better. A friend of mine used to shoot this bullet out of a .300 WM and killed more moose with it than a 5-year-old has seen telephone poles. I like shooting small, fast bullets even if they do have poor BCs. If I can get either of them to shoot straight, it could be fun to shoot.
In the past, I have taken some really light (as light as 55 grains) .30-ish (.309, .311, .312) caliber bullets and 'squoze' them down to .308. I got some of them going over 4000 f/s. I MIGHT try some of those in this rifle if the 86-grainers show any promise.
This rifle's barrel is only 20.5" long, so it doesn't really have the 'legs' to shoot heavier bullets. Heavy bullets from short barrels tend to make for 'flame-throwing' as the slower powders normally used by heavy bullets don't have enough time to fully burn in short barrels. Besides, I prefer the 130-grain bullet in the .308 Win as I have 'hammered' several caribou with that bullet from that cartridge.
I carefully and repeatedly measured the chamber length from bolt face to the lands just at the end of the leade. The distance from the mouth of a case with a length of 2.015", to the lands, is 0.215". That's another 'nail in the coffin' of heavier bullets, as they would have to be seated deeply into the case to stay away from the lands. Deeply seated means less space available for powder. I am pretty sure I could get a 150-grain Accubond to 'work', but I have serious doubts about any heavier bullet.
Since bullets have a 'nose' that is smaller than bore diameter, (which is 0.300" for a modern .308 caliber rifle), the total length of the bullet doesn't "work" to determine seating depth and distance 'off the lands'. Therefore, I measure the "bearing length" of the bullets I am interested in using. That value for each bullet determined seating depth and distance off the lands.
I have come to 'like' powders that burn all the powder in the barrel well before the bullet exits the muzzle. While it is not always the case that these powders produce the best precision, it has been my experience that they often do. In that light, I used the following powders:
- Hodgdon H4227,
- Alliant AR-Comp,
- Hodgdon CFE223, and
- Winchester W296.
As usual, I work 'around' theoretical timing theory nodes for exit times of bullets using QuickLOAD (QL).
OK... Armed with the above information;
- Case capacity in grains of H2O,
- Case length,
- Barrel length, and
- Bullet Bearing length,
I worked up some potential loads for each of the four bullets.
Here are the loads:
- 86-Grain "Mauser"
- 36.7 grains of W296
- Max Pressure = 46,206 PSI. You can see why I didn't go to a 'slower' node.
- MV = 3318 f/s
- ME = 2103 ft-lbs ("nice" recoil)
- 0.148" off of lands. I prefer to be between 0.030" and 0.050" off the lands, but if I seat out that close to lands with this short bullet I will have less than 67% of a caliber of the bullet in the case neck, and I don't personally like that.
- 110-Grain Spitzer
- 34.8 grains of W296
- Max Pressure = 50,257 PSI. High speed timing node.
- MV = 3007 f/s
- ME = 2208 ft-lbs (Still "nice" recoil)
- 0.030" off of lands.
- 110-Grain Spitzer
- 35.4 grains of H4227
- Max Pressure = 48,095 PSI. High speed timing node, but pressure too low to go to next lower node in this powder.
- MV = 2927 f/s
- ME = 2093 ft-lbs ("nice" recoil)
- 0.030" off of lands.
- 125-Grain Sierra FP/HP
- 41.1 grains of AR-Comp
- Max Pressure = 41,759 PSI. Low speed timing node.
- MV = 2789 f/s
- ME = 2159 ft-lbs (still "nice" recoil)
- 0.030" off of lands.
- 125-Grain Sierra FP/HP
- 44.4 grains of AR-Comp
- Max Pressure = 53,035 PSI. High speed timing node.
- MV = 2989 f/s
- ME = 2480 ft-lbs (not "bad" recoil)
- 0.030" off of lands.
- 125-Grain Sierra FP/HP
- 46.8 grains of CFE223
- Max Pressure = 42,115 PSI. Low speed timing node.
- MV = 2760 f/s
- ME = 2114 ft-lbs (still "nice" recoil)
- 0.030" off of lands.
- 125-Grain Sierra FP/HP
- 50.08 grains of CFE223
- Max Pressure = 52,937 PSI. High speed timing node.
- MV = 2977 f/s
- ME = 2460 ft-lbs (not "bad" recoil)
- 0.030" off of lands.
Now for my favorite bullet style. This exact same bullet style in the Speer 7mm 115 grain HP has accounted for probably 1/3 of all the big game I have shot including moose and black bear.
- 130-Grain Speer HP
- 41.0 grains of CFE223
- Max Pressure = 43,486 PSI. Low speed timing node.
- MV = 2768 f/s
- ME = 2212 ft-lbs ( "nice" recoil)
- 0.030" off of lands.
- 130-Grain Speer HP
- 49.9 grains of CFE223
- Max Pressure = 55,011 PSI. High speed timing node.
- MV = 2960 f/s
- ME = 2529 ft-lbs (not "bad" recoil)
- 0.030" off of lands.
Of course this is just so much paper-whipping, but this paper-whipping saves powder, bullets, and time. And besides, I LIKE numbers.
Paul
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Paper whipping is good and fun. And it gives you a good idea of what to go on. "Running the numbers" is a term we use.
I like the fact you didn't go for anything over 130gns too. LFC in the .308 is where it is at.
You may have many combos to choose from at day's end.
I think the 130 will prove to be the 'winner'. The really light bullets simply can't carry enough energy down-range to be effective big game bullets. If there were more small game opportunities up here, the light-for-caliber (LFC) bullets might be fun. (Given what I know - not too much - about OZ, the LFC bullets might find more use there, than in AK.)
J0e_bl0ggs uses the 125 and likes it. Because of its shape, I strongly suspect I will be able to get it to shoot straight. The difference in BC between the two bullets is .117 for the 125 vs .244 for the 130. The 130 basically doubles the BC of the 125. At short ranges - 100 yd and less - it doesn't really matter much. Beyond 100, it starts to matter.
As you can see, the estimated MVs for the two bullets are essentially the same. Starting them out at identical MVs, 2975 f/s, and sighted in to be 1" high at 100 yd, their trajectories and energies at 50-yd intervals are:
50 . . . . . 100 . . . . . 150 . . . . . 200 . . . . . 250 . . . . . 300
Trajectory 130 . . . . +0.2 . . . . .1.0 . . . . .+0.3 . . . . .-2.2 . . . . .-6.9 . . . . .-14.4
Trajectory 125 . . . . +0.4 . . . . .1.0 . . . . . -0.5 . . . . .-4.9 . . . . -13.2 . . . . -26.9
Energy 130 . . . . . . .2119 . . . .1746 . . . . 1426 . . . . .1154 . . . . .924 . . . . . 737
Energy 125 . . . . . . .1651 . . . .1172 . . . . . 831 . . . . . 612 . . . . .455 . . . . . .351
Might as well add an "impact velocity" set of data:
Impact Vel. 130 . . . .2710 . . . .2459 . . . . 2223 . . . . .2000 . . . .1790 . . . . .1598
Impact Vel. 125 . . . .2439 . . . .2055 . . . . .1731 . . . . 1485 . . . .1280 . . . . .1125
Impact velocity on the 125 is (in my opinion) 'good' out to 150 for big game. For small game and small deer, it's 'good' out to 300 - If you can hit them. ;) For big game, the impact velocities for the 130 are 'good' out to at least 250.
The times of flight to 300 yards are 0.4149 sec for the 130 and 0.5308 for the 125. 25% longer (or 20% depending on which number - 0.4149 or 0.5308 - is the reference), so any wind has 25% longer to "work" on the 125's trajectory.
The 130 reaches out to 200 at least, in the .308 Win case. The 125 is good to 125 to 150-ish for white-tail-sized big game. Would be fine on roe deer and smaller out to probably 250.
Paul
Sometimes I get focused on a line of thought and get 'tunnel vision'.:stars::help:
I went to do the actual reloading and REMEMBERED that the powder that ACTUALLY performed so well IN REAL LIFE was Reloder 10x! Which isn't even in the work-up above!
Anyway, I worked up the 10x loads in QL. When I finish actually reloading the ammo I'll post the loads here.
Paul
OK, so I just finished loading 20 rounds; 10 130s and 10 125s each with RL-10x. The loads are below.
- 125-Grain Sierra FP/HP
- 38.12 grains of RL-10x
- Max Pressure = 44,298 PSI. Low speed timing node.
- MV = 2760 f/s
- ME = 2114 ft-lbs (still "nice" recoil)
- 0.030" off of lands.
Notice how close this load is to the CFE223 load. Same MV. Very Similar max pressure.
- 125-Grain Sierra FP/HP
- 41.36 grains of RL-10x
- Max Pressure = 55,934 PSI. High speed timing node.
- MV = 2962 f/s
- ME = 2435 ft-lbs (not "bad" recoil)
- 0.030" off of lands.
Hotter than CFE223 fast node, and slower speed.
- 130-Grain Speer HP
- 40.34 grains of rl-10x
- Max Pressure = 54,561 PSI. High speed timing node.
- MV = 2881 f/s
- ME = 2397 ft-lbs ( "nice" recoil)
- 0.030" off of lands.
- 130-Grain Speer HP
- 38.0 grains of RL-10x
- Max Pressure = 46,051 PSI. Low speed timing node.
- MV = 2738 f/s
- ME = 2164 ft-lbs (not "bad" recoil)
- 0.030" off of lands.
Five of each load. Even without considering the other two bullets, I'm going to need to make some more cases and load some 'intermediate' charges. The "lows" are low, and the "highs" are higher than I want to be pressure-wise. It would be nice to have some intermediate charges. More often than not, the REAL timing node is about 3% down from the theoretical node time. We'll see.
Paul
Ok - So made another 15 "small base" cases and loaded them with 5 of the 86-grainers (W296), and 10, 110 grainers: Five with the H4227 load, and five with W296. I had 5 loaded with 130s and CFE223, so I am going to try those as well. Now, 40 rounds to test.
Supposed to rain for the next four days. I'll get to the range when the weather clears.
Paul