.308 powder choices
- Thread starter Hog head
- Start date
Negative Investment
New member
I've used Varget, 4895 and 3031 for my AR-308, so far 3031 is my favorite. Each powder effects the location where the brass lands on ejection. When I use 4895 it goes in front of the firing line 
I have yet to try others due to availability.
I have yet to try others due to availability.Didn't see your rifle, initially.
Perhaps, I can save you some time.
My son has the exact same rifle, after weeks of trying most everything, it came down to the exact same load he shoots in his .308 Savage. 'Course, might be different for you- but I'd make sure to try it.
Note that this is the accuracy load for long range. We were able to get more MV with other recipes, but none were as accurate.
Sierra 175 SMK, over 43.5 grains of Varget. MV= 2,585 fps.
David,
.308 Win. ammo with 150 to 190 grain bullets shot through a 1:12 twist barrel have won many a match on this planet. One of the favorite loads with 7.62 NATO Garands was 44 grains of IMR4320 under a Sierra 190 shot in their 24" 1:12 twist barrels.
Remember the first commercial .308's were Win. 70's with 22: 1:12 twist barrels. They shot Winchester's 200 grain hunting bullets very accurate. As did the target versions with 26" 1:12 twist barres with Western Cartridge Company 197 and 200 grain bullets in their match ammo.
.308 Win. ammo with 150 to 190 grain bullets shot through a 1:12 twist barrel have won many a match on this planet. One of the favorite loads with 7.62 NATO Garands was 44 grains of IMR4320 under a Sierra 190 shot in their 24" 1:12 twist barrels.
Remember the first commercial .308's were Win. 70's with 22: 1:12 twist barrels. They shot Winchester's 200 grain hunting bullets very accurate. As did the target versions with 26" 1:12 twist barres with Western Cartridge Company 197 and 200 grain bullets in their match ammo.
DAVID NANCARROW
New member
Thanks for the info, Bart. I may yet try some 190 grain Match Kings. I am hoping that the 26 inch barrel on my Remington will help a bit with the velocity. I have a lot of IMR4064 but might also investigate IMR4895, both look promising.
I don't think those 3 inch groups with the 155's are a bullet problem. Especially when Sierra's tests in the 100 yard range at their California plant were in the 1/4 inch range with lighter weight 30 caliber match bullets and 1/3 inch range with light weight hunting bullets. Something else in those reloads is the problem. They should shoot 1-1/2 inch or better at 100 meters; 3 inches indicates to me something else is out of whack.
IMR4895 was "the" powder to use with 150 and 155 grain bullets in the .308 until Varget came on the scene.
With 190's, 41 grains of IMR4064 in most commercial cases shot them very accurate across several barrels when the .308 was popular in medium to long range matches. 26 inch barrel lengths were popular. 42 grains was used in Western match brass that weighed only 150 to 155 grains; thin walled stuff that is very uniform.
IMR4895 was "the" powder to use with 150 and 155 grain bullets in the .308 until Varget came on the scene.
With 190's, 41 grains of IMR4064 in most commercial cases shot them very accurate across several barrels when the .308 was popular in medium to long range matches. 26 inch barrel lengths were popular. 42 grains was used in Western match brass that weighed only 150 to 155 grains; thin walled stuff that is very uniform.
trapper9260
New member
I have a rifle like the OP stated, I shoot Jacket and cast with it usen IMR 4064 and I found that it is the best compare to both the 4895.Also I know 4064 is easyer to find then the others stated.
DAVID NANCARROW
New member
Don't know what to tell you on the Palma Match, Bart. The cases were uniformed Lapua, once fired and trimmed to 2.007 +/- .001" after full length resize. Runout was .003" or smaller. Powders tried were Reloader 15, IMR 4064, and H4895. Federal 210M primers. Here is a sample target of Sierra 155 Match Kings fired a week earlier, same range. Powder was Reloader 15, Hornady match cases fully prepped and full length resized, OAL was 2.815", runout was .005" max.
Attachments
David,
0.003" tilt is enough to give you some spread if the bullet doesn't tend to straighten in the bore. In general, the further forward the center of gravity of the bullet is from the center of the bearing surface, the more spread you get from a given degree of tilt. If you load any more of these bullets up, try picking out some with that same 0.003" of runout, but mark the high side location on the case head with a Sharpie. When you go to the range, take half the rounds and shoot them all with the index mark at the same location in the chamber (12:00, 6:00, or whatever is easy to see; just be consistent). That causes the drift due to tilt to all be in the same direction, tightening the group, sometimes considerably. Then shoot a second target indexing the location of the tilt around the clock for the half of the 0.003" runout loads. If that group opens up considerably over the consistently indexed group, then tilt in your bore is the issue.
Self-straightening in the throat is what adjusting seating depth seems to improve. Since you have no wiggle room for adjusting seating depth with the short bearing surface these have, you are pretty much stuck with what you get.
The 175 grain bullet has a 7 caliber tangent ogive. This matches the one on the old M1 Type FMJ used in M72 National Match ammo and M118. With the very consistent Sierra bullet, it can be made to imitate those match loads, but do it with better precision. It's a great bullet. In general, tangent ogives self-center much better than secant ogives do. It's the reason Berger developed its hybrid ogive that starts out tangent, then becomes secant only after it is narrower than the land diameter.
There is a good bullet stability estimator at the free JBM online ballistics site. It is here. It gives you an answer in gyroscopic stability factor, a number for which a value of 1.000 is on the line between stable and unstable, and for which Sierra recommends 1.3 to 3.0 as best for good hunting accuracy and 1.4 to 1.7 as best for match accuracy. Geoffry Kolbe has a different calculator based on McGyro, a program the late Robert McCoy developed. Kolbe's version gives you a plot of what twist rates gives you a gyroscopic stability factor of 1.5 at different muzzle velocities, and, if you enter a twist (optional in the calculator) it also gives you a plot of gyroscopic stability factor vs velocity for your twist. The Kolbe calculator requires more complete bullet shape information than the JBM estimator, so it the Kolbe calculator is more exact. For the 175, from Litz, the data required by the Kolbe calculator is:
length 1.240"
ogive length 0.710"
meplat diameter 0.067"
boattail angle 9.1°
bottail length 0.165"
The Kolbe calculator's graph shows that at 2500-2600 fps, a 12.6" to 12.7" twist produces a stability factor of 1.5, while a 12" twist (lower graph when you enter a twist argument) produces a stability factor of about 1.68.
For the 175 grain Matching, under standard atmospheric conditions, the JBM calculator estimates a 2600 fps muzzle velocity stability factor of 1.667 for a 12" twist. That's pretty close to Kolbe's plot result. At 2500 fps its just slightly lower at 1.645. Even a 13" twist stays a little above 1.4 in that velocity range, and would be expected to work very well with this bullet. So, if 1.5 is ideal, then the first calculator says a 12.61" twist puts that number in the middle of that muzzle velocity range, while the second looks more like a 12.65" twist is ideal. Pretty darn good agreement.
0.003" tilt is enough to give you some spread if the bullet doesn't tend to straighten in the bore. In general, the further forward the center of gravity of the bullet is from the center of the bearing surface, the more spread you get from a given degree of tilt. If you load any more of these bullets up, try picking out some with that same 0.003" of runout, but mark the high side location on the case head with a Sharpie. When you go to the range, take half the rounds and shoot them all with the index mark at the same location in the chamber (12:00, 6:00, or whatever is easy to see; just be consistent). That causes the drift due to tilt to all be in the same direction, tightening the group, sometimes considerably. Then shoot a second target indexing the location of the tilt around the clock for the half of the 0.003" runout loads. If that group opens up considerably over the consistently indexed group, then tilt in your bore is the issue.
Self-straightening in the throat is what adjusting seating depth seems to improve. Since you have no wiggle room for adjusting seating depth with the short bearing surface these have, you are pretty much stuck with what you get.
The 175 grain bullet has a 7 caliber tangent ogive. This matches the one on the old M1 Type FMJ used in M72 National Match ammo and M118. With the very consistent Sierra bullet, it can be made to imitate those match loads, but do it with better precision. It's a great bullet. In general, tangent ogives self-center much better than secant ogives do. It's the reason Berger developed its hybrid ogive that starts out tangent, then becomes secant only after it is narrower than the land diameter.
There is a good bullet stability estimator at the free JBM online ballistics site. It is here. It gives you an answer in gyroscopic stability factor, a number for which a value of 1.000 is on the line between stable and unstable, and for which Sierra recommends 1.3 to 3.0 as best for good hunting accuracy and 1.4 to 1.7 as best for match accuracy. Geoffry Kolbe has a different calculator based on McGyro, a program the late Robert McCoy developed. Kolbe's version gives you a plot of what twist rates gives you a gyroscopic stability factor of 1.5 at different muzzle velocities, and, if you enter a twist (optional in the calculator) it also gives you a plot of gyroscopic stability factor vs velocity for your twist. The Kolbe calculator requires more complete bullet shape information than the JBM estimator, so it the Kolbe calculator is more exact. For the 175, from Litz, the data required by the Kolbe calculator is:
length 1.240"
ogive length 0.710"
meplat diameter 0.067"
boattail angle 9.1°
bottail length 0.165"
The Kolbe calculator's graph shows that at 2500-2600 fps, a 12.6" to 12.7" twist produces a stability factor of 1.5, while a 12" twist (lower graph when you enter a twist argument) produces a stability factor of about 1.68.
For the 175 grain Matching, under standard atmospheric conditions, the JBM calculator estimates a 2600 fps muzzle velocity stability factor of 1.667 for a 12" twist. That's pretty close to Kolbe's plot result. At 2500 fps its just slightly lower at 1.645. Even a 13" twist stays a little above 1.4 in that velocity range, and would be expected to work very well with this bullet. So, if 1.5 is ideal, then the first calculator says a 12.61" twist puts that number in the middle of that muzzle velocity range, while the second looks more like a 12.65" twist is ideal. Pretty darn good agreement.
DAVID NANCARROW
New member
Thanks, Unclenick. I normally index my test loads just for GP and in some cases it helps. I gave up on the Palma Match for this particular rifle due to the long lead, which I can't fix without either rebarreling or rechambering. I haven't jumped into the VLD bullets because most of the people I know who are getting good groups from them are loading less than .050 from the lands-up to and including jamming them into the rifling. Just not possible for me to do this with the rifle I have in its present state.
But being stuck with what I have isn't so bad. With most bullet shapes it does a under 1 MOA, some of them coming in under 1/2 minute for 10 shots and repeatable. That's not a bad place to be with an unmodified off the rack rifle.
But being stuck with what I have isn't so bad. With most bullet shapes it does a under 1 MOA, some of them coming in under 1/2 minute for 10 shots and repeatable. That's not a bad place to be with an unmodified off the rack rifle.