Revisiting reloading the 308 with heavy bullets and powder that metering perfect

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  • teddy12b

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    It's been about 6 years since I've thought about trying to reload for a 308 with precision accuracy in mind. I really didn't want to start reloading for 308 again, and was hoping to just run Fed GMM, but unfortunately I am what I am and factory ammo just isn't good enough. The last time I went through process of working up a load, I did it for my 30-06 and ended up with a powder that had to be run through an RCBS chargemaster combo to make sure it was dead on. If I used my 550B powder scale I couldn't always stay within .1, and with the RCBS scale I was always right on.

    Anyway, I want to use a heavy bullet so it carries more momentum down range. I've got nothing against the 168gr, but if I can get 175gr, 190, or 200gr bullets to fly accurately at the same speed then that's what I'd prefer. My bigger concern is mostly due to my own laziness, but I want to end up with a powder that meters 100% accurate every time. I've had great consistency with Ramshot TAC and some other powders, but I never get the .1 with Varget or other powders I read so much about.

    If any of you reloading guru's have any suggestions I'd like to hear it. I know there's a lot of new products out there since the last time I took a look at reloading for the 308.

    *Edit, I should have mentioned that this is being shot from a Rem 700 Magpul hunter with a 22" 5R barrel with 1 in 10" twist. Whatever load I come up with will need to fit inside a magpul AISC magazine.
     

    snapping turtle

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    The best reloader I knew (he has since past to the great range in the sky) was a big fan of heavy for caliber bullets. Shot lots of 308 win also and had several308 that he loaded heavies for. According to his notes he used vihtavouri n150 in the heavy for caliber loads.

    I think that that would be the one to start with. His prong horn load used n135 and 150 grain bullets.
     

    snapping turtle

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    Ps. Most of his barrels were one in 12. Not one in ten. He liked the Sierra HPBT 190’s for hunting. Hornady sp 180’s for target at distance. Just looked at his notes.
     

    ROLEXrifleman

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    i don't believe you will ever get that type of consistency using a density based powder drop system. There are to many variables that will cause the powder charge to be off by over .1 within the session. Powder weight in the hopper, rate at which handle is pulled, pressure used to pull the handle etc. can all cause more or less compression of powder causing variances. Depending on what powder is used it is more noticeable than others.

    I've seen no real difference between 1/10 and 1/12 twist barrels up to 175gr. Once you get into the 200gr range the 1/10 is the way to go.

    I shoot 175gr SMK's in Lapua Brass with VV powder all individually metered. My bolt gun isn't a high volume gun so I don't mind doing it one by one. I run a 22" Mike rock barrel with a 1/11.25 barrel
     

    Broom_jm

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    That Federal GMM you're trying to better? The powder charge in those cases is done by volume. When you first wrap your head around the FACT that weight is used to confirm volume, and that volume is what matters, reloading gets easier. Look up the Newberry OCW method and realize that many benchrest shooters do not weigh every charge. Quality components, case prep and concentricity is what leads to very good accuracy...not weighing every single charge down to the nearest tenth of a grain. I load 155gr A-max bullets for my son's 308 that shoot .3 MOA...and they are not charged by weight, but by volume. I use a scale to verify the volume has not changed, every 5th case. Understand the distinction and you'll be on your way to more satisfying results.
     

    Mgderf

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    That Federal GMM you're trying to better? The powder charge in those cases is done by volume. When you first wrap your head around the FACT that weight is used to confirm volume, and that volume is what matters, reloading gets easier. Look up the Newberry OCW method and realize that many benchrest shooters do not weigh every charge. Quality components, case prep and concentricity is what leads to very good accuracy...not weighing every single charge down to the nearest tenth of a grain. I load 155gr A-max bullets for my son's 308 that shoot .3 MOA...and they are not charged by weight, but by volume. I use a scale to verify the volume has not changed, every 5th case. Understand the distinction and you'll be on your way to more satisfying results.

    So, if you prefer using the volume over weight method, do you use something like the Lee dipper set?
    New(er) loader. Inquiring minds want to know...
     

    Mark 1911

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    Some people are probably going to disagree with me big time, but I'm a big proponent of weighing rifle rounds. Maybe I'm OCD, but I just can't bring myself to trust metered rifle loads.

    My experience is that when you are loading rifle ammo for the best accuracy possible, you want to weigh every single charge for the best uniformity. It doesn't matter what powder you are using. Metering is great for handgun loads. Handgun powders typically have much finer granules than rifle powders. Since rifle powder granules are coarser, there naturally is going to be more variation in the metered weight from one charge to the next. That's why you can't trust volume over weight with rifle powder, especially if you are working near maximum loads, don't risk exceeding the maximum, and that is what you are doing when going by volume. The amount of air space a given volume is going to vary more with coarser powder granules. I bought a Redding powder measure with a match grade micrometer, but as nice as it is, it just does not provide 100% consistency from round to round with rifle powder. I still use the powder measure. But then I check each charge on the scale, and I add or subtract a few granules to get the exact desired weight to the 1/10th of a grain. You would be surprised at how much variation there is between charges from the powder measure. Again, this is true for rifle powder, handgun powder measures much more consistently. Because of that, I would weigh every rifle powder charge even if it was just for plinking. No matter how high of quality of metering you are using, you will still get the best precision and thus the best consistency by hand weighing every load. Yes it is more time consuming, but that is the investment you have to make if you want to get the best accuracy. It's safer too.
     
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    teddy12b

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    I don't disagree with you on weighing every load in theory. Whenever I've loaded up my long range precision ammo I've used an RCBS chargemaster combo that would get the charge right on the dot or I'd dump the powder back in and start all over again. I know it's not perfect, but it's a time expedient way to get very good results. I'm not going to take the time to trickle in the last bits of powder on a mechanical scale to know 100% it's perfect, because I'm not competing and honestly that level of reloading realistically exceeds my level of shooting skills and patience. The chargemaster combo gets me very close at a minimum. Having said that, I've found Ramshot TAC to be a very consistent powder in my Dillon 550B, and when doing some 223 match ammo I've found that it'll be in the .1 range consistently if not better.

    The theory or goal, is to ultimately end up with a very consistent performance each time and if I get lucky and can use my powder dropper to get that then I'm going to be very happy if I get the results I want.
     

    Mark 1911

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    I don't disagree with you on weighing every load in theory. Whenever I've loaded up my long range precision ammo I've used an RCBS chargemaster combo that would get the charge right on the dot or I'd dump the powder back in and start all over again. I know it's not perfect, but it's a time expedient way to get very good results. I'm not going to take the time to trickle in the last bits of powder on a mechanical scale to know 100% it's perfect, because I'm not competing and honestly that level of reloading realistically exceeds my level of shooting skills and patience. The chargemaster combo gets me very close at a minimum. Having said that, I've found Ramshot TAC to be a very consistent powder in my Dillon 550B, and when doing some 223 match ammo I've found that it'll be in the .1 range consistently if not better.

    The theory or goal, is to ultimately end up with a very consistent performance each time and if I get lucky and can use my powder dropper to get that then I'm going to be very happy if I get the results I want.

    If you are ok with a little variation then I would say ok. Just be careful and weigh one every 5 or 10 rounds as a check, and stay far enough away from the max load to allow for tolerance so you don't exceed the max.

    I admit I'm a little anal, but I really do want to push my limits. I get so much pleasure from shrinking those groups down to where there is just one hole. I'll limit every variable that I can to get there.

    Considering the expense of the reloading tools, I figure I'll take maximum advantage. Otherwise I could have saved the expense and just bought top of the lime factory ammo.
     
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    Broom_jm

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    The inclination is to believe that weighing every single charge, down to the tenth of a grain, in a rifle load, will give the best possible accuracy. The reality is quite different, and there are ways to prove it to yourself.

    1) Take 10 cases that were fired from your rifle. Do not size them or anything else. Number them with a marker, weigh them, and take note of how much each individual case weighs. Fill with water until the surface is just level with the mouth of the case, not above or below. Weigh each case while it is full and note each one. Subtract the first number from the second number and you will have the case capacity. (You can also just weigh fired, empty cases, noting the difference in weight...heavier cases have less internal capacity, which weighing the water would reveal.) Now, the heavier cases have a smaller internal capacity, thereby creating greater pressure, all other things being equal. Is the variance in the internal case capacity of cases fired in your rifle greater than the one tenth of a grain difference in charge weight you are willing to accept?

    2) Adjust a quality volumetric powder measure until it drops the charge weight you want for your load recipe. (When adjusted properly, 10 dropped charges, with the total weight divided by 10, will be within a tenth of your target weight.) Now, load up 10 to 20 cases using JUST a volumetric drop of powder, without weighing. Load another 10 to 20 cases by carefully weighing every single charge down to the exact weight your recipe calls for, the way you normally would. Place each of these batches into their own plastic Ziploc bag. Do not label the bags in any way. Go to the range and have your friend or a stranger mix the bags up so you have no way of knowing which is which. Set up 2 targets and alternate back and forth, shooting one round from each of the bags at each respective target.

    Having done these tests, as well as countless ladder tests and, more recently, quite a few OCW load workups, I can tell you that weighing each charge down to the last tenth is fine for working up an accurate load, but totally unnecessary for loading larger quantities of a proven load. Not that I'm an expert, by any means, but I've been pulling the handle on the green monster for 30 years and loaded for a pretty wide variety of cartridges. The volume inside a metallic cartridge case, and the attendant volume of a powder of suitable burn rate, are critical aspects of internal ballistics; the weight of that charge is just a convenient way of measuring how much of the available space it is going to consume in the case. The volume MUST be known, to be safe...the weight simply confirms an appropriate volume.

    It's not an easy concept to get one's head around, but it sure makes reloading a lot more interesting, once you do.
     

    Mark 1911

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    The inclination is to believe that weighing every single charge, down to the tenth of a grain, in a rifle load, will give the best possible accuracy. The reality is quite different, and there are ways to prove it to yourself.

    1) Take 10 cases that were fired from your rifle. Do not size them or anything else. Number them with a marker, weigh them, and take note of how much each individual case weighs. Fill with water until the surface is just level with the mouth of the case, not above or below. Weigh each case while it is full and note each one. Subtract the first number from the second number and you will have the case capacity. (You can also just weigh fired, empty cases, noting the difference in weight...heavier cases have less internal capacity, which weighing the water would reveal.) Now, the heavier cases have a smaller internal capacity, thereby creating greater pressure, all other things being equal. Is the variance in the internal case capacity of cases fired in your rifle greater than the one tenth of a grain difference in charge weight you are willing to accept?

    2) Adjust a quality volumetric powder measure until it drops the charge weight you want for your load recipe. (When adjusted properly, 10 dropped charges, with the total weight divided by 10, will be within a tenth of your target weight.) Now, load up 10 to 20 cases using JUST a volumetric drop of powder, without weighing. Load another 10 to 20 cases by carefully weighing every single charge down to the exact weight your recipe calls for, the way you normally would. Place each of these batches into their own plastic Ziploc bag. Do not label the bags in any way. Go to the range and have your friend or a stranger mix the bags up so you have no way of knowing which is which. Set up 2 targets and alternate back and forth, shooting one round from each of the bags at each respective target.

    Having done these tests, as well as countless ladder tests and, more recently, quite a few OCW load workups, I can tell you that weighing each charge down to the last tenth is fine for working up an accurate load, but totally unnecessary for loading larger quantities of a proven load. Not that I'm an expert, by any means, but I've been pulling the handle on the green monster for 30 years and loaded for a pretty wide variety of cartridges. The volume inside a metallic cartridge case, and the attendant volume of a powder of suitable burn rate, are critical aspects of internal ballistics; the weight of that charge is just a convenient way of measuring how much of the available space it is going to consume in the case. The volume MUST be known, to be safe...the weight simply confirms an appropriate volume.

    It's not an easy concept to get one's head around, but it sure makes reloading a lot more interesting, once you do.

    Not that I doubt what you're saying. Honestly, I have so little time for my hobbies that the chances of me doing this test are probably slim. I could probably come close by loading up 10 cartridges with one weight, 10 with another .1 grain, 10 with another .1 grain, and keeping all other variables the same, see how the point of impact changes, or not.

    Here's the part that I don't understand. As long as the powder is consistant, then a certain weight on the scale should equate to a given volume of powder not counting the air spaces. That being said, changes in volume / weight will equate to a change in pressure, equals change in velocity, etc..

    The other day I was loading some .300 win mag using 71.5 grains of RL-22. Using the powder measure and checking each drop on the scale, I saw variations between 70.8 to 71.8. The powder measure seems to be sensitive to how quickly or slowly you cycle the crank. Now if I could get my powder measure to be more consistent, say between 71.4 to 71.6 (+/- .1 grain), I could understand how what you're saying might work out. But my powder measure has never been that consistent, even with the micrometer. That's why I feel, at least with my equipment, that weighing each load is essential. I think I have a pretty nice powder measure, but it sure doesn't give +\- .1 grain repeatability.

    Maybe I just need a more reliable power measure, as the OP said his was consistently within .1 grain. If mine would do that, I would have a lot more confidence.
     
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    billybob44

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    Sorry Charlie....

    "but I want to end up with a powder that meters 100% accurate every time."
    ^^^^

    There is NO such animal .. +/- .1 Grain is the norm. Powders that I know that work for me with 165/168 grain projectiles are:
    H414/WW-760
    WW-748
    CFE-223
    IMR-4320

    There are a WHOLE lot of other things that will open your groups, or not be consistent, and MOST of these are Shoot Error at the Bench, or in the Field..Bill.
     

    Broom_jm

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    Not that I doubt what you're saying. Honestly, I have so little time for my hobbies that the chances of me doing this test are probably slim. I could probably come close by loading up 10 cartridges with one weight, 10 with another .1 grain, 10 with another .1 grain, and keeping all other variables the same, see how the point of impact changes, or not.

    Here's the part that I don't understand. As long as the powder is consistant, then a certain weight on the scale should equate to a given volume of powder not counting the air spaces. That being said, changes in volume / weight will equate to a change in pressure, equals change in velocity, etc..

    The other day I was loading some .300 win mag using 71.5 grains of RL-22. Using the powder measure and checking each drop on the scale, I saw variations between 70.8 to 71.8. The powder measure seems to be sensitive to how quickly or slowly you cycle the crank. Now if I could get my powder measure to be more consistent, say between 71.4 to 71.6 (+/- .1 grain), I could understand how what you're saying might work out. But my powder measure has never been that consistent, even with the micrometer. That's why I feel, at least with my equipment, that weighing each load is essential. I think I have a pretty nice powder measure, but it sure doesn't give +\- .1 grain repeatability.

    Maybe I just need a more reliable power measure, as the OP said his was consistently within .1 grain. If mine would do that, I would have a lot more confidence.

    I have heard this response from a lot of folks who, ironically, will use a classic ladder test for their load development instead of the more efficient OCW method. If you really need to save both time and components, read up on the OCW method. It will dramatically decrease the time and components it takes to find a very good, reliable load for your rifle, that isn't so sensitive to charge weight (volume) or to which brand of case you use. (NOTE: This isn't necessarily true with the 300WM, which is notorious for different case capacity from one brand of case to another.)

    You speak of a full grain range of charge weights (+/- .5) in a 300 WM as though it's a bad thing. In a big-jugged case like that, what are you talking...a total range of 1.3% variance? In your example, the 70.8gr charge would be .7 grains under your specified charge weight. That's less than 1% low. What if I told you the difference in case capacity between your brass (all from one lot) is probably greater than that?

    Did you drop 10 charges from your volumetric powder measure, weigh them, and divide by 10? How far from your target weight of 71.5 grains were you? Dead on or .1 grain off? What if I told you that the difference in volume across those 10 drops wasn't even that high? :)

    I'm as OCD as the next person...but the OCW load development process really opened my eyes to how important case volume and charge volume can be. Charge weight is used to verify volume because it's the easiest way to accomplish that goal. Unfortunately, most reloaders today think that charge weight IS the goal, and lack the understanding about how volume of both case and powder charge are what ballisticians pay attention to.

    Ask yourself this question: Why is 71.5gr of RL-22 a suitable charge in your 300WM, but not suitable for a 300 Weatherby or a 300 RUM? Now, why would that same charge likely be just fine in a 30 Newton?
     

    Wolfhound

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    It never fails to amaze me the collective reloading knowledge that is here on INGO. Some of you guys have taken reloading to a whole different level and it is great how willing you are to share that knowledge. :yesway: You have my gratitude and respect.

    I have been reloading for a few decades and I still learn things here all the time.

    I have always reloaded for the economy of it. To save a buck. I find something that works and doesn't break the bank and stick with it. At this point in my life I just don't have the time to develop loads for precision shooting. Hopefully when I retire I can really explore wringing every bit of accuracy out of my loads as some of you masters have. :bowdown:
     

    teddy12b

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    Hopefully when I retire I can really explore wringing every bit of accuracy out of my loads as some of you masters have. :bowdown:

    It's really not as time intense as it can sound. For precision reloading start with breaking down the components. For brass I go with Lapua, and even folks who think there's something better would never be able to make an argument that it's bad. I've got 30-06 lapua brass that I've got well over 10 firings from and it's still as good as the day I first got it, so for me I will always chose Lapua. Next is primers, and for me that means the federal match primers, so that's done. Then when it gets to powder and bullet weight is where we can spend our time. As much as I'd like to claim any wisdom on powders, I usually find out what most reloaders are using in that caliber and bullet weight and start there. Anytime I read about 308 I hear of IMR 4064 & Varget, so that's where I'll start. I was really hoping someone would say try the new "XYZ" powder that came out 3 years ago that meters like water and has taken the precision shooting world by storm, but that's just not the case. I'm going to top these off with 190gr matchkings loaded at the max length to work in my magazines and then do it the old fashioned way by starting low with .5gr increments and shoot 5 shot and then looking back at them and find where the groups get tiny. Then I'll focus in on that range of groups and do it again in .2gr increments. If I find a load the rifle likes, then it's time to do nothing more than crank a handle on the blue press. I was hoping to find an easier/quicker/better way, but I still haven't gotten my head around the whole OCW thing.
     

    Wolfhound

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    Thanks for the info and the advice. I really do need to make some time do develop some loads for specific rifles I own. I have heard good things about Lapua brass but it is pricey. :spend:
     
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