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Discussion Starter · #1 ·
Alright try to stay w/ me since I might not explain everything clearily...

I reload .308, I don't get to shoot it much between college and the range I go to being at our lake house... during the fall I made a bunch of different test reciepes and tried them out so I have narrowed down what shoots good.

Now for producing them in quantity, my friend sold his 308 and gave me all his brass... there is a mixture of federal, winchester, hornady match, BHA match, etc.

When I did my test loads I used Remington, Hornady and BHA brass.

Off all the brass I have those 3 I have in the lowest quantity.

Today I took a few of each brass and measured the volume of each one by filling it w/ H4895(it meters good and its the first thing I grabbed)... averaging the numbers here is the volume of the brass I have.

Winchester White Box = 50.1gr
Winchester Nickel = 51.7gr
Federal = 50.5gr
Hornady Match = 52.43gr
BHA Match = 52.0gr
Magtech = 50.1gr
Remington = 52.5gr

I have A LOT of federal brass, I understand its ****ty brass and cannot be loaded many times, but I would still like to utilize it so I don't have to buy new brass.

I found a very accurate load to be

168gr SMK
44.0gr IMR 4064
Hornady Brass
OAL = 2.800" (+/- 0.005")

Hornady brass holds approx 2.0gr more volume than federal, if I load this into the federal shell, will I be looking at a significant difference in pressure resulting it differences in accuracy?

I will eventually be shooting out to 600yds(max at my range) so I am striving for good accuracy, is this something that will change results or am I just worrying too much?

Thanks,

MIke.
 

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You will need to test more than one piece of each brass to get a better overall viewpoint of capacity and I think you should probably do so with water instead of powder. As far as the accuracy question it depends on your gun and lots of other factors. Furthermore, you don't have to push pressures to the max to get good accuracy most times. I load for 308 and I really like the 168 SMK with 44 grains of Varget. This is two grains off max and gives me some excellent accuracy out to 500 yards.
 

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308 reloading

hi mike i like the 308 ihave loaded for it longer than any other cal. i have. this just me i dont shoot 600 yards so i cant say what different brass would do. i my case 1 to 3 hundred is the only ranges i shoot. i shoot mixed batches of brass never had any problems with the bulls eye. hope this helps. suppose if were me i would load some and to the lake and shoot it see first hand what it will do gat;)
 

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Discussion Starter · #4 ·
I tested a few of each brass and took the average.

I'm not loading anywhere near max, the 44gr of IMR4064 is I think 2 gr. below max as well... I just know that 43.5gr made a 2" grouping where as 44gr made a 0.5". I'm just curious if the extra room in the case will significant affect pressure/accuracy or am I worrying too much.

Is there a formula or calculator or known theory of what a given volume difference will do to a case?

I will try the water idea I think so that I will know the volume difference.

MIke.
 

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IMHO, sell the Federal and save yourself a broken gun or worse. Use the money to buy some GOOD brass and stay away from ALL 308 Federal brass. Primers have blown out in as little as 2 loads and head seperations are common as fleas no matter what the gun. Those are with light loads and not even close to hot.

If you can afford it and find it, get some Norma brass and you'll be set for life. Norma and Lapua are the best cases made and is the choice of many serious target shooters.
 

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I reload .308, When I did my test loads I used Remington, Hornady and BHA brass.Hornady brass holds approx 2.0gr more volume than federal, if I load this into the federal shell, will I be looking at a significant difference in pressure resulting it differences in accuracy? Thanks,

MIke.
Yes your pressure will be higher in the Federal cases. You'll need to work up a load for the Federal brand cases. Personally, I use Winchester cases and either WW-748, IMR-4064, or Varget powders with a 150 grain bullet. I've found the .308 fussy about powders, brass, and bullet selection.
 

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Mike,

The standard measure is case water capacity in grains of water weight. You want the capacity measured in cases as fireformed to your chamber, and not the resized case water capacity. The former is what helps determine peak chamber pressure in a gun at rifle pressures, not the latter. I have an Excel file with instruction that you can download free from my file repository, here. It also works in Calc, the spreadsheet program in the free Open Office suite, which may be downloaded from this location if you don't have Excel.

Powders pack with considerable variance in bulk density. Volume determined that way is not very reliable, so follow the water capacity instructions. Just use your fired cases and still take an average. At the least, use fired cases whose weight is average for the brand among the fired samples you have. Leave the spent primers in place as the flash hole plugs.

As you've discovered there is considerable difference in the capacity of .308 cases. In the late 80's Winchester got the contract to design and produce special high capacity cases with semi-balloon heads for the 1992 Palma match. Those cases were popular and used less brass, so Winchester later started making all their .308 brass to that design. Old and new Winchester .308 are therefore not the same. The new stuff weighs an average of about 156 grains. You'll find Remington weighs around 168 grains. Lapua around 171 grains, Lake City around 180 grains, and IMI around 186 grains. The last two are military spec. Since cartridge brass has a density of 8.53 (from Matweb.com) that 30 grain spread adds up to just over 3.5 grains difference in total water capacity. IMR rifle powders have bulk densities of around .88 if metered gently (you can pack them higher with a drop tube), so this is about 3.1 grains difference in powder capacity, regardless of the size they are blown out to in a chamber. It works out to almost 7% capacity difference, depending on the case and powder. Pressure has an exponential relationship to powder quantity, so it doesn't mean the powder charge can be increased by that percentage. Usually it's closer to half that going from the IMI to new Winchester brass, but it varies with the powder characteristics and the bullet weight. You still end up working up loads for each one.

Federal brass is famous for being soft and not lasting, so it is not worth puting a lot of work into it. Some is known to get loose primer pockets on the first firing of the commercial load Federal puts into them. Dan Newberry says flat out he does not consider it suitable for reloading. I have also run into folks who reload it all the time and don't have an issue. I think, as long as you are not loading near maximum pressure, if you have a lot of it and it hasn't been pre-stretched, then you can use it at least once. Keep a sharp eye on it. I wouldn't want to sell it because I wouldn't want to stick someone else with the problem. I don't much like the reliability of case head expansion as an absolute pressure indicator, but if you apply an OD thimble micrometer with ten thousandths resolution to the heads and monitor them and they don't expand, then you probably don't have a load in a hazardous range for those particular cases.

I once pulled a bunch of Federal Gold Medal match with the 168 grain SMK. It used 43.5 grains of IMR 4064. This was before ATK bought Federal Cartridge, Co. ATK also owns Alliant, and that round is now loaded with Reloader 15, same as military M118 LR. I don't know that those were canister grades, so you may find a different charge is best in your gun? It's not often an asmmunition manufacturer uses canister grade powders, but a few exceptions have arisen over the years. It makes sense to me that where higher than normal lot-to-lot consistency is desired, it would be done. Usually the powder's name designation is changed when it is a non-canister grade, so I expect these are among the exceptions. Just don't take that as gospel, and work your own loads up carefully, watching for pressure signs.
 

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I actually prefer Federal brass in my 308, but perhaps it is because I have a bunch of Match grade stuff. Winchester is my second choice. But I developed almost al my loads with milsurp stuff. It is heck for stout, and loads that max in mil brass are usually mild in civilian cases.

I have to keep loads on the mild side anyway, because my rifle is a Rem 788, and those rear lugs allow some receiver stretch. So that may be why my Federal cases last as long as any others. I usually load only to about 150 fps under book max for a given load, which happens at about 95% of the book max charge. I see no disadvantage in this practice whatsoever.
 

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Discussion Starter · #9 ·
Ya all the brass that I have are not fired out of my rifle... and what even worse is the brass that I did fire out of mine I resized this weekend to start getting it ready for our new years shooting trip :mad:

I can see what you are saying about the expanded brass being a more accurate measure of volume, judging by the fact that its smaller when resized I think it will have similar results expanded...

Just to be safe I think I'm going to try to sell it, I would rather standardize all my loads w/ one brass and I already know that my loads w/ hornady/remington/BHA brass are accurate...plus if they do fall apart I'd rather get my value out of them and purchase good brass you know?

I will still try the water method w/ the brass after shooting it next time to see what kind of variance there is.

MIke.
 

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The point of measuring it expanded is that it is the expanded volume that the powder builds to final pressure in, so that is what figures into the expansion ratio and all the other load pressure related behavior. It also gives you the percent difference for your chamber accurately. If you consider the sizing die a chamber, the absolute difference in grains may not be much different measured either way, especially not if it was all fired in the same gun before.

Nonetheless, I think you are right to standardize on one headstamp if you can. It makes load development simpler. A lot of match shooters buy new brass so it has never been fired in another gun, then take good care of it. I like to fire a squib load through it on its first trip to the range. This won't stretch the head back because the pressure isn't great enough to stick the brass to the chamber. That way I wind up with a fireformed case with no pressure ring stretch. If I then neck-size only or resize the minimum 0.002" shoulder setback for magazine feed, I am stretching and aging the brass only very slowly. Not much chance of a head separation, then.
 

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Mikeg1005: Just on the off chance that you don't have a scale that'll measure enough weight to use the method of capacity measurement that unclenick has provided, there is an alternative that I've found to be about equally accurate and repeatable: Use a syringe as one might use for insulin injections. Pull the needle out with pliers so that there's not an accident. These small syringes are marked on the side in cc (actually down to 0.01 cc), and the capacity measurement comparisons I've run using this method against the scale method result in very close agreement.

If you have a scale, use that; it's faster. :)
 
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