.308 precision loading

sylencer

sylencer

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Hello everyone, I'm new to precision loading. I've been doing 9mm loading for over a year now. I'm just looking for some good advice on real precision loading. I've gone out and bought pretty much everything i need to acomplish this. I have tons of match grade brass. Now some questions that i've have our. 1. What is the best way to measure the chamber of my rifle to get the exact length i need to sit my bullet. Another question is. After i have this measurement, what should i do with it. Should i match the bullet to the exact length of my chamber or should i have it less? I know every rifle is different and to get what works best for your rifle there is alot of trial and error. So i'm looking at for a good starting point. As of right now Federal Match 168hpbt is what works best for factory loads. I was thinking about completely remanufacturing that round and then adjust and tweak from there.
As i stated I am new to this so forgive me if my terminology is incorrect or if some of my questions don't make sense. Any and all advice will be greatly appreciated thank you.
 
You'll have to forgive me. In my previous thread i stated i wanted to know where to seat the bullet in the casing. What i actually meant was that i wanted to know how much to trim the case for the casing to fit. I think... lol
 
Hi. Suggest using paragraphs in your post. Makes 'em easier to read.
The key to loading match grade ammo is meticulous loading techniques. Everything should be exactly the same for each cartridge. Your cases, for example, need to be all the same length to start. Means you won't have to fight the case to get the OAL the same. Use the trim-to length of 2.005" as a minimum. Don't forget to chamfer and deburr.
You'll have to weigh each powder charge too. The powder you use can make a difference. IMR4064 gives me consistent accuracy out of my 1903A4(.30-06 and Hornady 168's. Not A-Max's though.). Not the only powder that will, of course.
Work up the most accurate load first, then you can fiddle with the OAL to tweak. You don't measure the chamber, unless you want to make a chamber cast. Easier to load a test cartridge with just a bullet, seated long. Chamber it and the bullet should be pushed into the case by the rifling. Then reduce the OAL 20 thou. Mind you, like you say, every rifle prefers a slightly different distance from the lands. The 20 thou is a place to start. Measure with vernier calipres. Guages aren't precise enough.
 
Take one of your de-primed cases, cut 3 verticle slots equidistant around the neck with a Dremel, so that a bullet can be pushed into the neck. Insert your bullet just enough that the neck grips it, and slowly chamber it. Carefully withdraw it, and measure the OAL. Do this a few times and average the results. This is the distance to the lands for your rifle.
Adjust from there- some bullets like to be jammed into the lands, some like to jump.
My current .308 load is jumping 10 thou, using Amax 155's over 47.0gr Varget in Lapua brass with CCI BR2 primers.
 
I go a few steps further. I full length resize the brass. I trim all the brass to the same length. I then neck turn the brass to get a uniform neck. Then I weigh each one and put them in trays with similar weights. I some times have 3 trays of 100 brass in them . Some guys go so far as to put them in order of weight. That's to finicky for me. Then I find the seating depth and powder charge the gun likes and load em up.
I use nosler custom competition 155 grain bullets in my 308. I tried 155 gr lapua scenars, 155gr sierra match kings.
Buy things in large lots so you can get the same lot number.
I buy bullets by the 1000 and 24lbs of powder at a time. 5000 primers at a time.
Then after a couple of thousand rounds you will buy an RCBS ChargeMaster and wonder how you ever loaded without it.
 
2.015" is the SAAMI max length for a sized .308 Win case. 2.005" is the trim to length, but you could trim shorter if so inclined.
 
hk33ka1 said:
2.015" is the SAAMI max length for a sized .308 Win case. 2.005" is the trim to length, but you could trim shorter if so inclined.
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I guess I'm railroading this thread a bit, but I'm looking for someone to give me clarity of exact length. is + or - .005" going to make a difference when exacting cases to length? My guage reads up to x.### " only. I"ve been using the Lee case trimmers that you order with the dies, and it doesn't seem to be that percise.
 
rooster22 said:
I guess I'm railroading this thread a bit, but I'm looking for someone to give me clarity of exact length. is + or - .005" going to make a difference when exacting cases to length?
Click to expand...
There is no "exact length". There is a max length - 2.015 - and a trim-to - 2.005.

Plus or minus five thousands of an inch is a lot of variance, but as long as you are trimming to 2.005", you will not exceed the max length and will therefore be in the safe zone. I thought you meant .0005" (5 ten-thousands of an inch).
 
As long as your cases aren't longer than 2.015" they should be safe. In theory a different chamber could tolerate a longer case, but this is the industry standard for .308 Win.

You could load one case trimmed to 2.000" one 2.010" and one 2.015" and be safe, but they may not all shoot in the same place at long distance.

For Precision Loading, you would want those cases to be as similar to each other as possible. You would choose a length between 2.005"-2.015" and trim all your cases in that batch to it. Develope a load that is accurate. And trim them to that same length every time you load them.

For plinking in my M14 I would just use cases that are under the max trim length and are safe.

I like my Lee trimmers and if they were consistent for you I would use them, but they only trim to one length every time. If I needed a different length I would buy a higher quality lathe type trimmer like Wilson or Forster.

This also takes into account that you are using all the same brass and not different brands/types.
 
rooster22 said:
People mention exact size for your brass casings. I used the Lee case trimmer and I get inconsistancies. I'm trying to achieve 2.005", but I get 2.045 to 2.049. Is this close enought to exact sizing? Were talking less than half a thou.
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There are some issues with significant figures in your numbers. Since 2.045 is not correct for the .308, I assume you mean 2.0045 to 2.0049? If so that is only an error of 0.0004" and totally insignificant. It is in the range of what you should achieve with a Lee. I cannot measure any difference in my case lengths after being trimmed with a Lee. It is almost impossible to get the lengths to vary if you make sure the case holder is tight on each cartridge before you start cutting.
 
Ron AKA said:
There are some issues with significant figures in your numbers. Since 2.045 is not correct for the .308, I assume you mean 2.0045 to 2.0049? If so that is only an error of 0.0004" and totally insignificant. It is in the range of what you should achieve with a Lee. I cannot measure any difference in my case lengths after being trimmed with a Lee. It is almost impossible to get the lengths to vary if you make sure the case holder is tight on each cartridge before you start cutting.
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I was at work and talking #'s from memory, My lee trimmer will give 2.005 up to 2.008. After reading the other posts I guess for bench shooting no good, but I think for game hunting should be OK.
 
thanks for all the info guys. As of right now Everything is working out except that when i resize my case i've been getting a small hump at the bottom of my neck. I tried trimming the neck down thinking maybe the neck is stretched and its getting squashed in the die. I removed the deprimer pin so all the die should be doing is resizing the case and thats it. I've heard of this problem happening with the bullet seating but not at this early in the stage. Any suggestions?
 
Now that i've got the reloading up and going smoothly. There has been alot ot talking about the size of the case. I settled for 2.005 for now. My next question is is there a maximum overall length of the round with the bullet seated?
 
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