COAL for my 308

peterk123

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I am looking for some help from you guys to make sure I am doing things correctly. I took one of my once fired brass and just gave a bit of a squeeze to the neck so it would hold a bullet snugly. Carefully placed it into my bolt action and slowly closed the bolt. Then carefully extracted the bullet. I did this twice. I ended up with a COAL of 2.877. I was planning to reduce the length by .015. Is my logic correct? I am reloading with IMR 4895. So far, my most accurate load was at 43.3 grains, so I am not near any max load. Is it fair to assume that I will have some increased pressure because there will be less jump before getting to the lands? So far I have only loaded at a COAL of 2.770, which was matching a factory COAL. I know the books say that 308 COAL should be 2.80 but everything I have read leads me to believe I should determine length based on my rifle.

Thank you . Pete
 

gerrycaruso

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The max. COAL may be less than the optimal length due to magazine length. Many believe that close to the lands is best but Berger Bullets says otherwise. I found what they said to be true with a bolt action .223. Read what they say about COAL and experiment.
 

peterk123

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I was just checking to see if that length will fit in the magazine. No go. 2.830 to 2.8395 is the max in the mag. So I will try to load some at 2.83 and see if I notice any difference.

Loading for rifle and shooting rifle is a new world to me. It is an awful lot of fun though trying to get the accuracy right. So far I have only shot small samples of each load, only three to five rounds per group. At 100 yards I get a couple of bullets touching each other, and a flier that is an inch to an inch and half left. Might be me. Interestingly, I shot a box of factory loads and my grouping was no where near as close. Certainly no holes touching.

I will check out the the Berger Bullet article. Thanks Pete
 

jpm

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rule of thumb is you go with the longest COAL that will reliably cycle in your gun
 

BTSDOG

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ive used a RCBS PRECISION MICROMETER in .308 when i used to shoot in competition with my M1A Supermatch. It would let me get the bullet .001 off of the lands for offhand and slowfire shooting. Only thing was that you had to load single shot as the round was too long for the magazine. For rapidfire, i just loaded them all at 2.800.....
 
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If you want to try to keep track of where you are in the reloading process I would suggest the Hornady comparator. You can establish your baseline then chronicle your progress with different COAL lengths for reference and repeat ability. First thing I do is establish the headspace of the chamber. Next is where your bullets are contacting the lands. Then you can play with your bullet depths based on your needs. For reference I always save and mark with a Sharpie a headspace case, a case with a bullet for land contact and one for each bullet with the dimensions I use as a quick reference to reset my seating die.

Incidentally I'm loading -.050 off the lands for .308
 

Picton

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I read the thread title and thought he wanted to trade a rifle for a bucket of coal. I thought that was odd.
 

mac1911

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If you want to try to keep track of where you are in the reloading process I would suggest the Hornady comparator. You can establish your baseline then chronicle your progress with different COAL lengths for reference and repeat ability. First thing I do is establish the headspace of the chamber. Next is where your bullets are contacting the lands. Then you can play with your bullet depths based on your needs. For reference I always save and mark with a Sharpie a headspace case, a case with a bullet for land contact and one for each bullet with the dimensions I use as a quick reference to reset my seating die.

Incidentally I'm loading -.050 off the lands for .308
this, you want to measure off the ogive. The variance in the bullet over all length from tip to base can be enough to make you go nuts if you start measuring the case to tip length and its a few thou off because the tip is not uniform or what have you.
Now If you must feed from a mag start with the longest COAL that will feed in your mag and make sure they bullet does not cram into the lands at that length.

Also go by what bullet your reloading with vs any factory ammo specs.
 

peterk123

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Thanks guys. Loaded some up at the max my mags would allow. Hopefully I will have a chance this week to test them out. Good place to start.
 

mac1911

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Tikka T3x lite. Hornady sst 165 grain .308. 2.830 is the limit on the mag.
one thing not mentioned is a rule of thumb is the bullet should be seated into the case about the same as the cal .30" of the bullet should be in the neck ?
I might be wrong here but the SST is a hunting bullet so its probably designed to "mag length" results. Maybe try seating it to the cannelure ?
Some bullet designs do well with jump some like less jump.. Some rifles lead/throat is so long you wont get close before the bullet falls out of the neck?
 

peterk123

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I had a chance to to shoot the 2.830 COAL loads. Interestingly, it made quite a difference. Six shots at 100 yards. Four shots touching each other, two fliers. One flyer was me and I am going to blame the other one on a warm barrel, at least for now. The fliers though, were only an inch from the grouped shots.

Lots of fun. I will keep it at this length for now and play with the powder charge some more. Man, do I wish we could hunt deer with rifles in Massachusetts :)
 
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