6.5 CM COAL HELP

sextonds

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I don’t have a COAL gauge. So I did it what I feel is a somewhat useful way to find the lands. First off, it is a Savage 10-Tsr rifle. I’m using 143 ELDX. The bolt wouldn’t close at 2.91”. So I backed down to the max that the mag would allow and still cycle fairly well. My end result was 2.87” COAL. I have not shot it yet to see how it does there. The rifle shot .4” groups with a 2.82” COAL, so wanted to see if it would get better going closer to the lands. This seems much longer depth than what I hear from most. Am I wrong somewhere?
 

GrayCreed

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You should be fine I shoot the 143eldx at 2.875 out of my savage and I get good results(hitting targets at 1200y). Being close to the lands isn't everything, once I shot the 120g gold dot and it was barely in the case and still .100" from the lands. I think it actually left the case right as it hit the lands 😂. But I digress it shot a 1hole group like that.

Look on YouTube for Eric Cortina and watch his video about why chasing the lands is stupid. It's a real eye opener.
 

sextonds

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You should be fine I shoot the 143eldx at 2.875 out of my savage and I get good results(hitting targets at 1200y). Being close to the lands isn't everything, once I shot the 120g gold dot and it was barely in the case and still .100" from the lands. I think it actually left the case right as it hit the lands 😂. But I digress it shot a 1hole group like that.

Look on YouTube for Eric Cortina and watch his video about why chasing the lands is stupid. It's a real eye opener.
Ok. Good to hear. I just don’t see many seating at that depth. How far off the lands are you at 2.875?

I am perfectly happy with the results it gives me at 2.82, but like most, I wanted to play and see what happened. 🤷🏽‍♂️
 

GrayCreed

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You don't see data for that because the Book writters don't want to get sued buy people shooting AR10s (they are limited to 2.800"). At 2.875 you can fit more powder too(I've shot up to 42.9g of h4350)(don't do that unless you go very slow and know what you are doing)(at your own risk)

How far am I off the lands at 2.875"? I don't know! Somewhere between .009 and .050.... Small groups matter more than how the lands feel about what you are doing. Know where the lands are when you start but adjust in the direction the group gets smaller. There are other things that affect accuracy such as barrel time/note and powder/primer relationship and powder fill %. I would worry about having quality brass too. Do a staterlee ladder at 2.870 and find where your powder likes to be. Then shoot 2-3 groups in the middle of the best flat spot. If the velocity/SD/ES is good but the group is not move further from the lands in .005" increments. If you find a good group but velocity consistency has fallen apart move the powder charge lower in 0.2g increments (keeping COAL the same)untill velocity consistency comes back


Joel
 

GrayCreed

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To show that the lands aren't everything here is the Nosler 140g RDF at .005" from the lands
 

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GrayCreed

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Here's the same load (Nosler 140g RDF .025" from the lands) at 400y (just the 4 red holes)
 

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GrayCreed

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Here's the 143ELDX at 2.875" which hit one shot after the other at 1200y (this is the group from 100y)
 

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FEENIX

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I don’t have a COAL gauge. So I did it what I feel is a somewhat useful way to find the lands. First off, it is a Savage 10-Tsr rifle. I’m using 143 ELDX. The bolt wouldn’t close at 2.91”. So I backed down to the max that the mag would allow and still cycle fairly well. My end result was 2.87” COAL. I have not shot it yet to see how it does there. The rifle shot .4” groups with a 2.82” COAL, so wanted to see if it would get better going closer to the lands. This seems much longer depth than what I hear from most. Am I wrong somewhere?
If your current CBTO feeds well, I'd leave it there and play with the powder charges towards the max but safe zone if you have not done so already.
You shouldn't concern yourself with any book values, nor what others end up with.
Instead, you should do full seating testing (like Berger's recommended) to find best accuracy and go with that.
^^^This!^^^
 

General RE LEE

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600 yard group and 100 yard group 143 grain ELD-X H4350 41.5 grains 2684 FPS ES22 SD 7

Loaded .020 off the lands
 

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jgs8163

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Chasing COAL is sometimes very hard to do as a lot of bullet lengths fluctuate a few thousandths or more from base to tip. If you want to chase the lands you really need to be measuring CBTO and invest in the tools to do so. The ogive is extremely consistent on bullets. Tips usually get somewhat minutely deformed when shipping, packaging, and sometimes when pressed into the brass when the dies don’t have a VLD or ELDX type seating stem. If measuring coal only, make sure your dies stem are not slightly deforming the tips when seating them, this can be very common item overlooked when beginning. Hornady and other Die MFG’s make ELDX and VLD type seating stems to eliminate this from happening when seating the bullet. The picture below shows 3 Hornady ELDX and 3 Berger VLD Hunting bullets. The Hornady all measured base to tip differently with one having a difference of .006 from lowest to highest. The Bergers measured all different as well with them being as far off as .007 from base to tip. Base of bullet to Ogive measured only had one bullet with a difference of .001. I measure COAL only for feeding properly from mag well. CBTO is your best friend when chasing lands.
image.jpg
 
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