How (and why) to Measure COAL and CBTO; an EXTREME RELOADING Special Edition

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@Sybreed117 8 ай бұрын

Great information, delivered very well in an easy to understand presentation. Appriciate the effort you put into the video. Thank you.

@sdkweber 8 ай бұрын

You are welcome. I appreciate it and thank you for watching and taking the time to post.

@boogerzekesweldingemporium4833 Ай бұрын

Excellent explanation. Very well done. Thanks.

@sdkweber Ай бұрын

You are welcome. Thank you for watching and taking the time to post.

@edboy916 3 ай бұрын

Very helpful! Thank you so much

@sdkweber 3 ай бұрын

You are welcome. Thank you for watching and taking the time to post.

@kennethmyers613 3 ай бұрын

I do not bother with a fired case to ensure that I am getting an accurate ogive dimension. The shoulder is the datum and not the base of the cartridge, so what counts is the distance from the shoulder to the ogive. That is the difference between the headspace dimension and the ogive dimension. Regardless of the headspace dimension, the difference between the ogive and the headspace will always be the correct number to use. I set bullet length to the difference between the ogive and the headspace. Whether you are using a new case or a fire formed case will not matter if you set your bullet to the difference between ogive and headspace.

@sdkweber 3 ай бұрын

That is a very good point. Thanks for bringing it up. Since reading your comment earlier today I have been thinking about how to measure "headspace to ogive" easily.

@tanarosegreen6175 3 ай бұрын

Once you size the case, assuming you do that consistently (and if not, then there is no reason to worry about bullet seating depth :) ) the CBTO is an accurate measure of seating depth. If you are REALLY concerned about getting the exact headspace to Ogive measurment, get a Forster Datum Dial set, and measure the case base to shoulder, and then subtract that from the CBTO.

@kennethmyers613 3 ай бұрын

@@tanarosegreen6175 The CBTO is an accurate measurement of seating depth to the base of the case, but the datum of the case is the shoulder and not the base. So, the dimension that really counts for seating depth to control bullet jump is from the shoulder to the ogive. If you control seating depth from the shoulder (datum) to the ogive, you can easily control bullet jump whether using a new case or a fire formed case. Or, as in the video when measuring where your bullet contacts the lands with a base to ogive dimension, you shouldn't need to modify (thread) a fire formed case for the ogive gauge to get an accurate measurement if you use the difference between CBTO and headspace.

@Aladinoricco 3 ай бұрын

@@sdkweber This can easily be done with the "Accuracy One Seating Depth Comparator, " which is what I use. Make a cartridge with a properly seated bullet and measure the datum to ogive with the comparator. This will be your baseline value (or zero value, if you wish) when you seat the rest of your bullets. Do note, however, that it will take measurements from an arbitrary datum line and an arbitrary ogive. Measuring the datum to ogive length will be relative to other cartridges so long as the same cartridge caliber is used and the same make/model/weight of bullet is used.

@sdkweber 3 ай бұрын

@@Aladinoricco Thanks for sending this. I looked into their website and that tool looks very promising.

@madman432000 7 ай бұрын

I wonder if a shallow cup shape that is the right size for different case heads would work in place of that anvil. Might eliminate some of the spinning the cartridge to square it up. But then I'm not measuring every cartridge coming off the press, first 3 or 4 and they are consistent then one periodically maybe every 20 as spot checks.

@sdkweber 7 ай бұрын

I have been thinking about a better way also. I talked to the folks at 21st Century reloading and we discussed an anvil that is essentially a case holder also. That may eliminate all wobble and make the measurement as exact as possible.

@FSU1HEMI1 11 ай бұрын

You could just superglue a shell holder to your anvil. I like the idea of hornady selling the anvil already setup that way

@sdkweber 11 ай бұрын

That's funny. Thanks for posting.

@Obelisk57 7 ай бұрын

I have been using the .22 cal insert to measure the .308 bullet seating depth. I don't understand if all we are doing is to find max COAL so I can set the die to seat .020 less, why would it matter where on the bullet we are taking measurements from as long as it's not the tip? It's a relative measurement anyway, so why must it be taken at the Ogive and not somewhere above it. Can you explain? Thanks.

@sdkweber 7 ай бұрын

If you are really trying to seat the bullet so it is just off the lands, using the correct insert is important. Each insert is designed to impact the bullet at the ogive. That point on the ogive is the same point that will first impact the lands of the rifling. Alternatively, if you want to get a good measurement of cartridge length, the approach you are using will work just fine. Just be sure you are always measuring using the same insert. I hope this helps.

@50Quid-d3x Ай бұрын

Head space is not the blank space between the front face of the chamber and the shoulder of the cartridge... because when the bolt is closed there should not be any space between the case shoulder and the front of the chamber because the case shoulder is suppose to fit up flush with the front of the chamber face. Headspace is the empty space between the head of the case or what you all are calling the base of the case and the bolt face. If we are talking about a shoulder and chamber face space... which is gona cause the case to explode forward and slam into the chamber face... thats not what we want. What we want is the case shoulder fitted up against the front of the chamber face and the case expanding backwards and hitting the bolt face. I set my COAL and CBTO not to fit my chamber... but to fit my clip... so my bullets are gona jump way more than what I would like. All I am doing is setting the lock ring on my seating die so the tip of the bullet clears my clip and my rifle functions. And yes... if I want to single load longer bullets for whatever reason or put a longer first shot in the pipe... well I can do that if I want.

@50Quid-d3x Ай бұрын

I really like the RCBS Precision MIC for setting headspace... on both empty cases and on dummy rounds... and for making custom go and no go cases which really help me find the proper headspace... or where I want to set the lock ring on my dies. With my Lee, Sinclair and Forster dies and Forster lock rings and Forster Co-ax press... I can full length re-size or neck only size or I can bump the shoulder back only and or I can bump the shoulder back and re-size the neck. I set the final neck tension with a Sinclair mandrel die and 21st Century carbide mandrel.