Measuring to the lands

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tomapleleafss

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Since I cannot find a #5 bullet comparator anywhere in Canada (I have one on order but 4 weeks away) I was trying to determine my OAL of my RPR. I had read of the Sharpie method, where you color the area where the o-give would be. You then seat the bullet a little long and load it. It should leave a mark in the Sharpie ink. You then seat the bullet a little bit at a time till no mark. I tried a couple but not wasn't sure if I was had a mark or not. Anyway this got me to thinking. Could you not seat a bullet long so it will jam into the lands for sure (thus pushing the bullet into the brass), then just measure the over-all length of the cartridge? I tried it a few times and I had to reload the cartridge a few times to get the oal to stop shrinking. What do you think?
Also, is there any risk of damage to the rifle or bolt?
 
I use a thin dowel and picked up several rubber rings at Depot that would fit down the barrel. They rubber needs to be flat not the rounded type. Put the dowel in with bolt closed and put the ring on the dowel at the barrel. I now drop 10 bullets only down the barrel as light as possible and then but the rod dowel back in (fit the 2nd ring in front of the first one before shoving down the barrel). With micrometer I write down the amounts and then take the average (not all bullets are identical). Now I just calculate 1,2,5,10,15,20 thousand off the lands and test load from there. Has helped me develop some very good rounds.
 
Are you only missing the .26" insert? If you have the oal gauge and modified case, you can just measure length to the tip. It will be pretty close. If you're setting back .010"-.020" you're probably not going to notice a difference.
 
Bustercluck said:
Are you only missing the .26" insert? If you have the oal gauge and modified case, you can just measure length to the tip. It will be pretty close. If you're setting back .010"-.020" you're probably not going to notice a difference.
Click to expand...

I do have the gauge and case but I find that the measurements to somewhat inconsistent. Last time I used it I ended up taking about 25 measurements before I settled in on a number. I then proceeded to make up some cartridges and they ended up in the lands. That is when I started to research a different way of measuring.
 
tomapleleafss said:
Since I cannot find a #5 bullet comparator anywhere in Canada (I have one on order but 4 weeks away) I was trying to determine my OAL of my RPR. I had read of the Sharpie method, where you color the area where the o-give would be. You then seat the bullet a little long and load it. It should leave a mark in the Sharpie ink. You then seat the bullet a little bit at a time till no mark. I tried a couple but not wasn't sure if I was had a mark or not. Anyway this got me to thinking. Could you not seat a bullet long so it will jam into the lands for sure (thus pushing the bullet into the brass), then just measure the over-all length of the cartridge? I tried it a few times and I had to reload the cartridge a few times to get the oal to stop shrinking. What do you think?
Also, is there any risk of damage to the rifle or bolt?
Click to expand...

This method works but it works better if you take a Dremel tool with a cut off wheel and make a couple of slits lengthwise in the case neck, that way the bullet slides into the case easier and does not get jammed into the rifling.
 
Use a once fired case to make your own modified case. That way it is the exact size of your chamber. The Hornady modified case will not be the same size as your chamber.
You will have to drill out the primer and tap the rear of the case to the same size and thread as the modified case.
Use a drill in the end of the case and work it back and forth with the side of the drill bit to remove some material inside the case neck so ther bullets you want to measure can slide freely.
I use this method for every rifle I reload for.
 
Sinclair Int. sells a hex nut that has several different size holes, one in each flat. They ship to Canada (owned by Brownells). You can make your own if need be, which is what I did. Simply drill the hole the same size as the land diameter, give or take a few thousandths of an inch, it's not that critical as long as it's close. The hole will contact the bullet on the ogive either close to or just where the lands will touch. You can find out your land diameter with some research on the web.

You subtract the diameter (or length depending on what you use for a gauge) of the tool from your measurement. This gives you your case-base-to-ogive measurement. Alternately, zero your caliper with the tool in the jaws if you use digital.

The Hornady tool will give you the distance to the lands, you measure it with the gauge you made, then load and measure your ammunition with the same gauge.
 
tomapleleafss said:
Since I cannot find a #5 bullet comparator anywhere in Canada (I have one on order but 4 weeks away) I was trying to determine my OAL of my RPR. I had read of the Sharpie method, where you color the area where the o-give would be. You then seat the bullet a little long and load it. It should leave a mark in the Sharpie ink. You then seat the bullet a little bit at a time till no mark. I tried a couple but not wasn't sure if I was had a mark or not. Anyway this got me to thinking. Could you not seat a bullet long so it will jam into the lands for sure (thus pushing the bullet into the brass), then just measure the over-all length of the cartridge? I tried it a few times and I had to reload the cartridge a few times to get the oal to stop shrinking. What do you think?
Also, is there any risk of damage to the rifle or bolt?
Click to expand...

This is exactly what I've been doing for a couple of years. Watch the neck tension on the unprimed case you're using, you don't want to "seat" the bullet fully. See comment re: cutting slits in the neck.

I generally do the measurement multiple times and take an average. I also set aside the bullet used to get the measurement and use it to setup the dies when they've changed since last loading. Close enough for me. As long as you're consistent with your loading practice I'm sure it will work fine for you.
 
As one of the members said. I do have the gauge and case but I find that the measurements to somewhat inconsistent.I frigged around and frigged around I gave up on the OAL gauge you can have mine it is in .223.
 
I seat a flat-based bullet backwards and long in a partially neck-sized case and carefully chamber it, and extract it. Rinse repeat at least 3 times to get an 'average' O/A length/B-L measurement. It usually varies .002.
 
The Sharpy method works but so does using your brain.

Set the bullet long- lay a sharpy line on the round in one or two areas.

slowly and lightly let the bullet chamber until you feel resistance and stop cambering it. eject bullet and look for the scratch... bango you have your OAL .. measure it and wright it down.. now you know the OAL too the shoulder.. but more than that you can also measure your initial seating depth of that round you just dummy tested and measure how far ahead its seated from the brass.. and make some educated measurements from there.

This is not at all rocket science , just accurate measurements , if you are already resizing and trimming your brass properly then the rest you can duplicate easily.
 
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