- April 4, 2016 at 10:56 pm #26793
So trying to assemble more accurate ammo, usually just use what’s published. Don’t have any fancy tools, and know the best way ( for a bolt action ) is to remove extractor and firing pin and seat till the bolt closes without resistance. Not wanting to go to that extreme (yet) only b.c. I broke my punch trying to remove roll pin and haven’t replaced it yet.
So I’m trying to old stand by methods to get me close. With action closed insert cleaning rod from muzzle and mark…..etc. place boolit in chamber an hold with dowl and make second mark…etc.
Then I tried to just seat the boolit long and close action.
I get approximately 0.100″ difference using the above methods. What am I missing or doing wrong?
Win. Mod. 70 30-06 and 30XCB
- April 4, 2016 at 11:10 pm #26794
When machining an object to .001″ and to be sure that the measurement is valid, you use an instrument that will read in .0001″, or has ten times the resolution.
You are going to have to break down and buy the Hornady O.A.L. tool with the modified case and measure with a steel caliper. A better measurement would be at bore diameter with the tool that attaches to the calipers.
- April 4, 2016 at 11:53 pm #26797
Doc agree 99% and familiar with the accurate shooter site, and also know that tool will only get you close and ( from what I read on that site ) different measurements each time. Thats why I would prefer to find my lands using this method..
More interested in why I get two different measurements? Both methods have been used to get “close” . and with load development, if I think I have a combo that will work can fine tune from there. I also use the Hornady comparator, just haven’t purchased their other tools yet.
- April 5, 2016 at 12:11 am #26798bjornbModerator
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since you are loading cast bullets there are more ways to skin this cat. Doc is correct; the Hornady/Stoney Point tool is the way to go. And with a little practice it’s not hard to get consistent readings on the ogives. I use the tool for ALL my jacketed loading, no exception.
However, before you get too far into measuring OAL try seating the bullets into the lands. With the exception of Larry Gibson I have probably shot more 30XCB bullets than most people, and that bullet likes to start off seated solidly into the rifling.
- April 5, 2016 at 1:33 am #26801
I agree the comparator will give consistent measurements because we are measuring off ogive, but those tools for finding overall length are inconsistent, 80% if I read that article correctly, and even the link states we are going off a “feel” ( human error) when finding the lands with it.
I am not saying it doesn’t work and do agree should be using it to get close. Rather, what am I doing wrong with the above mentioned methods to be off that much between the two?
And just so I’m getting off on the right foot, going to purchase the Hornady OLG tomorrow ( I know the local fun shop has it, but don’t think they have the modified case so will need to order it ), mainly because I’ve gotten to this point and my OCD is driving me nuts for the answer.
- April 5, 2016 at 3:32 am #26802
Using the Hornady tool is no different then learning to use a micrometer to read 1/10,000 and get repeatable readings. Also make sure the chamber and lead to the rifling is clean, dirt will make for inconstant measurements.
- April 5, 2016 at 3:49 am #26803
Dan, the thing I don’t like about the way that Wheeler Accuracy does it is they require you to remove the ejector on the bolt, 99% of the people will not know how to do that. I have the spring loaded ejectors removed permanently on my single shot Remington 40X rifles and some of my others are mechanical. I almost forgot to mention that the Hornady tool works great for single shot rifles like the Encore and falling block rifles like the Ruger No1.
I also forgot to mention how I use it. When the rifle is laying on it’s side and I have the tool with the modified case and bullet in the chamber, I also have a cleaning rod inserted from the muzzle. So when the bullet is just touching the lands, I also have the cleaning rod touching the bullet tip. This allows me to feel simultaneously with both hands and gives a much better feel and a more consistent measurement.
- April 5, 2016 at 4:01 am #26804ArtfulParticipant
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I’ve used your cleaning rod method for years – Some of what I learned
– I put tape around the rod so it’s a centered snug fit
– to put the boolit into the lands I take a once fired case and bend the neck so it will grip your boolit
– I have just slipped the Rim under the extractor and put the case against the ejector and then carefully closed the bolt.
– taken the measurement with the cleaning rod – will be with the leade rammed into the boolit
– Opened the bolt and withdrawn the case (lots of times the bullet sticks – then punched out the boolit
– then close the bolt and run the rod into the gun until it hits the bolt face. – mark the second time
– you will find that using a pencil is hard to see what I found best was masking tape wrapped at the muzzle – then mark with a sharp pencil
– you will now have the maximum COAL
– fine points to watch out for – is the boolit marked evenly by each of the rifling leades? If not the boolit was crooked
– Was the cleaning rod blunt tipped or just the threaded hole or a jag or loop? well you get the idea.
- April 5, 2016 at 4:44 am #26805GoodsteelKeymaster
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The Hornady tool is good to much closer than you might think. Yes it takes a bit of feel, but that does not mean that you cannot train yourself to use it correctly. After all, I would submit to you, that the very thing you are measuring will be used very shortly to place dozens of shots in close proximity to eachother using nothing BUT human touch by minimizing the error in the bag of bones draped over the rifle. That’s like paradigm shifting without a clutch of you ask me.
In the video, what’s the guy say at 3:10? He’s using feel as well. When you get down to the last .005, that’s all you’ve got no matter what method you’re using.
The method demonstrated in the video is valid (although it looks sooooo much more valid when demonstrated with a nice Panda action eh? LOL!) and I used that method for years, however, the Hornady tool struck me as an ingenious way to do the same thing with even more sensitivity. The only problem with it, is that it takes a measurement from the headspace datum line to the ogive of the bullet where it contacts the lands, and if you base that measurement on a FL sized piece of brass (like the ones sold by Hornady) it’s giving you a measurement that is about .002-.005 too short (oddly enough, that’s precisely where most people start working test loads from). I do not care to have a measurement that is anything other than reality, so I make my cases from brass that matches the chamber much more closely, and supply them to my clients as needed.
I made a custom OAL gauge like the Hornady, but It’s made of brass and the pusher rod is solid. I also make the cases for it from brass that was fired in the rifle I am measuring. Therefore, it is very accurate and repeatable.
You can buy the taps on ebay for a few bucks. The thread is 5/16-36 and requires a .2824-.2891 tap drill. A letter L drill is close enough (7.25mm is better).
In order to take the measurment, you simply clean the barrel very carefully, insert the tool into the chamber and insert a cleaning rod from the muzzle.
Push the OAL gauge into the chamber and seat it snugly.
Then, gently push the bullet forward till it stops on the lands.
Lock the rod gently with the thumb screw.
Use the cleaning rod to push the gauge out of the chamber gently (you only need to go 1/2″) then carefully extract the gauge from the action and take your measurement.
Do it several times until you are confident that your are repeating your measurement precisely, and call that measurement your zero point.
I usually build all my test loads by seating .008-.010 deeper than this measurement.
Just my 2 cents worth.
- April 5, 2016 at 11:34 am #26808
“so I make my cases from brass that matches the chamber much more closely” I picked this up from a thread by Eric C.over at accurate shooter. Also, which as Tim stated regardless of what method we use the “bag of bones draped over the rifle” is still a factor. I might have to repeat that someday again!
â€‹Thanks for everyones opinion.
- April 5, 2016 at 2:20 pm #26810
Dummy me I forgot to mention that I use the head space gage that Hornady also makes, and take a measurement for both the modified case, and cases that have been fired in the gun to get my final dimension and record it. If the Hornady modified case measures say .002″ smaller than my actual fired case I add that to my measurement.
- April 5, 2016 at 7:37 pm #26811Larry GibsonParticipant
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Over the years I’ve probably tried just about every method and tool that’s come down the pike. Some were better than others and some were more precise and consistent than others. Over the years I’ve come to a couple conclusions that some may disagree with but most often I’ve not seen any real results giving their disagreement more credence than mine. Whatever method you use if it works for you then that’s good enough.
Here’s the conclusions I’ve come to; a precise aol adjustment to seating depth is one of the minutia of “variables” that seldom really makes any real difference. Let me caveat that by clarifying the oal should be either against the leade or slightly engraved by it with cast bullets. With jacketed bullets the bullet ogive should be just off the leade by .00 – .002+/-. Many, if not most, rifles simply do not have the accuracy capability to benefit from any more oal refinement than that. The real benefit of seating bullet closer to the leade, especially in longer throated chambers, is the bullet is better aligned concentrically to the bore. This is most beneficial with cast bullets if the bearing surface is up into and is specifically sized to the throats.
Anyways this is how I’ve come to measure the oal for any given bullet in any cartridge. I use a FL sized case so the case can be used in any chambering of that cartridge. The neck is split on each side of the neck (180* apart) with a small fine tooth hack saw or a fine cutting wheel in a Dremel tool. I use a fine small round file to deburr the inside of the neck at the cut. The case is then run over an M-die appropriate for the bullet diameter if cast are used. It’s also good to do it jacketed bullets are to be used as you just want enough tension on the bullet so it isn’t pullet out when the cartridge is extracted from the chamber.. Not much tension is needed. The bullet of choice is started or partially seated in the neck and the cartridge is then chambered. Slowly extract the cartridge and measure the oal. Note the cut extends into the shoulder slightly.
Most often with harder cast bullets and jacketed bullets that initial oal will be with the ogive or leade drive band firmly against the leade. You can easily then subtract .001, for example, to have the cast or jacketed bullet .001 off the leade. Or, with a cast bullet you can add .001 to have the ogive or edge of the front drive band firmly against the leade. Simple and easy to use with very repeatable results. just use a kinetic puller to slightly tap the bullet out a tudge and repeat the seating to get several measurements with the same bullet for confirmed results. With cast bullets be sure to use one of the bullets of the alloy you’re using as alloy shrinkage can vary the oal otherwise. The bullet is easily removed from the case to be used with another bullet.
Notice the reversed jacketed bullets. That’s how I measure and track throat erosion or more appropriately referred to as leade erosion. A case and a flat based jacketed bullet with a relatively long bearing surface is used. The bullet is seated backwards and then chambered in the rifle. The base at the large diameter buts against the leade giving me an oal where the leade is. I do this 10 times for a consistent “average” (if there is one….usually there isn’t and difference) measurement. I record that length, mark the case with the rifle and leave the bullet in the case. That case with bullet is then kept just for that rifle. Every 1000 rounds (sooner on some high intensity cartridges) I will use the same cartridge to again measure the oal to the leade. Obviously a longer measurement indicates the throat is eroding and the rate (in .001s of an inch) of erosion.
An additional benefit of this method with cast bullets is you can actually see where the GC is in the neck. With a longer cut on one side of the cartridge you can also see the actual load density of any given charge and if a Dacron filler is used you can better determine the exact size of the filler needed. With jacketed bullets you can easily check load density and compression.
Nope, they ain’t pretty by any stretch of the imagination but this method works as well or better than any other method I’ve used.
- April 6, 2016 at 3:16 am #26817ArtfulParticipant
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Very Interesting technique Larry – thanks for sharing
- April 6, 2016 at 11:55 am #26820Kevin SParticipant
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+2 Thanks Larry
Well I now have another project.
- April 6, 2016 at 11:44 pm #26846chutesnreloadsParticipant
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Very clever indeed
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