# Sinclair Bullet seating depth tool



## jk3hunter (Dec 29, 2010)

Has anybody ever had any experience with the Sinclair bullet seating depth tool? It looks like a great idea and I would like to know how it actually works. I would just like to know how far my bullet is off the lands.


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## xdeano (Jan 14, 2005)

this one?
http://www.sinclairintl.com/.aspx/pid=35491/Product/Sinclair_Bullet_Seating_Depth_Tool

xdeano


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## AdamFisk (Jan 30, 2005)

I have no experience with that tool, but I do have the Hornady gauge, and I trust it about as far as I can throw it.. I have never taken consistent measurements with it, with a handful of bullets from the same box, and even the same bullet measured a couple different times.

I'd use the Sharpie method. On one of my rifles, I took MANY measurements with the Hornady gauge, with different bullets, took averages, and got my number. Than I did the Sharpie deal, and got a measurement .007 smaller than what I had with the tool. I trust the Sharpie, as I can SEE the results first hand.

Back your seater die out a lot, and create a dummy round long enough to be jammed when chambering. Coat bullet with Sharpie, chamber and look for marks on it left from the lands. Take measurement. Now, screw in the stem on your die a hair, re coat with Sharpie, chamber, and look for marks again. Take measurement.... Repeat this in .001 increments until you no longer get marks on your bullet when chambering. Eventually you'll have the OAL for that particular bullet, where it is jammed in that particular rifle.

If you don't have one, I'd buy a bullet comparator. It'd be a better tool to spend your money on than that OAL tool.


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## xdeano (Jan 14, 2005)

I do the poor mans seating depth. It's a lot easier than the sharpie method.

Take a fired brass from the weapon you fired it from and neck size the brass only so there isn't any slop in the chamber. Use a Dremel with a fine cutting wheel and cut down the neck and half way down the shoulder. This will allow the bullet to fit snug in the neck without being to snug. I use 4 cuts in the neck at 12 oclock, 3 oclock, 6 oclock, and 9 oclock. now just pick your bullet and load it into your dummy round, with it sitting the neck longer that you would load it, put the round in the chamber, cycle the bolt and gently remove the round and measure it. Do this several time and you'll come up with your max COAL.

I agree a bullet comparator is very handy for doing this.

xdeano


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## Savage260 (Oct 21, 2007)

Hornady OAL, Hornady bullet comp with insert, the proper OAL case, and I get results from .001-.002 on a regular basis. Of course it helps to use the comp and sort your bullets into groups first! Quick, easy, but not cheap!


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## liljoe (Jan 25, 2008)

jk3hunter said:


> Has anybody ever had any experience with the Sinclair bullet seating depth tool? It looks like a great idea and I would like to know how it actually works. I would just like to know how far my bullet is off the lands.


I have used one of these for over 20 years and they work very well. I will say that I would invest in a sinclair bullet comparator hex nut in addition to this tool.

Go through any box of bullets that you have and measure the length from the base to the ogive of the bullet and you will be very surprised in how they vary. Now do the same thing with the same brand, same bullet from a different lot number manufactured at a different time and watch your numbers really differ.

The only way I have been able to lessen this problem is to buy large quantities of bullets with the same manufactured lot number - which means they were made at the same time on the same machine.

If you have any specific questions please feel free to fire away.


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## liljoe (Jan 25, 2008)

xdeano said:


> I do the poor mans seating depth. It's a lot easier than the sharpie method.
> 
> Take a fired brass from the weapon you fired it from and neck size the brass only so there isn't any slop in the chamber. Use a Dremel with a fine cutting wheel and cut down the neck and half way down the shoulder. This will allow the bullet to fit snug in the neck without being to snug. I use 4 cuts in the neck at 12 oclock, 3 oclock, 6 oclock, and 9 oclock. now just pick your bullet and load it into your dummy round, with it sitting the neck longer that you would load it, put the round in the chamber, cycle the bolt and gently remove the round and measure it. Do this several time and you'll come up with your max COAL.
> 
> ...


Tried this a number of times. How the heck do you keep from getting the bullet from sticking into the lands of the rifling? I could not get consistent OAL readings at all and at times the bullet stuck into the lands after extracting very gently. I would love to get this method to work on a consistent basis.


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## xdeano (Jan 14, 2005)

liljoe,

I use a comp bushing die to give me .002" neck tension on my brass and I only run the bushing half way down the neck. This way the brass self centers in chamber off the neck which i know is straight. This might have something to do with it. I know what you're talking about though. Another trick you can try is to run a piece of steel wool down the neck to smoothen out any burs that are left by the cutting wheel. And maybe cut further down in the shoulder to give you a bit more relief for the neck to flex and move.

xdeano


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## Betterluckytg (Jul 19, 2011)

I think that the comparator and seating depth tool work well, IF you are very good with calipers. I tried both several years ago when looking for the ultimate prairie dog load. Unfortunately, I came to realize that I wasn't good enough w/ the calipers for either to be of any practical use for me. Haven't used either in 10 years or so.


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## jk3hunter (Dec 29, 2010)

Used the Hornady tools and with that measurement backed off my loads .01 off the lands. Shot the ten test loads i made and came up with some excellent results. shot .4 to .5 MOA 5 shot groups!  Now I'm debating on moving them up to .005 off the lands does anybody think that that is a good idea?


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## xdeano (Jan 14, 2005)

sure why not. You can keep going back at .005 or .010 at a time, heck some mfg's tell people to move back .040", .080", .120" off the lands, these are mainly for VLD bullets but you can sure try those same guide lines. If anything else you're getting good practice.  Just keep everything the same, when testing loads only alter one variable at a time, it'll keep your life simpler. Keep us updated on your results.

xdeano


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