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finding right OAL without comperator?

G

Glennp

Private
Minuteman
Oct 5, 2009
32
0
35
Peoples Democratic Republic of New Germany (NJ)
#1
I know that its not 100% possible, but I dont have a comperator nor can I afford one (I'm in college and basically spent everything I have on my rifle, and reloading gear). I have a remington 700 SPS varmint in .308 with an HS precision stock.

Would it be safe and better than nothing to get an OAL from tip to base with the method of the slotted case, etc? then use that same bullet which is seated at the lands (fresh out of the rifle) and press it down "X" distance, and set the die to that? Then play with it from there? Or am i treading dangerous waters here (or useless waters...)?

Or is playing with the seating depth a waste of time without using a comparator? I'm not trying to half-a$$ it and I know that a comperator would be alot more precise but thats just not in the picture...yet


Thanks for your input!
 
#4
Re: finding right OAL without comperator?

Take a sharpie and color the region of the bullet all the way around the circumference just beyond the ogive/bearing surface region. Load it really really long, chamber the dummy round carefully, then carefully unload it.

Measure the length of the rifling scratches left in the sharpie ink on the bullet. Load the next one about 75% of that length shorter.

IE, load a round to 3.000" long with a colored bullet

Scratches are .12" long, load the next round at 0.09" shorter or 2.910" long.

Try again. This time you'll be much closer to the lands. It's a bit of trial and error, but it usually only takes me 2-3 tries before I know where the lands are within about 5 thousandths.
 
#5
Re: finding right OAL without comperator?

The only problem I see with your lack of a comparator is that even if you find the right seating length which you can do using the sharpie method (or others), is that it's tough to get consistent OALs using just calipers as bullets (even same brand and lot, and even the best brands) differ from one another (and at times by more than just a couple thousandths of an inch). Now that may not be enough to make a difference in your shooting, but if you are a stickler about seating depth, then it's worth thinking about. All that said, PM me and I'll send you one, if I can fine my extra.

- Joe
 
#6
Re: finding right OAL without comperator?

I measured a box of 100 155smk's last night .... they measured anywhere from 1.128 to 1.145 with the biggest group between 1.134 and 1.136. I am going to set my seater to seat the longest bullet at mag length and then go from there. But I am making an assumption is that the difference in length is from the ogive to the meplat and not from the base to the ogive.
 
#7
Re: finding right OAL without comperator?

I do the same thing, but without the sharpie. I load long, and look for rifling marks on the ogive. Seat the bullet about .010" deeper each time, until no marks or I don't feel the bullet contact the rifling when closing the bolt. This will get you there. And make sure it still fits in the magazine. If it won't fit in the mag, then seat the bullet to .010" short of max mag length.
 
#8
Re: finding right OAL without comperator?

I had a question that maybe you guys missed.

You give good descriptions of how to measure the chamber of your gun, but

How are you guys setting up your dies from this measurement and being accurate?

I have a comparator set so its not for me. Just trying to keep the college student on the right track.

Thanks
 
#9
Re: finding right OAL without comperator?

Trial and error works if you have time but not money.

If you don't have a micrometer seater die, you can figure that the 1/4-28 threads on most seaters give you about .0357" per revolution and take it from there. Seat a bullet longer than you know you want it and measure OAL. Subtract the desired OAL from whatever you've started at and figure out how many turns gets you where you want to be. Once you have 1 "dummy" seated properly in a sized case, you can use that to set up your seater die the next time by backing out the seater screw and then running it down until it touches the dummy bullet firmly.

Let's say you seated long to 3.017" and want 2.815". Subtracting gets you .202". Divide that by .0357" and get 5.66 turns, or about 5 and 2/3rds turns. Sneak up on the last 2/3rd of a turn so you don't have to use a bullet puller.

Slight tweaks may be required as needed with this technique, but it'll get you there.
 
#10
Re: finding right OAL without comperator?

Cinobus, that hit the nail right on the head! THANKS!

What range of depths should i be trying? Ive heard everything from .5 (which i HOPE is a typo!) to .001 starting points. Ive also heard .05 and .005. Which of these have the right amount of zeros!? Is the range something to try something like .002-.006"?
 
#11
Re: finding right OAL without comperator?

hello,these guys are giveing you very good info.if you are like me and just want what works best for you this is what I do.I have a dummy for every bullet that I shot.I use a case brand that Iam not going to use.I size it and seat a bullet of choice at a long O.A.L. and then run it into the chamber closeing the bolt and remove it slowly.this is what one of the guys said up top earlier.then I'll load a few lots of 5 at this O.A.L. and go shot.after I have shot I then let the target talk to me.after reading the target I then play with the seating O.A.L.I may load them alittle longer or alittle shorter.In my experence I have found that some of my loads like to be in the lands so I just load them long and let the bolt do the rest of the seatimg.but after getting my powder and seating length down to what makes me happy or should i say what makes the rifel happy.I take my fist dummy that I started out with and seat it to the length that worked the best and keep it to reset the die if I have loaded a differant bullet from what I am reloading that works.It's alot of work and time but it pays fot its self.just remember one thing you have joined a great group of people.the reloading world of people.just don't let it run you into the ground.reloading can pick at your mind if one is willing to let it.so don't load when you need to keep focus on the books.John
 
#12
Re: finding right OAL without comperator?

Forgot to add:

In case your threads are NOT 1/4-28, just set your caliper to 1.00" and measure how many threads there are. Then divide 1 by the number of threads to get seating depth change for 1 revolution.

For example, my Lee and old Hornady/Pacific die seaters as well as my Lyman M die have 18 threads per inch, and move .556" per revolution.

Alternatively, just seat long, measure OAL, make 5 revolutions, measure again and divide the difference in OAL by 5. It's tough to get a good number with just 1 turn.
 
#14
Re: finding right OAL without comperator?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 4Rail_Gunner</div><div class="ubbcode-body">
How are you guys setting up your dies from this measurement and being accurate?

Thanks </div></div>


Trial and error.

After the Sharpie you measure.

Adjust your dies from there.


Initially I had mine set at 4.866 for a factory Rem 700VLS - it works GREAT for 25 tho off the lands.

but it doesn't load for crap, magazine issues all day long...not worth it.

Set it to 2.810 for a 308 and drive on, if anyone here can outshoot a factory AOL I'd be really impressed.
 
#15
Re: finding right OAL without comparator?

Take a old piece of brass and size it. Then take a dremel tool with a diamond cutting wheel and cut two slots either side of the neck. Polish any burrs off and polish the inside of the neck so the bullet will slide in it but there is still enough neck tension to hold the bullet from moving.

After you have that done place a bullet in the neck and chamber it! Carefully remove the round from the chamber and measure it. Do this several times with different bullets and average it. This will give you your OAL with the bullet touching the lands. Back off the desired amount and your good to go!

DSCI0003-6.jpg


Also note: With said method you can place the round in your press and run it into your seater die! Carefully and slowly run the seating stem down till you feel it touch the bullet. Lower the ram and remove the round. You can then turn the seater stem in a 1/4 turn and you should be good.

Terry

 
#18
Re: finding right OAL without comperator?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308sako</div><div class="ubbcode-body">Do a search for this post: Tech note from Berger on seating depth

It will save you thousands of bullets over the years coming. </div></div>
Do you have a link? I did a search but came up dry.
 
#20
Re: finding right OAL without comperator?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JDT</div><div class="ubbcode-body">What comparator are most of you guys using. Is this http://www.midwayusa.com/viewproduct/?productnumber=746974 worth anything, Im assuming you use it with calipers.</div></div>

I used to use that, but I switched over to the Sinclair with the Hornady lock and load inserts which attach directly to the calipers (they are a little more pricey) but they're easier to use and faster. I haven't actually measured the inside diameter to determine if there is a difference between comparators, but I would suggest if you use one, stick with one for a given batch of loads. Just my two cents.
 
#22
Re: finding right OAL without comperator?

Use of a comparitor saves you in the long run quite a lot, once you have the comparitor measurment then you can load another bullet and use the same measurement since your measuring the .244 " if 6 mm for example" diameter to the end of the case for the oal .

dont forget about bumping the shoulder .001 to .002 if you like to keep it tight?
Bill
 
#23
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