Finding the right COAL for my Rifle

[Equitum]

Hey guys - looking to start reloading and I'm trying to wrap my head around trimming the case and seating the bullet to the correct ogive OAL for my rifle. The whole process in the "Hand Loading for Long Range 3: finding start OAL" for finding the ogive OAL seems pretty easy to follow, except for the last part, where we actually measure the ogive OAL in the Sinclair comparator - with the last measurement of 3.908, do you subtract the 1.103 from the 3.908 to account for the holder, or is the 3.908 measurement your ogive OAL? The 3.908 seems a bit long to me, which is why I'm confused.

Also, related to the ogive OAL we determine with that process... After a few reloads, our brass will stretch out and we'll have to trim it. Do we just trim it to the length it was when we got it once-fired/new so we have a consistent bullet seating depth? Would the case stretch actually chase the riflings for us if we didn't trim and kept the seating die turned in the same amount?

Thanks in advance.

 

[Helmet]

Re: Finding the right COAL for my Rifle

That number seems too long. Did you mean 2.908"? What caliber are you reloading?
Yes, you would need to subtract the measurement of the comparator to get the correct measurement to the O-give. Since I measure the devise my dad made to measure the chamber with using my Hornady comparator also I don't bother getting the correct oal number. I just make sure the loaded rounds measure .010" less than what I measured the chamber since that's how far off the lands I'm seating them. To give you an idea my 308s measure about 3.21" to the O-give with the comparator attached to the caliper.

Your reloading book should show what length your brass should be. 308 brass should be 2.015" long. My Lapua brass was a few thousands shorter when it was new so it takes awhile to get too long. If it does get too long it will start getting smashed when you close the bolt. It will increase neck tension, raise pressure, and have a negative effect on accuracy.

 

[Equitum]

Re: Finding the right COAL for my Rifle

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ArmchairElite</div><div class="ubbcode-body">That number seems too long. Did you mean 2.908"? What caliber are you reloading?
Yes, you would need to subtract the measurement of the comparator to get the correct measurement to the O-give. Since I measure the devise my dad made to measure the chamber with using my Hornady comparator also I don't bother getting the correct oal number. I just make sure the loaded rounds measure .010" less than what I measured the chamber since that's how far off the lands I'm seating them. To give you an idea my 308s measure about 3.21" to the O-give with the comparator attached to the caliper.

Your reloading book should show what length your brass should be. 308 brass should be 2.015" long. My Lapua brass was a few thousands shorter when it was new so it takes awhile to get too long. If it does get too long it will start getting smashed when you close the bolt. It will increase neck tension, raise pressure, and have a negative effect on accuracy.
</div></div>

I was quoting the measurements from the stickied instructional... I don't think he was using .308, so that might be it was so long. I guess his OAL would be 3.908" - 1.103" = 2.805". He was also seating it purposefully 0.2" longer than book spec and letting the riflings seat it to the correct "just touching the riflings" length. After that he put it back in the press and seated it until it matched the reading between the rod-stops, and then measured the ogive OAL which would apply to all of the bullets instead of just that one. So, when I repeat the process, the ogive OAL I measure will be my start length for 0 jam/jump, I THINK.

 

[Helmet]

Re: Finding the right COAL for my Rifle

I thought you meant it was 3.908" long to the O-give. Even after subtracting the comparator 2.805" would still be too long to the O-give.
This is alot like what I use except I don't have the base for the caliper to sit the bullet on and the rod I use to measure the chamber is homemade, but almost identical.
http://www.6mmbr.com/catalog/item/1433308/977259.htm
Just so we are on the same page

 

[Equitum]

Re: Finding the right COAL for my Rifle

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ArmchairElite</div><div class="ubbcode-body">I thought you meant it was 3.908" long to the O-give. Even after subtracting the comparator 2.805" would still be too long to the O-give.
This is alot like what I use except I don't have the base for the caliper to sit the bullet on and the rod I use to measure the chamber is homemade, but almost identical.
http://www.6mmbr.com/catalog/item/1433308/977259.htm
Just so we are on the same page </div></div>

Like I said, I was just quoting what I saw on http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1705470#Post1705470 No idea how he has a cartridge that long unless he has like 0.5+" of freebore.
Anyways, you answered my question, so, thanks.

 

[Helmet]

Re: Finding the right COAL for my Rifle

OK then. Glad I could help. That's not a 308 in the picture. It's something much longer.

 

[armorpl8chikn]

Re: Finding the right COAL for my Rifle

Measure the Sinclair comparator. It should measure 1.000, subtract that from your number and you will have your length to the lands with that comparator.

 

[CleanMoostang]

Re: Finding the right COAL for my Rifle

What type of rifle will you be using and how will you be using it? Loading magazines or only one shot at a time? Big factors if you plan on using a box style magazine or semi auto.

If you plan on just using it for bench rest, one round at a time, nothing in the magazine, no quick follow up shot, target only, you should be fine...

As for me, I like having extra rounds in my box magazine remington so I measure the size of the box and seat it to that depth. Still closer to the lands than what the normal reloading manual suggests, but deep enough to hold more than one shell...

 

[Equitum]

Re: Finding the right COAL for my Rifle

I'm using a Rem700 SPS-V with a hinged floorplate. If my rounds that I measure for ogive OAL won't fit in my floorplate and won't feed, then I'll just load one round at a time into the chamber.

 

[milo 2.0]

Re: Finding the right COAL for my Rifle

Hate to argue here, my Sinclair 6.5 comparator measures "1.103", my Sinclair 338 comparator measures "1.099".The correct way to measure would be from the case head to the bottom of the comparator, that would be the length to the lands.
After that it is a mute point, it is just a baseline to work off of. And with that comparator, any change of bullet will still run the same number.

 

[Equitum]

Re: Finding the right COAL for my Rifle

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: milo-2</div><div class="ubbcode-body">Hate to argue here, my Sinclair 6.5 comparator measures "1.103", my Sinclair 338 comparator measures "1.099".The correct way to measure would be from the case head to the bottom of the comparator, that would be the length to the lands.
After that it is a <span style="text-decoration: line-through">mute</span> <span style="color: #CC0000">moot</span> point, it is just a baseline to work off of. And with that comparator, any change of bullet will still run the same number. </div></div>
Fixed it for ya. Anyways, what you can do with any comparator is just measure the insert and either zero the comparator or record the length and subtract after you insert the cartridge to measure the ogive length. It doesn't matter what length the insert is as long as you can actually measure the ogive length and the comparator insert.

 

[sic65stang]

Re: Finding the right COAL for my Rifle

How I measure my rifle ammo OAL is by making a dummy round. If this is wrong I apologize, but it works great for me.

I resized a case the way I normally do, and then cut two slits in the side of the neck. I then hand pressed the round I wanted to load into the neck LONG. The slits accommodated the round and allowed it to slip in the case, but holds it tight enough. Then I chamber the round EASILY, the lands press the round further into the case. If you are doing this on a Semi- DO NOT release the bold with the catch because it jamms the round into the lands, just slowly lower the bolt.

Remove the case gently and then measure the OAL. Remember this OAL is for that specific round, in that rifle. Also remember this OAL is on the lands, so subtract how much you want it off the lands.

Keep your dummy round for other rifles of same caliber, or other bullets you decide to try later. Hope this helps.

 

[milo 2.0]

Re: Finding the right COAL for my Rifle

Sounds like you have your shit together, have fun.
You're not a English teacher are you, if so, I don't like you!

 

[CleanMoostang]

Re: Finding the right COAL for my Rifle

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sic65stang</div><div class="ubbcode-body">How I measure my rifle ammo OAL is by making a dummy round. If this is wrong I apologize, but it works great for me.

I resized a case the way I normally do, and then cut two slits in the side of the neck. I then hand pressed the round I wanted to load into the neck LONG. The slits accommodated the round and allowed it to slip in the case, but holds it tight enough. Then I chamber the round EASILY, the lands press the round further into the case. If you are doing this on a Semi- DO NOT release the bold with the catch because it jamms the round into the lands, just slowly lower the bolt.

Remove the case gently and then measure the OAL. Remember this OAL is for that specific round, in that rifle. Also remember this OAL is on the lands, so subtract how much you want it off the lands.

Keep your dummy round for other rifles of same caliber, or other bullets you decide to try later. Hope this helps. </div></div>

They are several people on youtube doing this same thing, and seems to work perfectly. Saves you from having to buy the new gadget from midway or some other website and doing it at home your way.

Remember if its a bolt action to not slide it back and throw it across the room on the floor, because it will most likely move it.

You should also see, if the case neck is tight enough, where it has rubbed the lands with the pressure of you pushing..

 

[Helmet]

Re: Finding the right COAL for my Rifle

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sic65stang</div><div class="ubbcode-body">How I measure my rifle ammo OAL is by making a dummy round. If this is wrong I apologize, but it works great for me.

I resized a case the way I normally do, and then cut two slits in the side of the neck. I then hand pressed the round I wanted to load into the neck LONG. The slits accommodated the round and allowed it to slip in the case, but holds it tight enough. Then I chamber the round EASILY, the lands press the round further into the case. If you are doing this on a Semi- DO NOT release the bold with the catch because it jamms the round into the lands, just slowly lower the bolt.

Remove the case gently and then measure the OAL. Remember this OAL is for that specific round, in that rifle. Also remember this OAL is on the lands, so subtract how much you want it off the lands.

Keep your dummy round for other rifles of same caliber, or other bullets you decide to try later. Hope this helps. </div></div>I hope it's not wrong. I did something very similar. I also drilled a hole in the base of the shell so I could put a rod through the back to push it to the lands. I had to put a nut on it to mark it's progress as I know I would change the measurement when I poked it back out with the cleaning rod. Perhaps I'm pushing it too hard into the lands. I never thought of doing it by just closing the bolt. It would have been alot less work to make. I should have tried that first.

 

[Equitum]

Re: Finding the right COAL for my Rifle

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: milo-2</div><div class="ubbcode-body">Sounds like you have your shit together, have fun.
You're not a English teacher are you, if so, I don't like you!

</div></div>
Haha, no I'm not an Enlgish teacher xD
Thanks!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CleanMoostang</div><div class="ubbcode-body">
They are several people on youtube doing this same thing, and seems to work perfectly. Saves you from having to buy the new gadget from midway or some other website and doing it at home your way.

Remember if its a bolt action to not slide it back and throw it across the room on the floor, because it will most likely move it.

You should also see, if the case neck is tight enough, where it has rubbed the lands with the pressure of you pushing.. </div></div>

I've seen this method while I was looking up ways to measure for my OAL, but it seems so imprecise to me... As an engineering major the comparator style method looks really precise, more so than the "rifling seating OAL measure" style. Even if I have to pay for the comparator calipers and insert, I feel like I'll use the calipers for more than just this first OAL measure. The only other purchases would be the jag (I can just use the flexible cleaning rod from my cleaning kit) and the barrel stops (which are pretty cheap).

I'd rather have the more precise method and pay 20 something bucks, especially since I get some nice, reusable calipers out of the deal!

 

[AMG04]

Re: Finding the right COAL for my Rifle

Reading "Hand Loading for Long Range 3" was a great place to start. I read it over and over until I fully grasped the idea of how to measure the cartrige OAL and length from the case head to the Ogive.

I bought a few comparator bodies and the inserts for all the calibers I plan to shoot. I believe they are Hornady, I got them in a bulk set from Midway (see link). They help make things precise and in the end you save money because you develope better loads, faster saving ammo and component costs.

To make measuring with comparators easier I got a digital caliper which allows you to "zero" the reading with the comparator body in place. Super quick and easy with no math to subtract out the comparator length.

Here are the links of the products I am using:
<span style="color: #3333FF">http://www.midwayusa.com/product/231904/...-with-6-inserts</span>

<span style="color: #3333FF">http://www.midwayusa.com/product/417494/hornady-electronic-caliper-6-stainless-steel</span>

As for the brass stretching, I trim all my new brass to the book specs "Trim to Lenth." At that time I chamfer and deburr the case mouth. I generally get 4-5 loadings before it reaches the max length specified in the books. Once it does I just trim it back about half way between book max and trim to length. By the time it stretches to max again, the brass has served its usable life and I replace it.

 

[waste_knot]

Re: Finding the right COAL for my Rifle

Split case dummy round works very well along with the Hornady comparator.

 

[boltstop]

Re: Finding the right COAL for my Rifle

Guys, some of you cats just crack me up. One newbie shooter comes into the Optics forum looking for advice on a low-end scope and he gets told to pound sand. Some of you characters are spending nigh on $2k for optics but are afraid to spend $40 on a tool which will make the far more impactful OAL adjustments easy and accurate.