Is it necessary to determine the distance to the lands before seating bullets? For example the COAL for my 338 win mag is 3.340. Does this mean that as long I've seated a bullet to an OAL of less than 3.340 it wont be touching the lands? Thanks.

quote:

Originally posted by Ckemp:
Is it necessary to determine the distance to the lands before seating bullets? For example the COAL for my 338 win mag is 3.340. Does this mean that as long I've seated a bullet to an OAL of less than 3.340 it wont be touching the lands? Thanks.

Maybe, maybe not. Depends on how the OAL was established, who is doing it, and for what reason(s).

Sometimes, it is established as the maximum length which will work through the magazines of all the more popular rifles available in the chambering. In that instance it really does not bear any particular relationship to the distance to the lands.

Other times, it is established for a particular bullet brand and shape in a standard SAAMI chamber. In that instance, it is pretty common practice to set the OAL length standard at a dimension which will fall slightly short of touching the lands with that bullet.

Still others establish the OAL length so that pretty much all bullets will fall short of touching the lands in SAAMI chambers. In that instance, the shape of the ogive, which varies from one bullet producer to another, will pretty much determine just how much short of the lands the bullet ends up.

So I guess the short answer is "Yes, I recommend that all reloaders purchase the equipment to measure what the overall maximum length can (and should) be for their own individual chambers. The tools are not expensive, are easy to use, and make handloading both safer and potentially more accurate in performance."

Here is what i like to do Ckemp, I like to intentionally just start a bullet into the brass. So the bullet is just started into the brass, I measure the overall length at this point. then i put that into the gun and chamber the round by closing the bolt. then i pull it out and see if what how far the bullet has been pushed into the brass, and remeasure to see what the overal length is. That is how i do it. I just got my first real chamber that is not a factory wallered chamber so i'm very new to all of this. I tried to do this for factory chambers and found it a waste of time. when you change bullets though redo this exercise, cause the bullet ogive will change. then with that piece of brass i put it in my press with my bullet seating die, push the brass up into the die, and adjust the die to just starting pressure on the brass. then i know that my starting point for my die is the bullet deated into the lands. wow that took a lot of words to get out.

Ckemp and Nate:

Yes, buy a gauge that will tell you what the max length is from the bolt face to the lands. Don't worry about COAL, so long as the loaded round fits in your magazine, OR unless you don't mind a single shot if your rifle happens to prefer your choice of ammo loaded to the lands and it does not fit your mag.

You can take ANY bullet you want, use a case base to ogive gauge, or bullet seating depth gauge, whatever you want to call it (I have the stoney point, now Hornday), and measure what the distance is from the bottom of your brass to the tip of the bullet once you test it in your chamber(I prefer a plastic tipped bullet here b/c they tend to be more uniform than lead tipped).

Take THAT exact bullet now that you have its COAL and seat it into a dummy case to the exact same length. This is where a micrometer seater die comes in handy. Now take your dummy round and chamber it in your rifle gently. If the bolt closes with ease, then you may need to use a bullet puller and whack it once, gently....only enough to release the bullet by a few thousandths.

Try it again in the rifle until you can feel that the bullet is touching or into the lands. It should have a small degree of resistance. You may have to reseat it a little.

Now, remeasure your COAL for THAT bullet in the dummy case. Then measure your base to ogive. I use the RCBS precision mics for this. Take note of that number and the COAL. The latter being your rough guide when setting up your die to seat more bullets of same make and same lot.

Only using the COAL is a mistake b/c even bullets from the same box can have slightly different ogives, so you must record the base to ogive measurement.

Once you have any dummy round with any bullet and measure your base to ogive, you now have the actual seating depth in your rifle, base to ogive, for any bullet, but COAL will vary.

As an example, I created a dummy round with a 130 Btip in one of my 270s. I now have 5 different dummy bullet rounds, but base to ogive is identical even though COAL is different for each. Each and every one has an identical measurement in my precision mic. All are created to be touching the lands, so I know that in most instances, when doing load development, I'm going to go in one direction to fine tune a load, and that is to seat the bullet deeper, unless it is a secant ogive Berger VLD. I sometimes jam those into the lands by as much as .005.

Seat a bullet to the SAAMI max COL (3.340) in a EMPTY CASE and color the bullets ogive with magic marker. Chamber this "dummy" cartridge and see if there are marks in the ink from the lands scraping on the bullet. If so, seat deeper and recheck. I try to measure the lenght of the marks and seat the bullet that much deeper. The length of the marks relates closely to the depth into the lands the bullet was pushed. I try to keep the final couple depth adjustments to 0.010"- 0.005" so I don`t overshoot to far. When the marks disapear you can start fine tuneing to get your exact lenght to the leade, or just except that you are very close, and use this as your rifles max COL..

Edited to add: You will have to do this everytime you change bullet brand or style. Keep in mind too, every bullet will measure a touch different from base to tip. This is due to tolerance in he bullets design and normal. As long as the lenght fits in your magazine and feeds you don`t need to worry about it. The base to ogive distance will stay very tight and is the more important measurment.
A comparator tool like the Sinclair or Hornady will allow you to set each bullet you wish to use to very near the same depth at the ogive, and do away with monkeying with each new style/wgt bullet.. They are, IMO, well worth the few $$.

Ol Joe recommended the Sinclair measuring tool. I concur.

The Sinclair is less expensive in the long run. You can use it in almost all your rifles, whether single-shot or bolt, or break open actions, without having to buy different accessory chambers for each different chambering. It is just as easy to use, and just as accurate as well.

If you don't want to buy a gauge, you can easily make your own, but you will have to make one for each cartridge designation you use. The simple trick is to size a used cartridge case, then using a dremel cut-off blade or a 32-tooth thin hacksaw blade, make a slit down the middle of the case neck. One cut will slit both sides of the neck if properly centered. Voila, you now have a tool which will hold a bullet in position, but will allow the lands of the barrel to easily push the bullet further into the case when chambered.

To use it, seat a bullet barely into the EMPTY slit case, and chamber that dummy round in your rifle. Then take the case out of the rifle and use your calipers to measure the OAL from the bottom of the base to the tip of the bullet. That should give you an overall length with THAT MAKE of BULLET which will function in the distance from the bolt face to the lands in your rifle, without actually knowing the length to the lands themselves.

Because ogives vary slightly in shape and length among even bullets from the same box, you should probably reduce that OAL figure by about .005" for actual loading purposes.

Load another, unslit, dummy (EMPTY of powder and live primer) round and check to make sure it chambers easily and that the round, when extracted from the rifle, has no land marks on the bullet.

Then check it to make sure it will feed through your magazine, if your rifle has a magazine.

Once that is all done, you are ready to start loading your first test ammo. You can always seat the bullets out farther, or deeper into the case, as experiments for better potential acuracy.

For hunting ammo, where it important the rifle stay functional, I would never seat my bullets any longer than .005" off the lands or .005" shorter than the magazine, whichever is shorter.

That is some very useful info from all of you. I guess there's no other way than asking questions and trial and error with this type of stuff. My only other question is the dummy round. I've tried this a few times, but I'm doing something wrong. If I FL resize a case first The bullet obviously seats hard and I can't chamber the round. If I don't resize the bullet just falls into the case. How do you determine a happy medium? I've tried to crimp the bullet in using my seating dye, but I've never had much luck with the crimp built into the rcbs seating dies, unless I'm doing something wrong. Probably cause I'm trying to crimp with the bullet just placed into the mouth of the case and the cannule is not even close to the mouth of the case. Thanks.

quote:

Originally posted by Ckemp:
My only other question is the dummy round. I've tried this a few times, but I'm doing something wrong. If I FL resize a case first The bullet obviously seats hard and I can't chamber the round. If I don't resize the bullet just falls into the case. How do you determine a happy medium?

You should use a fl resized case. The neck needs to be tight. This is where the micrometer seater comes in handy as I mentioned. I can't think of a "happy medium." If the bullet is not held with enough tension, even in your dummy round, you could mess it up by seating it a little deeper when you are setting your seater die up with it in the future.

As I mentioned in my post above, you need to full-length size your case for the dummy round, then slit it with something like a hacksaw blade so the bullet is not held too tightly for the lands to easily force it farther into the case.

When you remove the dummy round from the rifle, do NOT use it to adjust your die. Measure the OAL with a set of calipers. If you are nervous about the acuracy of that reading, do it two or three times and average your readings.

Then reduce that measurement by .005" to give you a little clearance off the lands.

Then when starting to load, screw the seating stem a little farther OUT of your seating die than you think it needs to be. Put a dummy round together with a fully sized, unslit case, and measure the OAL of THAT round with your calipers. If the round is too long overall, screw the seating stem down a little farther into the die, and run the case and bullet back through the die again. Keep doing that until the round is no longer than the measurement you established using your dummy round. Then lock the seating stem in place; you're good to go.

It really is dead simple, and much faster to do than to tell about it.

quote:

Originally posted by Alberta Canuck:
Then lock the seating stem in place; you're good to go.

It really is dead simple, and much faster to do than to tell about it.

As always right on the money! roger

I just take a fired case pinch the case mouth a little and start a flatbase bullet backwards and chamber it. That should give me the distance to the lands.

Lyle

I used to use dummy rounds, but find the dowel method much easier and just as precise.

Stick a dowel down the bbl with a closed bolt and slide a razor across the muzzle making a mark while the dowel is against the bolt face. then remove the bolt and drop in a bullet, hold the bullet in place with a cleaning rod etc., drop the dowel back in the bbl and shove the bullet gently back and forth, make another razor mark on the dowel and you have the distance to the lands. Take that exact bullet and set it in an empty brass to make a dummy round, if you want it off the lands a certain distance, seat it to that length. You can use that dummy round to set your seating die for that lot of bullets, when you get another lot, you'll have to check it again.

Good Luck

Reloader

quote:

Originally posted by Reloader:
I used to use dummy rounds, but find the dowel method much easier and just as precise.

Stick a dowel down the bbl with a closed bolt and slide a razor across the muzzle making a mark while the dowel is against the bolt face. then remove the bolt and drop in a bullet, hold the bullet in place with a cleaning rod etc., drop the dowel back in the bbl and shove the bullet gently back and forth, make another razor mark on the dowel and you have the distance to the lands. Take that exact bullet and set it in an empty brass to make a dummy round, if you want it off the lands a certain distance, seat it to that length. You can use that dummy round to set your seating die for that lot of bullets, when you get another lot, you'll have to check it again.

Good Luck

Reloader

Trying to read between the lines...Drop the bullet into the chamber and press it into the throat of the rifle and hold it there against the lands while inserting the dowel down the barrel.

Right? Sounds like it would work well enough.

Unfortunately in my Rem700 .308 the magazine well length is my limiting factor unless I want to single load. I might give it a try for the range rounds since most of my hunting shots are single shots anyway.

Yeah, leoparddog, that's what I meant. I usually shove it back and forth alittle and then make the mark.

Yep, the SAs will often be governed by the mag length. That's one thing that has pushed me away from SAs as I've almost always been limited by mag length. It really kills the capacity with long bullets.

Have a Good One,

Reloader

Your results may vary, but in all of my rifles, it's almost impossible to reach the lands with most bullets and still fit in the mag. I have verified this with the stoney point tool and modified case. The only exception is the 6mmbr I had built throated to my specs, plus it sits in a 22-250 mag box so plenty of room in there.

On my hunting guns, I just seat the bullets so they fit in the mag nice and easy and then tune with powder charges. usually works for hunting accuracy.

Sorry about that Alberta. You answered my question originally. I just didn't read it well enough. One last question. I loaded a bullet very long in a FL resized dummy case and used a magic marker on the bullet so that I could see what "rifling" marks looked like on the bullet. Maybe I didn't push hard enough on the bolt, cause I really wasn't able to see anything on the bullet. Does anyone have a picture of what that is supposed to look like. I saw somewhat of a short line (approx 1 mm) that went horizontally around the olgive (I'm guessing here). Maybe I should try again and push a little harder. I'm just afraid of damaging the rifling. Is that possible? Thanks.

jb117. I thought that as well about if my 338 has a max COAL of 3.340 then the bullet wouldn't be touching the lands at that distance, but I finally got the dummy round figured out to determine distance, and I've determined the distance with the 250 grain A-frame in my 338 win mag to be 3.305. Much shorter than 3.340. Hopefully eventually I'll get this whole thing figured out.