? on bullet seating depth

D

davepa

New member
I've just started relaoding and I'm using different bullets. I'm reloading for a .223. I've got Hornady v-max 40gr,55gr, sierra blitzking 40gr, and sierra spitzer 45gr.

I made a dummy cartridge for each bullet setting them in to where they just stopped hitting the lands. I was then going to make up my reloads 20ths shorter. Measuring OAL of the cartridge.

I came to realize quite quickly into this that the bullet depth seating screw on the die is barely moved when swithcing between bullets even though the cartridge OAL changes greatly. Thats when a light in my head came on.

Does the bullet seating die contact the ogive of the bullet much the same way the lands would contact it? In other words when the seating die is set for one type of bullet it wouldnt have to be moved for any others because the i.d. of the die thats pushing on the ogive of the bullet is likened to the lands that would be touched when the cartridge is fired, thus if the die is set to a fixed position for a bullet to give so many thds gap, it then becomes a fixed setting distance just like the lands are in a fixed position in the barrel no matter what kind of bullet is used.

This make any sense?
 
Dave,
Your right, there will be some veration in seating depth with different shapped bullets. The good news is that most gun shoot about the same over a .005 to .010 range, the problem is that you don`t know if that range is just off that lands or with a .030 jump. I`ve never used a Stoney point gage for that reason. You may also find that different bullets will shoot more accurately with different jumps, and different powder charges. I shoot right outside my door so it`s very easy for me to load up 5 round and go out and shoot them and come back in and load 5 more. When trying different bullets I`ll load 5 rounds with each bullet with everything else the same and shoot them. I`ll then come back in and change 1 thing, powder charge, seating depth ect. and load 5 more of each. Finding the best load for a rifle is mostly trial and error but if you do it systimaticaly you can save alot of time.
 
davepa
No, that will not work. The seater does contact the sides of the bullet but not as far out as where the rifling hits. The seater does require less adjustment for different bullets than it would need if it hit the tip of the bullet, but there will still be significant differences with some bullets.

I wish it were that easy!

Jack
 
With handloading and establishing a seating depth I have found that if you start with the bullet barely touching the rifling as a starting point you have established a baseline.From this point you move your seating die in .005 increments down or seat the bullet deeper in the case.If you start .020 or .030 off the rifling you will make adjustments in both directions.By starting at the rifling you are working in one direction.A bullet comparator and dial calipers will let you measure from the thickest part of the bullet to the case head.you can account for the differance in length of the specific bullet loaded.The bullet comparator duplicates your rifles throating for a more accurate measurement. Good luck with your reloading.
 
Davepa: I will add this to the post as a new reloader you may know this, on the off chanch you do not bullet seating depth will have a effect on pressure in the rifle chamber so take that into account with you load charges combined with bullet seating depth.
 
Thanks for the replies. Each one of ya had a point that I need take into account. One important thing I didnt take into consideration was a different tapper for different bullets.

I'm half tempted to go back pull the bullets and start all over again. The way I loaded now I'm not going to get as much data as if I were to use the info in this thread.

Ok this brought on another question. When you start looking for the best load for your guns do you start first with a fixed distance off the lands and work up cartridges with the same powder, but different powder weights or do you go with different seating depths and the same amount of powder?
 
Seating depth is a fine tuning variable. Start out with the bullet either in contact with the lands, or .005 off the lands. Find your powder and bullet like that, then play with seating depth to fine tune.

Edit: To elaborate a bit - I've not even experimented with seating depth in working up loads for the last several barrels I've worked with. Just started at .005 off with one, hard jam with another (VLD's), magazine length with another. Found acceptable accuracy there, and never "got around" to playing with seating depth at all. Seating depth DOES make a difference, but bullet and powder choice have a much greater influence on accuracy. I used to fine tune seating depth exhaustively, on every barrel, and found that almost all rifles shoot best with the bullet not more than .010 from the lands (most shoot better touching or only .005 off). So, anymore, I start out with what SHOULD be a good seating depth and worry about finding "the biggies" - bullet and powder. Only later, if I feel like it, or I'm not satisfied with the accuracy, will I fine tune with seating depth.

YMMV!

- DAA
 
davepa:All have made some good points on bullet seating depth.I am no expert in reloading so take what I post for what it is information.Take it or leave it.Your question about load developement.In my view what you want to do with load developement is to find the barrel time or sweet spot for your specific rifle.A velocity that matches the specific barrel harmonic motion of your rifle.DAA makes a good point about a starting point for seating depth. .005 or more like .015 or .020 what ever you feel works then stick with that depth it is now a variable in the load that has become fixed at this point. Your question about powder weights.I fell the best way to work up a load and do load testing is by using what is refered to as the (Audette method).The method has limitations but with 30 rounds you will find the most accurate load for your specific rifle with the load combination,loading methods, and components you have selected to use.It would take a long time to explain it in this post.If you would like to know about this method of load testing perhaps a E-mail would be a better way of getting the information to you.Just a thought on load development.My view with load testing and the way I do it it is with the Audette method.
 
Just a note - and I hope this isn't deemed inappropriate (if it is, just go ahead and nuke this Jack), but... I'm developing a web site for my new video, it's just about done. It won't be "up" until we are actually ready to launch the video, but it should be before the end of the month. I've got several articles on load development and tuning that I've written, that will be part of the website. One of them deals specifically with the Audette method, another other outlines my personal "rapid load development" techinique.

Anyway, I don't want to get in trouble for promoting my product here, hope I'm not over the line by even bringing this up. Just that I've written some article length pieces dealing specifically with what we are talking about here, and they will be "on-line" soon. I've got another one in the works, dealing with seating depth (I've got a TON of real data from old tests, just need to get it organized into an article).

I'd suggest getting ahold of Steve Timm's load development series in TVHM too - good stuff.

- DAA
 
DAA
Sounds to me like a little promotion would be the least we could do for info like that. I will get back to you on it.

I agree completely with you about seating depth. Set it close and get everything else sorted out first. Then if needed try fine tuning the depth.

Jack
 
I've decided to pull the bullets and start with a closer seating of the bullets. Now I just have to get a bullet puller some time this week.

Until then Michael, if it is possible to shot me an email explaining the Audette method or even just point me to a website that has it posted, I'd appreciate it. I did a search and couldnt find it, at least not yet.
my email is [url=mailto:fxdwg1@yahoo.com
 
I always start out with a new type of bullet with it in contact with the lands of my rifle. I then start moving back like one of the previous posters suggested. I have a tool that alows me to measure my cartridges length from the bottom of the rim to the ogive of the loaded bullet. i use a candle to get soot on my loaded bullet {dumby round}, no powder or primer!!!!! then i chamber it in my rifle. the bullet is seated very long so it will contact the lands. i screw in my die a little bit and rechamber the sooted cartridge again. i then screw my die in deeper each time until the bullets soot has no land marks on it. screw in the die just a tiny bit each time {maybe an 8th of a turn} unless you have a BR seater with micrometer. i then measure how long the cartridge is from the rim to the ogive of the bullet. i now know how long to make my cartridges from the rim to the ogive for that rifle. once i have this measurement from one bullet i can seat all bullets close to or in contact with the lands of the rifle because i am going for the ogive lenth. then i go look for the "sweet spot". the measurement that matters is not the OAL from the bullet tip to the rim, its the measurement from the rim to the ogive! some rifles have long throats and when the ogive is close to the lands of some rifles the cartridge may be to long to get into your magazine. sorry for the lenth of this post.
 
P.S. some bullets have some variation in their lengths. especially the lead tipped bullets. even the higher priced plastic tipped bullets have some variation. rim to ogive length is a better way of measuring your cartridges. i dont even right down my OAL's. just the rim to ogive lengths.
 
I agree Ronald, OAL is pretty worthless when discussing seating depth in terms of relationship to the lands. Using a comparator to measure off the ogive is the way to do it. I'm not sure if I understood you quite right or not, but I think you said you then transfer the measurement with you comparator from one type of bullet to another? That doesn't work. Unless the leade of your comparator (most of them don't have a leade...) matches the leade of you chamber perfectly. The comparator measurement will be pretty close for bullets with the same ogive, but it can be pretty far off for bullets with a different ogive. Moral of the story - you have to get that initial measurement for each type of bullet.

- DAA
 
Hi DAA, The tool that i spoke of is a 1'bolt that has holes cut in each side of the bolt. each hole is a different caliber. i slide the bolt down onto the bullet and it stops where the ogive starts on the bullet. i then measure the cartridge with the bolt on the bullet part of the cartridge with my dial calipers and then subtract 1' from the measurement. this gives me the length of the cartridge from the rim to the ogive. once i get the bullet seated to where it is just off the lands i then have the rim to ogive lenght for that rifle. i seat all bullet ogives to this length. the bolt just touches the ogive of the bullet and not the tip so all bullets end up with the same ogive length. i hope i explained it well enough for everyone to understand. i got this bolt tool from a friend.
 
P.S. it doesnt matter what brand or shape of bullet you are using when you seat the bullets so the rim to ogive lenght is the same. you will have to find the "sweet spot" for each brand of bullet but i know where to put the ogive of the bullet in relation to the rim of the case "so it is close to or on the lands". that is where i start out. using this method you can put the ogives to all shapes and brands of bullets close to the lands because you have the ogive to rim length that is close to or on the lands for that rifle. it always stays the same for all bullets. rim to ogive measurement! you have to adjust your die from brand to brand but that is it.
 
That's exactly what I meant - you CAN'T transfer that rim to ogive measurement, taken with your comparator, from one type of bullet to another. The comparator you describe is the Sinclair tool, same one I use. Trust me, the spot on the comparator that makes contact with the ogive is NOT configured and dimesioned exactly the same as the throat of your rifle. So, the measurement is not trasnferrable to bullets with a different nose geometry. It can't be.

Use the method you described for actually definitively locating the seating depth at which a particular bullet is making contact with the lands of your rifle. Take a rim to ogive measurement with your comparator. Now, repeat the process of locating the lands by smoking a bullet (or however you prefer to find them), with a bullet of a different type (just for clarity, make it really different - secant vs. tangent ogive, of different calibers 7 vs. 9 for instance). Now, take the rim to ogive measurement of that one with your comparator. It will measure differently than the first one did. Like I keep saying, unless your comparator matches your throat perfectly (it doesn't), the two bullets have to measure differently when both seated to the same relationship with the lands.

This is one of the most common misconceptions in handloading. I've even seen it presented wrong in fairly sophisticated "precision oriented" handloading publications.

By the way, just for yahoo's, take down a few different types and manufacture of bullets off the shelf and start measuring them with a comparator. We all know that bullets vary a good bit from base to tip. But they are SUPPOSED to be the same when measured from base to ogive. That's why we use comparators to measure cartridge length. But, if you get to actually measuring some bullets, you'll find some boxes, of some brands, with a suprising amount of variation from base to ogive. Those bullets don't group as good as consistent ones...

- DAA
 
DAA you said overall legnth is no good to use. I dont understand why not.

I go though the process of sooting a bullet in a dummy, fired cartridge, chambering the round then checking it to see if it has contacted the lands just like Ronald described. When there is no more contact I then use this cartridge as my base for OAL when using that particular bullet. A different bullet will require a different OAL measurement.

If all the bullets of one certain type including the weight are all made the same, why couldn't OAL be used?
 
----If all the bullets of one certain type including the weight are all made the same, why couldn't OAL be used?----

Ahhh but that's just it. They aren't made the same! Take a box of bullets, start measuring them from base to tip. You'll find significant variation with even the best bullets.

- DAA
 
DAA is right. OAL does not mean much. There is just too much variation in the bullet tips. The hollow points seem to be the worst, but all types vary the tips enough so that referencing to the tip is inaccurate. The only thing measuring OAL is good for is magazine fit.

Idea!
The next time you have a rifle chambered, if you have some extra barrel length, have a comparator cut with the chamber reamer.

Jack
 


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