how are guys measuring how far to seat your bullets?

[catman]

i smoke my bullet in the case with a lighter then install them in my chamber [with no powder in the case for a tester] to see where the rifling lands are touching, have found of course all rifles are different and so are different bullets. on my win mod 70 in 30.06 once i do this process when i measure the overall length of the case it is longer than the max length of 3.34, they still work in my mag ok but, just wanting to find out what or how the rest of the world is doing this process on bullet seating. sorry for the long post, just looking for what you are doing if there is a different way.

[Jack Crevalle]

I was given a list of things I would need when I began reloading and on it was the Stoney Point OAL gage. I consider this a must have tool just like a scale. I remember in one of MSGT Jim Owens books a quote from him that  measuring the distance to the lands using the smoked bullet method is like "trying to measure the distance to California with a ruler".

The Stoney Point bullet comparator is also good because it measures bullets on the ogive rather than the tip that can vary from one to another particularly on soft points.

One thing about the Stoney Point gage is that they say using it with a dowel rod is optional. I would say it is very recommended.

[Iowegan]

Try these. 10 seconds with any bullet  http://www.cactustactical.com/reloading/reloading.html

[Robert]

Take an unsized/fired cartridge(no live primer). gently squeeze the neck so that it is slightly 'out of round'.  Insert the intended bullet and leave it as long as possible.  Gently chamber and close the bolt, then gently remove it and measure the over-all length.  This will give you the length to the point where that specific bullet is touching the rifling (lands).  Do this about 3 times to make sure it is an accurate reading. then back off of that measurement at least .010, or whatever measurement you have decided on.  Some match shooters seat right into the lands.
  This will vary with every manufacture of bullet dependeing on the shape of the bullet (ogive).
  Some bullets (Hornady Round-nose for instance) will never touch the lands.  I load a 358 Hornady that begins its taper immediately in front of the cannelure.  The only part of this bullet that measures .358 is behind the cannelure and inside of the case neck.  So with a bullet like this, load it to the cannelure, or use published data and you will just need to experiment with what length is most accurate in your rifle.
  Every bullet is different, so if you switch from a spire point Sierra, to a spire-point Hornady (for instance), it could be completely different.  
  Write down the length to remember it, or at least keep one bullet to use to reset your die for that particular load length.

[longwinters]

I use the Stoney point bullet comparitor.  Tried the other ways and this is much easier and more accurate.  But you can get by with the other methods, just takes longer;  and  they are free. :-)

long

[Bullseye]

Now I am not a bench rest shooter, and my longest range is 100 yards.  I get MOA with my guns that should shoot that good (based on caliber and gun).  I seat to the COL in the reloading manuals.  Not sure seating to the rifling is that important unless you are doing some serious accurate shooting.  I have read articles that state that sometimes some guns shoot better with the bullet seated a little deeper than up to the rifling.  I have never tested this since I use the COL.

Anyway, I am not saying what is right or wrong, this is just a simple mans way of doing it and getting the accuracy he desires.

[varmit_master]

Hi i do it the same way catman does But i use a permanent marker SHARIPE's black or red color  and color the hole bullet and it is easy to see the marking on the bullet. VM

[Jack Crevalle]

Now I am not a bench rest shooter, and my longest range is 100 yards.  I get MOA with my guns that should shoot that good (based on caliber and gun).  I seat to the COL in the reloading manuals.  Not sure seating to the rifling is that important unless you are doing some serious accurate shooting.  I have read articles that state that sometimes some guns shoot better with the bullet seated a little deeper than up to the rifling.  I have never tested this since I use the COL.

Anyway, I am not saying what is right or wrong, this is just a simple mans way of doing it and getting the accuracy he desires.

Seating a bullet at or in the rifling can increase pressure. OAL s listed in manuals should give the firearm used to develop the load. Is the throat in your firearm less or more?

[Glanceblamm]

Poor mans version would be to use a dowel to hold the bullet in the chamber right against the rifling. Insert your cleaning rod (I have a good one piece stainless) into the bore until it touches the bullet and mark the rod. Remove the bullet, close the action, and repeat this bottoming out the rod and make a second mark. Measure in between & you will be looking at your max OAL.
Now you can do additional testing using soot or color mark with the goal being to scrape off the soot without leaving an imprint on the bullet.

You are going to be over the calibers max OAL for sure. This is published So the shell will fit in the clip of any brand of rifle.
My Ruger M77 has a long action w/floorplate  so I can get by with this.
If you do have a clip fed you may be restricted to single feed. If you have a single shot, great!.

Seems like my  .22 centerfires prefer the bullet to be .010-.020  behind the rifling for optimal accuracy.

Always Begin Using Published Starting Loads. You are going to end up a grain or more short of the max load listed, but velocity will be the same.

[Bullseye]

Jake Crevalle

My understanding is that the COL in a reloading manual gives you the SAMMI COL for that round loaded with that bullet.  If a gun is also made to that spec there should not be a problem.  In my 10 plus years of reloading I have never loaded a round to the book COL length that would not chamber.  If my understanding is correct, reloaders who push the bullet out to the rifling are a lot more likely to get high pressure than you would by using the COL in a reloading manual.

Now I know the old Speer Manual did not give a COL because they stated you should determine the seating depth.  All other manuals I use (mainly Hornady) give COL.

[Jack Crevalle]

Not all firearms, ie. military surplus arms, follow SAMMI standards. Also, as someone has already pointed out, the bullet engages the rifling on the ogive and this can vary from bullet manufacturer even though the weight is the same. If the manual uses SAMMI standards and the loader uses the same bullet and the rifle adheres to the same standards you may be perfectly safe. It never hurts to measure however. The ability to close an action on a round is also no indication that it does not engage the rifling.

[Iowegan]

The key to accuracy in rifles is to eliminate or reduce bullet deformation.  When a round is fired, the bullet jumps from the case and starts into the rifled bore. If the bullet enters the bore perfect, the only deformation will be from the rifling. This is the optimum condition. Unfortunately, most chambers aren't cut perfect and most bullets aren't seated perfectly, so some deformation occurs. A deformed bullet will exit the barrel and be slightly out of balance. This causes a "whiffle ball" effect and will open up the groups.

To minimize bullet jump deformation, there are a few hand loading steps that will really make a difference in your group size.

Most handloaders trim their cases to SAAMI specs listed in reloading manuals. This usually results in a loss of accuracy. Almost all rifles have a deeper free bore than SAAMI minimum (trim length) so when you trim your cases, it leaves a void between the case mouth and the rifled bore. This empty free bore area is more than .025" larger than the bullet diameter (measure the neck on a spent case and compare it to the bullet diameter). When the bullet is forced under high pressure, it has an opportunity to move sideways a little and enter the bore slightly off center. The bullet will be deformed and will loose accuracy down range. The fix is to let your brass "grow" to fill as much of the chamber as possible. The perfect brass length would be .005 short of bottoming out, leaving a little room to grow without corrupting the chamber.

The next task is to find a way for the bullet to exit the brass straight. If you inspect your cases, particularly the neck, you'll see most brass cases have thick or thin areas and non-squared case mouths that cause the bullet to be released slightly off center. To get a nice squared case mouth, you can trim a tiny bit of metal from the mouth until you see fresh cuts around the circumference. Neck turning will true up the neck but is a pain to do. I anneal my cases from the shoulder to mouth and get the same effect. A soft neck will release the bullet before pressure is maximum and will start the bullet straight into the bore, even if the neck isn’t perfect.

The last task is to seat the bullet at the optimum depth. After years of testing, I’ve found when the ogive is .010” off the lands, bullet jump damage is minimized and accuracy will be at its best. I use a bullet seating tool to measure for optimum seating depth with the actual bullet I will be using in my loads. As mentioned before, all bullet styles, even in the same weight, will have a different ogive dimension. Some rifles have such a deep free bore that bullets want to be seated out too far for the cartridge to fit in the magazine. You can either single load, or find a bullet with the ogive farther forward.

Since I invented and started manufacturing the chamber tools referred to in my above post, I have used this 3-step approach (case length, annealing, and bullet seating depth) to make 3-4 MOA guns into sub-MOA shooters. I have also taken guns that fired decent groups and made “one holers” out of them. Assuming quality bullets, proper powder charge and a sound gun, (no eroded or off center chamber, bad bore, or non-symmetrical crown) this technique works very well.

[Robert357]

This is a very interesting discussion.

To answer the question, I also size an unprimed piece of brass and barely insert a bullet into it.  Then I gently chamber it in the rifle (done this for two bolt actions, a lever action, and a semi-auto).  I then gently remove it from the action and measure it with a Stoney Point Bullet comparitor of the right caliber so that I get a repeatable ogee "maximum" measurement.  I do it a few times so I am certain of the Max OAL.  I then load to less than this value.

I am a strong believer in the ladder method of load development.  As such I first work up various powder loads to find a "sweet spot."  Then after I find a powder sweet spot, I work up various OAL's to find a cartridge length sweet spot.  The sweet spot is a point at which a small change in powder or OAL produces virtually no change in POI.  In theory it occurs at or near a barrel vibration node for the given powder or OAL value.  This kind of work up minimizes the impact on Point of Impact (POI) due to natural quality control variations in OAL and amount of powder.

Once I have the OAL I want for a given bullet type and powder charge I use the Stoney point bullet comparitor to check all my rifle ammo for OAL.  If I change bullet type or weight, I need to come up with a whole new powder and OAL work-up.  I am very happy with this method of figuring out what works best in a given rifle and have used it on four rifles.

I thought I would include a link to a discussion on the ladder work up
http://home.snafu.de/l.moeller/Laddertest.htm#Laddertest

I also am including a link to a "cheap & dirty" method of measuring cartridge max OAL for a given rifle.
http://www.surplusrifle.com/shooting/oal/index.asp

P.S. thank you for the suggestion questioning SAMMI cartridge trim length.  I will have to think about this for awhile and maybe do some experimenting.

[Danny Boy]

This is a method off the Nosler site:

How do I determine the Proper Bullet Seating Depth for my gun?
To determine the best seating depth for your individual gun you will need:

1. A cartridge case that has been fired in your gun, and not resized.

2. A bullet of the type to be used, with a full, undamaged nose.

3. Calipers.

4. A dark felt-tipped marker.

Step 1 Insert the bullet into the neck of the fired case. It should fall freely into the case, with no resistance.

Step 2 Remove the bullet from the fired case and press the case neck lightly on a flat surface to create a small indentation or flat surface in the case neck so that it will grip the bullet.

Step 3 With the marker, completely color the bullet.

Step 4 Insert the bullet, base first, into the case so that the case just grips the bullet by itself. Just get the bullet started into the case–don’t seat it too deeply.

Step 5 Gently insert the case and bullet into the chamber of the firearm, and close the action. Do not pull the trigger.

Step 6 Carefully open the action and gently remove the case.

Step 7 Retrieve the bullet. It will either be stuck up in the lands of the barrel or still in the case. If the bullet is stuck in the lands, it can be removed by tapping the butt of the gun on the ground. Or, it can be dislodged by gently pushing it out with a cleaning rod. If the bullet is still in the case, then gently remove it with your fingers, taking care not to mar the ink, and proceed to Step 8.

Step 8 During Step 5, the lands will have contacted the bullet and pushed it back into the case, causing the case neck to scrape the ink off of the bearing surface of the bullet. Simply push the bullet into the case until the edge of the case neck is just to where the ink has been scraped off.

Step 9 Carefully measure the overall length of the dummy cartridge. This overall length is called your “rifle seating” depth. It is where the bullet contacts the lands of the barrel. This length is different for every different type of bullet, as it depends upon the shape of the ogive (the taper) and the meplat (the tip of the nose) of the bullet. This process should be repeated three or four times to obtain a consistent average.

Step 10 Set your seating die to seat at a depth between .015 and .030 inches less than your rifle seating depth (this is generally where the best accuracy is found), and check to see if the cartridges will function through the magazine at this length.
   
Danny Boy

[Robert]

Iowegan that is some great data, Dannyboy, that is a great addition to the el-cheapo tecnique that I use.  I never thought of the marker to show where the bullet was pushed to.  That will help to make the whole process faster, and more accurate.  I usually just do it enough times to get an average, and sometimes, yes the bullet DOES get stuck in the rifling and then I would have to start over.  But with your way, even if the bullet gets stuck it will give an accurate reading.  Thanks.

[Iowegan]

One more tidbit. If you take a batch of the same bullets and measure their lengths, don't be surprised if they vary as much as .010". The tips get bunged a little when they are polished at the factory. If you really want precision, measure at the ogive instead of the tip. Use a spent resized case and slip it over your loaded round. Then measure from the point where the spent case mouth contacts the ogive, to the base. This is the most consistant point on a bullet and a good reference point for future loads.

[Glanceblamm]

This has been very interesting reading and I endorse all of it. Kind of makes you wonder about the other side of the coin though.....

Weatherby and the built in freeboring. Accuracy goes without saying here.
I think the gasses help keep the bullet centered before contact with the rifling? You would think the bullet would really rattle down this area.

[Iowegan]

Weatherby and a few other manufacturers use a forcing cone technology in their chambers rather than a conventional free bore-to-rifled bore chamber. The good news is; forcing cones do less bullet damage thus are more accurate. The bad news is; the chamber throats erode faster and result in shorter barrel life due to flame cutting. Sako and Tikka use the forcing cone technology too and are both very accurate out of the box.  Most American made rifles have a 3 degree forcing cone, barely enough to detect. Weatherby uses a 11 to 13 degree cone that is also longer. If you can imagine a chamber where the free bore diameter tapers down to actual bore vs an abrupt step. I'll use a 308 Win case as a typical example. The free bore diameter measures .345" and the actual bore .308. That's a .037 difference. You can see there is plenty of room for the bullet to flop around and get forced off center.  With a tapered forcing cone, that movement gets corrected and the bullet starts pretty straight.

The brass case mouth works just like the barrel "crown". Escaping gasses around the bullet must be very uniform else the rear of the bullet will be forced off center. This will always result in bullet deformation and will have a negative impact on accuracy. If you "neck turn" or anneal your cases, they will release the bullet with fairly equal pressure on the bullet base and will force it straight into the bore.  Slightly non-symmetrical case mouths (necks) will force the bullet off center and deform the bullet. Remember, there's a lot of pressure here. It's like having 4 full sized cars standing on the base of the bullet.

We are seeing gun manufacturers cut their free bores deeper than ever. I suspect this is because of non-SAAMI foreign made ammo and milsurp stuff that won’t load in a properly cut chamber. Some manufacturers like Ruger do deep free bore with all their guns, no matter the caliber. A poor way to solve a problem in my opinion.

[Red Neck64]

I put the bullet,right on the lands.No free bore.

[hogship]

The best and most accurate method of determining cartridge OAL, and its relationship to the distance between ogive and the lands, is to use the Stoney Point tool. Measure from the ogive, not the tip of the bullet.  I have used some of the methods described above....not one of them give as accurate a reading as the Stoney Point tool does.



I have also used the RCBS precision mic.....but since it doesn't use the actual bullet for measurment, there is an inherent error. The RCBS precision mic is better than the Stoney Point for measuring headspace....and on the other hand, the Stoney Point is the better of the two for accurately measuring cartridge OAL from the ogive. This is why I use BOTH the Stoney Point tool and the RCBS precision mic on a few of my rifles that are capable of benefiting from both measurments

Sinclair used to sell a leaded steel insert that, when inserted into a fired case neck and chambered into the rifle, accurately determines the maximum case neck length.  You can only trim your cases shorter, not longer......so, the best way to handle this, is to use SAAMI specs for case trimming.

The one exception to the case neck length consideration is benchrest shooting. For the 99.999% of the rest of us, an extra .010" in case neck length will not show up in any measurabe way, at the target....

....but, cartridge OAL will ususlly yield accuracy benefits to most everyone.

hogship