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Posted:  8/18/2013 6:45 PM #38819
Bill Hodkinson


Joined: 8/5/2013
Posts: 5
Last Post: 9/21/2013
Subject: Reloading .308 Win.
I just starting to reload for my .308 Win and could use some help with the O.A.L  I have a Hornady press and just got the OAL gauge.
I took a measurement w/ 168 HPBT and it came out at 2.350 and then measured a Fed. gold match loaded cartridge we/168 HPBT and it was 2.222
that a difference of .128 or 1/8"...........Is that right, can there be that much free travel? Did I make a mistake?
 
thanks for any input
 
Bill Hodkinson
 


Posted:  8/18/2013 8:56 PM #38820
ancona77


Joined: 6/14/2012
Posts: 250
Last Post: 9/18/2013
Here's a good video to watch and as he explains the bullet match to rifling can affect accuracy. If your measuring two different brands of mass produced ammo, I would expect maybe some inconsistencies. Be sure to measure several different ones and several times to be sure. http://www.youtube.com/watch?v=WCPgKNp8i7o
HAPPINESS IS A WELL FED BELT FED!

Posted:  8/18/2013 9:02 PM #38821
ancona77


Joined: 6/14/2012
Posts: 250
Last Post: 9/18/2013
If you take a marker and color your bullet and then chamber your dummy rounds you will see the marks from the lands easily. You will also see marks from where your bullet comparator contacts the bullet. These usually will not be the same. Comparators aren’t usually measuring from the part of the bullet that makes contact with the lands, but are used as a reference measurement for setting seating depth and will differ with different shaped bullets (weight / brand). From SAAMI’s Glossary - OGIVE The curved portion of a bullet forward of the bearing surface. http://www.saami.org/Glossary/index.cfm Your seating die will probably seat your bullet from another place on the Ogive too. Use your measurement you made with your comparator (on your dummy cartridge) to set your seating die or adjust longer or shorter depending on where you want to be in relation to the lands.
HAPPINESS IS A WELL FED BELT FED!

Posted:  8/18/2013 9:29 PM #38822
ancona77


Joined: 6/14/2012
Posts: 250
Last Post: 9/18/2013
There are two thought processes for seating bullets and both have different applications, both can be very accurate. The first is to seat to an Over All Length (OAL), the length of the cartridge is the driving factor in this seating operation. This is for ammunition that has to fit into a variety of rifles or for magazine fed guns. For this type of seating most any type seating die will do you good service. The higher end dies that orient the bullet prior to forcing it into the neck MAY yield more consistency on run out. I’m not yet convinced. The other is seating by the Ogive. This method pays no attention to the OAL of the cartridge but instead is concerned with the distance from the bottom of the case to the portion of the bullet that will hit the lands in the rifling. This is where a micrometer seating die is worth its weight in gold. On the first pass through the seating die I will deliberately seat my bullets slightly long, I never adjust the die, that is “ZERO”. This is more to get the round closed up and sealed than for any other reason, except possibly to compress the jumbled up powder in the case. I have noticed that when loading near the case maximum VOLUME the bullet seems to “pushed back out” after seating, and never the same way twice. I measure each round before it goes back into the seating die and adjust the micrometer as needed via the markings. If my thumbs and eyeballs are working that day I rarely need to seat the round a third time and almost never need to back out a round. You will hear folks talking about being .0020” or .005” off the lands and such. You may be thinking “What’s the difference, if the OAL is the same, the ogive should be the same.” Not true or even close. Stoney Point (now Hornady), Sinclair and a few others makes a tool called the Cartridge Length Gauge or Ogive Length Gauge which clamps to your dial caliper and measures to the ogive length of the bullet. Taking a box of match bullets and simply measuring the bullets will show you just how inconsistent the ogive lengths of bullets from even the same box are, let alone from different lots or manufacturers. To say that you are seating .0010” off the lands and that your OAL is always 2.80” would be highly suspect. The terms and measurements are mutually exclusive and rarely match up.
HAPPINESS IS A WELL FED BELT FED!

Posted:  8/19/2013 5:07 PM #38834
Bill Hodkinson


Joined: 8/5/2013
Posts: 5
Last Post: 9/21/2013
First off, thank you for you input it was just what I was looking for.
I'm shooting a Remington 700 VLS, I did all the measurements you talked about but the one that made me think I was doing something wrong was the 1/8" difference from the OAL gauge and the loaded match ammo.
I'm going to recheck them tonight.
 
thanks again
Bill Hodkinson


Posted:  8/19/2013 10:39 PM #38835
ancona77


Joined: 6/14/2012
Posts: 250
Last Post: 9/18/2013
Also note you may be limited to how far out you can set the o.a.l, which may be limited to around 2.800 if you want them to feed correctly from your 4rd mag. Unless you plan on single loading each round. So its possible your magazine may prevent you from setting the bullet on the lands. Every rifle is different and this is why their is inconsistencies in manufactures ammo, their set to general lengths so they will work in a wide range of guns but not the best for accuracy. So like said the o.a.l gauge is more of a general reference measurement. The more accurate way for your specific gun would be to measure by the ogive. By setting it to the ogive you are ensuring that every load is touching or a specific distance from the rifling every time in your barrel, resulting in much more accuracy than manufactures ammo. This may take some trial and error on finding the sweet spot that your rifle likes and feeds well. So I would get the ogive length gauge that goes on the micrometer seating die. I wouldn't worry to much about what mass produced ammo measures, I would focus most on finding out what the best length for your specific rifle takes. I would try and set the ogive as close to the lands as much as the magazine and feed consistency would allow if not touching the lands. All part of the fun of reloading!
HAPPINESS IS A WELL FED BELT FED!

Posted:  8/19/2013 10:49 PM #38836
ancona77


Joined: 6/14/2012
Posts: 250
Last Post: 9/18/2013

HAPPINESS IS A WELL FED BELT FED!

Posted:  8/20/2013 5:34 PM #38847
Bill Hodkinson


Joined: 8/5/2013
Posts: 5
Last Post: 9/21/2013
I re-measured  my gun last night (rem 700) as well as my sons savage #11, there was .119" difference between them to the ogive.
I do single load when I shoot Targets so the OAL will be ok. my only other question (for now that is) when seating a bullet close to the lands it will only be in the cartridge by .187" is that enough to hold it in place?
BTW I do have all of the Hornady Measurement tool you have talked about, I didn't what to have to guess on what will work as this is my first try at it. I'm going to load up 3-4 different ogive lengths and give them a try this weekend.
 
as I said before, thank you very much for your time and knowledge.
 
Bill Hodkinson
 
 


Posted:  8/21/2013 3:44 AM #38848
ancona77


Joined: 6/14/2012
Posts: 250
Last Post: 9/18/2013
I'm not for sure on what the tolerance would be as to how much of the bullet should be in the cartridge. I would say and I'm sure you would too, it should be far enough in as not to move around or fall out. Should be secure and it may limit how far the o.a.l is. I probably wouldn't recommend the bullet actually touching the lands because in some cases cause it to get stuck in the barrel. Just shy of the lands is what is said to be the most accurate. But check this site out, its a good reference to see what other reloaders are doing in this calibre...... http://www.handloads.com/loaddata/?Caliber=308+Winchester&Weight=All&type=Rifle
HAPPINESS IS A WELL FED BELT FED!

Posted:  9/1/2013 3:52 AM #38985
Treadmark


Joined: 1/5/2013
Posts: 9
Last Post: 9/1/2013
Needless to say,  you have to have enough bullet inside the case to hold the bullet firmly.  That gets us into another subject called "neck tension".  I once trimmed some 22-250 cases to the recommended trim length. I then decided to experiment with lighter weight bullets.  I found that there wasn't enough length on the cases to hold the bullets at the overall length that I needed to keep the proper clearance (.002") from the lands and grooves.  I had to set the bullets deep enough into the case to hold them. and that set the bullet way back from the lands and grooves.   In those cases you can crimp, but if you're loading hot loads, be careful because crimping raises the neck tension and the chamber pressure (although slightly) which needs to be accounted for.
  In my .308 cases  (I have an auto loading rifle)  I am limited to setting the OAL to allow my shells to be loaded into my magazine.  That keeps them about .005 back from the lands and grooves.  I do however,  run all my loaded ammo through a Horanady Concentricity Guage to measure and adjust the run out. I even run my factory ammo through the guage.  I have found the factory ammo to have anywhere from .003 to .007 run out measurement.  The instruction handbooks tell you to adjust so that all the run outs measure to .002 or less.  Personally I notch that up to .001 or less.  It's really hard to get that down to zero.
   Redding has a set of dies that hold the bullet strait while seating it,  but the dies are well over $200.  I don't have those dies.  I would like to run a bunch through those dies, then run them on my concentricity guage and see how much better those dies seat my bullets than standard dies.  Maybe in my financial future I can splurge in a set of these dies.
Another thing that affects neck tension is the case wall thickness.  To get the most consistency,  they all have to be the same. You need to trim them to set your wall thickness,  Then you need to run them through a neck sizer that adjusts all of them to the same tension (what ever tension you desire), again, so that they are all consistently the same.
Hopes this helps you out some.


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