Case OAL VS pressure?

Evil_Dark said:
Well, My rifle is different I guess. I push my bullets 0.250" in the lands, as my chamber is soooo small, only 2.630", and I seat my bullets to have 2.820" or 2.880", depending on the bullet type. I remove unfired cartridges often from the chamber without any issues. If a measure back the cartridge, it's still ats its initial COAL, so no changes here.
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You are NOT seating bullets .250" into the lands. If you were .010" into the lands you'd have trouble ejecting a live round because the bullet would be stuck into the lands.

If you want to see just how impossible it would be to jam bullets .250" into the lands, take a bullet and try to jam it into the muzzle of the barrel. You won't be able to get it more than a few thousandths into the lands before it becomes impossible to push in with your fingers. No imagine the force required to push that bullet 1/4 inch into the lands. It is simply not possible.
 
Evil_Dark said:
Well, My rifle is different I guess. I push my bullets 0.250" in the lands, as my chamber is soooo small, only 2.630", and I seat my bullets to have 2.820" or 2.880", depending on the bullet type. I remove unfired cartridges often from the chamber without any issues. If a measure back the cartridge, it's still ats its initial COAL, so no changes here.
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As suputin has said, something does not makes sense about your measurements and the thought that you are seating the bullets 1/4" into the lands. This just does not make sense. I know earlier you made reference to measuring seating depth with a cleaning rod. That is unusual. Not saying it can't be done, but I would think it would be very difficult to do it with accuracy.

I gather you have a factory gun, built to SAAMI specifications. Factory cartridges are allowed to be from 2.490" to 2.810" and would normally leave the bullet well away from the lands even at maximum length. So, I have a feeling you really have not accurately measured where your bullet contacts the lands.

The method I use to determine the length to the lands is to sacrifice a fired case that is not resized and fits well in your gun. Cut a slot in the neck and shoulder, like the photo below. I only cut one slot however. With your fingers adjust the neck tension so the bullet is a fairly snug fit in the neck, but can be still moved with your fingers. Pull it out quite long, and carefully chamber it in your gun, and withdraw it very carefully. Measure the overall length. Do it several times to be sure you are getting a consistent length. Once you think you are close pull the bullet only a slight amount long and chamber again. That will give you the most accurate length.

Now you have a dimension to work with. Add the jam or subtract the jump from that length to set your die.

OAL-3.jpg
 
Ron AKA said:
The method I use to determine the length to the lands is to sacrifice a fired case that is not resized and fits well in your gun. Cut a slot in the neck and shoulder, like the photo below. I only cut one slot however. With your fingers adjust the neck tension so the bullet is a fairly snug fit in the neck, but can be still moved with your fingers. Pull it out quite long, and carefully chamber it in your gun, and withdraw it very carefully. Measure the overall length. Do it several times to be sure you are getting a consistent length. Once you think you are close pull the bullet only a slight amount long and chamber again. That will give you the most accurate length.
[/IMG]
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And with a case split like yours the rifling can grab the bullet and pull it partially out of the case on extraction and give a false reading.

The best way is to bump the case into the sizing die and partially squeeze the case neck so the bullet is gripped tight enough and will not move on extraction.

P.S. And the photo you posted is not even yours, so again you are posting ideas and images that are not even yours.

Here is the address on Ron AKA photo, (http://www.larrywillis.com/OAL-3.jpg)

www.larrywillis.com
http://www.larrywillis.com/OAL.html

"The picture at the left shows another use for our Digital Headspace Gauge. It is shown measuring the "split case tool". At this point, just zero the gauge and then measure your handloads. This gauge will then display the distance to the rifling that YOUR handloads will have in YOUR particular rifle. In most cases a -.002" jump to the rifling is ideal. Due to the irregular point on most bullets, you can't expect to measure a consistent OAL to the tip of the bullets. Except for a good fit in your magazine, the total over-all length is not as important. It is more accurate to measure the over-all length of your cartridges from the bullet ogive."
 
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Well - I'm guessing the OP is talking about 308, so the 2.63 datum is suspect. I have used the cleaning rod method for years and I find it superior to the split case technique - there is no chance of pulling the bullet when extracting the case. I suggest the OP redo the datum measurement.
 
The cheapest and easiest way is to get a cleaning rod to shove down the bore on a closed bolt. Mark the rod exactly at the muzzle with a small paper clip. Now insert a projectile into the chamber and slightly force it into place onto the rifling. Repeat the rod measurement and complete the process by measuring between the two clips. Subtract 1000 and you have your COAL.
 
My sources state that a 'jammed' bullet will increase the overall pressure 7200 psi.

I would not jam bullets for a hunting application, for the a fore mentioned reasons, don't want a magazine full of powder and a jammed bullet.

As others have stated jamming a bullet ~0.010" for competition insures all your seating depths are the same. Bullets generally don't stick as neck tension is light and are single loaded.

Also, to find the case head to ogive length ,seat a bullet a bit long and let the camming action of the bolt force the bullet into the case, do it 3 times to ensure the bullet is not withdrawn on extraction.
 
Long Range Load Development
Posted on July 3, 2014
Written by Sierra Bullets Product Development Manager Mark Walker
https://sierrabulletsblog.com/2014/07/03/long-range-load-development/

"When I first get a new barrel installed, I like to determine what the loaded cartridge “jam” length is. I do this by taking an empty case (no powder or primer) that has been neck sized with the proper bushing (I like to shoot for 0.002 smaller than the loaded cartridge neck diameter) and seat a bullet long in it so that the throat of the rifle will move the bullet back into the case when I close the bolt."

Ron AKA this isn't my idea because...................

I Heard it Through the Grapevine
Creedence Clearwater Revival · 1968
 
BCBRAD said:
My sources state that a 'jammed' bullet will increase the overall pressure 7200 psi.

I would not jam bullets for a hunting application, for the a fore mentioned reasons, don't want a magazine full of powder and a jammed bullet.

As others have stated jamming a bullet ~0.010" for competition insures all your seating depths are the same. Bullets generally don't stick as neck tension is light and are single loaded.

Also, to find the case head to ogive length ,seat a bullet a bit long and let the camming action of the bolt force the bullet into the case, do it 3 times to ensure the bullet is not withdrawn on extraction.
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7,200 psi is a Quickload guessimate and it is starting pressure and not overall chamber pressure and also "WHY" you are told to start low and workup loads.

And single shot schuetzen rifles has the bullets pushed clear into the rifling using a false chamber and push rod. The false chamber was removed and a loaded case capped with a paper wad was chambered and the rifle was fired. And a muzzle loader doesent have any "jump" before the bullet hit the rifling.

And anyone who reloads should be smart enough to chamber and extract a loaded round, and check for function.

And again many people use "jam" and it depends on the type of shooting being done.

Life was very simple in 1973 when I really started loading with my new Rockchucker press (I put my Lee Loader to bed) and I was still a newbie and I cheated. I bought Hornady bullets with a cannelure and seated the bullets to the center of the cannelure. (they even fit my magazine and hit where they were pointed)

This was before the internet and all the arguing by people without enough bullet grip, who tried jam and failed and dumped powder all over the action.

So again, "jam" is one of the most popular methods of fire forming cases and target shooting and they are still here to tell about it.

And "if" I was going out to hunt a Tyrannosaurus Rex, Elephant, Lions Tigers or Bears Oh My!, I would probably seat to the cannelure again and not worry about it. Then again you can follow the loading manuals OAL if your bullets don't have a cannelure. ;)
 
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Sqr said:
The cheapest and easiest way is to get a cleaning rod to shove down the bore on a closed bolt. Mark the rod exactly at the muzzle with a small paper clip. Now insert a projectile into the chamber and slightly force it into place onto the rifling. Repeat the rod measurement and complete the process by measuring between the two clips. Subtract 1000 and you have your COAL.
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Sure. And use a yardstick to take the measurements.
 
I always use a fired case and size the neck enough to grip the bullet. Seat it long and chamber it being careful when you extract the round and go slow.

With this method I can repeat it over and over and I will always get the same measurement. Don't waste your money on the OAL tool.
 
bigedp51 said:
You still here, I thought you would be hiding your head in shame.
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I'm sure your manhood is very large, but not so sure you are doing much to help the OP. Your examples of "jamming" seem to be apples while the thread is oranges. You can add me to your trash talk list I guess.

COAL vs case head to ogive distance is the issue here I think.
 
PitBull1973 said:
Not trying to be an d!ck but the title of the thread is case oal vs pressure
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Yes, the fact that the OP is using COAL in a pressure discussion is an indication he is unclear. Coupled with the fact that his COAL # seems to correspond to a 1/4" jam into the lands means something probably isn't as it seems. COAL is the least useful measurement when reloading for your specific rifle.

The OP may be actually describing accurately exactly what he is doing, but myself and many other posters who reload don't think so. I'm
 
emerson said:
I'm sure your manhood is very large, but not so sure you are doing much to help the OP. Your examples of "jamming" seem to be apples while the thread is oranges. You can add me to your trash talk list I guess.

COAL vs case head to ogive distance is the issue here I think.
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Actually I'm just tired of Ron AKA and his BS postings and if my posting offend anyone they can just jam it.

The problem is I keep running into Ron AKA and sunray in half the forums I go to and the BS is really bothering me.

And if you notice I posted some very good websites dealing with seating and OAL for everyone to read.

I do not care if any of you are .020 off the lands or have .010 jam, that its up to the reloader who is pulling the press handle. (and not any type of fruit)

Evil_Dark said:
Hi All, I just not sure that i'm correct...

The same Case/powder charge/bullet will give less pressure if I seat the bullet deeper, right? Or is the inverse?
I'm in doubt and I just wanted to be sure.

Thanks to enlighten me!

Dark
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And my first post covered his answer and was linked to Berger bullets with a full explanation and not a WAG or personal opinion. http://www.bergerbullets.com/effects-of-cartridge-over-all-length-coal-and-cartridge-base-to-ogive-cbto-part-1/

And another post linked to Sierra bullets and bullet seating. https://sierrabulletsblog.com/2014/07/03/long-range-load-development/

So show me the fruit on these pages.
 
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PitBull1973 said:
I always use a fired case and size the neck enough to grip the bullet. Seat it long and chamber it being careful when you extract the round and go slow.

With this method I can repeat it over and over and I will always get the same measurement. Don't waste your money on the OAL tool.
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I agree. And I believe if you buy into the Hornady OAL tool system they want to sell you a dummy cartridge for each different cartridge you load.
 
bigedp51 said:
7,200 psi is a Quickload guessimate and it is starting pressure and not overall chamber pressure and also "WHY" you are told to start low and workup loads.

And single shot schuetzen rifles has the bullets pushed clear into the rifling using a false chamber and push rod. The false chamber was removed and a loaded case capped with a paper wad was chambered and the rifle was fired. And a muzzle loader doesent have any "jump" before the bullet hit the rifling.

And anyone who reloads should be smart enough to chamber and extract a loaded round, and check for function.

And again many people use "jam" and it depends on the type of shooting being done.

Life was very simple in 1973 when I really started loading with my new Rockchucker press (I put my Lee Loader to bed) and I was still a newbie and I cheated. I bought Hornady bullets with a cannelure and seated the bullets to the center of the cannelure. (they even fit my magazine and hit where they were pointed)

This was before the internet and all the arguing by people without enough bullet grip, who tried jam and failed and dumped powder all over the action.

So again, "jam" is one of the most popular methods of fire forming cases and target shooting and they are still here to tell about it.

And "if" I was going out to hunt a Tyrannosaurus Rex, Elephant, Lions Tigers or Bears Oh My!, I would probably seat to the cannelure again and not worry about it. Then again you can follow the loading manuals OAL if your bullets don't have a cannelure. ;)
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With my completely stock Savage LRP/260 Rem, I have been playing with different load techniques for a few years now, sort of a test mule, lately I started jamming 140gr Hybrids 0.008".

Using all the QL 'tricks' including the 7200 added psi for a jam the rifle is putting 5 shots at 330 yards at 0.6 moa. I do not run to a velocity, this load is 39.96gr of H-4350 and runs 2640 ish at ~53k. The next node puts me at 66k so that is out.

So, whether the bullets are jammed or jumped you should have a sense of what is going on.

Anyway, jamming does take away the variability of COL, the gas produced by the burning powder does not get ahead of the bullet (a possibility on a long jump) and neck tension (actually it is the overall grip on the bullet ) becomes less critical due to the high static resistance of the jam.

Also deep seated bullets generally increase pressure especially when the jump is short, but when the jump is long ,such is in a long throated chamber, Tikka's and Sako's come to mind, then pressure increase because of seating depth is much less critical.

For example, all the powder has to do is over come the inertia of the bullet to get it moving, so there is a small pressure spike, lets say 0.090" later the bullet encounters the rifling, this is a major resistance so the pressure spike is exponentially greater but you have also increased the effective chamber volume by 0.090 x diameter of the bullet. This is what Weatherby did back in the day when velocity was king.

The tools and soft ware take much of the guessing out of the equation.
 
bigedp51 said:
Actually I'm just tired of Ron AKA and his BS postings and if my posting offend anyone they can just jam it.

The problem is I keep running into Ron AKA and sunray in half the forums I go to and the BS is really bothering me.

And if you notice I posted some very good websites dealing with seating and OAL for everyone to read.

I do not care if any of you are .020 off the lands or have .010 jam, that its up to the reloader who is pulling the press handle. (and not any type of fruit)



And my first post covered his answer and was linked to Berger bullets with a full explanation and not a WAG or personal opinion. http://www.bergerbullets.com/effects-of-cartridge-over-all-length-coal-and-cartridge-base-to-ogive-cbto-part-1/

And another post linked to Sierra bullets and bullet seating. https://sierrabulletsblog.com/2014/07/03/long-range-load-development/

So show me the fruit on these pages.
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Ed, why don't all the rest of us just go home, you answer all the questions for all the new shooters or anyone slightly confused and we'll sit back and relax.....FS
 
Hey, I'll answer one about nodes.
Nodes, bigfoot, the Lock Ness monster, it will make you blind-------.
What else is there to say about nodes?
 
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