Ok I was thinking when you start to jam a bullet into the lands lets say .015", how do you know for sure your not pushing the bullet deeper into the case some?
Question about jamming
- Thread starter Boisblancboy
- Start date
If your going to be jaming it into the lands that hard,chances are if you
open the bolt the bullet will pull out of the case and dump the powder
into the action.Makes a nice mess to clean up and if your out in the field
well,good luck getting the bullet out of the barrel.....Sorry,but only an
idiot would drive in in that far and your aski g for trouble...
If this is what you want to do then you better shoot it and hopefully you
are lucky not to have high pressure and can't get the bolt open or the
case will be stuck in the chamber as well...
open the bolt the bullet will pull out of the case and dump the powder
into the action.Makes a nice mess to clean up and if your out in the field
well,good luck getting the bullet out of the barrel.....Sorry,but only an
idiot would drive in in that far and your aski g for trouble...
If this is what you want to do then you better shoot it and hopefully you
are lucky not to have high pressure and can't get the bolt open or the
case will be stuck in the chamber as well...
Hmmnn I used to seat Barts Ultras .045" past just touching in my PPC and could still remove the bullet without dumping powder.
My 6.5X284 loved 140gn Noslers .060" past just touching. Can't recall ever trying to unchamber one so ?
Those are rather extreme examples of loading into the lands.
Personally I just use the Hornady tool to find my DTL and work from there.
Jam is actualy the terminology used for when the bullet does begin to be pushed back into the case. It will vary with every bullet, throat and neck tension variable.
In my opinion its an outdated terminology derived from times before there were decent measuring tools. I'm sure many will disagree. Lots of folks still cling to the method.
So the question here is "What are you calling +.015" jam?
My 6.5X284 loved 140gn Noslers .060" past just touching. Can't recall ever trying to unchamber one so ?
Those are rather extreme examples of loading into the lands.
Personally I just use the Hornady tool to find my DTL and work from there.
Jam is actualy the terminology used for when the bullet does begin to be pushed back into the case. It will vary with every bullet, throat and neck tension variable.
In my opinion its an outdated terminology derived from times before there were decent measuring tools. I'm sure many will disagree. Lots of folks still cling to the method.
So the question here is "What are you calling +.015" jam?
Keith Glasscock
Gold $$ Contributor
For me, I can run .020" past touching the lands without any bullet pulling or movement. I can even unchamber a round that is getting hot without problems.
Easy way to tell, make up a dummy round .040 past touching. Chamber and then remove. If it pulls the bullet, you know that is an issue. If th bullet stays in the case, remeasure and determine how much it moved, and which way.
Forgot - I run .002" of neck tension. The cases measure .331 before seating a bullet and .333 after. To get that, I'm using a bushing that is .330 and expanding them with a sinclair die.
Easy way to tell, make up a dummy round .040 past touching. Chamber and then remove. If it pulls the bullet, you know that is an issue. If th bullet stays in the case, remeasure and determine how much it moved, and which way.
Forgot - I run .002" of neck tension. The cases measure .331 before seating a bullet and .333 after. To get that, I'm using a bushing that is .330 and expanding them with a sinclair die.
MarkS
Silver $$ Contributor
Boisblancboy,
0.020" into the lands will make square marks on the bullets from the rilfings. I shoot everything into the lands. You need to check the overall length, to be sure you are not pushing the bullet back.
gatorman,
I guess many of my friends and myself are idiots. Most all of us run into the lands, and have set many IBS 600 yds benchrest records. And we know how to open the bolt and get the round out without dumping the powder.
Mark Schronce
0.020" into the lands will make square marks on the bullets from the rilfings. I shoot everything into the lands. You need to check the overall length, to be sure you are not pushing the bullet back.
gatorman,
I guess many of my friends and myself are idiots. Most all of us run into the lands, and have set many IBS 600 yds benchrest records. And we know how to open the bolt and get the round out without dumping the powder.
Mark Schronce
Alex Wheeler
Site $$ Sponsor
.015 jam isn't really that much. You should have no trouble. Chamber a round, pull it out and measure it. It wont be pushed back. You need to jam alot more than that before you will be pushing the bullet back.
I guess many of my friends and myself are idiots. Most all of us run into the lands, and have set many IBS 600 yds benchrest records. And we know how to open the bolt and get the round out without dumping the powder.
Mark Schronce
well you one of the very few then and a lucky one at that...Most people have no idea how far to seat out a bullet...with the ogive on a lot of bullets they can be well into the lands with out touching..But I kow for a fact and I am sure you do as well,that if the bullet jams into the rifleing,there is a damn good chance it is gonna pull out of the case..And sure if you have to unchamber all you need do it tip the barrel up...duh I know that...John
Mark Schronce
well you one of the very few then and a lucky one at that...Most people have no idea how far to seat out a bullet...with the ogive on a lot of bullets they can be well into the lands with out touching..But I kow for a fact and I am sure you do as well,that if the bullet jams into the rifleing,there is a damn good chance it is gonna pull out of the case..And sure if you have to unchamber all you need do it tip the barrel up...duh I know that...John
Thanks for the replies.
So a good practice, if you want to jam, would be to load up a dummy round and start increasing the OAL at small increments until it either starts to get pushed deeper into the case or get the bullet pulled during case extraction?
So a good practice, if you want to jam, would be to load up a dummy round and start increasing the OAL at small increments until it either starts to get pushed deeper into the case or get the bullet pulled during case extraction?
Ackman
Gold $$ Contributor
Boisblancboy said:
For checking seating depth to the lands, I use a split neck case. The bullet is pushed back into a caseneck under light tension. With some barrels the throat doesn't want to release a bullet, or maybe a particular bullet, and it'll be difficult to get a seating depth read. Jamming the lands on hunting ammunition, Gatorman is right. With a field/varmint gun, don't go into the lands unless you remember to fire the round once it's in there. If some people jam the lands and get away with unchambering, that's great. However it's not a matter of "if", but "when" you'll stick one and wind up with a chamber full of powder. It's happened to me a couple times shooting prairie dogs or chucks.......the gun is unusable until every kernel of powder is cleaned out of there. I normally use .003" neck tension.
Erik Cortina
Team Lapua Brux Borden Captain
Gatorman just called most of the F-Class High Masters idiots, what does that make him? ;D
There is jump, in the lands, and jam. You need to be in the lands pretty far before you jam. The higher the neck tension the further you can go into the lands without jamming.
To find the jam, load a dummy round with your preferred neck tension and seat bullet long, apply small amount of lubricant (I use die wax) to the ogive and chamber round with firing pin assembly removed from bolt. Close bolt and you will feel bullet being pushed into case, pop the bolt open and extract round. Your new OAL lenght is your jam point. As long as you seat bullet away from jam you will not have stuck bullets in your barrel.
Take this advise with a grain of salt because I am one of those idiots Gatorman speaks of. ;D
There is jump, in the lands, and jam. You need to be in the lands pretty far before you jam. The higher the neck tension the further you can go into the lands without jamming.
To find the jam, load a dummy round with your preferred neck tension and seat bullet long, apply small amount of lubricant (I use die wax) to the ogive and chamber round with firing pin assembly removed from bolt. Close bolt and you will feel bullet being pushed into case, pop the bolt open and extract round. Your new OAL lenght is your jam point. As long as you seat bullet away from jam you will not have stuck bullets in your barrel.
Take this advise with a grain of salt because I am one of those idiots Gatorman speaks of. ;D
well,I pollyjice if it was take the wrong way..Please forgive me....I have seen guys at F class have bullets stuck in the rifleing..So maybe they are pushig them in a lot more tha other guys are....I just hate to see the guy get in a jam while he is hutin or whatever..I had it happen to me once so that makes me a idiot as well..So there,I admit to it...John :'( :'( :'( :'( :'( :'(
Erik Cortina
Team Lapua Brux Borden Captain
gatorman said:
LOL, I've had it happen to me too, that's when I figured our what I was doing wrong, I was going past jam point!
BoydAllen
Gold $$ Contributor
As I have written before, the term jam has been corrupted and is used in more than one way, without explanation, which leads to confusion. It is my contention, based on my reading of early short range benchrest writings, that jam is the farthest point that a bullet can be loaded past the point where it first makes contact with the rifling, without being pushed back into the case, this, at the neck tension that is actually being used for loading rounds. With the same components and barrel, less neck tension will produce a shorter jam than more neck tension will. To round out things, better ways to indicate where a bullet is seated are, specifying a given number of thousandths longer than, or past touch (the length at which the bullet just touches the rifling), or some number of thousandths off, or shorter than jam. There is also the custom of doing what highpower shooters have referred to as soft seating, where the bullet is intentionally seated longer than jam, and seating completed as the bullet is chambered. One thing that I have noticed about this particular option is that if you rechamber and shoot the round, it will not produce the same result as its bretheren, that were fired without being removed and rechambered.
The tendency of bullets to be pulled when a loaded round is unchambered, varies with the throat angle, the shape of the bullet, and how much neck tension is being used. Personally, I find that I can load about .003 shorter than jam, and never pull a bullet, with the bullets that I use, and the leade angle that my 6PPC reamer cuts.
For my varmint loads, I have generally shot somewhere between .006 to .010 longer than hard touch, as measured with one of the Sinclair gauges. More recently, I have been experimenting with a seating depth, for my 6 PPC, with double radius ogive bullets, that produces light, (but long) marks, this based on a conversation with a very experienced shooter that did a lot of testing with a bullet with a similar ogive.
On a related matter, if one wants to be prepared for a bullet being pulled by opening the bolt, having a cleaning rod, some canned air, and a Bic lighter, with its flame adjusted to its longest can be handy. the latter to clean up residual grains of powder in the lug recesses, that bolt grease has stuck tighter than the air might dislodge, but be quick and careful, lest you stock finish be unintentionally flamed.
The tendency of bullets to be pulled when a loaded round is unchambered, varies with the throat angle, the shape of the bullet, and how much neck tension is being used. Personally, I find that I can load about .003 shorter than jam, and never pull a bullet, with the bullets that I use, and the leade angle that my 6PPC reamer cuts.
For my varmint loads, I have generally shot somewhere between .006 to .010 longer than hard touch, as measured with one of the Sinclair gauges. More recently, I have been experimenting with a seating depth, for my 6 PPC, with double radius ogive bullets, that produces light, (but long) marks, this based on a conversation with a very experienced shooter that did a lot of testing with a bullet with a similar ogive.
On a related matter, if one wants to be prepared for a bullet being pulled by opening the bolt, having a cleaning rod, some canned air, and a Bic lighter, with its flame adjusted to its longest can be handy. the latter to clean up residual grains of powder in the lug recesses, that bolt grease has stuck tighter than the air might dislodge, but be quick and careful, lest you stock finish be unintentionally flamed.
bigedp51
Gatorman
Long ago are ancestors shot very accurate schuetzen rifles, these rifles had a false chamber and the lead bullet was pushed through the false chamber into the rifling with a loading stick. The false chamber was removed and a cartridge case charged with powder was placed in the chamber, and the rifle was fired.
These lead bullets were not just jammed, they were pushed into the rifling ahead of the chamber neck. The cartridge case had a thick paper wad sealing the case mouth, and thus the powder in the case.
No one was hurt, no one died and these rifles shot groups rivaling groups shot today.
Long ago are ancestors shot very accurate schuetzen rifles, these rifles had a false chamber and the lead bullet was pushed through the false chamber into the rifling with a loading stick. The false chamber was removed and a cartridge case charged with powder was placed in the chamber, and the rifle was fired.
These lead bullets were not just jammed, they were pushed into the rifling ahead of the chamber neck. The cartridge case had a thick paper wad sealing the case mouth, and thus the powder in the case.
No one was hurt, no one died and these rifles shot groups rivaling groups shot today.
Boyd you have some of the best tricks up your sleeve!
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