Bullet jam How to Question

A

Andrew B

Member
I have searched the site and not found explicit instructions on this. I have been using a stoney point tool and am not satisfied with the results.

How do you determine bullet jam?

I end up pulling the bullet out of the case, not helpful when trying to determine length.

Do you lube the bullet?

What neck tension do you use in thousands of difference from the loaded round - i.e. 2 thousands under?

What marks do you look for on the bullet? Do you measure the marks?

Thanks for your help.
 
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Andrew

Take a case that's formed pretty well to your current chambered barrel. I like very little neck tension at this point - even if it means a case that's turned slightly more than the rest.

Without a primer or powder, start your bullet of choice and leave long so that the rifling will push into case. Slowly chamber. Repeat until you get 2 or 3 consistent measurements. This is only a reference point.

Now you are ready to go into the lands or away (jumping) the amount you desire. The more neck tension, the more into the lands one can go without the bullet being pushed back into the case.

If you are trying to get square marks, use a little steel wool to brighten the bullet. Square marks may or may not shoot best in a given barrel.

Using the reference point, as the bullet is tried with different depths keep moving if two won't go in the same hole.

Remember to start over when using different bullet brands.
 
Another way to allow visibility of rifling marks on the bullet is to coat the bullet with black marking pen. It's easy to see where the rifling has cleaned off the ink, and the ink is thin enough that it contributes practically nothing to bullet diameter. I have a devil of a time seeing rifling marks on a bullet otherwise.
 
Andrew
i like to put some case lube on the bullet to keep it from getting stuck in the lands.
Ted
 
Andrew, Tony gave you some good directions. I do similar but I approach it a little differently. I size with the bushing I plan to use; I shoot a 30BR. I seat the bullet out as far as possible and let the lands seat it just like Tony described. If the bullet stays in the rifling after extraction, I then seat the next one a little deeper. I keep doing this until I can extract the cartridge with bullet intact and my measurements are the same. This I figure will be the furthest I can see the bullet and still remove it if I need to without dumping powder. Get the necessary measurements as a reference. I then shoot as Tony describes but I only move the bullet further in. By doing it this way, I only have to go in one direction. I am sure there are other variants of this procedure; you just have to figure out what works for you. Randy J.
 
It helps me to determine where the lands are by "feeling" the bullet touching them along with visuals like black marker, layout ink, etc..

To help feel the lands much better I remove the firing pin from the bolt and have only the bolt body in the action.
 
All these guys are right on...........ONLY the actual chamber will tell you what's happening. Soooooo, using your own chamber just seat some bullets long and use the rifle to set them. Some thoughts.


----If you're sticking bullets you'll probably have to do as Randy says, back off incrementally until she don't stick.

----Using a SILVER Sharpie is a cool trick, works even better than black.

----Using a tighter neck bushing or a thicker neck or more neck tension will result in a deeper "jamset" dimension until you stick the bullet, this ain't rocket science but you do gotta' think just a little.

----Depending on the match of your ogive to your leade angle you'll find some bullets which show only .005 from "touch" to "jamset"......... and other bullets. typically those with long VLD ogives, will show as much as .090 difference from "touch" to "deeply jammed".

----There are no absolutes here, no "perfect setting" to strive for. What you're looking for is a baseline, a spot from which to work in and out. Many folks use a "square" mark as reference, many more go with a mark twice as long as it is wide and others just use the bushing that they shoot with and jamset it and use THAT for their baseline whatever it looks like. It's ONLY A REFERENCE, that's the key. I've seen guys come on these boards and argue about the "perfect oal". goofy.

----The measurement changes over time. This is a good reason to use the "jamset it with your normal bushing" routine. You can gain a feel over time for how your lands are holding up. Using the same FORCE each time, the result of using the same bushing, you'll be able to monitor your lands.

----I wouldn't ever lube a bullet because it'll not only give you a MEANINGLESS read, it'll also false on you.

----I see no need to measure anything as far as the marks go.

----Measure only with an ogive tool, I use the Sinclair "nut", and WRITE THIS STUFF DOWN!!! I've got friends who are forevermore GUESSING and scratching their heads every time they go back to the bench. Asking ME "what was my OAL last year?"............

hth


al
 
There's another way

Might take a little longer (maybe not) but has an additional function.

Using a case with strong neck tension (close the bolt on this empty case first to make sure it chambers smoothly), seat a bullet long enough to cause difficulty chambering the round (dummy of course). No reason to actually close bolt. Just realize that the bullet is the resistance and bump it in a bit more, repeating until you can just close the bolt without resistance from the bullet. At that point, the bullet is seated as far into the lands as you are willing to live with and the only way to go from there is further in. The rifle will tell you how much further if any. Never try to convince a rifle of anything.

The strong neck tension is no longer required or recommended.

"Willing to live with" is the additional function of this method. Believe me please that any aggravation in opening or closing the bolt will translate to a larger aggregate score.

No need to measure anything other than length of the adjustable component of the seater die.....and record it on your drawers with a Sharpie.
 
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I usually make a split case and a shoulder bushing for each new cartridge or rifle or bbl I acquire. For the split case I like to use a case that has been fired in the chamber and then neck sized with the normal bushing. Then slit the neck with a dremel cut-off disc and deburr the edges. Much more repeatable than the stoney point tool.



BRreloadingcasegaugeandjamfinder.jpg
 
As usual, The Wilbur may have just pithyfied the whole concept......reducing it to the one real problem and avoiding it entire.


suh-WEEET


al






BTW - - - "Never try to convince a rifle of anything."


write it down in your "Wilbur" file and refer to said file regularly :)
 
Andrew

I hope the posts have helped. The goal is to find where your barrel/bullet combination shoots best. Just a couple of last thoughts. If you are using a Wilson type seater, as was suggested record the length of the stem.

As a barrel gets wear, the bullet may need seating slightly farther. It's been my limited experience that 30 calibers - 30BR or similar - like bullets pretty hard in the lands with plently of neck tension. My PPC doesn't seem to need as much. There are exceptions.

I have some Gentner Boatails that like a little jump. The Bart's Ultras seem to like the lands.

I remember reading that powder burn rate can factor into all this too.

If two bullets won't go in the same hole in good conditions, keep searching.

Good luck
Tony
 
"At that point, the bullet is seated as far into the lands as you are willing to live with and the only way to go from there is further in"...[into the case and away from the lands]?

Would the above help the pith?
 
For $5 you can buy a modified case from Hornady, formally Stoney Point. If it is a wildcat caliber simply send them on of you cases and they'll modify it. That makes it about as easy as it gets to measure where the bullet touches the rifling.
 
notice the pics...!!

notice how "crooked" things look...there is several thou. of cant to the parts and pieces...
As so many of the "ole" timers say..."measure with the gun" ...and the ammount in inches doesnt matter....whatever it is -it is!!!!!....keep it simple and spend more time shootin than measurin and pounding on the puter keyboard.....Roger
PS...as Wilbur stated...if the gun rocks while operating the action...sumthin is not rite....
 
In my opinion

One should find where the bullet just kisses the lands and record that OAl as the basis for all work with seating depth. It seems to me that if we are going to demand perfection in the machining of our rifles and knowing exact dimensions of the process of assemblying it the ammo we feed it should deserve the same scrutiny.

If one knows where the bullets just kiss the lands then one can accurately know how many thou they are in or off the lands. Square marks don't tell one anything except, in their opion, the marks are square. If you know where the bullet just touches you then know a whole lot more down the road.

I use my normal neck tension. If the bullet is stuck I use a cleaning rod to tap it out. I then keep pushing the bullet in the case until , after polishing the bullet each time, I find the "Kiss". It is faster to do it this way, in my opinion. I know that a stuck bullet is , perhaps .025 in, for instance. One can lengthen their stem nearly that much the first go. P.
 
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What I do is

Wilbur said:
But...how does knowing help find the optimum seating depth?
Click to expand...

To increase the length of my bullets by .003 until I find a round hole. I know then exactly how far I am in and it is usually within .009 in. I use a lot of neck tension so I know that I can hold .009 and still pull a loaded round from the chamber.

From my setyp, what I call square marks are around .015 in. I have one rifle that likes that seating depth but most of them are less than that.

There are known nodes so that one pretty much knows how much powder. I try to stay as close to maximum as I can on the powder and then find the seating depth the barrel likes for the load. The seating depth method is a very clean way to tune; easy to keep track of where one is @.
 
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I'm new to this stuff but I am a machinist so I used what was at hand. I did this on my .308 and got results within a couple of thousandths of what the Hornady tool measured so I'm skipping buying the tool for my new 6BR.

Take the bolt out. Drop a light bullet into the chamber. The weight of the bullet into the rifling holds it in place while you put the rifle in a vise or rest. Use the depth measuring end of a set of dial calipers (i used my 8" digital Mitutoyo) to measure the distance from the rear of the bullet in the barrel to a flat surface at the rear of the receiver. Double check if you like. Record this length. Tap out the bullet from the muzzle end.
Now drop in a fire formed case and tamp it in firmly into the chamber. Take a depth measurement from the rear of the case head to the same reference location at the rear of the receiver. Record that reading.

Now most of you know what to do at this point. Measure the length of the case and bullet you used and you have all the info you need to determine the seating depth to contact point of the rifling. I make myself a little sketch of the case and bullet and just pencil in the dimensions. Now that I know how far in the bullet is seated when touching the rifling, I prepare a dummy round seated to the calculated over all length using the components used in taking the measurements and then just measure the ogive length of that round.
With the ogive to casehead length recorded, I can load up any bullet and seat the bullet where I want it when chambered.

It's easier to do than reading this post so give it a try.:D
 
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