"Jamming" bullet into the lands?

[Mikecr]

Tony Boyer and other great shooters consistently jam competition bullets into the bore

Any implication that one shooter's success with only a 6PPC, applies across the board, is pure rediculous.

There has not been a single shooter or ballistician who has provided a real basis for one seating depth over another -across the board. Nobody can predict it, as it hasn't been defined yet.
So it remains trial & error in the end. Right?

IMO, the only debate that continually applies here, lies with a BR relevance commonly assumed.
With this, it's clear to me that point blank BR success comes down to powder burn consistency to hold tune. This means Jammed and extreme pressure loads that typically can not apply to hunting cartridges.
As far as LR BR, there is nothing consistent there with either approach, or results. It's totally an abstract at this point. These shooters claim success yet with terrible winning percentages and lack of performance consistency below 1/2moa. Not one of their measures include single shot placement without sighters, or w/resp to center of mark(accuracy).
It's competitive group/score shooting, very specialized, and not so to contribute to hunting anymore than hunting contributes to BR.

 

[TnTom]

deleted

 

[boomtube]

Hoss, you can't seem to grasp at LEAST four things:

1. The OP wasn't talking about BR rigs nor was I.

2. BR methods don't routinely apply to factory sporters.

3. Not all HOF shooters shoot jammed and I don't need to have HOF points to be aware of that.

4. Proximity to HOF shooters doesn't impute wisdom or understanding of what they're doing into anyone else.

 

[Buffalobob]

And Im probably all wrong.

Yes you are wrong.

Jamming bullets is not hard to understand if you are willing to learn. A good learning exercise for you would be to measure the distance to the lands and then measure what jammed is and what jump is.

First point is that if you are going to jam bullets it is good to have a concentricity gauge and make sure that they are relatively straight to begin with. If you don't have such a gauge then you certainly have no business even talking about jamming bullets.

The neck tension on a properly handloaded long range bullet is not all that much. It is just enough that you cannot move the bullets with "moderate" finger force. If one were to really try hard then one can most of the time move a bullet deeper into the case with hand pressure. We anneal cases to try to keep that tension in a region that produces consistent and accurate neck tension. Certainly if one was to take a bullet and turn it upside down and place the point on a table and push on the rear of the cartridge one could move the bullet.

No then some simple metallurgy. The lands are a part of the barrel and the barrel is stainless steel. That stuff is real hard. The bullet jacket is copper or copper alloy and is deliberately soft so it can deform and mold to the shape of the barrel interior surface, but not so soft that it will not track the rifling. Whether you start the bullet into the lands slowly and easily with the camming of the bolt or violently with the ignition of the primer is the point under discussion. But unless you use magic pixie dust and can get the bullet out of the barrel without going down the barrel the soft copper is going to be engraved by the lands. Whether you do it slowly and easily or violently is up to you.

Now then some stray but important pieces of information. In addition to the cartridge having a bullet it also has some carbon based propellant. This propellant will accumulate in the barrel causing what is known as a carbon ring. This ring will progress both to the front and to the rear as it grows. Not jammed can become jammed if you don't pay attention to your rifle.

 

[TnTom]

Let me try again.

When a bullet is "jammed" .010, .020 or whatever "into the lands" what gives?

Seating a bullet "to" the lands to me means no jump, no "jam".

If I load a round that measures x.000" just contacting the rifling and then were to load a round that measures x.010" before it were chambered where is the extra .010 absorbed when chambered?

I see one of two things happening. (1) the bullet gets forced .010 deeper into the case or (2) the the lands embed into the bullet by that amount.

I would really like to get an understanding of this. In jamming a load are we talking about sinking the lands into the jacket by a specific amount, a point that is beyond just touching the lands or seating the bullet deeper into the case by chambering?

 

[TnTom]

Yes you are wrong.

Jamming bullets is not hard to understand if you are willing to learn. A good learning exercise for you would be to measure the distance to the lands and then measure what jammed is and what jump is.

First point is that if you are going to jam bullets it is good to have a concentricity gauge and make sure that they are relatively straight to begin with. If you don't have such a gauge then you certainly have no business even talking about jamming bullets.

The neck tension on a properly handloaded long range bullet is not all that much. It is just enough that you cannot move the bullets with "moderate" finger force. If one were to really try hard then one can most of the time move a bullet deeper into the case with hand pressure. We anneal cases to try to keep that tension in a region that produces consistent and accurate neck tension. Certainly if one was to take a bullet and turn it upside down and place the point on a table and push on the rear of the cartridge one could move the bullet.

No then some simple metallurgy. The lands are a part of the barrel and the barrel is stainless steel. That stuff is real hard. The bullet jacket is copper or copper alloy and is deliberately soft so it can deform and mold to the shape of the barrel interior surface, but not so soft that it will not track the rifling. Whether you start the bullet into the lands slowly and easily with the camming of the bolt or violently with the ignition of the primer is the point under discussion. But unless you use magic pixie dust and can get the bullet out of the barrel without going down the barrel the soft copper is going to be engraved by the lands. Whether you do it slowly and easily or violently is up to you.

Now then some stray but important pieces of information. In addition to the cartridge having a bullet it also has some carbon based propellant. This propellant will accumulate in the barrel causing what is known as a carbon ring. This ring will progress both to the front and to the rear as it grows. Not jammed can become jammed if you don't pay attention to your rifle.

I have to pass on this question if someone (BOB) can't cut past the BS. I understand quite well about loading to the lands, how to do it and how to measure it and loading with jump and how to do it and how to measure it. Maybe you have a short version. I dont understand what is meant by intentionally Jamming a load by a specific amount i.e .010 .020". Is the bullet imbedded into the lands or pushed back into the case? Should be a simple question to answer.

 

[Buffalobob]

I have to pass on this question if someone cant cut past the BS

You should find where your lands are and develop a load that is jammed. Then you can find out for yourself what is involved.

 

[TnTom]

You should find where your lands are and develop a load that is jammed. Then you can find out for yourself what is involved.

I have to pass on this question if someone (BOB) can't cut past the BS. I understand quite well about loading to the lands, how to do it and how to measure it and loading with jump and how to do it and how to measure it. Maybe you have a short version. I dont understand what is meant by intentionally Jamming a load by a specific amount i.e .010 .020". Is the bullet imbedded into the lands or pushed back into the case? Should be a simple question to answer

 

[Boss Hoss]

Any implication that one shooter's success with only a 6PPC, applies across the board, is pure rediculous.

There has not been a single shooter or ballistician who has provided a real basis for one seating depth over another -across the board. Nobody can predict it, as it hasn't been defined yet.
So it remains trial & error in the end. Right?

IMO, the only debate that continually applies here, lies with a BR relevance commonly assumed.
With this, it's clear to me that point blank BR success comes down to powder burn consistency to hold tune. This means Jammed and extreme pressure loads that typically can not apply to hunting cartridges.
As far as LR BR, there is nothing consistent there with either approach, or results. It's totally an abstract at this point. These shooters claim success yet with terrible winning percentages and lack of performance consistency below 1/2moa. Not one of their measures include single shot placement without sighters, or w/resp to center of mark(accuracy).
It's competitive group/score shooting, very specialized, and not so to contribute to hunting anymore than hunting contributes to BR.

Mike---sorry old man but I thought you were smarter than that. I always shoot for score (you know center of the target) all of my 1K HOF points and state championship were score not group size.

Also, Speedy has almost enough points to be HOF in NRA High-power Silhouette. Have shot with him at long range and fyi now that he is in Trinidad he has started shooting down the mountain in Raton. You would not want to shoot against him in F Class either he would make you look like a child with a bb gun.

The comment you make about shooting BR and how it has nothing to do with hunting reflects on your lack of understanding of how to shoot for extreme accuracy.
Folks like yourself are fun to shoot against either at a range or in the field. I was shooting extreme distance for 25 years before I started to compete and let me tell you the skills learned shooting BR has helped my hunting shooting skills immensely all the way around from the rifles I build to the way I load ammunition. Anyone who says otherwise is well just not speaking from experience imho.

 

[mikebob]

I have a 22-243 that I shoot 90gr berger VLD's in. I shoot retumbo powder, .004 tight neck and seat bullets .010 into the lands. When I eject a bullet it is the same length, it just has lines about .005 long all the way around it from the lands. They are so minute you cant even feel them.

I have had this rifle for 4 years and around 1200 rounds through it and have yet to pull a bullet apart, but I do run a .004 tight neck instead of .002. I do not believe you will have a bullet pull apart problems unless you seat them in deeper than .010.

I tried shooting from touching to .100 off the lands, which was not very good. At .010 into the lands it will shoot 1 ragged hole at 300 yards. All my other rifles I load at least .010 off the lands and get same results, this hart 26" just likes them in the lands. This 22 cal. 90gr berger VLD is the same length as a .30 cal 168gr berger VLD which might be why it likes being into the lands because it is so long.

 

[Boss Hoss]

Hoss, you can't seem to grasp at LEAST four things:

1. The OP wasn't talking about BR rigs nor was I.

2. BR methods don't routinely apply to factory sporters.

3. Not all HOF shooters shoot jammed and I don't need to have HOF points to be aware of that.

4. Proximity to HOF shooters doesn't impute wisdom or understanding of what they're doing into anyone else.

I was not talking about loading for BR either-----for me it is one and the same. Never had a problem yet however, a lot of pain is taken to ensure everything is Perfect in the loading process. What most people do not understand is accuracy is accuracy period end of story. The chances that you build your "hunting" rifles, dies, develop loading for, measure bullet bearing surfaces, use special dies to uniform meplats to the same level of precision as I do is not likely.

Some strive to be the very best with equipment, processes and skills --- it is a pain to do this with every rifle and tube but some of us are cut out that way.

 

[Boss Hoss]

Bob is SPOT ON!!!!!!!!!!!! Most folks do not own a bore scope to ensure a clean neck and let me tell you if you are jamming pills then even a little carbon build up will just RUIN YOUR DAY!!!!

 

[TnTom]

I have a 22-243 that I shoot 90gr berger VLD's in. I shoot retumbo powder, .004 tight neck and seat bullets .010 into the lands. When I eject a bullet it is the same length, it just has lines about .005 long all the way around it from the lands. They are so minute you cant even feel them.

I have had this rifle for 4 years and around 1200 rounds through it and have yet to pull a bullet apart, but I do run a .004 tight neck instead of .002. I do not believe you will have a bullet pull apart problems unless you seat them in deeper than .010.

I tried shooting from touching to .100 off the lands, which was not very good. At .010 into the lands it will shoot 1 ragged hole at 300 yards. All my other rifles I load at least .010 off the lands and get same results, this hart 26" just likes them in the lands. This 22 cal. 90gr berger VLD is the same length as a .30 cal 168gr berger VLD which might be why it likes being into the lands because it is so long.

Why are the imprints on the bullet as faint as you describe with the bullet seated .010" into the lands? I keep thinking they would be much more discernible if you were to un-chamber the round. Apparently not I just don't understand why? Obviously the ratio isnt 1:1. Does anyone have an idea what the ratio might be?

 

[SBruce]

Why are the imprints on the bullet as faint as you describe with the bullet seated .010" into the lands? I keep thinking they would be much more discernible if you were to un-chamber the round. Apparently not I just don't understand why? Obviously the ratio isnt 1:1. Does anyone have an idea what the ratio might be?

This is just an idea, seems perfectly logical but I can't say I know for absolute sure:

The angle difference between the bullet ogive and the lands.
In other words, if viewed from the side; the angle of the lands are outward from center, while the bullet ogive angle is inward from center. This angle, or difference thereof would be different with every rifle, and especially with different bullets.

Back when I was jamming bullets in my factory varmint rifles, I only saw slight decrease in group size as compared to 20 to 40 jump. First time I left a bullet in the lands, I decided the slightly better accuracy wasn't worth the headache........for me anyway.

To each their own, do as you will.

Oh, one other thing. The method/tool used to measure BF to Lands will more than likely give slightly different results too. You would probably get a different measurement using a stony point tool than if using an RCBS Precision Mic. I've always use a Prec Mic on factory chambers, but they are only offered for factory chambers.......perhaps they custom build, I don't know.