Help with load dev, Where's my node?

[SixPointEight]

But if that's how I shoot the gun, isn't that what's going matter anyways?

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[ar15barrels]

But if that's how I shoot the gun, isn't that what's going matter anyways?

That's true.
If you keep your headspace small (as you should) and you keep your bullets OFF the lands, it won't matter.

[bsumoba]

The method depicted in the video is faulty.
The SAME bullet is getting jammed into the lands over and over.
How can an accurate measurement be made when the part getting measured is getting re-formed during each measurement?

A new bullet should be seated for each step, or at least at the end, a new bullet should be seated to verify that the earlier measurement was actually correct.

Yup...I agree. Once I get close to the touch point, then I use multiple bullets to make sure I am within 0.002-0.003" from the touch point. So, I determine what I think my touch point is, then seat the bullet 0.002" from this point. If I feel nothing, then I get another bullet and seat the bullet OUT that same 0.002". If I "touch" the lands, then I know I am right where I want to be.

[SixPointEight]

To be honest most of what I load is "mag length" anyways

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[Whiterabbit]

Complex stuff.

OP, consider you already have data. You just don't like the range. So load one using your dies, full strength, the whole process (a dummy round), proper neck tension. Select your longest OAL measured and make it that.

Now chamber it. The bolt will be hard to cam over, or it wont. If it's hard, that OAL is too long and you are jammed into the lands. If it's easy, you nailed it.

If it's too hard, and the bullet comes out with the case when you open the bolt and extract the cartridge, turn the seating die a smidge and reseat the same bullet. Wash, rinse, repeat till the bolt closes easy. You got it. Retest with a fresh bullet to confirm the setting.

It's pretty straight forward when you are in the ballpark, like you are now. No reason to hrow the data you have out now.

And when the bolt closes, keep that round somewhere. Mark it as your chamber gauge so you can ALWAYS reset the die to max length anytime you want to.

[Whiterabbit]

Doing the above requires no extra tooling or new measurements. Either the bolt cams over like normal, or it doesn't.

[LynnJr]

Soshootme
Full length size one empty case. Put a bullet into the case and put the round into your gun. Now close the bolt as far as it will go and tap on the back of the bolts shroud with a rubber hammer until the bolt closes.
Extract the round and measure it. This is your full jam length.
You don't need to know were your just touching the lands because it has nothing to do with accuracy.
Magazine length would be important but touching the lands is a useless number.

Now that you have your full jam length subtract 0.020 from that number and start working incrementally from there.
If your gun has a magazine and your going to use it start at your magazines length minus 0.020 and start from there.
When you work up a load for a different rifle in the future full jam length minus 0.020 before you start looking for your powder charge.

[bsumoba]

You don't need to know were your just touching the lands because it has nothing to do with accuracy.
Magazine length would be important but touching the lands is a useless number.

Agreed that touching the lands is a useless number for most people and this will apply to almost all people shooting factory rifles, where the freebore is very long to ensure that a person mag feeding cannot "stick" a bullet into the lands when they unload a round from the chamber. It really is a relative number and most will find this data pointless. Load to mag length, find a bullet/powder combination that works at or very close to mag length and you're done. That is what I did with almost all my ARs.

In all of my precision/comp guns, I do use the "touch" measurement to make sure I am not anywhere near the "touch" point +/- 0.003" when I choose my final load. It is either a full jam (0.015+ into the lands) or a jump (0.005"-0.008" or longer). Reason being, pressures begins to rise or fall dramatically due to a bullet being jumped, touched, or jammed and I believe that there is a critical relationship between consistent pressure and accuracy, especially at long range. It is hard with all the tolerances in components, processes, etc that if you decided that your best accuracy for example, was 3K away from the lands, that it is really easy to create ammo that is 3-5K longer and now you are touching the lands and you have just created a pressure spike and most likely a bad shot. Likewise, you a jamming 0.003" into the lands and then you make ammo that is 0.003" shorter and now you are just jumping the round and that pressure is much different than a jammed round.

I can almost always find a load that works well jumped and this is important to me so I do not "stick" a bullet into the lands in the event I need to unload. The minimum jump I would even consider is 5-8K off the lands (and that is truly knowing where the "touch" point is. This gives me enough room to ensure that even in the most extremes of my components and reloading process tolerances, that I am jumping the bullet.

If I do jam, and I do jam fireform loads, I jam them hard, 0.030" into the lands and this ensures that I really jammed the bullet hard into the lands so I can get a good shoulder blow out. And...this load is super accurate as well I would not want to fireform with a load that is only 5K into the lands. There is too much risk.

[LynnJr]

Bryan
The whole pressure going crazy when into the lands is just that Crazy!
Most long-range benchrest shooters are hard into the loads and load hotter than most forms of competition. Yet we don't see too many stories on the evening news about all there guns blowing up.
The reason you don't see it or read about it is there is very little spiking of pressure taking place. The same with fast twist barrels.
To test this out use your maximum load and run a bullet to the full jam length and look at the primer. Now ad more powder and look at the primer. Seating variation is a fine tuning operation.

[bsumoba]

Bryan
The whole pressure going crazy when into the lands is just that Crazy!
Most long-range benchrest shooters are hard into the loads and load hotter than most forms of competition. Yet we don't see too many stories on the evening news about all there guns blowing up.
The reason you don't see it or read about it is there is very little spiking of pressure taking place. The same with fast twist barrels.
To test this out use your maximum load and run a bullet to the full jam length and look at the primer. Now ad more powder and look at the primer. Seating variation is a fine tuning operation.

I never said pressure into the lands gives a person crazy pressures. I simply said that the difference in pressure with the same load being jammed or jumped will cause differences in accuracy and most likely ES/SD and vertical problems. So, if someone finds a load that is near the true "touch" number, then variations in their reloading process, components, etc could put them in a situation where one round is jumped say 0.002" and one is actually jammed 0.001" into the lands, for example. And, when someone "hard jams" the bullet into the lands, that person does not know when he is actually starts jumping the bullet versus still being jammed as he seats the bullet further down during the "fine tuning process" because a hard jam could mean 0.040" into the lands, or 0.010" into the lands, depending on how they go about doing it.

It is most likely a non-issue for most people, but I do not want to be anywhere near the lands for a final load so I make sure of this by knowing my true touch and making sure I am at least 0.005-0.008" jumped or 0.010" jammed from this number (this ensures that my load stays jammed as my throat wears). A load that shoots well "kissing" the lands to me, sounds like a recipe for inconsistency.

[ar15barrels]

the difference in pressure with the same load being jammed or jumped will cause differences in accuracy and most likely ES/SD and vertical problems.

Exactly.
So develop loads either INTO the lands or OUT of the lands, but don't try to straddle the line.

[bsumoba]

Exactly.
So develop loads either INTO the lands or OUT of the lands, but don't try to straddle the line.

I've seen guys post loads and they say the word "kissing" or "just touching" the lands and that scares me from a consistency standpoint.

[LynnJr]

Bryan
Been doing this for a number of years and never found a load in any caliber that likes just touching or just off of the lands.
Most don't know where the lands are and they tend to find accuracy there.
Those that know rarely if ever do.
In the old days Sierras were always 50-60 off. Bergers are 125-200 off. And of course into the lands.