Adjusting length

Hi all,

As someone who is relatively new to reloading, I'd love to hear how you experienced folks approach a change in overall length. Let's say I've done a standard ladder test and identified a powder charge that my rifle likes. Seems like the next step is to play around with depth a bit. Do you usually start increasing the depth, or decreasing? What increments do you use? Just in case it matters, I'm interested in this subject generally, but am specifically working on a load right now with the Barnes LRX. Also, the powder charge in question is 1.5 grains below published max. Thanks!

I usually increase and decrease in .010-.015” increments. Just be careful as you increase length since it can cause an increase in pressure if you’re jamming the bullet into the lands

In starting to work up a new load, I start of either max mag length or max distance to lands. I then work up the powder charge. Then, if I need to adjust length there's only one way to go (shorter) and that way will only reduce pressure.

Barnes recommends .050 jump to the lands.
http://www.barnesbullets.com/load-data/

1_pointer hit the nail on the head...

As one pointer said.......
The way to go for sure.
Though you may find your magazine length will determine your coal for you. Unless you have or don't mind a single shot rifle.

1_pointer said:

In starting to work up a new load, I start of either max mag length or max distance to lands. I then work up the powder charge. Then, if I need to adjust length there's only one way to go (shorter) and that way will only reduce pressure.

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That seems smart.

Guess there is no more to say then.

1_pointer said:

In starting to work up a new load, I start of either max mag length or max distance to lands. I then work up the powder charge. Then, if I need to adjust length there's only one way to go (shorter) and that way will only reduce pressure.

Click to expand...

It doesn't work that way...it actually increases pressure...as you seat the bullet deeper it shrinks the case's capacity, this with the same charge causes pressures to rise not fall.

This isn't really a lot of pressure, but if you are already pushing the limit be mindful of the pressure gains.

And like already said...a bullet in the Lands spikes pressure.

..........

RookieHunter said:

It doesn't work that way...it actually increases pressure...as you seat the bullet deeper it shrinks the case's capacity, this with the same charge causes pressures to rise not fall.

This isn't really a lot of pressure, but if you are already pushing the limit be mindful of the pressure gains.

And like already said...a bullet in the Lands spikes pressure.

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The increase in pressure from the shrinking case capacity does increase pressure, but not as much as increased distance to the lands reduces pressure until the bullet is very far from the lands. Pistols are also different than rifles in this regard, largely due to the differences in the powders used.

Dougfirtree said:

Hi all,

As someone who is relatively new to reloading, I'd love to hear how you experienced folks approach a change in overall length. Let's say I've done a standard ladder test and identified a powder charge that my rifle likes. Seems like the next step is to play around with depth a bit. Do you usually start increasing the depth, or decreasing? What increments do you use? Just in case it matters, I'm interested in this subject generally, but am specifically working on a load right now with the Barnes LRX. Also, the powder charge in question is 1.5 grains below published max. Thanks!

Click to expand...

Relatively new to reloading. I would suggest you go back to FL sizing by following the direction's that come with the dies. And I would suggest you figure out how to measure the OLL you can use. From there simply back down the length as needed. In about 50 yrs of loading, I have never loaded a cartridge to less than just off the lands unless it wouldn't fit he magazine. I do not have competition rifle's never have but I have had several rifle's over the years that would make 1/2" easily. I have never kept around a rifle that would not do right at 1" and have found that most bolt actions can be made to shoot right at an inch if you want it to. Before I would mess with seating depth, I would go through the bedding of the rifle. You cannot fix a bedding problem with bullet jump!

I use the Hornady OAL gauge and bullet comparator. Usually start pretty close to the lands .005-.008 and work my way back to book published OAL.

1_pointer said:

In starting to work up a new load, I start of either max mag length or max distance to lands. I then work up the powder charge. Then, if I need to adjust length there's only one way to go (shorter) and that way will only reduce pressure.

Click to expand...

This statement is 100% incorrect and is going to get somebody in trouble some day.
Don't want to start a pizzing match so before you jump on me test it out for yourself.
Take whatever rifle and load you use and run it through a reliable chronograph - then take 5 rounds of same reloads and shorten oal by .025" - shoot them thru. Shortened ones will be faster because you have reduced the size of the combustion chamber thus increasing pressure after combustion occurs.

1_pointer said:

The increase in pressure from the shrinking case capacity does increase pressure, but not as much as increased distance to the lands reduces pressure until the bullet is very far from the lands. Pistols are also different than rifles in this regard, largely due to the differences in the powders used.

View attachment 78208

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Thanks for the research....I'll look into that 1965 U of M study...

...But at least a few modern "Experts" would suggest otherwise.

The 6mmBR site as well as a few others have great write ups about seating depth and its effects as to accuracy and pressure.

FYI...6mm-06 Load bullet .020" off lands (54,345psi) and .040" off lands (58,295psi) as predicted by QuickLoad. (.020" increase in jump nets almost 4k psi...wow that's more than I ever realized...thanks for the exercise!)

Again thanks for the info, James

I'm thinking the loads would need to be pushing maximum case capacity in which the deeper seating after the load has been worked up would then compress the powder. Thus creating more internal pressure even before the round was fired.
I work up my caol in the way 1-pointer has described, but at well below max load. Then after seeing improvement in accuracy at a given seating depth, I will move up the powder charge, checking for pressure sighns as I go , along with accuracy differences.
Can't see how that can or could cause a dangerous situation.
Especially since the max charge data is published using standard over all length in a cartridge.
Yes, I sometimes see an increase in velocity, but never had a cartridge suddenly show pressure sighns as I seated a bullet deaper.

Do what you feel safe doing gentleman. More importantly stay within the boundaries of your skill level of experience and always air on the side of caution with load capacity,working up slowly.
Alot easier to seat a cartridge deeper, and deeper, little by little than it is to keep loading an individual round with the bullet seated less and less till it touches the lands of the barrel.
Why not start out with the longest you can load the bullets depth without it sticking in the lands and work back?
If done using a max loaded casing it will obviously compress the load.
But will it cause an unsafe situation?
Not if you haven't surpased the load data's listed max.
If any of you think that I am wrong here, then do what you feel safe doing. But in all the thousands of rounds I have loaded this way I have never ever had an over pressure or sighn of a problem of any type.
Unless you have the extremely expensive equipment needed to actually measure the pounds per square inch of pressure created then just going off bullet speed is ludicrously silly.
We look for pressure by examining the brass and feeling for a hard lifting bolt or noticable increased recoil.

That's my opinion. Apparently it's also the opinions of many reloaders much more experienced than I and all the competition shooters I have conversed personally with through the years.

Millsworks said:

I'm thinking the loads would need to be pushing maximum case capacity in which the deeper seating after the load has been worked up would then compress the powder. Thus creating more internal pressure even before the round was fired.
I work up my caol in the way 1-pointer has described, but at well below max load. Then after seeing improvement in accuracy at a given seating depth, I will move up the powder charge, checking for pressure sighns as I go , along with accuracy differences.
Can't see how that can or could cause a dangerous situation.
Especially since the max charge data is published using standard over all length in a cartridge.
Yes, I sometimes see an increase in velocity, but never had a cartridge suddenly show pressure sighns as I seated a bullet deaper.

Do what you feel safe doing gentleman. More importantly stay within the boundaries of your skill level of experience and always air on the side of caution with load capacity,working up slowly.
Alot easier to seat a cartridge deeper, and deeper, little by little than it is to keep loading an individual round with the bullet seated less and less till it touches the lands of the barrel.
Why not start out with the longest you can load the bullets depth without it sticking in the lands and work back?
If done using a max loaded casing it will obviously compress the load.
But will it cause an unsafe situation?
Not if you haven't surpased the load data's listed max.
If any of you think that I am wrong here, then do what you feel safe doing. But in all the thousands of rounds I have loaded this way I have never ever had an over pressure or sighn of a problem of any type.
Unless you have the extremely expensive equipment needed to actually measure the pounds per square inch of pressure created then just going off bullet speed is ludicrously silly.
We look for pressure by examining the brass and feeling for a hard lifting bolt or noticable increased recoil.

That's my opinion. Apparently it's also the opinions of many reloaders much more experienced than I and all the competition shooters I have conversed personally with through the years.

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Please sir no disrespect to you or to your opinion, but...

..."Compressing the load" in itself doesn't increase the pressure, it's the reduced chamber volume (Space for combustion) that raises the pressure.

You have made a few statements regarding max loads, that are dangerous....first of all max load doesn't mean compressed load, a case can be 80% filled and be at max load. Another assumption you made was, if a MAX LOAD is at MAX COL then it's maxed...Assumption, going shorter must be safer?

Safe, Sound reloading principles should always be stressed when giving advice regarding anything that could cause bodily injury and/or damage to firearms of another.

To the original poster of the thread...

The internet forum is no substitute for a good Reloading book/manual. And is full of guys who have been "doing it for years" and "know a guy" those kind of credentials speak volumes...beware!
Same goes for what I've written...don't just run with it, become a student of reloading and prove it to yourself...after all I'm just "a guy" too.

James

If you have already done a ladder test how far off the lands is your current load? If it's .050 off or further I would load .010,.020 longer and shorter. Then find your seating depth node and work in .003 around it to fine tune.

cahunter805 said:

If you have already done a ladder test how far off the lands is your current load? If it's .050 off or further I would load .010,.020 longer and shorter. Then find your seating depth node and work in .003 around it to fine tune.

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That's what I have now done. Haven't fired them yet, but it seemed like a good idea. Thanks!

RookieHunter said:

Please sir no disrespect to you or to your opinion, but...

..."Compressing the load" in itself doesn't increase the pressure, it's the reduced chamber volume (Space for combustion) that raises the pressure.

You have made a few statements regarding max loads, that are dangerous....first of all max load doesn't mean compressed load, a case can be 80% filled and be at max load. Another assumption you made was, if a MAX LOAD is at MAX COL then it's maxed...Assumption, going shorter must be safer?

Safe, Sound reloading principles should always be stressed when giving advice regarding anything that could cause bodily injury and/or damage to firearms of another.

To the original poster of the thread...

The internet forum is no substitute for a good Reloading book/manual. And is full of guys who have been "doing it for years" and "know a guy" those kind of credentials speak volumes...beware!
Same goes for what I've written...don't just run with it, become a student of reloading and prove it to yourself...after all I'm just "a guy" too.

James

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I have several manuals, but find them all lacking in the description of this process.