Reloading Question - OAL

[Fargus]

When I was introduced to the hobby of reloading, I was taught to mark up a new bullet, put it inside the neck of a fired casing then chamber it to determine overall length of a loaded cartridge since every gun is different. I do this every time I work with new components (casing/bullets). Tonight, while doing this, the overall length exceeded SAAMI maximum length. My measurement is 3.410 and SAAMI is 3.340.


What would that .07" do to my pressures? Increase? Decrease? More than likely I would set it at like 3.39 instead of 3.41 just to get the bullet off the lands a skosh.

[mzurovec]

You will likely exceed SAAMI length on any reload depending on the throat of your rifle. Not sure what you are shooting, but my 700 5R in .260 exceeds it by .07 at 2.87 (this is with a .012" jump). I load it up with slightly more than the Hornady manual listed max with 4831SC and with Lapua brass I've been through 6+ loads with it with no failures. While I can't speak to what it does to pressure I've had zero issues.

That said, get a Hornady OAL guage and the right dummy case and be done with it. Nothing more accurate out there that I've used.

[cwd500]

With the bullet in the lands its going to spike your pressure. I would back it off .02 and start lower and work stopping when you see pressure.

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[Fargus]

Thanks guys. I was able to use the Googler and find what I was looking for.

[PondPopper]

With the bullet in the lands its going to spike your pressure. I would back it off .02 and start lower and work stopping when you see pressure.

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This^^^I always back it 5 thousandths off and start from there..

[Rem40x]

I am currently setting my length. 030 over and jamming. Lots of factors there what's your neck tension, how much free ore do you have. . Berger vld like jam .. I think splitting case neck on a properly resized case and finding the lands is just as accurate if not more than your hornady OAL gage.

[Fargus]

With the bullet in the lands its going to spike your pressure. I would back it off .02 and start lower and work stopping when you see pressure.

Sent from my XT1687 using Tapatalk

This^^^I always back it 5 thousandths off and start from there..

Yea, I always back mine off a tad. Generally .02"

[sir shovelhands]

This^^^I always back it 5 thousandths off and start from there..

Yep, same here. If you jam a round into the lands far enough and then eject the un-fired cartridge, you might strip the brass from the bullet and dump your powder charge in your action...I've done it

[howabouttheiris]

. . Berger vld like jam ..

I am not sure this is always the case. (I know it is not for my Savage 12 F/TR.)

For example, here is an article cautioning that you may search for a seating depth with the Berger VLDs that may be up to 120 thou off.

After extensive jump testing, my best seating depths were 90 off and 20 off. I shoot the 90 off load, as it gives me the option to crimp and use my handloads in my AR-10 magazines.

https://www.eabco.com/Berger_Seating.htm

[XR650RRider]

If you know how to remove ejector and firing pin assembly, this is the best way to find lands.

Finding lands
https://www.youtube.com/watch?v=TWmIwPwLyyg

Sizing brass
https://youtu.be/WfWS7R1CdZI

[dustoffer]

You will likely exceed SAAMI length on any reload depending on the throat of your rifle. Not sure what you are shooting, but my 700 5R in .260 exceeds it by .07 at 2.87 (this is with a .012" jump). I load it up with slightly more than the Hornady manual listed max with 4831SC and with Lapua brass I've been through 6+ loads with it with no failures. While I can't speak to what it does to pressure I've had zero issues.

That said, get a Hornady OAL guage and the right dummy case and be done with it. Nothing more accurate out there that I've used.

When I was in the business of custom accuracy work-ups, this was all I needed or used---

[scott.str]

I have found using a ladder test to find good speeds and nodes then use seating depth to make load accurate. I never jam into the lands but airways back off .005-.050. I find the accurate load in that seating depth with the speed i want.

[meltingfeather]

That said, get a Hornady OAL guage and the right dummy case and be done with it. Nothing more accurate out there that I've used.

RCBS Precision Mics are at least as accurate... probably more so.

[meltingfeather]

When I was introduced to the hobby of reloading, I was taught to mark up a new bullet, put it inside the neck of a fired casing then chamber it to determine overall length of a loaded cartridge since every gun is different. I do this every time I work with new components (casing/bullets). Tonight, while doing this, the overall length exceeded SAAMI maximum length. My measurement is 3.410 and SAAMI is 3.340.

What would that .07" do to my pressures? Increase? Decrease? More than likely I would set it at like 3.39 instead of 3.41 just to get the bullet off the lands a skosh.

I just realized that this thread headed off on a tangent and didn't address the fundamental issue with your question.
What you are measuring is the chamber of the rifle, which is ALWAYS going to be longer than the SAAMI maximum length of the cartridge. That's how they ensure fit.
The minimum length of the chamber is longer than the maximum length of the cartridge so that you will never have jam in a factory gun with factory ammo.
SAAMI min/max dimensions have no bearing on your loading for your rifle... just don't take your reloads and stick them in another gun without understanding what you are doing first.

What would that .07" do to my pressures? Increase? Decrease? More than likely I would set it at like 3.39 instead of 3.41 just to get the bullet off the lands a skosh.

That 0.07" doesn't do anything to your pressure unless you load to it, which you would do just as you would with any other load-- approaching carefully from a starting load and checking each fired round for pressure signs. Jamming can theoretically increase pressure, but it depends on other things too. Loading a case with more space in it can theoretically lower pressure, but again it depends on what else is going on.
Backing off the lands a few thou is a good starting place for load development.