308 seating depth

[Jmccracken1214]

So, I have a COAL with 168bthp Hornady bullets at 2.816, the book says 2.800...

I put a dummy round in and to the lands, measures 2.878, so I’m longer than the book says but still jumping .062. Rifle is a RPR

The rifle shoots my hand load at about .7” and a SD of 11 and ES of 25. Do you guys think I should seat these bullets 16 thou deeper to 2.816 or seat them longer to get closer to the lands?

I have AI mags without binders, but was kind of wanted the ability to run the AR mags if I had to.

 

[straightshooter1]

So, I have a COAL with 168bthp Hornady bullets at 2.816, the book says 2.800...

I put a dummy round in and to the lands, measures 2.878, so I’m longer than the book says but still jumping .062. Rifle is a RPR

The rifle shoots my hand load at about .7” and a SD of 11 and ES of 25. Do you guys think I should seat these bullets 16 thou deeper to 2.816 or seat them longer to get closer to the lands?

I have AI mags without binders, but was kind of wanted the ability to run the AR mags if I had to.

For my .308 RPR, I'm seating 168 SMK's to 2.854 (.020 off the lands) and getting groups at or less than .5 MOA with single digit SD's and ES's in the mid teens using either AR-Comp or IMR 4064. I have a mag that allows very long seating and could go much longer if it needed and have in fact loaded some longer out to the lands during load development.

You've got lots of room too experiment to find the seating depth that works best. There's no reason for not seating at 2.816 unless you can find a depth that works better.

 

[cnwrobb]

I don't have any idea how much longer your AI mags will allow you to adjust your COAL. If I were you, I would load 5 rounds at the max length your mag will allow you and run a couple more COAL's between 2.816 and the max length. Shoot these and then compare your results. You might find an more accurate COAL that way. Personally, on older model 10 Savage I am running 2.82" with 175 SMK at roughly .5

 

[Josh1978]

I got some great information from a member on this forum. He said, “Your book doesn’t know what your chamber wants.” I would try and get the bullet closer to .020 off the lands and see how your rifle likes it. As long as it will feed from the magazine consistently.

 

[Jmccracken1214]

I don't have any idea how much longer your AI mags will allow you to adjust your COAL. If I were you, I would load 5 rounds at the max length your mag will allow you and run a couple more COAL's between 2.816 and the max length. Shoot these and then compare your results. You might find an more accurate COAL that way. Personally, on older model 10 Savage I am running 2.82" with 175 SMK at roughly .5

I can run them to the lands and fit in the mag no problem. But def won’t fit in the AR 10 mag

 

[Lunchbox27]

I say go for it, nothing to lose... but you may find that the 168smk doesnt care about jump. I have had barrels that are double what you have in terms of jump, and kept them at 2.810” and they shot great. My current 308 barrel gets to the lands at 2.865 with the 168’s and I still run them at 2.810”.

 

[Jmccracken1214]

I say go for it, nothing to lose... but you may find that the 168smk doesnt care about jump. I have had barrels that are double what you have in terms of jump, and kept them at 2.810” and they shot great. My current 308 barrel gets to the lands at 2.865 with the 168’s and I still run them at 2.810”.

I’m running Hornady 168bthp. Wonder how much of a difference there is between this and the SMk

 

[Lunchbox27]

I’m running Hornady 168bthp. Wonder how much of a difference there is between this and the SMk

Ahhh I’m an idiot... look at that, you even said it your first post.

So, with the 168 Hornady HPBT I also ran them at 2.810. Looking at my book, I used that for 168 ELD’s, too. I do like the Hornady 168’s hpbt better, fwiw. Cheaper and they are more consistent from base to ogive vs the smk.

I still say try it 20 thou off the lands and see.

 

[spife7980]

Test at the lands and in increments going shorter. Then youll know what it does.

 

[Jmccracken1214]

I’ll run a ladder test tomorrow at 20 off

 

[Jmccracken1214]

Had some luck on the last 3 rounds fired. Loaded up a group of 20 to shoot tomorrow. Hopefully they’ll do good.