Starting seating depth for 308

[bluto77]

I posted this on the reloading board, but not as many people view that as this board, and I'm trying to get these loaded tonight.



I loaded about 10 rounds last month for my 308, but they were 168's, and my rifle seems to really like 175's. The 10 rounds last month were my first 10 to ever load as I am new to reloading. I am about to load around 100 rounds with 175 SMK using Varget. Right now I'm trying to determine how far off the lands to start loading. The rifle is built on a Rem 700 action with a Kreiger 26" barrel 12 twist.

I measured the distance to the lands with the Hornady OAL device with the modified case. I did it 10 times, and took and average.

Avg Ogive Measurement: 2.267

How far back from the lands should I start?

Based on the many things I've read, I'm thinking to start 0.010 back, figure out what charge the rifle likes, then work my way closer to the lands. Thanks in advance for your replies. All responses are appreciated.

 

[redneckbmxer24]

SMK's like to jump. What is mag length? Can you load .010 off and still have enough clearance in the mag? If not .020 shorter than mag length would be what I tried first.

 

[Nate O.]

I would start .020 off and see if you can get to a velocity that is satisfactory to you. Then start tweeking the powder charge and finally messing with seating depth..just my opinion.

 

[bluto77]

0.010 works in the mag. I should clarify, my plan is to figure out which charge works the best, then I will work on the seating depth. What I'm trying to figure out right now is how far off the lands I should seat the bullet in order to do the OCW testing. I won't be changing the seating depth at all while doing this.

 

[Nate O.]

i don't think it matters....at least it hasn't in my load development

 

[jdgray]

I seat mine st 2.800"
And after my OCW test, that proved to be the best oal.

 

[bluto77]

2.80 is COAL I believe. I'm referring to measuring from base to Ogive.

 

[redneckbmxer24]

175 SMK's aren't going to give you many seating depth problems, they are very tolerant to even long jumps. If .010 is where you want them then rock it and see what it does.

 

[haroldwilson]

Read the OCW instructions on the OCW website. It specifically talks about seating length for the test.

 

[bluto77]

Checking it out now. Thanks.

 

[jdgray]

I'm on the lands at 2.815", so I'm a cool .015" off at 2.800"
I don't own a comparator tool, but made one for checking shoulder distance to set up my sizing die.

Good luck in your OCW test! Love it when results are repetitive

 

[bluto77]

I ended up backing it off .020 and loaded 100 rounds. I didn't have time to read through the OCW test website, so I"m sure I'm doing it the way they do. I started at 43.0 and went up in .2 increments until I reached 45.0 loading 9 rounds at each charge weight. I'm going to shoot 3, 3 shot groups with each charge weight to find what she likes. I got the load info from Hodgdon's load manual. They show a starting load at 42.0 and max at 45.0. Based on many things I've read here, I went with the assumption the optimal charge weight wouldn't be in the 42.0 - 42.8 range with the 175 SMK's and Fed 210 primers.

 

[jdgray]

Heres my OCW work up with Varget and 175SMKs. 2.800" oal, Win brass, 2730fps with the 44.6gr load...
A proven 45gr node is published on Dan Newberrys web page with these componets, prooved very close in my rifle too...
They use a percentage in the load increments, so you did yours a bit different.

I ended up backing it off .020 and loaded 100 rounds. I didn't have time to read through the OCW test website, so I"m sure I'm doing it the way they do. I started at 43.0 and went up in .2 increments until I reached 45.0 loading 9 rounds at each charge weight. I'm going to shoot 3, 3 shot groups with each charge weight to find what she likes. I got the load info from Hodgdon's load manual. They show a starting load at 42.0 and max at 45.0. Based on many things I've read here, I went with the assumption the optimal charge weight wouldn't be in the 42.0 - 42.8 range with the 175 SMK's and Fed 210 primers.

 

[Pinecone]

For OCW, pick an OAL and load the OCW test. Once you find the proper powder charge, THEN play with seating depth.