Seating Depth

RedRidge

WKR
Joined
Jul 6, 2014
Messages
311
Location
Alabama
I decided to load up some rounds for my Tikka 7RM and wanted to experiment with seating depth. My last load I just loaded for magazine length and called it good. I came across the video and thought it was pretty neat way of finding your lands. Does anyone else use this method?

How to find your lands exactly - YouTube

I tried it and thought it was pretty simple. Loaded up some Hornady 162 SSTs and Barnes 140 gr both .020 off the lands. We'll see how it goes. Anyone have a favorite pet load for their Tikka in 7RM? Currently using H1000 and federal or winchester primers.
 
Joined
Feb 2, 2016
Messages
87
My method is the same principle but with less work in that I don't remove the extractor.

1. I start with a cleaned case that was fired in the gun. This ensures the case is "chamber fitted" (fire formed) and there is no gap between the at the datum line or at the case head (bolt face) when chambered.
2. I then resize the neck area only (to hold test bullet), being careful not to push the shoulder back any.
3. I split the neck from the mouth down to the shoulder area. You want to use something thin (I've used a thin hack saw blade, dremal tool,..). Check and remove any burrs with fine sandpaper on the inside and out of the neck area. This is the hardest part but it is not super critical. When finished the neck needs to hold the bullet tight but you should be able to move it with your fingers if you grab it tight.
4. Insert the bullet where it is long and straight into the neck.
5. Place the cartridge underneath the extractor by hand on to the bolt face and slowly guide the cartridge into the chamber. Depending on your extractor (push or controlled feed) you may need to push on the cartridge as it enter the chamber to keep it aligned.
6. Fully chamber the round allowing the bullet to be easily pushed back into the cartridge as it touches the lands.
7. Carefully remove the cartridge from the chamber, while not letting the extractor to push the bullet against the chamber or action walls as it nears the open area of the action.
8. Remove the cartridge from the bolt, measure and record.
9. Repeat from step 4 several times, I normally get good consistency but the measurements may vary 1, or 2 thousandths.

I repeat and record these numbers for every different bullet I use.
I would also recommend using a measurement that is off of the ogive and not the bullet tip, as the bullet tips may vary from bullet to bullet some based on the type. And the more important number is the "jump" number anyway.

I hope that is understandable.... my mind gets ahead of my typing many times.

Be Safe,
 

Axlrod

WKR
Joined
Jan 8, 2017
Messages
1,122
Location
SW Montana
I decided to load up some rounds for my Tikka 7RM and wanted to experiment with seating depth. My last load I just loaded for magazine length and called it good. I came across the video and thought it was pretty neat way of finding your lands. Does anyone else use this method?

How to find your lands exactly - YouTube

I tried it and thought it was pretty simple. Loaded up some Hornady 162 SSTs and Barnes 140 gr both .020 off the lands. We'll see how it goes. Anyone have a favorite pet load for their Tikka in 7RM? Currently using H1000 and federal or winchester primers.

Absolutely the best video for this! He builds guns that hold records for long range shooting and he also holds some records. He has some other videos posted that are very informative.
 
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