Seating depth questions
- Thread starter goodgorilla
- Start date
You can go about it different ways, but if you work up to max charge with the bullet into the lands, then holding that charge weight start backing the bullet out .010" at a time you will find quickly if that bullet has a preference for how far it jumps. Theoretically, starting with max charge in the lands when you back the bullet out you will be decreasing pressure.
If you find a particular OAL it likes then you can tweak the powder charge up or down.
This is just one way to do it.
If you find a particular OAL it likes then you can tweak the powder charge up or down.
This is just one way to do it.
I'd suggest you visit OCW Overview - Dan Newberry's OCW Load Development System and look at the procedure for optimal charge weight. This is a very reliable method for finding a load in any rifle, highly reccommended.
I'm just saying it's one way to do it and it's a quick way to find out if a particular bullet likes a particular distance from the lands.
CoryT gave you another way, OCW, find the charge weight first.
MtnCreek's point about mag length is a valid question you need to answer for yourself also, but I was assuming if you want to fiddle with the OAL you had already thought of that. The method he mentions is used by many many shooters, pick some distance off of the lands, find a powder charge that works and then fiddle with the bullet jump.
There is no right or wrong way. Three methods mentioned so far all get you to the same place, one method may burn up more components than another but it's about the destination.
I will be using a clip so I'm not sure if it is possible to load it into the lands. Is it desirable to load into the lands?
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What do you use to measure the seating depth? I was considering getting RCBS PRECISION MIC CARTRIDGE HEADSPACE TOOL, but I wonder if you could just use digital calipers instead.
It's best to use an overall length gauge and bullet comparator that will reliably measure seating depth off the bullet ogive. Measuring COL is not as reliable.
I use these:
Hornady Lock-N-Load Overall Length Gage Automatic/Lever Action
Hornady Lock-N-Load Overall Length Gage Modified Case 6.5 Grendel
Hornady Lock-N-Load Bullet Comparator Insert 264 Diameter
Hornady Lock-N-Load Bullet Comparator Body
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For a 7mm rem mag I would need the overall length gage bolt action, comparator body, 284 diameter insert, and a 7mm length gage modified?
284 diameter insert
7mm gage modified case.
bolt action overall length comparator.
I don't think that lock n load system requires a press right? So it shouldn't matter that I have a RCBS press.
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I believe this is how Tony Boyer (BR hall of Fame) does it..
Tuning Method
1.Boyer Jam= Jam-.003 prevents disengagement of loaded bullet
2.Load Groups of Three 3 @ __Clicks
Upward
3. Pick best shooting conditions Shoot each set
4.Best one or two loads should be apparent
5.Load 5 Rounds for the two BEST LOADS Fire for Group
6.Pick the Best of the above group and Adjust Seating -.003”
7. Load 5 or 10 and shoot groups
8. If Improvement is seen Adjust depth -.002”
9. Load 5 or 10 rounds and shoot groups
9 If groups do not improve or open up stick with Jam Length
Tuning Method
1.Boyer Jam= Jam-.003 prevents disengagement of loaded bullet
2.Load Groups of Three 3 @ __Clicks
Upward
3. Pick best shooting conditions Shoot each set
4.Best one or two loads should be apparent
5.Load 5 Rounds for the two BEST LOADS Fire for Group
6.Pick the Best of the above group and Adjust Seating -.003”
7. Load 5 or 10 and shoot groups
8. If Improvement is seen Adjust depth -.002”
9. Load 5 or 10 rounds and shoot groups
9 If groups do not improve or open up stick with Jam Length
"Jam" would be .003" LONGER than your OAL length. You want to "JAM" into the lands. .003" off the lands would be a .003" "JUMP" Hope this helps.
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