243 bullet seating

[warrenb]

These are my first reloads.
What would be a good distance to start seating 243 bullets from the rifling?
I have a combination of vmax in 58, 65, 75 and 87 grn to start.

Also is this the correct way?

Mark the bullet with felt pen so I can see if the bullet pulls out
Insert the round in chamber and close bolt.
Check for rifling marks and measure overall length.
Seat bullet further by X amount where X is the distance required from the rifling.

help appreciated.

oh and gun is a rem pump twsit rate 9 1/8"
powder H4895

 

[Boomer]

That depends on whether or not you want to use the rifle's magazine. When I load for accuracy, I work up the load with the bullet contacting the rifling. Once I have determined my maximum load, I then tweak the load in half grain increments working away from the maximum load. Once I have determined the most accurate load, then I will experiment with increasing the bullet jump. Note that each adjustment I make decreases pressure rather than increases it. Most of my target loads have the bullet touching the rifling, but if you want to experiment, rather than worrying about the exact length, just turn in your seating stem a full turn then try a group. If accuracy improves turn it in another turn. When accuracy deteriorates, back it out a half turn.

 

[warrenb]

Yes I want to use the magazine. I'm not sure how the magazine effect this .
I'm obviously not expecting this to be a bench gun but would like to make the most accurate ammo I can.
Sorry, I've read the term but not sure I understand bullet jump. Is that the distance to the rifling? If I increase the distance don't I increase the pressure in the casing?
I know I'm asking dumb questions. I really have read lots but I just want to make sure I fully understand what I'm doing.

Or should I just seat to the depth that makes my ammo the same overall length as a manufactured round to start and experiment with seating at a later date.

thanks.

 

[CyaN1de]

Well....If you want to use the magazine then the longest you will be able to seat your bullets is just short of the magazine length.

I think a safe assumption is that this most likely will NOT let your bullets touch the rifling.

Start with your max OAL that the magazine will allow and still feed properly and work up your powder loads with that OAL. Once you have the best powder load then try seating the bullets deeper into the case and see if that tightens up the grouping or starts to open it up.

Increasing the bullet jump to the lands will decrease spike pressure. If the bullet is already resting on the lands it will take more pressure to get it moving down the barrel.