by Apollo » 03 Feb 2018, 11:20 pm
Where to go from here, I take it you mean with the 80gr Matchkings. (Opps, looks like the post was deleted..??)
Load them shorter and go from there. The COAL is a suggestion. I don't even bother looking at that part of reloading information.
I measure each type of bullet in a case gauge to establish where that particular bullet is touching the lands in just about every chambering I have. If it's to be magazine fed then I then see if that length will fit in the magazine. If not I start with the bullet seated to maximum magazine length and start load development. If I'm not happy with all that I pick the best load and start seating the bullet deeper into the case.
The opposite may apply to you, seat the bullet as long as you can which may be your 2.496" and work up a load. Be aware that if the bullet is jammed into the lands and you extract a live round you may leave the bullet behind in the chamber and spilt powder all through your action. Unless it's a target only use I wouldn't suggest jamming rounds unless you always fire the round and never need to extract a live round.
If the closing of the bolt pushed the bullet back without it jamming in the lands then it sounds like you don't have a lot of neck tension. That is called "Soft Seating" and what I use in a few custom target rifles where they shoot the best accuracy. The bullets are seated to about a 0.020" jam past where they would normally just touch the lands. No Magazine, single shot target rifle. If you don't want the bullet to move then it needs more neck tension which may or may not be easy depending on what sort of dies you are using.
Other choice is use a shorter perhaps lighter bullet or different shape bullet which may be shorter. I'm not familiar with Matchkings so I don't know if they are a Tangent or Secant Ogive design. I have a feeling they may be tangent and if you changed to a secant design you may well have the opposite problem where the bullet ogive may touch the lands and it's way to long to fit in your magazine. An example my be say a Berger 80gr Match VLD.