Seating problem
- Thread starter fuel80guy
- Start date
As would mine.
An accurate rifle will show you it's preferences, ... to jump?, or, to jam?.
Every different bullet tried is a rule unto itself. Some, like the TSX's and many game bullets, will often do best with some jump. Others, like Berger or Scenar target vld's will probably want to be jammed.
"Chasing the lands" can indeed be tedious. Should one choose to set their seating depth to just 'kiss' the lands, constant tweaking will likely be needed to stay in the sweet spot. The throat erodes back with every shot fired, and kiss soon becomes a short jump. Most precision rifles are quite sensetive to the transition from one to the other.
My most accurate rifles start their load work up with a firm jam (Remingtons excepted
), powder charge is determined, then a minor tweak or two on the seating depth to optimum. The bullet seating depth is lengthened by a thou. or two every hundred rounds fired. This is easy to do with a micrometer BR die. Done this way, very rarely do the loads need a tweak to stay on node.
Hunting cals. are loaded with the first emphasis ... to mag feed flawlessly. They will always have a jump. The charge is then adjusted for max accuracy. Only the odd rifle has ever needed a seating depth adjustment to produce good accuracy.
I have hunting rifles with enough room in the magazine to handle rounds that would be well into the lands, I also have rifles where that isn't even close to possible.
Some rifles like a 30 thou jump, some like them stuffed, some like .... Well you get the point.
You will never know what is going to work for you and your rifle until YOU try it, that's half the fun of reloading!
Some rifles like a 30 thou jump, some like them stuffed, some like .... Well you get the point.
You will never know what is going to work for you and your rifle until YOU try it, that's half the fun of reloading!
Maybe darcy ... but maybe not.
If you are loaded at 1.5gr's below book max. (book testing was not in your rifle, nor powder lot, nor chamber specs., nor bore dimentions, etc, etc.), and with the bullet jumping a full .130" to the lands, it is most likely that the pressure is not near to a concerning level.
When a bullet is seated farther out pressure does tend to go down somewhat .... until it touches the lands and starts to jam. At that point pressure goes up, sometimes dramatically.
If you find yourself near, or at, max. with a jump, and then decide to seat out to jam ... it would be prudent to drop the charge and work back up.
Your brass will thank you.
And, as Warren Page also pointed out, on the intended use of the load. For benchrest purposes, touching the lands is quite acceptable, if that is what your rifle prefers. Warren intended to fire every round he loaded, within the time alloted for the string of fire.
For use in the field, however, Warren points out that you may need to unload a round un-fired - Bambi might not be cooperating, and may just send out his mommy or spike brother to troll for hunters. In which case, at the end of the day, or the edge of the ditch, or beside the fence, you may need to remove the chambered round intact. If the round is jammed to the lands, and if, just maybe, there was a speck of dust on your bolt face, or a bit of grit in the leade, your beanfield shooter may convert into a bullet puller, spilling ball powdeer all through your action. Time to go back to camp to clean your rifle.
Warren acknowledges that the microscopic improvement in group size between "jammed" and backed off 5 thou is irrelevant in the field, and just may save a day's hunt. YMMV
For use in the field, however, Warren points out that you may need to unload a round un-fired - Bambi might not be cooperating, and may just send out his mommy or spike brother to troll for hunters. In which case, at the end of the day, or the edge of the ditch, or beside the fence, you may need to remove the chambered round intact. If the round is jammed to the lands, and if, just maybe, there was a speck of dust on your bolt face, or a bit of grit in the leade, your beanfield shooter may convert into a bullet puller, spilling ball powdeer all through your action. Time to go back to camp to clean your rifle.
Warren acknowledges that the microscopic improvement in group size between "jammed" and backed off 5 thou is irrelevant in the field, and just may save a day's hunt. YMMV
