Jump or jam? bullet seating for accuracy
- Thread starter guninhand
- Start date
I understand the concern, and I think the benefits or disadvantages can vary with each individual chamber dimension, and how the brass is conditioned. The gun I use a jam in has a fairly tight neck -- about 0.0025" clearance, and I also only resize 2/3rds of the neck. This leaves the rear 1/3 fitting even tighter. I think this minimizes the possibility of the jam causing a cant in the initial position of the bullet.
Ron touches on one of the real fringe benefits of bushing dies... you never re-size 100% of the neck with a bushing, and the accumulation of brass (sort of a reverse doughnut, or as my shooting buddy calls them "a gunt") acts as a bushing in and of itself, thus centering the neck in the chamber. When used with a match chamber, and particularly in conjunction with neck-sized-only brass, the bullet is dead-on.
I have to disagree with my esteemed friend" Boomer, on jamming "intorducing more variables than it solves". Anyone that shoots with brass that has not been properly prepped for the the type of shooting they are trying to do, should be using a factory 308 and Federal Gold Match ammo.
Either your gun likes the bullets or it doesn't. It will tell you what it needs, and if the gun needs jammed bullets, prep and load accordingly. I have also been quite successful with jamming bullets and using light neck tension. It is all a question of what it takes to achive optimal results, and whether you are up to the challenge.
I have to disagree with my esteemed friend" Boomer, on jamming "intorducing more variables than it solves". Anyone that shoots with brass that has not been properly prepped for the the type of shooting they are trying to do, should be using a factory 308 and Federal Gold Match ammo.
Either your gun likes the bullets or it doesn't. It will tell you what it needs, and if the gun needs jammed bullets, prep and load accordingly. I have also been quite successful with jamming bullets and using light neck tension. It is all a question of what it takes to achive optimal results, and whether you are up to the challenge.
Seems to me a few years ago somebody knowledgeable in precision shoot told me that was a bad idea?
I (of course
) ignored this advise and have continued to use this method for several years.I got my best accuracy with 70% turned Ultra mag brass using this method....Of course Rem Ultra mag brass is about as imprecise as it gets.
Your seating method is interesting and certainly depends on bench rest brass preparation. Though methods like this may produce the last tenth I wonder if it is as accurate over the course of a weekend shoot.
This is just a general observation and you of course know your rifle best.
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True, but the best thing about the bushing dies is you can bump the shoulder while partially sizing the neck.
FWIW I also like the theory that the bushing floats and centers itself over the brass.
The reality check is I see a lot of guys have gone back to a conventional die with a custom spec neck diameter.
I wonder if Redding will cut a bump (step) in the neck size to allow sizing 3/4 of the neck?
Wouldn't that be the best of both worlds and help with any dread donut issues?
FWIW I also like the theory that the bushing floats and centers itself over the brass.
The reality check is I see a lot of guys have gone back to a conventional die with a custom spec neck diameter.
I wonder if Redding will cut a bump (step) in the neck size to allow sizing 3/4 of the neck?
Wouldn't that be the best of both worlds and help with any dread donut issues?
Forster offer a service to hone the neck of a FL or Neck only die. This allows you to ditch the expander ball. In the case of the FL you are still left with a factory size body. Some go to the extent of having a custom reamer made to match the FL die they plan to use. This is a method to get the equivalent of a full custom dimensioned die. If you plan to buy a reamer anyway then it can cut the cost some.
