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rodmkr

Temecula California
If you measure from the muzzle a bullet in the chamber and the distance from muzzle to bolt face and get 3.100
how much do you set back (clearance) do you give the bullet when seating in the case?
Working on an old Mosin Nagant.
Dimensions are as listed above showing a max length of 3.100.
Have always set cast to touch lands.
With jacketed I usually go .015 off lands.
Good or bad with cast??

Jim
 

fiver

Well-Known Member
I look at it like this.
if I work a load starting out engraved or touching the lands it probably isn't going to get a lot better by moving it.
it might if I change powder and alloy a little looking for something, or if it isn't working at all right from the start.
I'd just as soon change primers as oal as a first step though.
 

Bass Ackward

Active Member
Have always set cast to touch lands. With jacketed I usually go .015 off lands. Good or bad with cast??

Jim
Seem a lot of folks do that as SOP. Day’ll come though you get a long throat, or short slug, or when you close the bolt & the rifling or case neck damages the slug & then you’ll have to have a plan B. We all adapt. I do a “cast dance” when I seat my slugs. Wife says it sorta resembles a rain dance. Silly woman has no idea the “science” we call upon to get cast to work. I’m excited as I’ve got a box loaded & soon as it stops raining, I’ll try’em out.
 
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Bret4207

St Lawrence river valley, NY
The way I do it is to take a case and insert the bullet I want to use. I keep seating the bullet deeper until the action closes. With some bullets you can't seat it out long enough to be a problem, with others you end up with the base way down in the neck or even below the start of the shoulder. I don't think there is a hard and fast distance that's "perfect".
 

rodmkr

Temecula California
Did as Brett suggested.
Bolt will close on bullet with 47 thousenths in the case.
Not much holding it.
Thought 15 off might help overall.
The 314299 is a relatively long bullet so the throat on this one is massive.

Jim
 

fiver

Well-Known Member
sounds like your loading for an Argie.
just set the bullet down near the neck shoulder junction and let it jump, 16-17 grs of 2400 isn't gonna cause you enough grief to worry about it and you'll probably be surprised by how it defies all the rules and just shoots 1-1/2" groups with regularity anyway.
 

462

California's Central Coast Amid The Insanity
Fiver,

That is very informative! I have a shortened 1891 Argentino that has defied my abilities to find an accuracy load, so will try seating bullets deeper. As it is, to just barely touch the rifling, a bullet is seated not much deeper than to the top of the gas check.

Michael
 

fiver

Well-Known Member
chuckle.
yeah I figured it would never work either.
I even have a 3 cavity aluminum mold from Tom to prove I didn't think it would work.
still haven't loaded or shot any of those 210gr modified loverigns yet.
 

Ian

Well-Known Member
I do basically the same thing with my Blackouts, make the bullet just a fuzz over groove diameter, seat it to magazine length, and let them sail down the hallway unassisted until they find some steel. It shouldnt work......but.
 

Intheshop

Well-Known Member
It can get as complicated as you want to make it..... and "then some". Ogive shape/dimension interface with the chamber's leade is a metrology nerd's nirvana. And that's before we start "bumping" noses.

Or.......

You try a few things..... some might say,blind squirrel and a nut? But,because we have so many more controls over the bullet vs JB's.... sometimes you are just as well off taking the calculated "guessing" approach? In other words,load/shoot first..... measure later.

I'm usually bound by magazine length and how well loaded round gets JACKED up into chamber from bolt guns. I "try" to play nice but,will resort to bumping and swaging to make it work.
 

Bret4207

St Lawrence river valley, NY
If the throat is that big, just seat it where you think you want it to be and start there. In cases like that, where mag length (as ITS mentioned) or throat length keeps you from doing what you think is the "right way", you adapt. But! In cases like that you aren't going to get any guidance from the throat for a long ways, so that brings other issues. You have to seat the bullet as straight as possible and watch for run out. Hopefully the case will lay concentrically in the chamber and the bullet will be lined up good with the throat. It can ruin your day if it isn't, but you'd be amazed the number of times a bullet making that jump shoots good groups. Gotta try it to see whats going to happen.

You said it's a M-N, right? Never messed with one of those. What's the nose on you bullet measure?
 
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CZ93X62

Redlands, Kalifornistan
I have remembered these discussions on this subject I had with my old mentor Leo Reyes just before he passed. Among the ideas that REALLY stuck with me......"If all else fails, give the bullet one caliber's-worth of seating depth and send them." This has worked a lot more often than one has a right to expect.

The "conventional wisdom" is sometimes neither conventional, nor wise.
 
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quicksylver

Well-Known Member
I rarely if ever contradict Ian, but here's my'definitive answer.. I like the bolt to work like it was timed and polished, so my bullets don't get engraved and I'm happy .. don't get me wrong I have tried it the other way and see no advantage, to each his own , so much for science.. Happy Shooing Gentle men , and Women
 

Ian

Well-Known Member
How was that contradicting me, Dan? Sounds like we load our autoloaders the same way, cartridges go in and out without interference.
 

quicksylver

Well-Known Member
Hi Ian We aren't, I was playing on the word "definitive"I have a definitive answer for me and boy you are so right you don't want anything to keep the bolt on an auto loader from FULLY going into battery ... actually what I was trying to say so clumsily was that I like the bolts on my bolt guns to work effortlessly... BTW Ian thanks again for all your help..Dan
 
Reactions: Ian

Ian

Well-Known Member
Oh...ya got me on "definitive" LOL! It ain't so much a shoot better thin as it is a function thing. As you know, if you do it right then a non-interference fit works just as well. Problem is not everybody has the "do it right" part down but can jam-fit a bullet reasonably well, so their "mileage" may be better with that technique.