OK. I know this isn't a 1000 yd. cartridge. But, I have a question that is way out of my league. Currently awaiting my new .20 Practical with a no-turn .233 neck. It's the only reamer PAC-NOR has. I sized my .223 Lapua brass as follows: .223 FL die, bushing die with .233 and then finished with a .225 bushing,( process used to turn .223 brass to .20 caliber). So, I loaded a dummy round using a 40 gr Berger and it measured .227-.228 at the neck. I believe I read somewhere that it's recommended to have at least .002 clearance in the chamber. So, am I right that my loaded round should measure around .231?? REM 700 SA and Lapua unturned cases. Or do I have to actually fire a round and then bushing size the case with a bushing that will get me closer to the chamber .233 neck? Hope I made some kind of sense.
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.20 Practical question
- Thread starter newmexkid
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Bullet bumper
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If your chamber neck dimension is .233 and you want .002 clearance around the diameter then the case necks after seating a bullet need to be .229 diameter .
.002 clearance on one side .002 on the other side = .004 . .233 - .004 = .229 loaded neck diameter .
Your loaded round neck diameter with Berger bullet @ .227 to .228 would work ok .
Some people quote clearance across the diameter and some quote around the diameter it's two different situations . The clearance should be all around the diameter .
The thing is for hunting you don't want too tight neck as it is possible to get jams on unburnt powder grains or some other rubbish that can enter the chamber on the rounds .
If you wanted .002 clearance across the diameter then that is .001 on each side it's fairly tight for a stalking rifle but probably ok for a varmint /target rifle with care taken . That would be .233 - .002 = .231 . You have already show that the loaded neck diameter is smaller than this so as far as I can see the gunsmiths reamer is made to allow nominal .002 clearance around the diameter using necked down .223 brass .
.002 clearance on one side .002 on the other side = .004 . .233 - .004 = .229 loaded neck diameter .
Your loaded round neck diameter with Berger bullet @ .227 to .228 would work ok .
Some people quote clearance across the diameter and some quote around the diameter it's two different situations . The clearance should be all around the diameter .
The thing is for hunting you don't want too tight neck as it is possible to get jams on unburnt powder grains or some other rubbish that can enter the chamber on the rounds .
If you wanted .002 clearance across the diameter then that is .001 on each side it's fairly tight for a stalking rifle but probably ok for a varmint /target rifle with care taken . That would be .233 - .002 = .231 . You have already show that the loaded neck diameter is smaller than this so as far as I can see the gunsmiths reamer is made to allow nominal .002 clearance around the diameter using necked down .223 brass .
I am not really sure what your question is but you have plenty of clearance. Just for informational purposes neck clearance is measured in total clearance. If you have a .233 reamer and loaded rounds are .228 then you have .005 clearance. if you are using a .225 bushing then you have right around .003 tension(.228-.225) which should be fine. My experience with the 20s is they are not picky at all.
CatShooter
Well-Known Member
The standard used when describing neck clearance is not "all around"... it is the diameter of the chamber neck, minus the diameter of the loaded neck - if you have a 0.233" chamber and a 0.227" loaded neck, then you have 6 thou (0.006") clearance.... which, by the way, is a hellova lot of clearance for a "no turn neck" in any calibre. A no turn chamber neck should be 0.0025" to 0.003" larger than the loaded neck.
A chamber with a neck that is 0.006" larger is not a no turn, it is a plain ol' factory, over the counter, boring neck!!
Bullet bumper
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Never said the " standard should be " . Said the clearance he was talking about should be all around making .004 total across not .002 . Which is born out by the dimensions quoted . Your playing with semantics .
CatShooter
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I never said that you said anything... in fact, I never mentioned you at all.
"Playing with semantics???
You should understand that that there is a way things are described in shooting, so everyone will know what others are talking about, and if you don't subscribe to that language and terminology, then people will not know what you are talking about, and you will sound like a green kid who is just making noise.
Bullet bumper
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Don't BS me . You made a direct miss quote from my post . Even put "all around "in inverted commas . No one else said , all around , but me .
However you got the meaning wrong anyway .
However you got the meaning wrong anyway .
CatShooter
Well-Known Member
Yeah, sure... whatever you say.
P.S... they are called "Quotation marks", not inverted commas.
