About bore capacity?
That's my concept on what under and over bore capacity means for different cartridges. Based on when accuracy degrades some standard amount.
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Full Length or Neck Only; What's Best Resizing for Accuracy?
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That's my concept on what under and over bore capacity means for different cartridges. Based on when accuracy degrades some standard amount.
birdiemc
Well-Known Member
Bore capacity is a concept foreign to me...is this something you came up with? Are you saying that a 22-250 with 24 grains of powder is baseline for barrel life, and doubling it to 48grns reduces barrel life to just 25% of the baseline?
birdiemc
Well-Known Member
Where did that come from Edd?
My laptop, I don't remember where it was before it was there.
Man where is the beating a dead horse gif. Not going to read 21 pages. There is no inherent benefit to neck sizing only versus proper full length sizing. Notice I said proper. Most all the 1000 yd comp guys fls. There is a reason for that. Several years ago I saw a test done where some guys strapped test rifle in a shooting machine and shot hundreds of rounds neck sized versus partial length resizing( yeah that was a thing) and Fls. The FLS was more accurate.
birdiemc
Well-Known Member
That's very interesting...like I said I've never heard of this before. Or maybe I have and just didnt understand at the time...
Based on that chart my 308win is gonna last almost twice as long as my 6.5cm...does that seem true? I've never shot out a barrel before, so I have no personal experience from which to form my own opinion.
Based on that chart my 308win is gonna last almost twice as long as my 6.5cm...does that seem true? I've never shot out a barrel before, so I have no personal experience from which to form my own opinion.
That's my spreadsheet developed years ago based on data from Sierra Bullets and top ranked competitive shooters.
Forum member mikecr updated it with powder heat index data linked below
https://www.6mmbr.com/BlogSept2005.html
Buck Buster
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The 1000m yard shooters used to seat each bullet in the rifle, the bolt held the back and the lands held the bullet the same each time. that was back in the 70's . I don't know how they do it now but the record 10 shot 1000 yard group at that time was around 3 inches, and that is good enough for me to this day ! What they did was barely size the end of the neck, just enough to hold the bullet, then seat each bullet when they pushed the round into the chamber, then they would shoot it. It was very accurate in the 70's and held the world record at Bodines Original 1000 yard Benchrest club, North of Williamsport PA
birdiemc
Well-Known Member
So how does it do at predicting barrel life?
Very good, according to top ranked competitive shooters and others who use good conditions and standards.
For example, if the barrel starts out averaging 1/4 MOA and X number of shots later averaging 3/8 MOA, 50% bigger, time to rebarrel.
Varmint hunters may use a larger group reference starting out with 1/2 MOA then rebarrel at 3/4 or 1 MOA. They'll get near twice the barrel life as competition folks.
3 times the group sizes and round count for big game hunters. 4 times for service rifles used in combat.
It's popular for people to use the smallest group shot as the accuracy claim. Doesn't matter to them that all the other groups are up to several times bigger. None of the long range single 5-shot or 10-shot record group holders also hold the six 10-shot group aggregate (average) records that are much bigger. The current NBRSA 1000 yard six 10-shot group aggregate record has its largest single group 7 inches plus with a 5.96" average.
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It is 99.9% all top LR shooters FL size with fitted FL dies, either by honing or custom. NS has gone the way of the dodo bird. This dog has been beat to death, but you have guys trying to resurrect the dead. They are running 10 shots in 20 seconds and will not risk an oversize piece of brass throwing the gun out of synch with the bags, failing to chamber or extract. Bumping shoulders back normally around .002 even .003. Does not really change things in my testing and developing LR charges.
