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March 13, 2015, 02:04 PM | #1 |
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Case head and bolt face ?
When a bolt is closed on a cartridge , is the case head pushed into the recess of the bolt face underneath the extractor claw, or does the ignition phase of it push it under the extractor claw into the bolt face ?
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March 13, 2015, 02:15 PM | #2 |
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It is flush with the bolt face. .001 headspace.
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March 13, 2015, 02:24 PM | #3 |
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Thanks Cw308
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March 13, 2015, 03:32 PM | #4 |
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There's three situations.
One is with Mauser style claw extractors; M98 and Win 70 classic (pre '64) and M1903's, another is the sliding ones used in post 64 Winchesters, then the circlip or snap over ones used in Rem. 700 and Garands. All of these will slip over a case rim then into the case extractor groove when the bolt's closed on a round hand pushed into the chamber. When rounds are fed from the magazine: Claw extractors on Mausers and control fed pre 64/classic Win 70's are set off the bolt face and the round's rim slides up into them as it leaves the magazine. Sliding extractors slide out over the case rim as the round is chambered and stops against the headspace point and snaps over the chambered round's rim. Circlip/snap-over ones do the same thing. Once the round's chambered, there's a few thousandths head clearance; the space between the bolt face and case head. It's maximum with the ejector's in the bolt face and pushes the round as far forward in the chamber as possible; it stops against the headspace point; belt or shoulder or rim, that is some distance from the bolt face to the chamber that's the headspace reference. Cases normally do not have their rim pushed against the extractor claw; there's clearance enough to allow easy chambering and the extractor to slide over the case rim. In line ejectors push the case head off the bolt face so there's a few thousandths head clearance. Head space is the distance from the bolt face to the chamber reference; shoulder for rimless cases, belt ridge for belted ones or rim recess for rimmed cases |
March 13, 2015, 06:29 PM | #5 |
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Thanks Bart B
my vanguard s2 has a 2 lug recessed bolt face with a sako style extractor ( I think ) I don't know much about it. |
March 13, 2015, 07:47 PM | #6 |
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.007 to .014 on a Remington 700 if you only had .001 you would need a clean room to shoot In because a spec of dirt would either prevent bolt closing or a possibility of slam fire when you close the breach and something on the bolt face depresses the primer ! Also if under immediate expansion of the gases at the point when the bullet molecules change frome a solid state to a term called plastic state just then the case expansion occurs sealing the chamber gasses away from your face and safety glasses it if you measure can expand up to .005 in all directions depending on the quality of the chamber die used or chamber wear. Neck sizing your casing with rcbs or Lee if you can send them 5 spent casings and your full length die they will perform a hone on the inside of the Lee die the same dimensions of the chamber so when you full length your Lee die it only forms the neck (seems like a lot of work just buy a neck die from rcbs and only full length every 5 firings annealing every 5 as well .. Some people experiment with the amount or length of neck sizing maybe just doing 1/4 1/2 of the neck enough to hold the bullet that's it !!! This is the ultimate in casings long life 40 plus reloads !!! There will be a ring of brass building up at the base of the neck I've heard of people turning there casings but it is wrong you must re incorporate the ring back into the casing to maintain safe wall thickness winchester having the thinnest I've measured at .0125 and a surplus military having .0180 the thickest I've measured Remington is .015 lapua is .014 Norma .014 all measurements were on the 308 casing and I don't know about the webbing !!!! I researched this for the M118 LR the M118 uses lake city brass but the volume of the lake city brass is bordering on going non - supersonic at 1000 yards so is most others when the M24 needed a new temporary bullet till the more powerful M40 could replace it the M118LR was developed using winchester brass which I thought was no good because of the thinnest walls but the volume I think is 58.5 cc of water and this kept in line with specific guidelines of a 1000 yard 7.62X51 bullet but even with today's powders only a few will keep a 308 super sonic at 1000 yards it's been a large development in projectiles and there BC's that have Givin us the opportunity to see more people setting there goals at 1000 !!!!! I read yesterday that in projectiles nothing bad ever came out of a green or a yellow box !!!! And soon to be tested by me very new and quite popular 208 grain A MAX and 208 grain Match both with the AMP Jacket !!! This is the heaviest bullet I could find a load for in 308 !!!! Top of my head BC 600 maybe just shy of it !! These will turn the short action king into an empowered rifle likes of which we need!!! Proper shot placement out to unheard of distances with and supercharged heavyweight 308 testing needs to be done I can only guess but The 308 isn't being pushed out the door by any gun !!! So to answer your question on a Remington 700 as you rotate the bolt to lock it it slightly jumps ahead that is the case head going into the recess if you were to take a dial indicator and put it on the end of your bolt had push forward hard on your bolt it springs back and forth you can measure available head space as long as wear doesn't cause your handle to contact the receiver or stock but you would have noticed that wear long ago F class try for 5 to 6 thousands end play .0025 at each end or some equalization in there of the two numbers !! Hunters with dust in the air leaves grass etc getting accidentally into your recovers time for .010 to .014 so the bolt will slide and close smoothly even with a dirty rifle about as thick as a piece of paper !!! These measured tolerances are purposeful to the hunter for a reliable rifle and us long distance shooters spend 1000's $ extra tightening it all up squaring this lapping that fitting he and removing there in our quest for 2500 yards out of a 6 mm bullet because 1000 just isn't far enough anymore with these March 8X- 80X power scopes there selling for 7 grand
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March 13, 2015, 07:49 PM | #7 |
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March 13, 2015, 09:27 PM | #8 |
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Thanks JJ72
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March 14, 2015, 03:37 PM | #9 |
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JJ72, that has to be one of the most "chaotic" pieces of writing I have ever seen!
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March 14, 2015, 03:52 PM | #10 |
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Haha !!!! At least it wasn't the most !!!! You just have to step back and see it all at once instead of little pieces at a time !!! That is why they say communication is a two 2 at thing it includes eye contact body language understanding the little things before moving forward with a conversation with someone sort of response !!! You can't get that in writing a one sided story plus I'm guilty of not using punctuation !!!!! Believe me in a two way communication you would understand !!!
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March 14, 2015, 05:11 PM | #11 | |||||||
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JJ72 says:
Quote:
And primers typically need to be dimpled at least .020" so if a tiny hard thing's tinier than that in diameter, it won't cause a problem if it's between the bolt face and primer when the bolt closes even in a zero head clearance system. Quote:
Quote:
Neck only sizing fired .30-06 cases ends up with them having only about .001" head clearance. You've got to full length size them to have any more. If they rifle's got minimum chamber head space, to start with, I doubt you'll ever have more than a few thousandths head clearance; never as much as you would like. Quote:
LC 7.62 NATO cases, match or service, have had plenty of room for powder charges to shoot all 30 caliber match bullets fast enough to stay supersonic through 1000 yards since 1964; with safe pressures, too. The issue of subsonic bullets came from people shooting M852 match ammo with Sierra 168's in barrels oversize in groove diameters or the right size but worn out with too much throat wear. Most often with M14's and M1A’s with 22 inch barrels. Garands with 24" barrels rarely had a problem; none of the four barrels in them I wore out had subsonic bullets at 1000 yards. Quote:
Quote:
Quote:
Last edited by Bart B.; March 15, 2015 at 01:10 PM. |
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March 15, 2015, 06:08 AM | #12 |
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You did a fair job understanding Bart !!! Like I said communication is a two way street! !!+
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March 15, 2015, 07:02 AM | #13 |
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Waste!
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March 16, 2015, 05:56 PM | #14 | |
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Quote:
F. Guffey |
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March 16, 2015, 07:33 PM | #15 |
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Depends on the size of it. Elephant ones usually won't fit in a violin case. Maybe a viola case if the bowl's full of punch.
Last edited by Bart B.; March 16, 2015 at 08:22 PM. |
March 17, 2015, 09:28 AM | #16 | |
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Quote:
I am the fan of cutting down on all that case travel, I am the fan of forming cases to fit. F. Guffey |
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March 17, 2015, 09:49 AM | #17 |
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Martin Hull's point was, and still is, the case needs some clearance around its body for bullets to shoot accurately; they must not interfere with the chamber body and neck walls whatsoever. There can be minimal clearance between the bolt face and case head, case shoulder to chamber shoulder will naturally have zero clearance, as well as a little or no clearance at bullet and throat at the origin off the rifling. I talked with him in the 1960's about that. He was a good friend.
Some people don't understand that. Benchresters finally did some years ago when they started full length sizing their fired cases and gave up neck only sizing. |
March 17, 2015, 10:40 AM | #18 | |
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Quote:
F. Guffey Last edited by F. Guffey; March 17, 2015 at 10:51 AM. Reason: change g to k |
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March 17, 2015, 10:50 AM | #19 | |
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Quote:
F. Guffey |
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March 17, 2015, 11:03 AM | #20 |
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Guffey, I don't think you get the bigger, realistic picture; none of what's in Sierra's manuals and web site, too, for that matter. Anyone gleaning Sierra's reloading manuals will see less than 1% of the reloading information he shared with rifle competitors shooting matches with him so they, too, could make the most accurate ammo possible. Especially when he gave them a tour of Sierra's plant showing and explaining stuff to them.
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March 17, 2015, 02:21 PM | #21 |
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Hang on, here is: Sierra, Second Edition under authors. that section comes before they start numbering the pages. Of all the accomplishments he is given credit for and recognized as one of the great shooters the only thing you could come up with is the tur#d in the fiddle case and punch bowl, and we both know where you got that information from.
F. Guffey |
March 17, 2015, 02:53 PM | #22 |
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Any thought as to where I got that info from had better be identical to when both he and I were shooting a rifle match at Camp Pendleton in the summer of 1965 where I first met him. A former National Champion introduced me to him so he could give me some reloading tips. Any thoughts otherwise is an assumption based on ignorance.
http://www.longrangehunting.com/foru...03/index5.html Last edited by Bart B.; March 17, 2015 at 03:15 PM. |
March 17, 2015, 03:03 PM | #23 |
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F.Guffey, back to your full circle post. I shoot Benchrest with the same rifle at the same range. All the people I shoot with share information & would answer any question. Guess I shoot with a great group of shooters. This got off the thread's question
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March 17, 2015, 03:39 PM | #24 | |
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Quote:
F. Guffey |
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March 18, 2015, 08:22 AM | #25 |
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That is a better explanation. The other way you sounded like a hard ass. Thanks Chris
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