headspace gauges

[docn8as]

in the 40's when i first got interested, an awful ot of jobs were h/spaced w/ cartridges..some 3006 ga. around, not much else, .....100 cases were slected ( would generally last the barrel) ,chamber was roughed , finish reamer used & stopped maybe 1/64 short...10 or so cases inserted in chamber & depth mike checked , .....longest was selected for h/space ga...dab of grease on piece of gillette blade added .003-.004,crush fit took away .0015 to .002,& you were left w/ .002 +/- hdspc.( for urself, ,probably left zero hdspc)...this worked well enuff ..if one case was tight , u pitched it , if too many , u put the t handle ext . on reamer & gave a twist....the one problem was the guy who bought his ammo, & needed a quick second shot ,with the old case jammed in chamber , or worse yet, the head torn off! but then again , any one hunting game that would just as soon track u ,& didnt run the cartridges thru the nite befor, is probably a candidate for the Darwin award, doing society a favor by removing himself from the human gene pool....noooowwww e. narramore ,recognizing th e fact that most everybody was poor,at that time, wrote his great book on handloading & the manufacture of ammo(principles of handloading?).....for rimmed h/space ga. it was pretty obvious before the book ....turn up a replica of the base of cartridge w/ rim thikness, the max cartridge drawing in loading h/book+ .002.....for rimless turn up a two diam. ga. , the base part about 1/4 in. + long ,atjust under the min. chamber spec ( h/book or other source)the front of the GA. is the x/act shoulder dim. at the datum line , total length is the max. cartridge drawing line from shldr datum to cartrdge base + .002 . if ur heavy handed in useing ga. ,u can roll the front edge,....if u harden ga. & are ham fisted , chamber will score .....but ,never to worry, himmel!, ve are gunschmitts, ya?...buchsenmachers!...und buchsenmeisters..!!!.........now if u realy want to make up a full shouldered one ,like the big boys do, ...clamp a sinbar on the compound, on its side ,w/ rolls facing towards end of bed, after eyeballing the compound in line w/crossfeed....grab an indicator in t/stock chuck & tap sinbar till it indicates SAME on both rolls as u crank it in /out ....now it is in same plane as compound,....next rotate compound so bar is near parallel w/ bed & rolls facing bed ( 1/4 turn left)...now grab an indicator in chuck & set compound to shldr angle by trigging out the difference in readings on two rolls .sin 1/2 shldr angle x inches between roll centers u now have correct angle to turn ga. also to MAKE A REAMER!!!(thank u d. johnson from keeping me from inadvertandly making wildcats by missing shldr angle...idea is not new, but he brought it to my attention!...if u had a proof bar & aligned centers, could instead,put ga. blocks between roll & bar to set the sin bar/compound...now is the tough part....one way to get length is turn up a short length of bar & bore a hole x/act shldr dim. at datum line ( usually 1/2 way down shldr,not always & 3006 on top edge of shldr,)..set a block/angle plate on surfaceplate/whatever,put a thick square against the angle plate (looks like a gallows)...put base of ga. under overhung square & slide down into hole in bar ...idea is to keep ga. plumb!...now measure from block to underside o f square ....note the difference from length on max cartrdg drawing & shorten ga correct amount .if ur really good ,u dont need to re check it ..har,har.....probably easiest to tslescope ga. the distance w/ ur third hand!!DONT use a dial caliper!......if u have a known correct chamber , just test ga. in rifle & & turn down till bolt closes!!...bit maybe if u already had that caliber ,u wouldnt be making another ...although many of the 06 family use the same ga.... when u come up w/ a simpler way to get correct length , i am all ears ,(at least the good left one)....what ? EAR protection!..nah!!!!
nice thing is ,engine on my 20 year old truck gets quieter every year!
best wishes
docn8as

[Thrud]

Doc
Why don't you write some gun articles for the mag - Neil would love ya! I know you can do it, so quit screwing around (a pun!).

I had to get rid of my Gremlin 258 tire burner when the stereo died - could hear the car rusting then!


[This message has been edited by Thrud (edited 04-29-2002).]

[mike thomas]

Doc, I am going to have to print this one. It will take some digesting. Thanks. Mike

[docn8as]

Mike ....shud have said to set an angle plate on SIDE,& hold a square to the inside of it , like a gallows hanging out,as this will keep the square plumb in both planes ,helping to keep ga. true as u slide it down into contact w/ shoulder datum hole in block.......& there really shud be an easier way to get the length!
best wishes
docn8as

Ps wish i could draw on this thing!

[John Lawson]

You can use a cartridge, preferably a dummy, to establish chamber depth provided you use a headspace gauge such as the ones Midway sells. You drop a sized case into the gauge and it the head rests someplace between the two flats, you are within SAAMI specs.
If you make a steel (standard pattern) headspace gauge, you will need to leave stock all over, harden, draw and finish grind. One that is left soft will deform in short order; a bolt action puts enormous pressure on the case head.
I recently had a set of wildcat reamers made to my specs and Clymer also made me two go-no go sets for chamber and forming die. If you are going to do it, don't be halfway about it; do it properly. You will have to send the one set to RCBS or whoever makes your dies. In my case, I bought blank RCBS dies and made my own, but I didn't harden them. I'm thinking of making my next die set from Timken Graph-air stock I have in 1" diameter. It takes a lot of time to cut the 7/8-14 threads, but that set of dies should outlast any possible grit that gets between the unformed cases and the die walls. Those soft dies look like they have been in a sand storm.

[docn8as]

John ..the outlay u have for reamers dies & ga.s..is a strong component of the reasons i started making my own reamers dies /ga.s..... right up there w/ "i did it my way" ..."surely , i can do better than that"..& "i dont need u to do it for me"... i spect that standards are higher now , but i checked dies & reamers 40 yrs ago that that were pathetic ... viz. necks reduced .011 & then expanded .008......& i stoned more than one & actually had to grind one reamer to get it into spec....so i am not a great fan of "doing it right " particularly for experimental wildcats ...2/3revisions & u have a grand tied up w/ no commercial guarantees or even if u continue to use the cartridge..........also not a great fan of hardening anything that doesent cut metal/hardwood...back in the 60's when i shot a lot competitively , I made a set of forming dies taking 30-30 win brass down to 32-35 stevens...swaging head from .317 down to .305 ( if remembered )...after 100 cases ,i miked dies & couldnt read any wear..dont think i even used a tool steel .... i guess a serious competitor can wear out a set of dies in a few years ,but i never did....also wonder about the specs after hardening a die .maybe they grind the deformation out ,but i doubt it....by spinning my reamers in drill press when heating & bringing quench up to reamer while spinning, i reduced runout from around .020 to .009-.011.which is subsequently ground out...................cant imagine how a stndrd ga. ,unhardened would deform ....shoulder is in taper contact & nothing is going anywhere .....bolt action has tremendous camming force , but no more than what U put on it....I have used paper shims to check hdspc ,& miked them afterwards w/ no deformation...yes , they will wear ,but we are talking amateur or at most, part time smithing ...if u have a 2 year backlog of work ,u r losing money making ur own tooling, but if u r staring out the window, u r useing up valuable capital buying tooling.........didnt have ga.s for setting dies back in dark ages...didnt see a need !!!!!.u set the die up so case was resized just enuf to seat it easily if f.l. sizing (mostly neck sized)..if concerned ,u smoked the shoulder w/ a kerosene lamp to see where u were,or added a piece of razor blade to back of crtrdg for no go if u thot u went too far...stndard of living has gotten higher & i guess more money available for "accessories"...but then i still get a hand saw to cut one or two boards,rather than drag out skillsaw & extension cord...& hav e so far resisted cordless tools..no one has ever accused me of being on the cutting edge ...still useing the first tractor i ever bought....tnx for answering post ,
best wishes
docn8as

Ps anybody else wondered why every military mauser & russian checked had .010 to .012 hdspc ? sprgfld would be long gone to the armory!!!!!........maybe excess hdspc not the big bugaboo we have been led to beleive? ( & caseheads not enclosed either) in mac farlands book , he said the commercial mausers coming over here had lots excess hdspc,but the Germans didnt mind killing a few americans BETWEEN wars!funny remark ,but still leaves a ?