.750x16 tpi, cut shoulder for 1 rotation?

J

jGEE

Guest
I want to engage my rifling deeper for Rimfire. How much would i cut my barrel shoulder for 1 complete round of my extractor slots? To keep my headspace the same i would also cut the same amount from the end of the bbl and deepen my extractor slots just a bit.

I'm thinking this would engage my second driving band just a bit. thanks -joe:)
 
To get the amount of advancement with one turn of a particular pitch, get out you calculator and divide 1 by the pitch. In the case that you asked about that would mean 1 divided by 16, which, as Scott said is .0625".
 
I'd suggest cutting it short of .062" and then creep up on it by cutting and trying it to get the shoulder where it needs to be. If you go too far the only thing you can do is go in another full turn or maybe half turn depending upon how your extractor cuts are lined up on the barrel.
 
thanks guys!
thanks Mike for your input also!
I'll write the info just above my lathe and of course on my wall!
1 divided by the pitch or .0625 in this case. joe
 
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Just remember, it's 16tpi which is 16 threads per inch (16threads/inch)

which means one full turn is 1/16 inch (in a perfect world)

which means 1 over 16

which means 1 divided by 16

which means .0625.

al
 
alinwa said:
Just remember, it's 16tpi which is 16 threads per inch (16threads/inch)

which means one full turn is 1/16 inch (in a perfect world)

which means 1 over 16

which means 1 divided by 16

which means .0625.

al
Click to expand...

:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D......................You kill me Al!!!!!
 
ok this is an \official test!! i'm working on it now.... gun's apart!!
I'm in for a burger but back to cleaning up my lathe.... i'm waitin on 5min epoxy to dry my indicator on my saddle and then and then and then... i'm gonna remove .061 and test fit! joe
 
Mike Bryant said:
I'd suggest cutting it short of .062" and then creep up on it by cutting and trying it to get the shoulder where it needs to be. If you go too far the only thing you can do is go in another full turn or maybe half turn depending upon how your extractor cuts are lined up on the barrel.
Click to expand...

-one smert cookie! Gotta factor a certain amount of "squish". Threads yield a bit (especially on the initial clamp up)

Good luck!!
 
ok.. first trial fit coming up

after

i recutt my extractor slots!!

i'll say PS now.... i also did a 1/2 counter bore -because i want to!

joe
 
ok.... confirmed dumbass on this end

missed my slots

gonna rechuck the bbl and take a few more thou

and i thought i would get it first try, lol joe
 
well it is a long story... short version last nite about 2:30 am i quit rimfire for good, i said for good!! I would have throwed all my tools out the door but i was just too tired....

Today about 1:30 pm i'm thinking i sure was glad i was too tired!! joe:D:D:D
 
crb said:
Creeping up on it is the only way to do it.
Click to expand...

I thought this kinda' went without saying but YES...... I agree completely with this statement!

Doing anything like this strictly "by the numbers" is a guaranteed recipe for disaster.....

al
 
alinwa said:
I thought this kinda' went without saying but YES...... I agree completely with this statement!

Doing anything like this strictly "by the numbers" is a guaranteed recipe for disaster.....

al
Click to expand...

ok, "for richer or poorer" lol...... i think i got it

... it's finished and looks good to!! i'm gonna re-assembly the gun tonite - it's only 10:17 central

thanks everyone!!~ joe
 
Joe:
Glad you got it worked out. Here's what I do. I screw the action into the action until it locks up. I then back it out 1 full turn. I measure the gap with a feeler gage and subtract .003". (crush) I then have my machinist remove the final amount. IE: Measured amount= .0625, minus .003 equals .0595. Works for me. That's what I have done on 3 different 52 actions that I wanted to set back one complete turn. I also have him remove an eqal amount from the breech. Touch up the extractor cuts and you're done. All you have left to do, is run your reamer in to clean up the chamber.
 
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Fred J said:
Joe:
Glad you got it worked out. Here's what I do. I screw the action into the action until it locks up. I then back it out 1 full turn. I measure the gap with a feeler gage and subtract .003". (crush) I then have my machinist remove the final amount. IE: Measured amount= .0625, minus .003 equals .0595. Works for me. That's what I have done on 3 different 52 actions that I wanted to set back one complete turn.
Click to expand...

Wow that's pretty easy Fred!..... My next project probably will be my CMP 40X or my 52C. That Shilen i got from you is back on my Kimber 82G... these projects are killin me, lol!! joe
 
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