fulton bolt lapping

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dimeN

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Hi
thought i'd post my work in progress incase other may like to see ( follow at your own peril )

ok.. this is going onto a norc receiver with a criterion med chrome lined barrel .. my goal was to have it in spec for the clymer go gauge at 1.630" and reject the nogo gauge at 1.634"

Note: norc receiver may not initially fit fulton bolt lugs... how you deal with it is up to you !
 
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better pic's
http://i43.photobucket.com/albums/e396/dimenickel/bolt lapping/20131105_132930_zps7b2f8813.jpg

Nogo
http://i43.photobucket.com/albums/e396/dimenickel/bolt lapping/20131105_133039_zps2aa50ea3.jpg


so now i can begin to lap in the rear lug area of the bolt... I saw this jig on m14 forum .. its to keep pressure on the bolt head while you lap


just a spring with a cut in half 308 case ( spring is from an old worn out M1 spring cut to size )

Next step:
since the bolt is quite close to being right on... i'll only lap a little with 600 grit ( brownells 600grit silicon carbide )

put the compound on the bolt


and the receiver
 
lap the bolt by inserting the bolt and into the lug area... move about 1/8 inch up and down for say 100 strokes... don't forget to put in the brass/shell spring jig

now check to see if it still rejects the nogo gauge


yes it does... ( just make sure you don't go toooooooo far... you can overlap and give yourself excess headspace !!!! or eat right past the case hardening ... )

here is the bolt... look at the contact area... looking good so far



ok... thats as far as i got today as time would permit !
 
Yomomma - you would be correct ! that is the wrong side to lap, initially... but in this case the norc lug well was on the tight side ... so I thought about it ... i'd rather take some off the front side, firstly ... then it won't be messing with my headspace

--- and i worked out ok ... as it does reject the nogo... and accepts the go gauge

my typing skills are not the quickest ... hah.... my fault there !
 
here is what the Go and Nogo gauge look like... this is the nogo at 1.634"



basically ... when using the gauge, it is inserted into the chamber ... and the bolt with extractor removed, is allowed to close on the gauge... when the NO go gauge is place in chamber, the bolt should not close shut on the gauge ... as you can see in the pic's above that there is a gap with the nogo inserted

thought i'd explain that abit more in detail...as i was vague about it before
 
Nice job. I am interested in replacing my norc barrel with a critereion as you did. Any issues with the threading? How much did you torque it to?
 
Thanks for your pics!!

Also can you share where you got the fulton bolt? The new export parameters offer more choices, but I haven't seen anyone import one yet... They seem to pop up time to time...
 
the threads are the same on the criterion as are on the norc factory barrel ... it should spin on just fine
-i'm not sure how much torque.. as you have to tighten it till the front sight is properly indexed to the receiver... otherwise your front sight will be crooked ( it didn't take much torque with the criterion... it would be easy to over index it, if you pulled to hard on the wrench )

here the jig i used to time it
http://www.canadiangunnutz.com/forum/showthread.php/983919-simple-barrel-timing-jig
 
the 308 win is abit different from the 7.62 nato

308 win Go gauge: 1.630" and No go gauge: 1.634"

7.62 nato Go gauge is 1.6355" and No go gauge: 1.6455" ( this reference was taken from Kuhnhausen service rifle manual )

therefore the 308 win nogo gauge is safe in the 7.62 nato ....

On the rifle i'm working on ... the plan was to shoot 308 win, as that is what i reload ... and shooting that in the nato chamber would lessen the life of the brass .. or at least thats my thought on the subject




lavoltiges said:
is it true that the 7.62x51, rejects the gauge 308 sometimes while GO is good for 7.62x51
Click to expand...
 
Specified draw to correctly install a barrel to an M14/M1A is 80 to 90 foot lbs at index.
All usgi, krieger, hart, springfield, smith ent, criterion, douglas ect barrels share the same receiver thread as the chinese barrel/receiver. They are not however a direct replacement. Barrels need shoulders prepped on most with a 1 degree undercut, or in many cases, roll swaged to afford correct draw.
If yer unsure.... Get it done by someone experienced.

And just to be a pain hehehehe , you don't mess with the front of the bolt lugs when installing a bolt, nor the receiver. ONLY the bearing surfaces with lapping compound. No files or stones should be used during this job.
 
yep... i agree completely..

i should have taken a better picture to show the bit of a raised spot on the front of the receiver ( only so much my phone/camera will pic up ).. that high spot never bothered the norc bolt, but the fulton was wider and would just bind on this bit of a high spot and wouldn't sit in the channel ..

cest la vie ... not everything is text book
 
NOTE: remember if you change the barrel to purchase a NEW gas cylinder LOCK !!!!!


thought i'd take gun out for a spin at the range .... click er all together and surprise !!!!! and ofcourse the norc gas lock is threaded differently ... ( insert 5 minutes worth of swears and cusses )


thats why we have friggin standards ... wholly jeez jumpin jeeeeehosafat

ok.. thats my psa for today
 
thank you very much for the kind offer !! i have one coming from brownells, ordered it as soon as i found out

had a funny feeling that things were going a little toooooo good ..
 
dimeN said:
Hi
thought i'd post my work in progress incase other may like to see ( follow at your own peril )

ok.. this is going onto a norc receiver with a criterion med chrome lined barrel .. my goal was to have it in spec for the clymer go gauge at 1.630" and reject the nogo gauge at 1.634"
- i changed the barrel and found that the nogo would easily fit ... so i opted to buy the fulton bolt after hearing that they are abit on the large size

a problem was encountered, and this is not a normal part of fitting a bolt
Problem 1) when i went to fit the bolt and get a reading ... bolt would not close all the way and would bind.. .. so I put some dykem on there and worked the bolt back n forth to see where the contact was on the receiver ..
- there was abit of contact on the front of the receiver lug area ... this was carefully filed away with a diamond file and then lapped with 600 grit compound to make sure surfaces were smooth



now lap the forward face just to give it some smoothness and nothing to hold back



Now... Bolt will close shut !
- i can now proceed and see what the go and nogo gauges show me ...

Go gauge :


NoGo gauge :
Click to expand...
Your an idot!
Who the hell taught you to lap a bolt?
Laz2k???
Well done cause you might as well toss that beauty of a bolt in the trash.
READ STICKIES PEOPLE!
And the only stupid question is the one not asked.
Cause this post is the reason why.
OMG!
Dude I fell for people like TT and 45king.
 
dimeN said:
the 308 win is abit different from the 7.62 nato

308 win Go gauge: 1.630" and No go gauge: 1.634"

7.62 nato Go gauge is 1.6355" and No go gauge: 1.6455" ( this reference was taken from Kuhnhausen service rifle manual )

therefore the 308 win nogo gauge is safe in the 7.62 nato ....

On the rifle i'm working on ... the plan was to shoot 308 win, as that is what i reload ... and shooting that in the nato chamber would lessen the life of the brass .. or at least thats my thought on the subject
Click to expand...
Kuhnhausen manual is only meant for experienced gun smiths to read and understand. After your bolt lapping post please attend a clinic and hold off doing what you think is right for a bit. Tell you get more comfortable with gun's and the way they work.
 
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