Adjusting primary extraction

Hello all !

I was wondering if anyone else has tried to adjust the primary extraction dimension as described by sharpshooter in this thread http://savageshooters.com/SavageForu...p?topic=3429.0

I'm currently working on tuning a Stevens 200 243Win. I've trued the front receiver ring and barrel nut in the lathe, and taken a very small cleanup cut off of the bolt head locking lugs. After swapping out the bolt handle for a SSS tactical handle the primary extraction distance dropped to about 0.049" - just below the 0.055" quoted by sharpshooter. I don't blame the new bolt handle for the change, the original handle had a 'bird dropping' of a slag or casting protrusion right on the extraction ramp that added about 0.025" to the extraction dimension.

Anyway in an attempt to correct this I tried to shorten the bolt body by putting the body in a spin/index fixture in my mill with the intent of shortening the bolt body by an appropriate amount, however after trying a 5 thou test past it just dulled my end mill ::) Turns out the bolt body is harder the the hubs of **** ! I assume the hardness is for the cocking ramp.

So if you've shortened your bolt body to correct the primary extraction, how did you do it ? I'm considering chucking up a small grinding stone and trying my same setup and taking it off a thou at a time or so ...... I'm not relishing the idea of getting grinding dust all over my mill. Yeah I can cover up the table and slides etc, but I thought I'd ask if anyone had a better way ??

My other options would be to remove the material from inside the bolt bore ( I really don't want do this ), or to pull a Bubba and grind the back of the bolt body by hand and eye on a bench grinder. :o

I hope someone has a better idea :)

Take a look at the lug ramps and when the extraction can take place. You most likely have lots of room to correct but it would be wise to check. The other thing to worry about if you remove material off the bolt body end is the clearance of the bolt handle and the action. Same senario when you take some off the bolt head just the other direction. I deburred the bolt body on one after cleaning up the handle and used the drill press with a diamond dremel disk. Depth stop and cross slide vise, not that its needed but it was easy. Grinding dust on a lathe or mill makes me shiver.

Thanks for the reply Rob !

To check how much I could remove off of the bolt body, I put progressively bigger feeler gauges between the rear baffle and the receiver while opening the bolt and found I could could remove up to about 0.025" before I started to run into any binding of the locking lug ramps.

I like your idea of using a diamond wheel for the bolt body. I suppose I could rig up something to use on the drill press, but I prefer the precision of the mill. I guess I have to figure if I can protect my mill well enough to do the job without causing harm. Like you, the thought of grinding dust on my machines gives me chills. :)

Now if'n ya wanna cheat......

I only done this once ,wasn't my rifle and didn't think of taking pictures, but...

You'll need a drill, tap and two 6-32 or 8 -32 set screws an 1/8" long. (I used brass). Drill and tap each side of the rear baffle as close on horizontal center as you can get (careful of the detent ball on the right side) deep enough for the set screws to turn in flush. Start with a starter tap and then a bottom so you can go only as deep as necessary. Apply some 242 (blue) Loctite on the threads then run the screws in flush. Now setup the action, measure the PE and adjust the set screws out equally on both sides. You can do that by trail and error or by an actual measurement.

It accomplishes the same thing as shortening the bolt body by allowing the lug on the bolt handle to contact the PE cam earlier. It also eliminates the possibility of having to modify the notch in the action for the bolt handle if its moved too far forward and in the future if a new bolthead or bolt handle is installed it can be readjusted or the set screws removed if need be.

Bill

Bill

Thanks BillPa,

That certainly is an option. My bolt handle currently sits in the back of the receiver notch with about 0.005" of clearance between the back of the bolt handle and the receiver, so if I shorten the bolt body it will center it in the notch properly. I'll reserve the option to use your set screw method of adjustment, but I think I can pull off shortening the bolt body. Right now I'm just soliciting ideas ;D

Has sharpshooter ever talked about how he accomplishes this adjustment ?

Yeah, Fred mentioned shortening the bolt body to move the handle forward. Thats the reason I used the set screws on that action, the bolt handle was close the forward side of the notch to start with. Rather than get into a bunch of grinding, the screws seem a better "fix" in that instance. The guy have been shooting it for two years without a hitch, so I guess it worked out.

Of the 16 actions I have only one was bad off, too much (early) the lug on the bolt handle was gouging the PE cam. I re-cut the cam on that one. About the only time I worry about or check them is if a problem shows up.

Bill

Have'nt you guys heard of CARBIDE endmills??? The case runs about .015" deep, after that it is softer.

Quote:

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Originally Posted by sharpshooter

Have'nt you guys heard of CARBIDE endmills??? The case runs about .015" deep, after that it is softer.

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;D Guess I'm a cheap SOB ! I'll pick up a carbide end mill and try again, Thanks Fred :)

I must confess the mill I use on occasion isn't in my shop. :'(

Otherwise yes, my lathe tooling is kennametal. A bud gave me a bucket full of various solid carbide bars, many with coolant through.

Cheers

;D
I just thought I'd update, the carbide end mill worked perfectly ! Primary extraction now at 0.076" . Here's a photo of the setup for milling:
http://i194.photobucket.com/albums/z...Image00001.jpg

And here's a photo the end of the bolt body after milling:

http://i194.photobucket.com/albums/z...Image00002.jpg

I have to say, this site is a great source of information !

;D ;D ;D

Thanks for your link to this post. Here are pictures of the shims that I installed. 0.031" inch. Works great.

Shim on rear baffle
http://i759.photobucket.com/albums/x...ofDSC_2241.jpg

Shim up close
http://i759.photobucket.com/albums/x...ofDSC_2242.jpg

This is the link back describing what I did.
http://savageshooters.com/SavageForu...html#msg237727

I didn't know it was even called primary extraction. I might have found this in a search if I knew that.

Cheers