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Guys I am looking at getting a ptg bolt body for my build. The research I have done on it is two sided. You guys that have used them before, are they a direct bolt on or is there machine work involved? Some things I read say a simply swap and others say they have had to mill them down, so what the deal with them?
I am going to take a shot at this but honestly don't know for certian. The milling down probably has to do with the primary extraction. On the end of the bolt there are two reliefs cut at 180* from each other. This locates the bolt handle and establishes the primary extraction ramp engagement and timing. Not hard to fix if you are handy.
direct on... nothing needed but finishing "blueing"
also, buff up the cocking ramp...
i had this 1 nitrided
http://i.minus.com/jFGVY0U8egpPB.jpg
Definitely want to recheck with your go/no-go gauges to make sure you are still in spec.
I've got one on my 260 Rem. I had it cerakoted and should note that it is a good fit. There won't be any slop and with that being said, depending on how you rack the bolt, it can get "stuck". Slow and smooth doesn't have issues, but fast and furious will sometimes cause it to bind. Probably wouldn't be an issue if not cerakoted, but even as thin as cerakoting is, there isn't much play in the first place.
I know that I am an amature but can someone please explain how changing a bolt body effects the headspace?Quote:
Definitely want to recheck with your go/no-go gauges to make sure you are still in spec.
I would NEVER assume that each bolt body is made the same. Your moving from a factory bolt body to a precision machined bolt body. It doesn't take much to change headspace.Quote:
Originally Posted by stangfish
I guess you could just see if a round chambers properly, but suppose the bolt body was shorter, then that wouldn't be a good gauge of headspace.
Quote:
Originally Posted by capreppy
The head space is off the bolt head not the bolt body. The only way (if you have the proper head space to start with) you could change head space would be too long a bolt body and then the headspace would be correct when the weapon is fired due to the bolt lugs being forced back against the action lugs. Hence you can not get too much head space unless you change the bolt head. The head space changing after changing the bolt body is a remington, mauser ect.. thing due to a solid body and head design. Notice Remington is going to a floating bolt head.Quote:
Originally Posted by stangfish
Earl39 :cool:
The reason being is that if you use the action lugs as a datum then the distance between the bolt head face and the rear of the bolt head is what determines the headspace. The bolt could be 47 feet long and as long as you use the same bolthead it does not matter.
Stang thats right. the shorter head space would be because when you lock the bolt down the cut in the tang holds the bolt forward and that is the only way headspace would change but as i said when fired it would be correct cause it would push the bolt head back against the lugs. We are on the same page at any rate. Now if we could just get all the remington fans to understand that a savage just ain't and don't want to be a remington.
I have one for a short action and tried it on 4 actions before I found one it fit. On the first 3 when you closed the bolt and pushed the handle all the way down it would trip the trigger, after talking to the engineer at PTG he finally told me to send it out to him and he would try it in one of his. I tried it in one more of mine, a 16 action and it worked perfectly. After several conversations with the engineer we determined it may well have been the cocking ramp wasn't deep enough.
Actually, in our case of Savage & Stevens, changing a bolt body COULD vary headspace. Not due to different length, but, the PTG is probably held to tighter tolerances. May actually be more square with the world, and may change where the bolt lugs contact the receiver. Could vary timing as well.
Quote:
Originally Posted by dcloco
I think you pose a valid point Ddcloco. I Like the cautious COULD as well. I would have to see it to believe it. I might buy it as an exception but not a rule. In any event it would make it shorter not longer.
stangfish - yep. Could. Because the bolthead is pinned to the bolt body, all three axis are at work here...so, there could be a variation in one, two, or three. Who knows which bolt body was machined to correct dimension for this receiver/bolt head?
My statement, was looking at it from the contact of the bolt lugs to the receiver and what arc the bolt body would close the bolthead in relation to the receiver after new bolt body was installed.
Far out there? Probably, but, unless a person is set up to measure, it would be hard to know for sure.
So, what would I do? Blacken the back of the bolt lugs, open and close with original bolt body (multiple times), take pictures, blacken again with a trusted SHARPIE...and open/close multiple times with the NEW bolt body. Compare the pictures.
The above is what I do with EVERY action. I lap Savage bolt lugs to the actions as well....while the barrel is off. Made a barrel stub, with a spring and steel ball (centers on the firing pin hole), apply favorite lapping compound (non gel toothpaste works in a pinch), increase tension on bolt face by turning barrel stub in, and have at it. When satisfied with lapping, clean, then clean again. :)