Gunsmithing PTG One Piece Bolts and Timing

[aaronk]

If one were to buy a trued R700 action could you throw a PTG bolt in it and not worry about the primary extraction needing tuning/timing?

 

[LRI]

If one were to buy a trued R700 action could you throw a PTG bolt in it and not worry about the primary extraction needing tuning/timing?

It all depends on who does the BP and how much they peel off the lug abutments. Minimal strategy being the optimum.

 

[aaronk]

It all depends on who does the BP and how much they peel off the lug abutments. Minimal strategy being the optimum.

Glad you chimed in, because it was your blueprinted receivers for sale that prompted the question!

 

[LRI]

Glad you chimed in, because it was your blueprinted receivers for sale that prompted the question!

We probe the lug face and put a .005" offset to the tool height. Long/short of this is that from the face we probe off, .005 gets peeled off. That's the "go to" for any late model RR prefix serial number. On the older 40x's and some of the fringe stuff we see, or stuff that's been previously molested, it can vary. I think the most I've ever had to go is around .015".

Fooling around with this has a big influence on Primary extraction. A .001" on the lugs cascades to a significant amount of rotational change from where the handle did hit compared to where its going to after the machine work. The RR's being the most affected. It's why we push hard for folks to let us time/tig the handles. We build up the cam surface on the handle with weld and machine it with "advance" built into it.

PTG's handles on the true one piece bolts don't do too bad of a job when they are made right. Years ago when these first came out David consulted with me about it and I just asked him to leave some "fat" on the back side of the lugs. That way a guy could buzz the bolt in a lathe and fit the bolt to an action that had already been barreled. It seemed to work pretty well. Hell of a lot easier than pulling a barrel to chase a shoulder or cramming a tool down the chamber to alter H/S.

Have not fitted one of these up in quite awhile so I can't say if its still done that way.

Hope this helps.

C.

 

[carlsbad]

I've installed a lot of them lately and the primary extraction has been excellent in all of them. A couple were too tight and needed work to close. That's why PTG says that they aren't "drop in". Also, sometimes the lugs need to be lapped into the rails. I buy them oversize and ream the boltway.

I haven't seen an R700 action made lately that needed more than .002" to clean up the lugs.

--Jerry