Gunsmithing FN made M70: to blueprint or not?

[MYore]

I just took apart my M70 Extreme Weather (.300WM) for a new barrel. The factory barrel would throw 2+MOA with most of my loads and the best I got was just under 1 MOA... So I have a #3 Brux in the mail...

So, has anybody worked on these much? Should I true up the action or just install the new barrel? I'd be happy with a 1/2 moa rifle for what I am going to use it for.

From what I am measuring, it looks like the tenon is 1.0625-28. Sound right?

Should clarify: I am doing the work, but have not worked on a M70 before.

 

[x ring accuracy]

Re: FN made M70: to blueprint or not?

If it is apart, now would be the time to true it before the barrel is fitted. You wont be sorry

 

[Bryan27]

Re: FN made M70: to blueprint or not?

Go ahead and true it if you have the ability to do so, no better time than when you already have it apart and you're waiting on the new barrel to arrive.

 

[eddieharren]

Re: FN made M70: to blueprint or not?

None of the SC FN receivers, that I have had in the shop, required any "trueing". I guess I could have charged the customer for trueing but.......

 

[turbo54]

Re: FN made M70: to blueprint or not?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DocEd</div><div class="ubbcode-body">None of the SC FN receivers, that I have had in the shop, required any "trueing". I guess I could have charged the customer for trueing but....... </div></div>

I recently completed a build on an FN SPR, which FN "trues" in-house. When I indicated the raceway in true, the lug abutments and receiver face were running true .0005" TIR.

Good to go.

 

[cattle buyer]

Re: FN made M70: to blueprint or not?

Factory s get it right at times. This CNC stuff must be awesome. good luck with build. Im a winchester for ever guy an FN seems to be doing the design and mod 70 proud. The hammer forge barrels seem to be a crap shoot at times but Ive been lucky there as well on some 90's guns, and a couple of mid 2000 wssms

 

[matthias]

Re: FN made M70: to blueprint or not?

both fn rifles i worked on were nice and straight. i did not need to do anything on them. the biggest thing i noticed was the chamber was not concentric. i fitted a new barrel on mine in 308 and it shoots groups a bit bigger than half what it used to. spend time on the barrel not the action.

 

[MYore]

Re: FN made M70: to blueprint or not?

Thanks for responding here matthias. I was hoping someone with some experience with these would chime in.

I will probably not do it, for the simple fact that I need to get it done sooner than later for a possible trip to Africa this summer and I think time behind the trigger will be better spent than getting setup to do an action I probably wont be working with that often. I'm tooling up a cnc to do this so there is a lot of trial and error (at least for me) and tooling to make. A little bit of error with my setup and those 28tpi threads wouldn't look so good either. I was kind of thinking turning them off and opening it up to Rem dims might be the way to go anyway.

The machining on the bolt on this rifle looks fantastic and I suspect the receiver ain't too shabby either.

My barrel is due to show up tomorrow and I think I will just chamber it and start shooting. This way I can always put the factory barrel back on too if I want. I suspect a crown job on it might improve things but it just doesn't feel as nice as a cut rifled barrel when running a patch down it.

 

[matthias]

Re: FN made M70: to blueprint or not?

no problem. just like every other barrel job take your time get it right or the barrels get short quick. dont ask how i know