Gunsmithing Anyone have a junk FN SPR action?

[turbo54]

I know its a long shot, but Im hoping someone might have a junk/trash SPR action I could have/buy for a nominal fee? It doesn't need to be complete, and sawed in half would be just fine (better, actually).

I'd like to have a material analysis done on it to determine alloy and heat treat. My primary motivation is to learn if melonite is safe.

I would gladly share any info I learn.

 

[BiggerStick47]

Re: Anyone have a junk FN SPR action?

I doubt you'll find an action, but you might be able to talk one of the guys who does bolt mods on them to send you the scrap piece they cut off the bolt handle. Might try Hooper here on the Hide.

 

[turbo54]

Re: Anyone have a junk FN SPR action?

Interesting thought.

Not sure I'd be comfortable with analyzing only that piece.

I've noticed SPR actions have a ring of discoloration just rearward of the "front ring" of the receiver, that I believe is an artifact of their heat treatment...meaning I suspect the entire receiver isn't treated homogeneously.

I think I'd realky need to analyze a piece from both the front and rear rings, as well as the bolt...

 

[BiggerStick47]

Re: Anyone have a junk FN SPR action?

OK, makes sense. Well good luck!

 

[hero's machine]

Re: Anyone have a junk FN SPR action?

If you could get the material spec on the action, a metallurgist can likely tell you the results and save you the scratch.

 

[turbo54]

Re: Anyone have a junk FN SPR action?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hero's machine</div><div class="ubbcode-body">If you could get the material spec on the action, a metallurgist can likely tell you the results and save you the scratch. </div></div>

Any suggestions on finding that information out? Other than asking FNH, I can't think of a way...and I've tried that. They would give <span style="font-weight: bold">ZERO</span> indication.

You're right though. If I knew the alloy, a couple pings with a hardness tester would indicate heat treatment used. A hit or two on C scale, A scale and 30N would tell all.

 

[turbo54]

Re: Anyone have a junk FN SPR action?

It's *probably* 4140, but I am not going to bet my face on it.

 

[hero's machine]

Re: Anyone have a junk FN SPR action?

You could also spark test it on the bottom. My local spring shop has a hardness tester.

I will have to look into the melonite treatment application, I used to work in heat treatment of various metals, but have never looked at melonite.

 

[Jonathon Scott]

Re: Anyone have a junk FN SPR action?

It's the same as the model 70, they are zone heat treated around the lugs on the front ring and the cocking cam on the rear bridge.I'm pretty sure the material is 4140 but I'll ask someone who would know to be sure.Still any good heat treater can test the material without destroying it,if they couldnt I would not let them touch my action.Bad heat treating and firearms dosent end well.

 

[Sup]

Re: Anyone have a junk FN SPR action?

If you want to really get into it you find a local Inspection Company or NDE lab that has a PMI gun in house. All you need to do is file off any coatings to bare metal and have them take a reading, the PMI will tell you what the exact chemical composition of that piece of material is. Then you could have them hardness test it with something such as an Equotip (don't let them use a Teller style Brinell bar system) to give you multiple hardness readings in either the Brinell or Rockwell C scale.

Thats how I would go about it, but I have access to all above mentioned equipment.