I'm looking at pruchasing a PTR-91 Which model is prefered? The KFM4 with the 16" barell with forward hand rails or the F model with the 18" barell and no forward hand rails? Which one will be more accurate at longer distances? I already have a S&W AR17, Rem 870 and a Mini14 and S&W M&P 40SW pistol. Just looking for that final addition to round out my SHTF collection. Thanks for your help.

I originally wanted the PTR MSG model for (long range shooting) with the adjustable stock, rails, bipod, etc., but it was not available. So I did the next best thing and got the PTR-91 with the 18 inch barrel and the tactical handguard for about $500 dollars less. I've put about $200 into it by adding a Harris bipod, YHM bipod mount, a PTR three inch rail to mount the bipod and the MFI low profile rail for a scope. I like the original stock just fine, so I saved myself $300 by going this route. The 16 inch barrelled model didn't appeal to me b/c I have carbines that fit that role much better than a heavy, hard-kicking 308 rifle.

I just got the standard 18" PTR91 (I think it's the "K" model)

Love it!    I added a H&K wide forearm with the bipod and a carry handle.

I would get the 18" version, then added what I want after I figured out what I like=cheaper  The rails and all the do-dads might look cool, but on that rifle they are not need/add too much weigh and serve no goo purpose

YMMV

There is another section under armory for just HK guns, you'll prolly get better respones in there. The mods might move it anyway.