I just put my NF scope back on my gun after a trip to NF for a tweak. After torquing the scope down, I grabbed the barrel wrench that breaks at ?? lbs. Cant remember how inch or ft pounds. But I felt like the cheap wrench that comes with didn’t break, it just tightened the shit out of the screws.
Don’t those little black wrenches with L handle on it supposed to break? What pound do you torque your MWS barrel in at ?
I kinda stripped the screw in process to boot. Hit me with your thoughts.
PB
Hey brother, I don’t have the new smaller styled torque wrench like the one you describe I believe, however the torque value hasn’t changed since IIrc late 2004 or 2005 with regard to the torque amounts. This is true for both MRPs and MWSs. The spec is 140 inch pounds whereas in the very beginning it was 90 inch pounds.
The following pic is from my MWS manual even though it says MRP…
I have many of the older much cheaper styled t wrenches that have been set, tapped, and signed. They were notorious for going out of spec, and people never hearing the snap of the torque limiter engaging. Ask me how I know:)
Your lucky you got off with a little stripping of the bolt, the designed function of these specially made bolts is shear or snap at certain over amount of torque to protect the chassis. They will break way before your chassis incurs damage.
I honestly just tighten them down with a t handle now by feel. Most other long time MRP MWS owners I know do the same.
All torque wrenches that I know should indeed snap or break once they hit the assigned torque amount.
Thanks Brother, good to hear from you. Ugly snapped bolt.
PB
Yes they are suppose to “break”. I keep 4 bolts for just in case. Notify LMT of what happened, they may send you replacement bolts. If you need it, here is the online downloadable manual, page 25 is barrel removal. https://lmtdefense.com/media/2017/10/LMTMRP-Operation-and-Safety-Owners-Manual-F.pdf
I can’t remember where I read it, but I recall that the 140 in/lb spec was mainly (only?) for return to zero. Is my recollection off, or is this true?
what do you mean for “return to zero”?
Referring to a barrel, once zeroed in the upper with whatever sights/optics installed, could be removed, then reinstalled, and the barrel, upper, and sights/optics combo would still be zeroed. I don’t remember where I read this, it may have been an article by Eric Poole a few years ago. It wasn’t a perfect return to zero, but really close, and the specified torque was to achieve a consistent fit of barrel to upper for this purpose.
Is “return to zero” the correct phrase for this concept?
I don’t think incorrect. But the same inch pounds should be used if changing caliber barrels or getting a new barrel. The inch pounds is broader than return to zero but in the end. It’s just semantics, I just wasn’t sure what you meant.
It’s all good
I hoard old gun mags, I’ll look through my collection for the article, to refresh my recollection of what was written.
I have a pretty large collection of gun magazines featuring anything MRP/MWS related so I decided to dig into bin for that information…
I found two different magazines with articles written by Poole, the first was for COMBAT ARMS 2010 titled "First Look L129A1 BRITS CHOOSE LMT .308. This article didn’t mention anything about barrel swapping, etc.
The second one had a small that hinted at what you are referencing, it too is for COMBAT ARMS 2012 titled LM8 “KARL LEWIS GIVES YOU MORE OPTIONS”…here is the text that references the barrel changing portion.
Here is post his personal results/test
It’s from the magazine on the right:
Here is my own test from some time ago with regards to torque amount and RTZ…
Trident, my gun mag stash also is mostly MRP/MWS related. I recognize that cover, I’ll be re-reading that, and others, because of this thread.
I’ve always said that gun mags are better than porn, because gun mags show stuff that I already got, or I’m gonna get, unlike porn:o