Action screws came loose

Discussion in '308/ 7.62 MVP and Variants' started by boostless, Mar 17, 2017.

  1. boostless Active Member

    Member Since:
    May 5, 2014
    Message Count:
    189
    Has anyone else had a problem with their action screws? Went to the range today with my buddy and looked over my rifles when I got home and the action screws were loose. I know for a fact that I have tightened them since having the rifle. I torqued them down to 55 in/lbs on the front and 50 in/lbs on the rear, guess I'll have to keep an eye on it from now on. The mags started dropping loose today as well and I'm wondering if this could have been caused by the loose action, if anyone has any insight on this I'd love to hear it. I currently have about 250 rounds through it and shot 117 today. I added a muzzle break earlier this week as well.
  2. spamassassin Well-Known Member

    Member Since:
    Aug 8, 2014
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    All the time with various guns, always the ones that I didn't bed properly.

    If it becomes irritating try a dab of blue loctite and back off on the torque. 55inlbs is almost certainly way too much but I can't be sure because I don't recall which stock or mag well you have. Normally on composite or wood stock without metal pillars I'll do no more than 35inlbs BUT that's only if there are metal ferules in place to prevent stock deformation. With a plain wood stock without pillars or ferules then finger tight and 15inlbs is as high as anyone should go. If it has proper metal pillars then no more than 45inlbs. For metal v-type mounting blocks and most chassis stocks 65inlbs is appropriate.

    Action screw torque specs are there to provide a baseline for laymen owners who wanted a standard to use and are not sufficient for the purpose of applying torque to a shear load fastener. Smiths should know a bit more about how tight is tight enough and why friction load attenuates shear loads. Laymen probably won't. Pro-Tip: Because of what the purpose of torque on fasteners is you'll never get enough preload on them in a non-metal rifle stock to be "correctly" torqued without completely destroying the stock.

    For stock screw torque, consistency is usually more important than pounds. A certain amount of harmonic tuning can be done but it's best to just bed the gun if that's becoming an issue.
  3. boostless Active Member

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    May 5, 2014
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    I have the tan wood patrol stock. I usually go 15-20 on wood and plastic stocks. If it has some sort of metal pillar system I usually go 45 and up. There was red lock tite on the front screw but not in a location where it would have benefited anything. If it comes loose again I'll drop down the torque and throw some lock tite on.
  4. GrocMax Active Member

    Member Since:
    Jun 12, 2014
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    138
    Torque tuning for groups with the rear screw on an action in a decently bedded, free floated barrel stock almost always works. Sneak up to like 50% of recommended torque on both, then front screw to your 25-35 lb/in, then step the rear screw up by 2-3 lb/in per group while shooting 3 shot groups with a known good load. You will find a torque range on the rear screw it likes, above and below it won't like, groups shrink up just like load dev charge weights. In my experience rear torque of 60%-80% of front is usually the range it likes.

    Stocks that put a small pressure strip on the bottom of the barrel within the forearm, rear screw torque will have a pretty large influence on POI.
  5. boostless Active Member

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    May 5, 2014
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    Got back out to the range yesterday and I noticed the screws were loose at 40 rounds. Got home and put some loctite on the screws, hopefully that'll hold.
  6. boostless Active Member

    Member Since:
    May 5, 2014
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    Well got out to the range again. Screws still came loose. I'm thinking that the front action screw is too long, so I'm gonna grind it down.
  7. GrocMax Active Member

    Member Since:
    Jun 12, 2014
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    If it was too long it would prevent the bolt from rotating into battery/out of battery or stroking. Overtorqueing may have stressed/collapsed the soft bits, now it keeps going deeper. Look it over close.
  8. boostless Active Member

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    May 5, 2014
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    On the 7.62 models it tightens down to the barrel threads not the bolt lug area.
  9. spamassassin Well-Known Member

    Member Since:
    Aug 8, 2014
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    BTW, be aware, the factory screws for the scope bases and the action screws are apparently often too long. Mine were impinging on the barrel tenon. Almost cost me a lot of money. Did cause a lot of back-out issues till .020 was buzzed off off the offenders.
  10. boostless Active Member

    Member Since:
    May 5, 2014
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    I'm gonna try trimming it down once I get some time to play with it. My work load for school is piling up so that's my main priority and the range I mainly go to is closed til August so no huge rush.
  11. boostless Active Member

    Member Since:
    May 5, 2014
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    So I got the front action screw trimmed down where I don't think that there is any more unwanted contact on the barrel tenon.

    Something has been on my mind recently and was curious about. Has anyone bedded the recoil lug area on these rifles? I don't really want to sink a lot of money on an aftermarket stock since I like it the way it is and it's really just a range and hunting rifle. I'd still like to see someone make a magwell for the 7.62 models.
  12. spamassassin Well-Known Member

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    Aug 8, 2014
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    I bedded the lug fully on my LSS stock. Seems to have helped with the random flyers.
  13. boostless Active Member

    Member Since:
    May 5, 2014
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    So I got bored yesterday and was doing some tinkering with my rifles. I decided to bed the recoil lug on my MVP. I trimmed a little bit, really just enough to get the paint, off the recoil lug inlet and mixed up some JB Weld. I pulled it out this morning and it doesn't look like the lug was contacting the stock. Hopefully this will cure my screw coming loose. I put it back together with some blue loctite and torqued down to 45 in/lbs. It might be a while until I get back out to shoot to test the results.
  14. entrepreneur1969 New Member

    Member Since:
    Aug 18, 2016
    Message Count:
    5
    I believe you will like your results with bedding the recoil lug. I have a MVP 223 and made several improvements to my factory rifle. I have a write up in Modifications My MVP 223. I always bed the recoil lug no matter the material the stock is composed.
    The recoil lug has to fit snug to take the recoil strain off the action screws, and other parts of the assembly. My 2 cents.

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