Mid to Long Rage Vertical displacement

[N Jensen]

I'm new to this board. I have a question for vertical displacement at mid to long range (600 to 800 yds). I have AR 10 in 308, 6mm, 6.5 Creedmoor and have noticed that after shooting 60 rounds that the action becomes more and more sticky/binding when unlocking. When this happens I see more high shots not on call. When the action is clean, the rifle is far more consistent in vertical displacement. I was wondering if anyone else has noticed this and if anyone has heard if the Army M-110 sniper rifle has the same problem.

[unforgiven]

Welcome from Indiana brother N Jensen. <dontknow>

[IowaFClass]

My first question is: Are all the rifles in the AR style platform? Are some bolt action? Have you actually tried to make up a load for each for the rilfes?

I feel there are too many varibles involved to actually give you a good answer. Sorry more than just one question

[survivalshop]

It is possible that a longer lock time, may be adding velocity or other things may be in play, have you been using a chronograph ?

By using a Chrono. , you can test the first 10 shots , then the middle & then when the action starts to act up. It might show other things going on with your ammo or the barrel .

[N Jensen]

Between being busy at work and out of town I missed the replies both of you have posted. The rifle are all LR308 rifles,  just chambered in different cartridges. I’ve chronograph the ammo and I can tell the same ammo tested worse after 60-80 rounds are fired than when the action BCG is clean. I feel it has something to do with how well the action unlocks after each shot is fired, the more constant it is the better the rifle holds elevation at 600yds. I have seen BCG that are real dirty and without lube  shoot high shots real bad but when cleaned and lube they shoot very well. I have heard the Army AMU team at Perry will sometimes put CLP lube into the gas ports to help remove/dissolve the carbon on the gas rings just before the next stage for better accuracy. I have tried this as well and the rifle does shoot better.  Putting a few drops of CLP into the BCG is simple to do every so often in a day of shooting. I was just curious if anyone had notice the same issue or not. If so, what was the solution.

[survivalshop]

I use synthetic grease or Gun Slick grease on the backs of the bolt lugs , cam pin & guide rails of the bolt carrier, also on the hammer contact area & I can shoot hundreds of rounds with out any slow down .

The heavy synthetic ( red & tacky )is for warmer climates & the Gun Slick grease ( it looks black ) is for colder climates & of course in sub freezing weather only light oils ( preferably synthetics )

There are a lot of good products out there now a days for these rifles . I also use CLP almost exclusively, but almost always with a good grease .

A little dab , will do ya ! Almost sounds like a commercial .

[N Jensen]

Thanks for he tip. Will have to try it. Right now I use outboard gear box oil the BC and in the cam area and leave the lugs dry. Until I figure out something better I will keep putting a few drops of CLP into the vent holes before each string. Today I used the 308 LR in a palma practice match.  I kept a high master avg overall, a 439-15x (800yds, 147-6, 900 yds 148-6, 1000yds 144-3X). I would normally use a Mod 70 with a 30 inch barrel and would probably would of shot a few point better overall. But considering a semi auto and a 24inch barrel it did pretty good. I just had to try it and see how it did.