Accuracy problem after barrel threading

[RingSteel]

I would swear it was a loose screw or something broke, but I found noting of the sort.

This is a long shot, but could your front scope base screws be too long and actually bottoming out on the barrel threads? They'll torgue up just fine like that, but the base will still have some wiggle room. Just a thought.

[txfireguy2003]

This is a long shot, but could your front scope base screws be too long and actually bottoming out on the barrel threads? They'll torgue up just fine like that, but the base will still have some wiggle room. Just a thought.

I don't think so, it's exactly the same parts that I took off before sending it off to be cut. One thing I did notice when I pulled the base before sending it off, it has wear spots on the action under the base, which tells me that it, at one point before I sent it off, shifted under recoil. Maybe it's just shifting until it finds a spot to settle. If things don't get better, I'm going to replace the base with a steel one that has a recoil shoulder, and I'm going to bed it to fit the action better.

[Coach W]

I don't think so, it's exactly the same parts that I took off before sending it off to be cut. One thing I did notice when I pulled the base before sending it off, it has wear spots on the action under the base, which tells me that it, at one point before I sent it off, shifted under recoil. Maybe it's just shifting until it finds a spot to settle. If things don't get better, I'm going to replace the base with a steel one that has a recoil shoulder, and I'm going to bed it to fit the action better.

I think that's your problem.. if it moved before and you've done absolutely nothing to ensure it doesn't move again. . Then what's keeping it from doing it again?

This problem has all the symptoms of scope malfuntion/mount problems.. if you suspect the mount change it.

[txfireguy2003]

Yeah Coach, but the groups never were bad before. The ONLY indication of movement, is the finish wear under the pic rail. It's an EGW 20 minute aluminum rail. I pulled it off last night and reinstalled it. I've heard differing opinions about thread locker on base screws, but I use it, so I torqued the screws back down using blue Loctite. The rings are Warne QD, so I'm thinking they are not my problem, they are about as solid as any rings I've ever seen, and the stainless steel recoil block in them is WAY better than the cross bolt my old Vortex tactical rings had (which damaged two aluminum rails btw).

[kcnatural]

Do you have another stock or maybe a friend with a better stock you could put the action in and try it. Torch it to spec and try that to see if it holds. I would clean the barrel and take it out again to see if it performs the same before changing anything. Take the torch wrench to the range and if it starts to open up re-torch and try it again. I agree with you that you should bed the rail. I always use 1 piece steel rails but if your is aluminum on a 308 it shouldnt be a problem. This may be a dumb question but does your scope have enough clearance over the barrel? Hope it works out there is nothing more frustrating.

[RevMS]

Not sure if you said it upstream (didn't see it as I scanned the tread) but what caliber is it and what thread did you have put on it?

[txfireguy2003]

Yeah, scope has 1/4" clearance. I'm going to be buying a new stock soon anyway, just may be sooner than I planned.

[txfireguy2003]

It's a 308, threaded to 5/8-25.

[txfireguy2003]

maybe it was shooter fatigue? I would check all screws on bases and scope mounts and action screws again. I hate hearing this because i have a 308 i would like to cut and thread. I'm now thinking maybe I'll just thread it and not mess with the crown.

Possible, but I don't think so. I will say this, it's just a 308, so nothing major, but the recoil is noticeably harder with 6" less barrel.

[kcnatural]

I bought a 700 aac sd in 308 last year it was a 1 minute gun with the hogue stock after I opened the channel up. I took an HS precision off another 700 I had and put on it . Now it shoots .25-.5, stocks touching the barrel are a no go for sub minute accuracy.

I had a custom 300WM built in 2010 that was not as accurate as I thought it should be. I took it to the range got it in my shoulder and loaded the bipod and had a friend check the free float. sure enough barrel was touching about 2-3" back. Now it puts them in the same hole if I do my part. It weighs 18 pounds so you don't notice your heart beat so much in the cross hairs.

[dclifton]

Is it the hogue stock??

If so when you had it rested the first time maybe the stock wasn't touching. Then when you re-positioned to shoot another group it started touching? Shifted on the rest or bags maybe?

[dclifton]

It's a 308, threaded to 5/8-25.

5/8-24 i hope.

[txfireguy2003]

Yeah, that would be a typo. I will say, the thread are TIGHT! I put an A2 flash hider on it for the time being, just to protect the threads, and it went on fine about 1/2 way, then required a wrench, but it's not cross threaded, just real tight.

Not the Hogue, but not much better. Think SPS varmint, without the bottom metal.

[RevMS]

It's a 308, threaded to 5/8-25.

Then the thread size shouldn't be a problem. The standard thread on a 30 cal is 5/8-24, I'm guessing your 5/8-25 is a typo. Problems can happen if you use a smaller than normal thread. If the barrel wall thickness in the muzzle area is too thin you can get an expansion of the barrel diameter near the crown, and reduced accuracy.

(edit - I see I got beat to the punch on catching your typo )

[RevMS]

... I will say, the thread are TIGHT! I put an A2 flash hider on it for the time being, just to protect the threads, and it went on fine about 1/2 way, then required a wrench, but it's not cross threaded, just real tight. ...

The fact that it's so tight MAY mean you're introducing stresses that could impact your accuracy. Maybe have the threads chased with another 5/8-24 die and see if the excessive tightness clears up. Just a wild guess idea.