Help! Gun will no longer group at all!

[Bruce Rickey]

I have a Ruger 77 in 280 that will no longer group. In the past I have shot .75 moa with 100 grain hollow point and 1.25 with just about everything else. It will no longer soot a group average group no is 8" at 100 yards fliers every where. The barrel has been lapped, custom trigger, muzzel brake, heavy barrel, pillar posts, glass bedded. Bore cleaned out electronically and has no effect I am shooting 140 gr Nozler Ballistic tips and Hornady 140 grain equivalents. The same grouping happens even when scopes have been changed. I am beginning to think I have shot out the barrel but loss of accuracy happened so quick. Can any one help?

 

[Dave King]

Is this a new LOT of bullets??? A LOT that has not been previously fired through the rifle.

 

[LB]

Did you check, and did you trim to length?

 

[STL_Shooter]

Maybe you should try reaming flash holes on a lathe or adjusting your seating depth in .0000001" increments using the bifurcated ladder method. Try shooting only due east or west to minimize coriolis force...

Seriously, though.

8" groups at 100? Something's loose or the bullet is hitting that new muzzle brake on the way outta town, sir.

[ 08-18-2004: Message edited by: STL ]

 

[SeniorSendero]

Stop drinking. Your seeing double and your picking the wrong target.

Ronnie

 

[4ked Horn]

I agree with all the above tips.

I assume that you have looked down the bore with a good light at the other end. If you havent then I suggest that you do. I knew a benchrest shooter that suddenly got rotten groups only to find that the rifling had all but dissappeared in the bore. He blamed the polishing compound he added to the corncob media in his case tumbler. He thinks that it coated the inside of the case and made a goopy mixture of corn cob dust that abraided(sp?) the bore with each shot.

It might be a crap story but dosent hurt to look.

You also mentioned that you have a new brake. Did the group open up immeadiatly after the install? If so it could be a burr on the muzzle.

Lastly have a friend shoot the same ammo from your gun and/or from their gun. This will tell you alot about the problem being the gun or the ammo or you.

2 cents.

 

[Fiftydriver]

Ambush,

If a rifle came into my shop that was a know 3/4 moa rifle and then after this work you listed shot into 8" groups I would first and formost look at the muzzle crown.

About the only way to go from 3/4 moa to 8" groups is either a loose scope ring, loose action screws or a damaged crown.

What brake was fitted to the barrel and was it recrowned after the brake was fitted?

Who did the extra work on your rifle?

More information is needed.

THis problem is far to severe for a loading problem, you have a mechanical problem with the rifle somewhere.

Good Shooting

Kirby Allen(50)

 

[Guest]

trash it and get a remington...

check out the action screws... scope bases and rings... scope may have taken a crap on you... several leups sent back for misbehaving... check out your primer pockets as well.. did this happen over night or a progression? throat may have taken a choke on you... check em out, might help...

 

[chessman]

It might be caused by all the things listed above...........or not. I shot the barrel out of my old tried and trued commercial Mauser 98 in 30-06. Sounds just like what you are describing. Groups were tight, then started to have a wild shot or two now and again that I figured must have been me. Then all at once it started shooting 5" groups. I went nuts trying to fix it. It must have been the powder lot, of primer lot, or.......

Then it must be that the scope went south, so I swapped scopes.........

I don't know how many times I had it apart and under the scope looking at every detail. That rifle got a better cleaning than any rifle ever has - several times, and nothing changed the group one bit. I confirmed that it wasn't me by printing sub-moa groups with my other rifles.

Look at everything everybody else has recommended - all of these things can affect the groups. But in the end, you may be right that the throat is eroded badly enough to cause what you are seeing. The .280 isn't as bad as some about burning barrels, but it does hold enough slow-burning powder to erode the throat faster than some other calibers.

If you like the Ruger, then keep the Ruger. Your accurate rifle didn't just become inaccurate because it just discovered that it said Ruger on the barrel. I've had my butt kicked in competition with rifles and calibers that I wouldn't have given you ten cents for before the match. The proof is in the shootin'.

 

[Mysticplayer]

Review what and how you loaded your ammo before. Look at the bedding, stock for cracks, any looseness in bases/rings. See if the barrel is hitting the stock now - wood stocks will shift over time.

Review your shooting technique and see if you shoot as well as you did before. Have you changed any lots of components?

By looking at all the little steps, you can quickly decide if the barrel is shot out or not.

Another quick test is to measure runout of your ammo. Dies do wear out. Also measure the throat and see if the bullet must clear the neck before engraving the rifling.

If either of these occurs, you will need to remedy.

Jerry

 

[Agunner012]

I think it has something to do with the brake. Maybe the barrel harmonics are messed up because of the brake. How does it shoot with the brake removed?

All good advise is posted above. Did the gunsmith have a look down the bore with a bore scope? Could be the barrel bit the dust too, in which case I would re-barrel with a Lilja.

Good luck,

Andrew

 

[james_ogburn]

It really sounds like a scope problem to me. Take the scope off, tighten everything, and put a known good scope on it. If it still is shooting 8" groups at 100 yards, try to straighten the barrel out with a large hammer and see if that helps. But, check that scope.

 

[EXPRESS]

I had a similar problem recently and found, after checking and verifying everything you would normally check, that the barrel was actually loose in the reciever.