Glass bedding job gone bad

[trg42wraglefragle]

Hi all,

I recently tried ti inprove the accuracy in my Tikka T3 sporter in 223 by free floating and glass bedding it, sadly though I had tbe opposite effect.

It used to shoot Hornady training ammo under .75moa all the time, and would often be close to .5, but I thought Id see what more accuracy I could get.

Thankfully I bought a second hand synthetic stock for it, I generously free floated the barrel taking off the pressure points the stock had. A friend helped glass bed it, he had done 3 rifles in the past with good success. But I shot the rifle this weekend and it would shoot 2 or 3 shots extremely well, like clover leafs, but tben throw a few to the left about 4" or 5" at 100yards. I checked action and scope bolts and screws and im very certain the scope is good, as it was before i took it off to bed the rifle.

Can anyine make some suggestions on what may have gone wrong?
I didnt bed the first few inches of barrel, as the stock design wouldnt have made that easy, but I wouldn't have thought itd make this much difference. I have read that perhaps sporter barrels need pressure points on the forend, is this something i should try?

Im going to put the original stock back on and test tbe rifle to rule out possibility of my bedding job, but wouldn't k ow where to begin if i wanted to fix tbe new bedded floated stock.

Any advice would be much appreciated

 

[mulespurs]

Bedding adjustment

You can easily put pressure back on the barrel any place you would like with some hard cardboard shims for instance. You can experiment to your hearts content.
First I would doublecheck your free float job by running a dollar bill or similar down the barrel. I had a rifle that would string its shots sideways in a ten shot string. The barrel was touching the stock on one side only.
After a glassbedding job and freefloating the barrel it quit stringing shots and has mantained zero for over 15 years.
I had a string of 7 dead crows in a row at 225 yards till I botched a shot with that rifle.

 

[HiBC]

I have a fwt bbl 257 on a mex mauser that generally keeps 3 shots on the orange diamond of a sight in target at 300 yds.
All of the bbl is free floated.

I made steel pillars the right length to allow the guard screws to tighten on the pillars while still allowing .025 or so clearance on the mag box.

I sleeved plastic bushings around the barrel so it would center in the barrel channel.

I clearance the holes in the stock for the pillars so I could glass the two pillars and the recoil lug area with the receiver completely relaxed.Everything else was clearance.

Then I bedded the rest of the receiver,with the pillars and recoil lug being "in charge",but no flex or strain being applied to the receiver when the guard screws are snugged up.
IMO,its quite critical that tightening the guard screws not flex the receiver.

Its also important the guard screws not bear on the stock.Some stray epoxy can cause that.

My belief(which could be wrong) the foundation the barrel rests on is the shoulder and receiver face.If that foundation is true and solid..if there is no rattle,then IMO,"stock dampening",while it MAY have some benefit,at times,introduces a whole new set of variables.Sling tension,for example.

Once again,I could be wrong,but if you need to bed the barrel shank,it may be that the barrel/receiver joint is not sound,so the stock is used to pre-load the slop out.
I'm an amateur,not an authority,but think over what I offered.

 

[Nathan]

Often lighter hammer forged barrels need tip pressure. Wrap tape aroun the barrel at the tip, until it shoots. When it shoots, you know how thick to make the epoxy at the tip.

 

[tobnpr]

A bedding job can look beautiful- but if the receiver was stressed when being placed into the epoxy bed, the end results on paper can be less than desirable.

Thankfully I bought a second hand synthetic stock for it, I generously free floated the barrel taking off the pressure points the stock had.

I'm not clear on this...the stock you're referring to above (that you used for bedding)- was this another, identical T3 sporter stock? What I'm getting at is, if the factory stock had a pressure point for the barrel- and you eliminated it- that's obviously the first place to look as the source of the new problem.

Stressing a receiver when bedding can be easily done IMO. There are still those that advocate using stockmakers' screws to tighten the action down into the epoxy bed- creating point-loads on the receiver and inducing stress; instead of using surgical tubing (or even electrical tap) to produce even pressure across the length of the receiver.

If the barrel pressure point doesn't solve the problem, I would suspect some aspect of the bedding job.

 

[Jimro]

Try bedding the barrel under the chamber, usually about the first 6 inches or so.

If that doesn't fix the issue, try slipping business cards under the tip of the stock until accuracy returns. Once you've got the thickness, fold some wax paper until it is just slightly thicker then put it in place.

Jimro

 

[mete]

I have a Kimber Montana , synthetic /stainless .It was not as free floating as it should be so I put a shim under the front of the receiver. Still not good enough so I looked at the hidden box magazine . It was too long ! I cut it down so when the screws were tightened the mag just snugged up .The I got my 1/2" groups .I don't know if it's practical to go for smaller groups with a light rifle and thin barrel

 

[hoghunting]

I recently tried ti inprove the accuracy in my Tikka T3 sporter in 223 by free floating

The T3 should be free floated from the factory. If you check the owner's manual it even states the barrel should be free floated. My last T3 Lite had polymer touching the barrel a few inches in front of the chamber. I cleared it out before shooting the rifle and it shoots sub moa like the others.

Did your friend do the bedding job on the synthetic stock or wood stock?

 

[T. O'Heir]

Sounds like the screws are coming loose. Lock-Tite 'em.
"...second hand synthetic stock..." That might be the issue, but the chamber area not being bedded is an issue. Needs to be bedded under the chamber area. You do not get a choice. The chamber is current completely unsupported.
"...the owner's manual it even states..." Irrelevant just the same. Floating a barrel is NOT a guarantee of anything.

 

[Slamfire]

Thankfully I bought a second hand synthetic stock for it, I generously free floated the barrel taking off the pressure points the stock had. A friend helped glass bed it, he had done 3 rifles in the past with good success. But I shot the rifle this weekend and it would shoot 2 or 3 shots extremely well, like clover leafs, but tben throw a few to the left about 4" or 5" at 100yards. I checked action and scope bolts and screws and im very certain the scope is good, as it was before i took it off to bed the rifle.

Thing like this are very puzzling. You are going to have to experiment with one thing and then another before it becomes obvious (hindsight is 100%) what the problem. Before you do anything to the stock, try a different scope. Scopes do go out at unpredictable times, and so do Red Dots. If you have irons, try a group with them and see if it is round. I have had scope bases get loose, but you said they checked them.

If the action is sliding in the stock, you will get left to right dispersal. But play with scopes first to eliminate that as a cause.

Something else, how is the rifling? I was at the range and a shooter was complaining about the bullets he was using. Walked down to the 100 yard targets and he had keyholes with a good brand of bullet. I forget which. A bud and myself looked at his rifle, everything was tight, the scope mounts OK. But Bud decided to dismount the upper from the lower (this was an AR action) and look down the barrel. It was smooth bore for most of its length! So, look at the rifling.

 

[burrhead]

Just so this is straight in my mind; you have a hunting rifle shooting consistent 0.75" groups and you wanted to FIX it? Well, I guess it's fixed.

 

[Clark]

Only on the internet are 0.75" groups a problem.
The other guys at the range would call it a miracle.

 

[trg42wraglefragle]

I bought a second stock, the same as the original to fo the bedding job just in case it didn't go right, in hindsight it was lucky i did.

The barrel on Tikkas are said to be free floated but tjey all have two small pressure points about a 1/3 of the length away from the action.
I think I will try adding pressure to the tip of the stock or where they originally were.

I didn't want to fix the rifle, as obviously it didn't need fixing, just wanted to see if i could squeeze anymore accuracy from it

 

[tobnpr]

Only on the internet are 0.75" groups a problem.
The other guys at the range would call it a miracle.

Especially with factory ammo- you ain't kidding...

OP, want more accuracy (though that's going to be difficult to do)- start handloading...it'll save you $$, even if you can't shrink the groups.

 

[hoghunting]

T. O'Heir: but the chamber area not being bedded is an issue. Needs to be bedded under the chamber area. You do not get a choice. The chamber is current completely unsupported.
"...the owner's manual it even states..." Irrelevant just the same. Floating a barrel is NOT a guarantee of anything.

Every Sako and T3 that I have or shot has a free floated barrel and shoots sub MOA, that's why Sako and Tikka have a MOA guarantee.

 

[HiBC]

I'll say it again.
Playing with pressure points or bedding under the chamber sometimes can give you a gain in accuracy.Maybe by tuning barrel harmonics.Or maybe by pre-loading the slop out of a substandard barrel receiver joint.

A fully free floated barrel delivers dependable,consistant accuracy.

However,remember the scope is mounted to the receiver.The barrel/receiver joint must be well fitted and stable.This may require truing the face of the receiver ring.

If there is a problem with the fit of the barrel to the receiver,the scope looks at the target,and the barrel rattles around.

That is where the voodoo patches come in.If a loose fencepost wobbles around in a hole,you can make it wobble less by putting your hand on it and pushing it till it stops.

And so a production,non-trued receiver ring /barrel fitup may show improvement by any number of methods to pre-load the rattle out .
And,by golly,it does show improvement!!Amazing!!.

The problem is the conclusion that gets jumped to.

Building the barrel/receiver joint as a foundation of accuracy beats stuffing bat wings and toad lips between the barrel and the stock.

Probably of equal importance is that the bedding job was done correctly.It is critical that tightening the guard screws does not distort the receiver.
When you draw up the screws,do they go from free and loose to tight in a sudden,solid way?Maybe 1/3 or 1/2 turn? Or do you draw them up 3/4 turn,or a full turn from free to tight?
Did you check to make sure the guard screws still have full clearance?Or might a dribble of epoxy have crawled in the hole?The release agent will allow the screw to be removed,but that contact on the screw will ruin accuracy.

An amateur bed job CAN come out great.I'm an amateur,and I have been successful.But I go through stages,and begin with establishing a strain free bed job on steelpillars ,with the rest of the receiver touching only air.
Then I go back and replace the air with epoxy.
And that suggestion about clearancing the mag box is valid.