Home Forums Hunting & Shooting Hunting Rifles Forend flex

The accuracy of my stainless/synth. Ruger .308 has deteriorated markedly .. I'm getting a lot of fliers which spreads the groups to around 3" at 100yds.

The barrel has only had a few hundred rounds

The only thing that I can think offhand is that by floating the barrel the flex in the forend may be the causing the problem.

Could the flex be a problem when shooting off the bench?

Cheers,
DBT

Sure it can, you need to make sure that it doesn't touch the barrel. One way to do this is to place your hand at the forend tip while gripping the barrel at the same time. Squeeze and if the barrel touches you may have found the problem. I would suggest at least .020 clearance(sides of the forend) in the barrel channel and about .030 under the barrel at the forend tip down towards the bedding. You can get a pretty good "measurement" by adding electrical tape to the barrel. Each strip is about .005" thick. Do the math on the number of pieces and you'll have some idea of how much to use. Adjust from there. You may have to go to .030" all the way around.

I'm assuming you have the action bedded. If not, try that first. Remember, removing more stock material than needed will be a sure sign of amateurish job. Take your time and it should work out just fine.

Another way to do it is to place a piece of tape on the forend (see pic) and sand to the edge. Doesn't work quite as well, but easier to visualize. The tape I use is metallic and used to seal duct work. Very sticky, yet easy to remove and leaves no residue. Unlike masking tape which seems to come loose from the stock-be it wood or plastic.

One of the reasons for floating the barrel is so that the forend does not have any influence. If the rifle shot well for a time after you floated it, then I'd look elsewhere for the problem.

Loose action screws come to mind.
Same for scope mounts and rings.
Possible binding from the mag box on the bottom of the reciever.
Have you changed your ammo parameters at all?
Have you cleaned it lately?
Did you do a good copper removal?

JimF

Yes, for several POSSIBLE reasons, which may or may not be an issue. Do you have a set screw modification on the forend hangar? Is your barrel really completely floated, or does the forend perhaps touch a bit when the bags are forward, or near the end? Have you tried shooting the gun with your hand holding the forend rather than resting it on bags?

The questions are specific to the #1 and #3, their effect is often pronounced. IF your answers were yes and yes to the first two, adjust the tension to zero on the tension screw, or completely relieve the forend contact. If No to the last, try it and see what happens.

I've seen #1's shift POI over 12 MOA due to change of tension in the forend attach screw. They can be persnickity, but the day it gets ironed out is a happy day. One more question: If it was shooting good before why'd you fix it? Mebbe you should arrange for a forend pad again?

Sorry I should have said that it is a short action 77.

There is plenty of clearence between the barrel and the forend,perhaps I gave it too much.

I'm thinking that with the forend resting on the sandbag the excessive flex is shifting the point of impact when firing?

Was the accuracy OK before you floated it?

Did it shoot well for a while after you floated it??

Or....did the accuracy go south immediately after???

JimF

"Was the accuracy OK before you floated it?"


Roughly 1" at 100yards,I was happy with that, but then I also got at least one flier that would blow the group. Annoying,so I tried the free floating.



"Or....did the accuracy go south immediately after???"

JimF

That is what happened...it doesn't seem to work well with the floating barrel for whatever reason.

Given this info I'd guess that there is a problem with the action bedding job, but that's a guess on my part. You might want to try inserting some card stock between the forend and barrel to create a new pressure point. See how it shoots with about 5# of pressure on the forend/barrel interface. I know it takes you back to where you started, but if it shoots reasonably well like that I think you need to redo the bedding job.

I encountered the same problem with my Model 70 in 300 Win Mag with a floated Obermeyer No. 2 barrel at 24 inches. I learned that this particular barrel because it was so skinny (and possible stress problems) had distinct vibration problems. My gunsmith suggested that I put pressure on the barrel from the stock at a point about 1/2" behind the forend tip at about 3 to 4 lbs. as measured with a trigger-pull guage. I did and this rifle now shoots sub-MOA. This might not work for anyone else, but it worked for me. You can simulate this to see if it might work by placing business cards at this point for pressure as a trial.

Thanks for the imput guys.
It's busy at work and I only get to the range once a month but I'll try a shim under the forend tip first and take it from there.

Shooting!... I love it, but it can be frustrating.

Cheers,
DBT