Help Wanted - Accuracy Issues With New Stock

[strousek]

Years ago a won a Ruger American .243 at a banquet. Shot the gun maybe once and put it in the safe and forgot all about it. This year my daughter completed her hunters safety so I decided I needed to get her a rifle and the .243 seemed about right. I took the rifle out with the factory stock on it, and though it wasn't shooting sub 1/2 MOA, it shot extremely well with factory ammo.

Given that my daughter is only 8 the LOP on the factory stock is just far too long. I purchased a laminated Boyd's stock and cut the but down and did a little reshaping to make a good youth rifle. I did this same conversion on a 6.5 CM Kimber rifle for my son a couple years back. This rifle shoots the exact same sub MOA with both the factory stock as well as the modified Boyds stock. I have swapped them back and forth several times a year and never had any issues or differential in accuracy.

The Ruger however is shooting absolutely terrible in the new Boyd's stock. It went from about a 1" 3 shot group at 100 yards to nearly 4" groups. Same ammo, same shooter, relatively same weather conditions, same everything except the stock. I used the provided epoxy and bedded the lugs in the new Boyds per the instructions. There is no barrel contact on the new stock and everything seems to be free floating and tightened properly. I went ahead and grabbed 2 more rifles out of the safe and shot them to make sure the issue wasn't me. They both shot flawlessly so I feel like the new stock is truly the issue with the .243 rifle.

Looking for suggestions from you guys to see why the factory stock would shoot so much better than the new Boyd's and what I can try and tweak with to get the accuracy back.

 

[littlewolf]

Mag box or bolt binding? Different thread depths vs old stock? Does it still shoot tight groups if you replace the original stock (to rule out scope issue)?

 

[MuleyFever]

Something may be putting force on the action. You could try different torque values on the action screws. Make sure they are the right length too.

 

[Wrench]

Put a dab of grease on the front screw. Torque it up....if the grease on the end of the screw is pushed out of the way....it's touching the bolt and can destroy accuracy.

If the bottom metal binds on the mag box it'll do nothing good too. The action touching the trigger housing or anywhere other than the bedding surfaces will cause issues.

4moa is typically scope issues.....but if you're flexing the action with bind it can do some crazy stuff.

 

[TaperPin]

Ditto what Wrench said. I’d start by swapping the scope and retorquing the scope mount screws.

 

[strousek]

I never touched the scope when moving from one stock to the other. So if the Vortex Viper scope shoots on one platform and never gets touched I would assume it would shoot the same on the other stock? Everything in the scope mounting is solid and I have had no issues tracking with this scope before.

I did however swap out the standard mag for an AR style mag in the new stock. The factory cheap mag was very sloppy and would tip forward and not cycle. The AR mag metal is pretty tight and the mag is pressed up pretty hard against the bottom of the action to get it to seat fully. That very well may be my issue.

I will check the screws as well however they don't seem to be too long or bottoming out by any means. The screws came with the Boyd's stock kit and appeared to be the proper length. Maybe getting 3/8" of thread on each screw into the action.

I will work with trying to relieve the mag well pressure on the action as a starting point. Thank you guys for the help.

 

[HandgunHTR]

I never touched the scope when moving from one stock to the other. So if the Vortex Viper scope shoots on one platform and never gets touched I would assume it would shoot the same on the other stock? Everything in the scope mounting is solid and I have had no issues tracking with this scope before.

Vortex scopes have a long history of working, until they don't. It also looks as if you are using aluminum rings. Just because you didn't touch anything doesn't mean that the scope or mounting system didn't change.

The first thing I would do is put it back in the factory stock and shoot it in the configuration that you stated shot well. If it shoots well again, you can rule out the scope and mounts. Then use the new mag in that setup to rule that out as well. If it is not either of those, then you can start messing with the new stock as it is the most likely culprit.

What torque do you have the action screws tightened to?

 

[strousek]

Vortex scopes have a long history of working, until they don't. It also looks as if you are using aluminum rings. Just because you didn't touch anything doesn't mean that the scope or mounting system didn't change.

The first thing I would do is put it back in the factory stock and shoot it in the configuration that you stated shot well. If it shoots well again, you can rule out the scope and mounts. Then use the new mag in that setup to rule that out as well. If it is not either of those, then you can start messing with the new stock as it is the most likely culprit.

What torque do you have the action screws tightened to?

This weekend I will put the action back on the factory stock and shoot it. The AR style mag is not compatible with the factory stock so we cant rule that out by installing it in both stocks. But I can easily shoot the rifle without the mag in place. I know when the mag is pressed all the way in it sits hard against the bottom of the action.

Action screws are tightened to 60 lbs.

I am going to take all these ideas and do some tinkering around this weekend with it. Thank you everyone. I will follow up next week with my findings.

 

[strousek]

Sorry for the late check in on this one. Between bad weather and kids sports it took me a bit more time than expected to get the rifle back out. But I am happy to report that with all of your guys help we should have the issue solved.

I found that the new magazine well was in fact putting pressure on the bottom of the action. I had a minimal amount of epoxy that pushed out between the mag well and the action so when the action screws were snugged up it was putting pressure up on the action. The new after market magazine was also very snug and putting an upward pressure on the end of the action when fully seated.

Before I did anything I took 3 shots off the bench. Those are circled in red in the picture below. I then filed off all the extra epoxy in the stock. I also filed down the magazine where it was touching the action. I used some inletting black to make sure that when the magazine was seated properly there was no contact with the action at all. Put the whole thing back together torqueing the action screws back to 50 lbs. and put 3 more rounds through it.

Well the proof is in the pudding as the next 3 shots taken are in the yellow star. This group is consistent with the shot grouping I was getting from the factory stock so I am pleased. Honestly I had no idea that such marginal pressure from the plastic magazine and slight tension on the well could cause such an issue but it sure seems like that was the problem. Again thank you all for your help.

 

[ResearchinStuff]

realistically, you need to shoot a bunch more shots to reach any conclusion. both of those groups could easily be 3 shot samples from your 30 shot cone.