The Accurate Reloading Forums
Re: Vertical stringing

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18 March 2004, 19:23
Loner
Re: Vertical stringing
Hi, Paul, Float the barrel with something other than rubber "O" rings. Use a 3/8 nylon washer. The purpose of the washer is to remove any contact of the forearm from the barrel. If you can accomplish this, then I wouldn't worry too much about over torqing the screw -- nice & firm should work. Also when shooting for groups, be sure that the swivle sling doesn't touch the benchrest. Handi's shoot better when you shoot the rifle on the rest just ahead of the barrel joint. This keeps things more stable with respect to different forearm pressure against the barrel. Keep in mind, that the groups you are getting are very good. Especially the .357 at 100yds. Remember it's a $200 rifle. I've seen a lot of guns costing into the thousands, that do not do much better than that.
Loner
19 March 2004, 04:14
aladin
Quote:

I have been fighting vertical stringing with my Handi rifle barrels. I have "floated" the barrels with "O" rings and tried different amounts of tightening on the forearm screw. It has also been suggested that the forearm should be tightened and then add 2 more turns. That is very hard to do with a synthetic forearm. I tried to tighten to 60 in-lbs with a 1/4" drive torque wrench, but the screw just wants to pull through the synthetic material.



With multiple barrels, the POI will change if the screw isn't tightened the same amount each time the barrel is changed.



The best groups so far have been 200 gr Sierra JSP with 14.0 gr Lil'Gun in the .357 Mag barrel (1 1/4" at 100 yards) with the screw snugged down and then backed off 1/2 turn. The .223 will shoot a couple of loads at around an inch at 100 yards with the screw backed off 1/2 turn. I don't know that any of these groups are repeatable unless I just happen to get the tension on the forearm the same as before.



Any suggestions?





Yes-- forget the washers. I ran extensive testing with a Buffalo Classic and found tension induced into the barrel from the screw was the overall problem. Granted the BC's barrel is slightly more 'whippy' per hole size vs barrel profile, but any tension added to the barrel at that point is going to change impacts as the barrel temp changes.



Bedding the forearm to the barrel works. I added three sections of glass, two between the stud and action-- and now the screw just holds the wood in place. And the gun shoots.. consistently maintaining impact point.



Some of the other factors causing vertical are recoil variation-- how you hold the gun, neck tension of the bullet and wide ES's per powder choice.



http://www.accuratereloading.com/ubbthreads/showflat.php?Cat=&Number=598918&page=0&view=collapsed&sb=5&o=21&fpart=1
19 March 2004, 06:45
Paul5388
The reason for the rubber "O" rings was the abundance of VW case "O" rings on hand! I'll have to scrounge around and see if I have any nylon washers. May end up at the hardware store for those.

I normally rest the Handi on a Caldwell rest at the barrel hinge pin, which is almost up against the trigger guard. My off hand is on the comb of the stock. All of this in an effort to reduce pressure on the barrel.

I posted a vertical string group on www.handloads.com in the ".357 Mag rifle" thread that wasn't as extreme as some I have had. It was about a 3" group (can I call that a group?) in a vertical line. I have had some strung vertically in the 6" neighborhood!

I think I will try a wooden forearm today and see if the pressure can be regulated on the screw. That should give some indication on the direction I need to go in.
19 March 2004, 11:14
Paul5388
I posted new targets here with just a change in forearms. I used wood that was just snugged down instead of the synthetic forearm. Even with wood I can't actually tighten the screw, because the screw head keeps reaming out the hole.

I guess the next step will be using a shotgun forearm with a longer screw.